[Federal Register Volume 87, Number 42 (Thursday, March 3, 2022)]
[Rules and Regulations]
[Pages 11934-11950]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-04374]


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NUCLEAR REGULATORY COMMISSION

10 CFR Part 50

[NRC-2017-0025]
RIN 3150-AJ94


Approval of American Society of Mechanical Engineers' Code Cases

AGENCY: Nuclear Regulatory Commission.

ACTION: Final rule.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is amending its 
regulations to incorporate by reference revisions of three regulatory 
guides to approve new, revised, and reaffirmed code cases published by 
the American Society of Mechanical Engineers. The NRC is also 
incorporating by reference one NRC NUREG associated with a condition on 
one of the regulatory guides. This action allows nuclear power plant 
licensees and applicants for construction permits, operating licenses, 
combined licenses, standard design certifications, standard design 
approvals, and manufacturing licenses to use the code cases listed in 
these regulatory guides as voluntary alternatives to engineering 
standards for the construction, inservice inspection, and inservice 
testing of nuclear power plant components. These engineering standards 
are set forth in the American Society of Mechanical Engineers' Boiler 
and Pressure Vessel Codes and American Society of Mechanical Engineers' 
Operation and Maintenance Codes, which are currently incorporated by 
reference into the NRC's regulations. Further, this final rule 
announces the availability of a related regulatory guide, not 
incorporated by reference into the NRC's regulations, that lists code 
cases that the NRC has not approved for use.

DATES: This final rule is effective on April 4, 2022. The incorporation 
by reference of certain publications listed in the regulation is 
approved by the Director of the Federal Register as of April 4, 2022.

ADDRESSES: Please refer to Docket ID NRC-2017-0025 when contacting the 
NRC about the availability of information for this action. You may 
obtain publicly-available information related to this action by any of 
the following methods:
     Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025. Address 
questions about NRC dockets to Dawn Forder; telephone: 301-415-3407; 
email: [email protected]. For technical questions, contact the 
individuals listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS 
Search.'' For problems with ADAMS, please contact the NRC's Public 
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or 
by email to [email protected]. For the convenience of the reader, 
instructions about obtaining materials referenced in this document are 
provided in the ``Availability of Documents'' section.
     NRC's PDR: You may examine and purchase copies of public 
documents, by appointment, at the NRC's PDR, Room P1 B35, One White 
Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. To make 
an appointment to visit the PDR, please send an email to 
[email protected] or call 1-800-397-4209 or 301-415-4737, between 
8:00 a.m. and 4:00 p.m. (ET), Monday through Friday, except Federal 
holidays.
     Technical Library: The Technical Library, which is located 
at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland 
20852, is open by appointment only. Interested parties may make 
appointments to examine documents by contacting the NRC Technical 
Library by email at [email protected] between 8:00 a.m. and 4:00 
p.m. (ET), Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Martha Barillas, Office of Nuclear 
Material Safety and Safeguards; telephone: 301-415-2760, email: 
[email protected]; or Bruce Lin, Office of Nuclear Regulatory 
Research, telephone: 301-415-2446; email: [email protected]. Both are 
staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001.

SUPPLEMENTARY INFORMATION:

Executive Summary

A. Need for the Regulatory Action

    The purpose of this regulatory action is to incorporate by 
reference into the NRC's regulations the latest revisions of three 
regulatory guides (RGs). This regulatory action is also incorporating 
by reference, NUREG-2228, ``Weld Residual Stress Finite Element 
Analysis Validation: Part II--Proposed Validation Procedure,'' that is 
associated with a condition in one of the regulatory guides. The three 
RGs identify new,

[[Page 11935]]

revised, and reaffirmed code cases published by the American Society of 
Mechanical Engineers (ASME), which the NRC has determined are 
acceptable for use as voluntary alternatives to compliance with certain 
provisions of the ASME Boiler and Pressure Vessel Code (BPV Code) and 
the ASME Code for Operation and Maintenance of Nuclear Power Plants, 
Division 1, OM Code: Section IST (OM Code), currently incorporated by 
reference into the NRC's regulations.

B. Major Provisions

    The three RGs that the NRC is incorporating by reference are RG 
1.84, ``Design, Fabrication, and Materials Code Case Acceptability, 
ASME Section III,'' Revision 39; RG 1.147, ``Inservice Inspection Code 
Case Acceptability, ASME Section XI, Division 1,'' Revision 20; and RG 
1.192, ``Operation and Maintenance [OM] Code Case Acceptability, ASME 
OM Code,'' Revision 4. The NRC is also incorporating by reference 
NUREG-2228, which provides the procedure for validating the weld 
residual stress analysis methodology associated with ASME Code Case N-
847. This final rule allows nuclear power plant licensees and 
applicants for construction permits, operating licenses, combined 
licenses, standard design certifications, standard design approvals, 
and manufacturing licenses to use the code cases newly listed in these 
revised RGs as voluntary alternatives to engineering standards for the 
construction, inservice inspections, and inservice testing of nuclear 
power plant components. In this document, the NRC also notifies the 
public of the availability of RG 1.193, ``ASME Code Cases Not Approved 
for Use,'' Revision 7. This document lists code cases that the NRC has 
not approved for generic use and is not incorporated by reference into 
the NRC's regulations.
    The NRC prepared a regulatory analysis to determine the expected 
quantitative costs and benefits of this final rule, as well as 
qualitative factors to be considered in the NRC's rulemaking decision. 
The analysis concluded that this rule results in net savings to the 
industry and the NRC. As shown in Table 1, the estimated total net 
benefits relative to the regulatory baseline range from approximately 
$5.86 million (7-percent net present value) to $6.67 million (3-percent 
net present value).

                                          Table 1--Cost Benefit Summary
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                                                                            Total averted costs (costs)
                                                                 -----------------------------------------------
                            Attribute                                             7% Net present  3% Net present
                                                                   Undiscounted        value           value
----------------------------------------------------------------------------------------------------------------
Industry Implementation.........................................              $0              $0              $0
Industry Operation..............................................       4,920,000       3,920,000       4,450,000
                                                                 -----------------------------------------------
    Total Industry Costs........................................       4,920,000       3,920,000       4,450,000
NRC Implementation..............................................               0               0               0
NRC Operation...................................................       2,460,000       1,940,000       2,220,000
                                                                 -----------------------------------------------
    Total NRC Costs.............................................       2,460,000       1,940,000       2,220,000
                                                                 -----------------------------------------------
        Net.....................................................       7,380,000       5,860,000       6,670,000
----------------------------------------------------------------------------------------------------------------

    The regulatory analysis also considered the following qualitative 
considerations: (1) Flexibility and decreased uncertainty for licensees 
when making modifications or preparing to perform inservice inspection 
or inservice testing; (2) consistency with the provisions of the 
National Technology Transfer and Advancement Act of 1995, which 
encourages Federal regulatory agencies to consider adopting voluntary 
consensus standards as an alternative to de novo agency development of 
standards affecting an industry; (3) consistency with the NRC's policy 
of evaluating the latest versions of consensus standards in terms of 
their suitability for endorsement by regulations and regulatory guides; 
and (4) consistency with the NRC's goal to harmonize with international 
standards to improve regulatory efficiency for both the NRC and 
international standards groups.
    The regulatory analysis concludes that this final rule should be 
adopted because it is justified when integrating the cost-beneficial 
quantitative results and the positive and supporting nonquantitative 
considerations in the decision. For more information, please see the 
final regulatory analysis as indicated in Section XVI, ``Availability 
of Documents,'' of this document.

Table of Contents

    I. Background
    II. Discussion
    III. Opportunities for Public Participation
    IV. Public Comment Analysis
    V. Section-by-Section Analysis
    VI. Regulatory Flexibility Certification
    VII. Regulatory Analysis
    VIII. Backfitting and Issue Finality
    IX. Plain Writing
    X. Environmental Assessment and Final Finding of No Significant 
Environmental Impact
    XI. Paperwork Reduction Act
    XII. Congressional Review Act
    XIII. Voluntary Consensus Standards
    XIV. Incorporation by Reference-Reasonable Availability to 
Interested Parties
    XV. Availability of Guidance
    XVI. Availability of Documents

I. Background

    The ASME develops and publishes the ASME BPV Code, which contains 
requirements for the design, construction, and inservice inspection 
examination of nuclear power plant components, and the ASME OM Code,\1\ 
which contains requirements for inservice testing of nuclear power 
plant components. In response to BPV and OM Code user requests, the 
ASME develops code cases that provide voluntary alternatives to BPV and 
OM Code requirements under special circumstances.
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    \1\ The editions and addenda of the ASME Code for Operation and 
Maintenance of Nuclear Power Plants have had different titles from 
2005 to 2017 and are referred to as the ``OM Code'' collectively in 
this rule.
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    The NRC approves the ASME BPV and OM Codes in Sec.  50.55a, ``Codes 
and standards,'' of title 10 of the Code of Federal Regulations (10 
CFR) through the process of incorporation by reference. As such, each 
provision of the ASME Codes incorporated by reference into and mandated 
by Sec.  50.55a

[[Page 11936]]

constitutes a legally-binding NRC requirement imposed by rule. As noted 
previously, the ASME code cases, for the most part, represent 
alternative approaches for complying with provisions of the ASME BPV 
and OM Codes. Accordingly, the NRC periodically amends Sec.  50.55a to 
incorporate by reference the NRC's RGs listing approved ASME code cases 
that may be used as voluntary alternatives to the BPV and OM Codes.\2\
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    \2\ See Federal Register final rule, ``Incorporation by 
Reference of ASME BPV and OM Code Cases'' (68 FR 40469; July 8, 
2003).
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    This final rule is the latest in a series of rules that incorporate 
by reference new versions of several RGs identifying new, revised, and 
reaffirmed,\3\ and unconditionally or conditionally acceptable ASME 
code cases that the NRC approves for use. In developing these RGs, the 
NRC reviews the ASME BPV and OM code cases, determines the 
acceptability of each code case, and publishes its findings in the RGs. 
The RGs are revised periodically as new code cases are published by the 
ASME. The NRC incorporates by reference the RGs listing acceptable and 
conditionally acceptable ASME code cases into Sec.  50.55a. The NRC 
published a final rule dated March 16, 2020, that incorporated by 
reference into Sec.  50.55a the most recent versions of the RGs, which 
are RG 1.84, ``Design, Fabrication, and Materials Code Case 
Acceptability, ASME Section III,'' Revision 38; RG 1.147, ``Inservice 
Inspection Code Case Acceptability, ASME Section XI, Division 1,'' 
Revision 19; and RG 1.192, ``Operation and Maintenance Code Case 
Acceptability, ASME OM Code,'' Revision 3.
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    \3\ Code Cases are categorized by the ASME as one of three 
types: New, revised, or reaffirmed. A new Code Case provides for a 
new alternative to specific the ASME Code provisions or addresses a 
new need. The ASME defines a revised Code Case to be a revision 
(modification) to an existing Code Case to address, for example, 
technological advancements in examination techniques or to address 
NRC conditions imposed in one of the RGs that have been incorporated 
by reference into Sec.  50.55a. The ASME defines ``reaffirmed'' as 
an OM Code Case that does not have any change to technical content, 
but includes editorial changes.
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II. Discussion

    This final rule incorporates by reference NUREG-2228 and the latest 
revisions of the NRC's RGs that list the ASME BPV and OM code cases 
that the NRC finds to be acceptable, or acceptable with NRC-specified 
conditions (``conditionally acceptable''). Regulatory Guide 1.84, 
Revision 39, supersedes the incorporation by reference of Revision 38; 
RG 1.147, Revision 20, supersedes the incorporation by reference of 
Revision 19; and RG 1.192, Revision 4, supersedes the incorporation by 
reference of Revision 3.
    The ASME code cases that are the subject of this final rule are the 
new and revised Section III and Section XI code cases as listed in 
Supplements 0 through 7 to the 2015 Edition of the ASME BPV Code, 
Supplements 0 through 7 to the 2017 Edition of the ASME BPV Code, 
Supplements 0 and 1 to the 2019 Edition of the ASME BPV Code, and the 
OM code cases listed in the 2020 Edition of the ASME OM Code and on the 
ASME Codes & Standards (C&S) Connect website.\4\
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    \4\ The ASME included code cases with the published editions and 
addenda of the OM Code through the 2017 Edition. Starting with the 
2020 Edition, code cases were not published with the OM Code; an 
applicability index for ASME OM code cases was published. Code cases 
are available on the ASME website under the ``O&M CASES'' tab in the 
left-hand column at https://go.asme.org/OMcommittee.
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    The latest editions and addenda of the ASME BPV and OM Codes that 
the NRC has approved for use are referenced in Sec.  50.55a. The ASME 
also publishes code cases that provide alternatives to existing Code 
requirements that the ASME developed and approved. This final rule 
incorporates by reference the most recent revisions of RGs 1.84, 1.147, 
and 1.192, which allow nuclear power plant licensees, and applicants 
for combined licenses, standard design certifications, standard design 
approvals, and manufacturing licenses under the regulations that govern 
license certifications, to use the code cases listed in these RGs as 
suitable alternatives to the ASME BPV and OM Codes for the 
construction, inservice inspections, and inservice testing of nuclear 
power plant components. Because the NRC is requiring the use of NUREG-
2228 within a condition on Code Case N-847, the NRC is also 
incorporating by reference NUREG-2228. The ASME publishes the OM Code 
Cases and lists the code cases in the ASME OM Code edition and on the 
ASME C&S Connect website. In contrast, the ASME publishes BPV code 
cases in a separate document and at a different time than the ASME BPV 
code editions. This final rule identifies the code cases by the edition 
of the ASME BPV Code or ASME OM Code under which they were published by 
the ASME.
    The following general guidance applies to the use of the ASME code 
cases approved in the latest versions of the RGs that are incorporated 
by reference into Sec.  50.55a as part of this final rule. 
Specifically, the use of the code cases listed in the latest versions 
of RGs 1.84, 1.147, and 1.192 are acceptable with the specified 
conditions when implementing the editions and addenda of the ASME BPV 
and OM Codes incorporated by reference in Sec.  50.55a.
    The approval of a code case in the NRC's RGs constitutes acceptance 
of its technical position for applications that are not precluded by 
regulatory or other requirements or by the recommendations in these 
RGs. The applicant or licensee is responsible for ensuring that use of 
the code case does not conflict with regulatory requirements or 
licensee commitments. The code cases listed in the RGs are acceptable 
for use within the limits specified in the code cases. If the RG states 
an NRC condition on the use of a code case, then the NRC condition 
supplements and does not supersede any condition(s) specified in the 
code case, unless otherwise stated in the NRC condition.
    The ASME code cases may be revised for many reasons (e.g., to 
incorporate operational examination and testing experience and to 
update material requirements based on research results). On occasion, 
an inaccuracy in an equation is discovered or an examination, as 
practiced, is found not to be adequate to detect a newly discovered 
degradation mechanism.
    Therefore, when an applicant or a licensee initially implements a 
code case, Sec.  50.55a requires that the applicant or the licensee 
implement the most recent version of that code case, as listed in the 
RGs incorporated by reference. Code cases superseded by revision are no 
longer acceptable for new applications unless otherwise indicated.
    Section III of the ASME BPV Code applies to new construction (i.e., 
the edition and addenda to be used in the construction of a plant are 
selected based on the date of the construction permit and are not 
changed thereafter, except voluntarily by the applicant or the 
licensee). Hence, if a Section III code case is implemented by an 
applicant or a licensee and a later version of the code case is 
incorporated by reference into Sec.  50.55a and listed in the RG, the 
applicant or licensee may use either version of the code case (subject, 
however, to whatever change requirements apply to its licensing basis 
(e.g., Sec.  50.59)).
    A licensee's inservice inspection and inservice testing programs 
must be updated every 10 years to the latest edition and addenda of the 
ASME BPV Code, Section XI, and the OM Code, respectively, that were 
incorporated by reference into Sec.  50.55a and in effect 18

[[Page 11937]]

months prior to the start of the next inspection and testing interval. 
Licensees that were using a code case prior to the effective date of 
its revision may continue to use the previous version for the remainder 
of the 120-month inservice inspection or inservice testing interval. 
This relieves licensees of the burden of having to update their 
inservice inspection or inservice testing program each time a code case 
is revised by the ASME and approved for use by the NRC. Code cases 
apply to specific editions and addenda, and code cases may be revised 
if they are no longer accurate or adequate, so licensees choosing to 
continue using a code case during the subsequent inservice inspection 
or inservice testing interval must implement the latest version 
incorporated by reference into Sec.  50.55a and listed in the RGs.
    The ASME may annul code cases that are no longer required, are 
determined to be inaccurate or inadequate, or have been incorporated 
into the BPV or OM Codes. A code case may be revised, for example, to 
incorporate user experience. The older or superseded version of the 
code case cannot be applied by the licensee or applicant unless it was 
applied prior to being annulled or superseded.

    If an applicant or a licensee applied a code case before it was 
listed as superseded, the applicant or the licensee may continue to 
use the code case until the applicant or the licensee updates its 
construction Code of Record (in the case of an applicant, updates 
its application) or until the licensee's 120-month inservice 
inspection or inservice testing update interval expires, after which 
the continued use of the code case is prohibited unless NRC 
authorization is given under Sec.  50.55a(z). If a code case is 
incorporated by reference into Sec.  50.55a and later a revised 
version is issued by the ASME because experience has shown that the 
design analysis, construction method, examination method, or testing 
method is inadequate, the NRC will amend Sec.  50.55a and the 
relevant RG to remove the approval of the superseded code case. 
Applicants and licensees should not begin to implement such 
superseded code cases in advance of the rulemaking.

A. ASME Code Cases Approved for Unconditional Use

    The code cases discussed in Table I are new, revised, or reaffirmed 
code cases in which the NRC approves for use without conditions. The 
table identifies the regulatory guide listing the applicable code case 
that the NRC approves for use.

                                         Table I--Acceptable Code Cases
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             Code Case No.                      Published with supplement                      Title
----------------------------------------------------------------------------------------------------------------
                                   Boiler and Pressure Vessel Code Section III
                                         (Addressed in RG 1.84, Table 1)
----------------------------------------------------------------------------------------------------------------
N-249-17..............................  0 (2019 Edition)........................  Additional Materials for
                                                                                   Subsection NF, Classes 1, 2,
                                                                                   3, and MC Supports Fabricated
                                                                                   without Welding, Section III,
                                                                                   Division 1.
N-539-1...............................  0 (2017 Edition)........................  UNS N08367 in Class 2 and 3
                                                                                   Valves, Section III, Division
                                                                                   1.
N-692-1...............................  6 (2015 Edition)........................  Use of Standard Welding
                                                                                   Procedures, Section III,
                                                                                   Division 1.
N-721-1...............................  5 (2017 Edition)........................  Alternative Rules for Linear
                                                                                   Piping Supports, Section III,
                                                                                   Division 1.
N-801-3...............................  1 (2017 Edition)........................  Rules for Repair of N-Stamped
                                                                                   Class 1, 2, and 3 Components,
                                                                                   Section III, Division 1.
N-822-4...............................  7 (2015 Edition)........................  Application of the ASME
                                                                                   Certification Mark, Section
                                                                                   III, Divisions 1, 2, 3, and
                                                                                   5.
N-855.................................  2 (2015 Edition)........................  SB-148 C95800 Valves for Class
                                                                                   3 Construction, Section III,
                                                                                   Division 1.
N-856.................................  2 (2015 Edition)........................  SA-494 Grade CW-12MW (UNS
                                                                                   N30002) Nickel Alloy Castings
                                                                                   for Construction of NPS 2\1/
                                                                                   2\ and Smaller Flanged Valves
                                                                                   for Class 3 Construction,
                                                                                   Section III, Division 1.
N-859.................................  5 (2015 Edition)........................  Construction of ASME B16.9
                                                                                   Wrought Buttwelding Fittings
                                                                                   and ASME B16.11 Forged
                                                                                   Fittings Made From SB-366 UNS
                                                                                   N04400 Material for Section
                                                                                   III, Class 3 Construction,
                                                                                   Section III, Division 1.
N-863-1...............................  1 (2017 Edition)........................  Post Weld Heat Treatment
                                                                                   (PWHT) of Valve Seal Welds
                                                                                   for P4 and P5A Materials,
                                                                                   Section III, Division 1.
N-866.................................  0 (2017 Edition)........................  Alternative Materials for
                                                                                   Construction of Section III,
                                                                                   Class 2 Vessels, Section III,
                                                                                   Division 1.
N-870-1...............................  4 (2017 Edition)........................  Rules for the Elimination of
                                                                                   External Surface Defects on
                                                                                   Class 1, 2, and 3 Piping,
                                                                                   Pumps, or Valves After
                                                                                   Component Stamping and Prior
                                                                                   to Completion of the N-3 Data
                                                                                   Report, Section III, Division
                                                                                   1.
N-879.................................  1 (2017 Edition)........................  Use of Micro-Alloyed Carbon
                                                                                   Steel Bar in Patented
                                                                                   Mechanical Joints and
                                                                                   Fittings, Classes 1, 2, and
                                                                                   3, Section III, Division 1.
N-884.................................  0 (2019 Edition)........................  Procedure to Determine Strain
                                                                                   Rate for Use with the
                                                                                   Environmental Fatigue Design
                                                                                   Curve Method and the
                                                                                   Environmental Fatigue
                                                                                   Correction Factor, Fen,
                                                                                   Method as Part of an
                                                                                   Environmental Fatigue
                                                                                   Evaluation for Components
                                                                                   Analyzed per the NB-3200
                                                                                   Rules, Section III, Division
                                                                                   1.
N-887.................................  6 (with errata issued in 3/19E).........  Alternatives to the
                                                                                   Requirements of NB-4424.2(a),
                                                                                   Figure NB-4250-2, and Figure
                                                                                   NB-4250-3, Section III,
                                                                                   Division 1.
N-891.................................  0 (2019 Edition)........................  Alternative Requirements to
                                                                                   Appendix XXVI, XXVI-2400,
                                                                                   XXVI-4130, and XXVI-4131 for
                                                                                   Inspection and Repair of
                                                                                   Indentations for Polyethylene
                                                                                   Pipe and Piping Components,
                                                                                   Section III, Division 1.
----------------------------------------------------------------------------------------------------------------
                                   Boiler and Pressure Vessel Code Section XI
                                        (Addressed in RG 1.147, Table 1)
----------------------------------------------------------------------------------------------------------------
N-561-3...............................  0 (2019 Edition)........................  Alternative Requirements for
                                                                                   Wall Thickness Restoration of
                                                                                   Class 2 and High Energy Class
                                                                                   3 Carbon Steel Piping,
                                                                                   Section XI, Division 1.
N-638-10..............................  1 (2019 Edition)........................  Similar and Dissimilar Metal
                                                                                   Welding Using Ambient
                                                                                   Temperature Machine GTAW
                                                                                   Temper Bead Technique,
                                                                                   Section XI, Division 1.
N-653-2...............................  2 (2015 Edition)........................  Qualification Requirements for
                                                                                   Full Structural Overlaid
                                                                                   Wrought Austenitic Piping
                                                                                   Welds, Section XI, Division
                                                                                   1.
N-702-1...............................  1 (2019 Edition)........................  Alternative Requirements for
                                                                                   Boiling Water Reactor (BWR)
                                                                                   Nozzle Inner Radius and
                                                                                   Nozzle-to-Shell Welds,
                                                                                   Section XI, Division 1.
N-716-2...............................  0 (2017 Edition)........................  Alternative Piping
                                                                                   Classification and
                                                                                   Examination Requirements,
                                                                                   Section XI, Division 1.

[[Page 11938]]

 
N-768.................................  0 (2019 Edition)........................  Alternative Volumetric
                                                                                   Coverage Requirements for
                                                                                   Ultrasonic Examination of
                                                                                   Class 1 and 2 Pressure Vessel
                                                                                   Weld Joints Greater Than 2
                                                                                   in. (50 mm) in Thickness,
                                                                                   Section XI, Division 1.
N-786-3...............................  1 (2017 Edition)........................  Alternative Requirements for
                                                                                   Sleeve Reinforcement of Class
                                                                                   2 and 3 Moderate Energy
                                                                                   Carbon Steel Piping, Section
                                                                                   XI, Division 1.
N-789-3...............................  1 (2017 Edition)........................  Alternative Requirements for
                                                                                   Pad Reinforcement of Class 2
                                                                                   and 3 Moderate Energy Carbon
                                                                                   Steel Piping for Raw Water
                                                                                   Service, Section XI, Division
                                                                                   1.
N-809.................................  2 (2015 Edition)........................  Reference Fatigue Crack Growth
                                                                                   Rate Curves for Austenitic
                                                                                   Stainless Steels in
                                                                                   Pressurized Reactor Water
                                                                                   Environments, Section XI,
                                                                                   Division 1.
N-845-1...............................  6 (2015 Edition)........................  Qualification Requirements for
                                                                                   Bolts and Studs, Section XI,
                                                                                   Division 1.
N-848-1...............................  0 (2017 Edition)........................  Alternative Characterization
                                                                                   Rules for Quasi-Laminar
                                                                                   Flaws, Section XI, Division
                                                                                   1.
N-851.................................  0 (2015 Edition)........................  Alternate Method for
                                                                                   Establishing the Reference
                                                                                   Temperature for Pressure
                                                                                   Retaining Materials, Section
                                                                                   XI, Division 1.
N-858.................................  2 (2017 Edition)........................  Alternative Volumetric
                                                                                   Coverage Requirements for
                                                                                   Ultrasonic Examination of
                                                                                   Class 1 Nozzle-to-Vessel
                                                                                   Welds, Section XI, Division
                                                                                   1.
N-865.................................  2 (2017 Edition)........................  Alternative Requirements for
                                                                                   Pad Reinforcement of Class 2
                                                                                   and 3 Atmospheric Storage
                                                                                   Tanks, Section XI, Division
                                                                                   1.
N-867.................................  0 (2017 Edition)........................  Clarification of NDE Practical
                                                                                   Examination Requirements,
                                                                                   Section XI, Division 1.
N-873.................................  1 (2017 Edition)........................  Examination Requirements for
                                                                                   the Core Makeup Tanks,
                                                                                   Section XI, Division 1.
N-874.................................  7 (2017 Edition)........................  Temporary Acceptance of
                                                                                   Leakage Through Brazed Joints
                                                                                   of Class 3 Copper, Copper-
                                                                                   Nickel, and Nickel-Copper
                                                                                   Moderate Energy Piping,
                                                                                   Section XI, Division 1.
N-877.................................  2 (2017 Edition)........................  Alternative Characterization
                                                                                   Rules for Multiple Subsurface
                                                                                   Radially Oriented Planar
                                                                                   Flaws, Section XI, Division
                                                                                   1.
N-882.................................  6 (2017 Edition)........................  Alternative Requirements for
                                                                                   Attaching Nonstructural
                                                                                   Electrical Connections to
                                                                                   Class 2 and 3 Components,
                                                                                   Section XI, Division 1.
N-885.................................  0 (2019 Edition)........................  Alternative Requirements for
                                                                                   Table IWB-2500-1, Examination
                                                                                   Category B-N-1, Interior of
                                                                                   Reactor Vessel, Category B-N-
                                                                                   2, Welded Core Support
                                                                                   Structures and Interior
                                                                                   Attachments to Reactor
                                                                                   Vessels, Category B-N-3,
                                                                                   Removable Core Support
                                                                                   Structures, Section XI,
                                                                                   Division 1.
N-892.................................  0 (2019 Edition)........................  Alternative Requirement for
                                                                                   Form OAR-1, Owner's Activity
                                                                                   Report, Completion Time,
                                                                                   Section XI, Division 1.
----------------------------------------------------------------------------------------------------------------
                                         Operation and Maintenance Code
                                        (Addressed in RG 1.192, Table 1)
----------------------------------------------------------------------------------------------------------------
OMN-13, Revision 3....................  2020 Edition............................  Performance-Based Requirements
                                                                                   for Extending Snubber
                                                                                   Inservice Visual Examination
                                                                                   Interval at LWR Power Plants.
OMN-15, Revision 3....................  2020 Edition............................  Performance-Based Requirements
                                                                                   for Extending the Snubber
                                                                                   Operational Readiness Testing
                                                                                   Interval at LWR Power Plants.
OMN-17, Revision 1....................  2020 Edition............................  Alternative Requirements for
                                                                                   Testing ASME Class 1 Pressure
                                                                                   Relief/Safety Valves.
OMN-18 \5\............................  2020 Edition............................  Alternate Testing Requirements
                                                                                   for Pumps Tested Quarterly
                                                                                   Within 20% of
                                                                                   Design Flow.
OMN-22................................  2020 Edition............................  Smooth Running Pumps.
OMN-23................................  2020 Edition............................  Alternative Requirements for
                                                                                   Testing Pressure Isolation
                                                                                   Valves.
OMN-24................................  2020 Edition............................  Alternative Requirements for
                                                                                   Testing ASME Class 2 and 3
                                                                                   Pressure Relief Valves (For
                                                                                   Relief Valves in a Group of
                                                                                   One).
OMN-25................................  2020 Edition............................  Alternative Requirements for
                                                                                   Testing Appendix I Pressure
                                                                                   Relief Valves.
OMN-26................................  2020 Edition............................  Alternate Risk-Informed and
                                                                                   Margin Based Rules for
                                                                                   Inservice Testing of Motor
                                                                                   Operated Valves.
OMN-27................................  2020 Edition............................  Alternative Requirements for
                                                                                   Testing Category A Valves
                                                                                   (Non-PIV/CIV)
----------------------------------------------------------------------------------------------------------------

     
---------------------------------------------------------------------------

    \5\ As a result of a public comment, the NRC agreed that the 
condition to require the slightly more restrictive upper-end values 
of the acceptable ranges for flow and differential pressure are not 
necessary to provide reasonable assurance that the implementation of 
Code Case OMN-18 will demonstrate the acceptable performance of 
pumps within the scope of the ASME OM Code. Therefore, the NRC 
deleted the condition proposed and moved OMN-18 to Table I.
---------------------------------------------------------------------------

B. ASME Code Cases Approved for Use With Conditions

    The NRC determined that certain code cases, as issued by the ASME, 
are generally acceptable for use, but that the alternative requirements 
specified in those code cases must be supplemented in order to provide 
an acceptable level of quality and safety. Accordingly, the NRC imposes 
conditions on the use of these code cases to modify, limit, or clarify 
their requirements. The conditions specify, for each applicable code 
case, the additional activities that must be performed, the limits on 
the activities specified in the code case, and/or the supplemental 
information needed to provide clarity. These ASME code cases, listed in 
Table II below, are included in Table 2 of RG 1.84, RG 1.147, and RG 
1.192. This section provides the NRC's evaluation of the code cases and 
the reasons for the NRC's conditions. Notations indicate the conditions 
duplicated from previous versions of the RG.

[[Page 11939]]



                                  Table II--Conditionally Acceptable Code Cases
----------------------------------------------------------------------------------------------------------------
             Code Case No.                      Published with supplement                      Title
----------------------------------------------------------------------------------------------------------------
                                   Boiler and Pressure Vessel Code Section III
                                         (Addressed in RG 1.84, Table 2)
----------------------------------------------------------------------------------------------------------------
N-71-20...............................  6 (2015 Edition)........................  Additional Materials for
                                                                                   Subsection NF, Class 1, 2, 3,
                                                                                   and MC Supports Fabricated by
                                                                                   Welding, Section III,
                                                                                   Division 1.
N-155-3...............................  5 (2015 Edition)........................  Fiberglass Reinforced
                                                                                   Thermosetting Resin Pipe,
                                                                                   Section III, Division 1.
N-755-4...............................  1 (2017 Edition)........................  Use of Polyethylene (PE) Class
                                                                                   3 Plastic Pipe, Section III,
                                                                                   Division 1.
N-779.................................  8 (2007 Edition) \6\....................  Alternative Rules for
                                                                                   Simplified Elastic-Plastic
                                                                                   Analysis Class 1, Section
                                                                                   III, Division 1.
N-852.................................  0 (2015 Edition)........................  Application of the ASME NPT
                                                                                   Stamp, Section III, Divisions
                                                                                   1, 2, 3, and 5.
N-883.................................  5 (2017 Edition)........................  Construction of Items Prior to
                                                                                   the Establishment of a
                                                                                   Section III, Division 1
                                                                                   Owner, Section III, Division
                                                                                   1.
N-886.................................  6 (2017 Edition)........................  Use of Polyethylene Pipe for
                                                                                   Class 3, Section III,
                                                                                   Division 1.
----------------------------------------------------------------------------------------------------------------
                                   Boiler and Pressure Vessel Code Section XI
                                        (Addressed in RG 1.147, Table 2)
----------------------------------------------------------------------------------------------------------------
N-513-5...............................  6 (2017 Edition)........................  Evaluation Criteria for
                                                                                   Temporary Acceptance of Flaws
                                                                                   in Moderate Energy Class 2 or
                                                                                   3 Piping and Gate Valves,
                                                                                   Section XI, Division 1.
N-516-5...............................  6 (2015 Edition)........................  Underwater Welding, Section
                                                                                   XI, Division 1.
N-597-3...............................  5 (2013 Edition)........................  Evaluation of Pipe Wall
                                                                                   Thinning, Section XI.
N-705-1...............................  2 (2017 Edition)........................  Evaluation Criteria for
                                                                                   Temporary Acceptance of
                                                                                   Degradation in Moderate
                                                                                   Energy Class 2 or 3 Vessels
                                                                                   and Tanks, Section XI,
                                                                                   Division 1.
N-766-3...............................  2 (2017 Edition)........................  Nickel Alloy Reactor Coolant
                                                                                   Inlay and Onlay for
                                                                                   Mitigation of PWR Full
                                                                                   Penetration Circumferential
                                                                                   Nickel Alloy Dissimilar Metal
                                                                                   Welds in Class 1 Items,
                                                                                   Section XI, Division 1.
N-778.................................  0 (2010 Edition)........................  Alternative Requirements for
                                                                                   Preparation and Submittal of
                                                                                   Inservice Inspection Plans,
                                                                                   Schedules, and Preservice and
                                                                                   Inservice Inspection Summary
                                                                                   Reports, Section XI, Division
                                                                                   1.
N-831-1...............................  7 (2017 Edition)........................  Ultrasonic Examination in Lieu
                                                                                   of Radiography for Welds in
                                                                                   Ferritic or Austenitic Pipe,
                                                                                   Section XI, Division 1.
N-847.................................  0 (2017 Edition)........................  Partial Excavation and
                                                                                   Deposition of Weld Metal for
                                                                                   Mitigation of Class 1 Items,
                                                                                   Section XI, Division 1.
N-864.................................  2 (2017 Edition)........................  Reactor Vessel Threads in
                                                                                   Flange Examinations, Section
                                                                                   XI, Division 1.
N-869.................................  6 (2017 Edition)........................  Evaluation Criteria for
                                                                                   Temporary Acceptance of Flaws
                                                                                   in Class 2 or 3 Piping,
                                                                                   Section XI, Division 1.
N-876.................................  2 (2017 Edition)........................  Austenitic Stainless Steel
                                                                                   Cladding and Nickel Base
                                                                                   Cladding Using Ambient
                                                                                   Temperature Automatic or
                                                                                   Machine Dry Underwater Laser
                                                                                   Beam Welding (ULBW) Temper
                                                                                   Bead Technique, Section XI,
                                                                                   Division 1.
N-878.................................  1 (2017 Edition)........................  Alternative to QA Program
                                                                                   Requirements of IWA-4142,
                                                                                   Section XI, Division 1.
N-880.................................  2 (2017 Edition)........................  Alternative to Procurement
                                                                                   Requirements of IWA-4143 for
                                                                                   Small Nonstandard Welded
                                                                                   Fittings, Section XI,
                                                                                   Division 1.
N-889.................................  7 (2017 Edition)........................  Reference Stress Corrosion
                                                                                   Crack Growth Rate Curves for
                                                                                   Irradiated Austenitic
                                                                                   Stainless Steel in Light-
                                                                                   Water Reactor Environments,
                                                                                   Section XI, Division 1.
N-890.................................  0 (2019 Edition)........................  Materials Exempted From G-
                                                                                   2110(b) Requirement, Section
                                                                                   XI, Division 1.
----------------------------------------------------------------------------------------------------------------
                                         Operation and Maintenance Code
                                        (Addressed in RG 1.192, Table 2)
----------------------------------------------------------------------------------------------------------------
OMN-1, Revision 2.....................  2020 Edition............................  Alternative Rules for
                                                                                   Preservice and Inservice
                                                                                   Testing of Active Electric
                                                                                   Motor-Operated Valve
                                                                                   Assemblies in Light-Water
                                                                                   Reactor Power Plants.
OMN-3.................................  2020 Edition............................  Requirements for Safety
                                                                                   Significance Categorization
                                                                                   of Components Using Risk
                                                                                   Insights for Inservice
                                                                                   Testing of LWR Power Plants.
OMN-4.................................  2020 Edition............................  Requirements for Risk Insights
                                                                                   for Inservice Testing of
                                                                                   Check Valves at LWR Power
                                                                                   Plants.
OMN-9.................................  2020 Edition............................  Use of a Pump Curve for
                                                                                   Testing.
OMN-12................................  2020 Edition............................  Alternative Requirements for
                                                                                   Inservice Testing Using Risk
                                                                                   Insights for Pneumatically
                                                                                   and Hydraulically Operated
                                                                                   Valve Assemblies in Light-
                                                                                   Water Reactor Power Plants
                                                                                   (OM-Code 1998, Subsection
                                                                                   ISTC).
OMN-19................................  2020 Edition............................  Alternative Upper Limit for
                                                                                   the Comprehensive Pump Test.
OMN-20................................  2020 Edition............................  Inservice Test Frequency.
----------------------------------------------------------------------------------------------------------------

     
---------------------------------------------------------------------------

    \6\ Correcting editorial error from proposed rule to final rule 
to state correct supplement 8.
---------------------------------------------------------------------------

1. ASME BPV Code, Section III Code Cases (RG 1.84)
Code Case N-71-20 [Supplement 6, 2015 Edition]
    Type: Revised.
    Title: Additional Materials for Subsection NF, Class 1, 2, 3, and 
MC Supports Fabricated by Welding, Section III, Division 1.
    The conditions on Code Case N-71-20 are the same as the conditions 
on N-71-19 that were approved by the NRC in Revision 38 of RG 1.84. 
When the ASME revised N-71, the code case was not modified in a way 
that would make

[[Page 11940]]

it possible for the NRC to remove the conditions. Therefore, the 
conditions are retained in Revision 39 of RG 1.84.
Code Case N-155-3 [Supplement 5, 2015 Edition]
    Type: Revised.
    Title: Fiberglass Reinforced Thermosetting Resin Pipe, Section III, 
Division 1.
    The conditions on Code Case N-155-3 are the same as the conditions 
on N-155-2 that were approved by the NRC in Revision 38 of RG 1.84. 
When the ASME revised N-155-2, the code case was not modified in a way 
that would make it possible for the NRC to remove the conditions. 
Therefore, the conditions are retained in Revision 39 of RG 1.84.
Code Case N-755-4 [Supplement 1, 2017 Edition]
    Type: Revised.
    Title: Use of Polyethylene (PE) Class 3 Plastic Pipe, Section III, 
Division 1.
    This code case is applicable only to butt fusion joints and the 
content was incorporated into Mandatory Appendix XXVI in the 2015 
Edition of Section III of the ASME Code. The relevant provisions of 
Code Case N-755-4 are the same as those in Mandatory Appendix XXVI. 
Therefore, the NRC is applying the same conditions to Code Case N-755-
4. The NRC has determined that these conditions are necessary to ensure 
structural integrity of the polyethylene piping and fusion joints when 
the polyethylene piping is used in Class 3 safety-related applications.
Code Case N-779 [Supplement 8, 2007 Edition]
    Type: New.
    Title: Alternative Rules for Simplified Elastic-Plastic Analysis 
Class 1, Section III, Division 1.
    The NRC finds the code case satisfactory and technically acceptable 
for use only with code editions Summer 1979 and later. This code case, 
as written, is not acceptable for use with editions of Section III 
earlier than the Summer 1979 Edition, which included the term Delta T1 
in NB-3600 Equation 10, because the code case is based on equations 
used in the Summer 1979 Edition and later editions of the Code.
Code Case N-852 [Supplement 0, 2015 Edition]
    Type: New.
    Title: Application of the ASME NPT Stamp, Section III, Divisions 1, 
2, 3, and 5.
    The NRC approved this code case with a condition in a Sec.  50.55a 
rulemaking issued in 2017 (82 FR 32934; July 18, 2017), and the 
supplement was not modified in a way that would make it possible for 
the NRC to remove the condition. Therefore, the condition is retained 
in Revision 39 of RG 1.84.
Code Case N-883 [Supplement 5, 2017 Edition]
    Type: New.
    Title: Construction of Items Prior to the Establishment of a 
Section III, Division 1 Owner, Section III, Division 1.
    This code case allows certificate holders to construct all items 
prior to the establishment of an Owner. Code Case N-883 was developed 
to address international stakeholders and identify the ASME as a global 
standard development organization. The NRC's main concern is that 
without the designation of an Owner, the NRC would not be able to 
provide regulatory oversight of the ASME certificate holder 
manufacturing the items, which is not consistent with appendix B to 10 
CFR part 50 and the requirements in Sec.  50.55(a) for a basic 
component. During discussions with the ASME staff on this code case, it 
was determined that the NRC would condition this code case based on 
regulatory oversight, as would other regulatory bodies depending on 
each countries' specific regulations. This is evident as this code case 
specifies that the ``the items have been constructed by [ASME] 
Certificate Holders who are specifically authorized by the Regulatory 
Authority having jurisdiction over the Owner's facility to construct 
items using this Case.'' The condition, ``This Code Case may be used 
for the construction of items by a holder of a construction permit, 
operating license, or combined license under 10 CFR part 50 or part 
52,'' provides this specific regulatory authorization thereby ensuring 
the appropriate regulatory oversight. As a result of public comment, 
the NRC clarified the condition on the code case as follows: ``This 
Code Case may only be used for the construction of items by a holder of 
a construction permit, operating license, or combined license under 10 
CFR part 50 or 10 CFR part 52. This Code Case may not be used by a 
holder of a manufacturing license or standard design approval or by a 
design certification applicant.''
Code Case N-886 [Supplement 6, 2017 Edition]
    Type: New.
    Title: Use of Polyethylene Pipe for Class 3, Section III, Division 
1.
    This code case is applicable for the use of polyethylene pipe in 
Section III, Class 3, Division 1 above ground applications. This code 
case refers to Mandatory Appendix XXVI of Section III of the ASME Code. 
The 2015 Edition of Appendix XXVI contains requirements for butt fusion 
joints for buried piping. The 2017 Edition of Appendix XXVI contains 
requirements for butt fusion and electrofusion joints for buried 
piping. Therefore, all the conditions as noted in Section III of the 
2015-2017 Code Edition rule related to buried piping Mandatory Appendix 
XXVI apply to this code case. The same conditions as buried piping also 
apply to above ground application. One additional condition is needed 
for above ground applications related to fire protection. A condition 
on fire protection is needed because polyethylene material is 
combustible and above ground uses are more susceptible to fire hazards.
    The NRC agreed with the public comments to remove conditions 1, 2, 
and 3 because the three conditions are the same as those for Section 
III, Mandatory Appendix XXVI, which was conditionally accepted by the 
NRC in Sec.  50.55a. It is redundant to specify these conditions to 
Code Case N-886.
    As a result of public comment, the NRC clarified condition 4 to 
state that for aboveground applications, licensees must ensure that 
plant fire protection program addresses any high-density polyethylene 
(HDPE) consistent with the requirements of 10 CFR 50.48. The licensee 
must identify the specific program to satisfy this objective such as 
the plant fire protection program. Therefore, the condition is retained 
in Revision 39 of RG 1.84.
    The NRC agreed with the public comment to remove condition 5 
because the requirement that carbon black distribution in HDPE pipe to 
be homogenous to prevent windows and delamination is a pipe 
manufacturing process issue. The staff determined that the requirements 
in Mandatory Appendix XXVI-2231(b) adequately address this issue. Code 
Case N-886 is only for design, and all materials must meet the 
requirements of Appendix XXVI.
2. ASME BPV Code, Section XI Code Cases (RG 1.147)
Code Case N-513-5 [Supplement 6, 2017 Edition]
    Type: Revised.
    Title: Evaluation Criteria for Temporary Acceptance of Flaws in 
Moderate Energy Class 2 or 3 Piping and Gate Valves, Section XI, 
Division 1.
    Code Case N-513-5 contains provisions to permit temporary

[[Page 11941]]

acceptance of flaws, in moderate energy Class 2 or 3 piping, including 
elbows, pipe bends, reducers, expanders, branch tees, and gate valves 
without performing a repair/replacement activity for a limited period. 
The code case contains provisions regarding the scope, flaw 
characterization, periodic leakage monitoring, flaw evaluation, and 
augmented examinations. The NRC finds that the provisions of N-513-5 
are acceptable except that the augmented examination provisions in 
Section 5 of the code case require clarification.
    When a licensee applies N-513-5 to disposition a through-wall leak 
or wall thinning in a piping system, Section 5 of the code case 
requires augmented examinations for flaws and significant flaws. The 
augmented examination requirements in N-513-5 are the same as in Code 
Case N-513-3.
    In 2018, the NRC found an instance where a licensee misinterpreted 
the provisions in Section 5 of N-513-3 and did not perform the required 
augmented examinations to disposition a through-wall leak in a service 
water system pipe. Other licensees have similarly misinterpreted the 
augmented examination provisions in Section 5 of N-513-3. The NRC found 
that the issue stems from the definition of the terms ``flaw'' and 
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3, 
respectively. The NRC, therefore, imposes two conditions to define 
``flaw'' and ``significant flaw'' as those terms are used in Section 5 
of N-513-5. Licensees would be required to apply these definitions to 
Section 5 when using the code case.
    The first condition defines a ``flaw'' as a non-through-wall planar 
or nonplanar flaw with a wall thickness less than 87.5 percent of the 
nominal wall thickness of the pipe or the design minimum wall 
thickness. The NRC notes that the pipe wall thickness at the time of 
the plant construction may deviate from the nominal pipe wall thickness 
slightly as part of manufacturing process. The generally accepted 
deviation is 12.5 percent of the nominal pipe wall thickness or the 
design minimum wall thickness.
    The second condition defines ``significant flaw'' as any pipe 
location that does not satisfy the provisions of Section 3 of N-513-5 
or if any detected flaw that has a depth greater than 75 percent of the 
pipe wall thickness. The NRC staff notes that the criterion of the 75 
percent wall thickness criterion originates from the provisions of IWC/
IWD-3643 of the ASME Code, Section XI, which prohibits a flaw that 
exceeds 75 percent of the pipe wall thickness to remain in service. 
Under Section 5 of N-513-5, a planar flaw that exceeds 75 percent of 
the pipe wall thickness may remain in service; however, the licensee 
must perform an augmented examination. The NRC agreed with the public 
comment that Condition 2 needed clarification. As a result, the NRC 
revised Condition No. 2 as follows: ``For the purposes of section 5 of 
Code Case N-513-5, the term ``significant flaw'' means any flaw found 
during augmented examinations performed per Section 5 of N-513-5 that 
has a depth greater than 75 percent of the pipe wall thickness or that 
does not satisfy the applicable requirements of the flaw evaluation per 
Section 3 of N-513-5. If a significant flaw as defined above is 
present, then the licensee must perform the additional augmented 
examination specified in Section 5.''
Code Case N-516-5 [Supplement 6, 2015 Edition]
    Type: Revised.
    Title: Underwater Welding, Section XI, Division 1.
    In the rulemaking for the 2009 Addenda through 2013 Editions of the 
ASME Code (82 FR 32934; September 18, 2017), the NRC-specified 
conditions that should be applied to Section XI, Article IWA-4660 when 
performing underwater welding on irradiated materials. These conditions 
provide guidance on what level of neutron irradiation and/or helium 
content would require review and approval by the NRC because of the 
impact of neutron fluence on weldability. These conditions provide 
separate criteria for three generic classes of material: Ferritic 
material, austenitic material other than P-No. 8 (e.g., nickel-based 
alloys) and austenitic P-No. 8 material (e.g., stainless steel alloys). 
These conditions are currently located in Sec.  50.55a(b)(2)(xii)(A) 
and (B). The conditions located in Sec.  50.55a(b)(2)(xii)(A) and (B) 
are identical to the conditions that were imposed on Code Case N-516-4 
that were approved by the NRC in Revision 19 of RG 1.147. When the ASME 
revised N-516, the code case was not modified in a way that would make 
it possible for the NRC to remove the conditions. Therefore, the 
conditions are retained in Revision 20 of RG 1.147 by stating the 
provisions of Sec.  50.55a(b)(2)(xii)(A) and (B) must be met when 
applying this code case.
Code Case N-597-3 [Supplement 5, 2013 Edition]
    Type: Revised.
    Title: Evaluation of Pipe Wall Thinning, Section XI.
    Based on public comments, the NRC found that existing Condition 
2(b) references Figure-3622.1(a)(1), which does not exist in Code Case 
N-597-3. The NRC revised Condition 2(b) in the final rule to reference 
Figure 3622-1 of the code case.
Code Case N-705-1 [Supplement 2, 2017 Edition]
    Type: Revised.
    Title: Evaluation Criteria for Temporary Acceptance of Degradation 
in Moderate Energy Class 2 or 3 Vessels and Tanks, Section XI, Division 
1.
    The condition on Code Case N-705-1 is identical to the condition on 
N-705 that was approved by the NRC in Revision 19 of RG 1.147. When the 
ASME revised N-705, the code case was not modified in a way that would 
make it possible for the NRC to remove the condition. Therefore, the 
condition is retained in Revision 20 of RG 1.147.
Code Case N-766-3 [Supplement 2, 2017 Edition]
    Type: Revised.
    Title: Nickel Alloy Reactor Coolant Inlay and Onlay for Mitigation 
of Pressurized Water Reactor (PWR) Full Penetration Circumferential 
Nickel Alloy Dissimilar Metal Welds in Class 1 Items, Section XI, 
Division 1.
    The conditions on Code Case N-766-3 are identical to the conditions 
on N-766-1 that were approved by the NRC in Revision 19 of RG 1.147. 
When the ASME revised N-766, the code case was not modified in a way 
that would make it possible for the NRC to remove the conditions. 
Therefore, the conditions are retained in Revision 20 of RG 1.147.
Code Case N-778 [Supplement 0, 2010 Edition]
    Type: New.
    Title: Alternative Requirements for Preparation and Submittal of 
Inservice Inspection Plans, Schedules, and Preservice and Inservice 
Inspection Summary Reports, Section XI, Division 1.
    Code Case N-778 was originally listed in Table 2 of Revision 18 of 
RG 1.147 with two conditions. As a result of public comments, the NRC 
revised the second condition on Code Case N-778 to be consistent with 
Code Case N-892 by increasing the time period for submittal of the 
inservice inspection summary report to 120 days following the 
completion of each refueling outage.
Code Case N-831-1 [Supplement 7, 2017 Edition]
    Type: Revised.
    Title: Ultrasonic Examination in Lieu of Radiography for Welds in 
Ferritic or Austenitic Pipe, Section XI, Division 1.

[[Page 11942]]

    The condition on Code Case N-831-1 is identical to the condition on 
N-831 that was approved by the NRC in Revision 19 of RG 1.147. When 
ASME revised N-831, the code case was not modified in a way that would 
make it possible for the NRC to remove the condition. Therefore, the 
condition is retained in Revision 20 of RG 1.147.
Code Case N-847 [Supplement 0, 2017 Edition]
    Type: New.
    Title: Partial Excavation and Deposition of Weld Metal for 
Mitigation of Class 1 Items, Section XI, Division 1.
    The ASME Code Case N-847 provides guidelines for a repair/
mitigation process for welds. The process, excavation and weld repair 
(EWR), removes susceptible material from the outside diameter of the 
pipe, and replaces it with more resistant weld material. This technique 
allows for the potential of two mitigation methods, the use of more 
crack-resistant material and the potential for compressive stresses on 
the inside surface of the repaired/mitigated weld to arrest or prevent 
cracking. Finally, the excavation can be done 360-degrees around the 
weld or only for a partial arc of the weld.
    The code case would allow for application of this process to both 
BWR and PWR designs. However, the EWR process, as defined in this code 
case, has certain challenges addressing the cracking mechanisms in 
these operating environments and materials. In addition, the regulatory 
requirements or guidelines related to the code case vary depending on 
the design of the reactor. For PWR designs, the inservice inspection 
rules are provided by Sec.  50.55a(g)(6)(ii)(F), which mandates the 
implementation of a version of ASME Code Case N-770-5. For BWR designs, 
the inservice inspection guidelines are provided by Generic Letter 88-
01, ``NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) 
in BWR Austenitic Stainless Steel Piping,'' or BWRVIP-75-A, ``BWR 
Vessel and Internals Project Technical Basis for Revisions to Generic 
Letter 88-01 Inspection Schedules.'' Therefore, the NRC is imposing six 
conditions to ensure the inservice inspection frequency guidelines of 
the code case are consistent with the previous requirements and 
guidance, which are based on the effectiveness of the overall design of 
the repair/mitigation to address the various cracking mechanisms of 
these operating reactor designs.
    The first condition is a continuation of the condition of Sec.  
50.55a(g)(6)(ii)(F)(16), which requires that a partial arc EWR, as 
described in Inspection Item O of ASME Code Case N-770-5, cannot be 
used without NRC review and approval for PWR designs. The NRC notes 
that the issues addressed in the final rule incorporating by reference 
the 2015 and 2017 Editions of the ASME BPV Code and the 2015 and 2017 
Editions of the ASME OM Code remain applicable, and further apply to 
BWR design application of a partial arc EWR. These concerns are for the 
effectiveness of the repair through a weld residual stress calculation 
and flaw growth analysis to confirm design of the mitigation for the 
required inspection interval, non-destructive examination uncertainty 
analysis of the as-found flaw remaining in the reactor coolant pressure 
boundary, and the potential for further crack initiation or growth. The 
NRC requires, through the first condition, that approval of the use of 
this code case is only for the application of the 360-degree EWR.
    The second condition is related to Figure 1A and Figure 1B of the 
code case. The NRC has experience with relief request submittals, where 
the details associated with the configuration of the prep area, where 
the defect is being removed, have shown sharp bottom edges and steep 
walls. This geometry can result in welding issues, which could result 
in unfused material, leading to stress risers, which may promote 
cracking. The NRC requires, through the second condition, that the 
intersection points at the interface between EWR metal and existing 
base metal must be rounded to minimize stress concentration.
    The third condition is related to Section 2(d) of the code case, 
which discusses the flaw evaluations required for the design 
considerations of the EWR. In recent testing conducted for the NRC 
measurable stress corrosion cracking (SCC) growth was detected past the 
interface between the SCC-susceptible and less susceptible material. It 
was demonstrated that the crack can branch and propagate in a direction 
normal to the original direction along a SCC-susceptible path. In the 
Alloy 52M deposited onto Alloy 182 specimens tested, this occurred in 
the diluted region of the Alloy 52M material as well as the weld metal. 
The NRC requires, through the third condition, that flaw analysis 
include the potential for crack growth through the dilution zone 
including crack branching. As NRC-approved crack growth rates are not 
available for all material types (e.g., Alloy 690 weld material), the 
alternative requirements for development of crack growth rates should 
be consistent with ASME Section XI Appendix C, ``Flaw Growth Rate Due 
to Stress Corrosion Cracking,'' C-3220(a). As a result of public 
comment, the NRC agrees this condition should be updated to reference 
Section 2(d)(1), rather than 2(d)(2) as discussed in the proposed rule 
(86 FR 7820, February 2, 2021), for nickel-based alloys. The NRC 
clarified the condition to state the evaluation in Section 2(d)(1) of 
the code case must include evaluation of crack growth into the Alloy 
690 weld material, including the dilution zones and allowing change in 
flaw growth direction.
    The fourth condition is related to Section 2 of the code case. The 
NRC is requiring the use of NUREG-2228, because it provides a proven 
method for validating the weld residual stress analysis methodology. 
Because the NRC requires the use of NUREG-2228 within this condition on 
the requirements in the code case, the NRC is incorporating by 
reference NUREG-2228 into Sec.  50.55a(a)(3)(iv).
    The fifth condition is related to the longer-term volumetric 
inspection frequencies of Table 1, including notes (1), (3), and (4). 
These notes provide the BWR design inspection frequency of various EWR 
types based on Generic Letter 88-01 (1988) as supplemented by Generic 
Letter 88-01, Supplement 1 (1992), ``NRC Position on Intergranular 
Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel 
Piping,'' or BWRVIP-75-A, ``BWR Vessel and Internals Project Technical 
Basis for Revisions to Generic Letter 88-01 Inspection Schedules.'' The 
NRC has concluded that the inspection requirements for EWRs for BWRs 
need to be augmented.
    The first volumetric examination following application of BWR EWR-
2A, EWR-1B, and EWR-2B welds is performed to verify effectiveness of 
the repair/mitigation before the new weld can be placed in a longer-
term volumetric inspection frequency. The code case allows licensees 
the option of performing this examination during the first or second 
refueling outage after installation. However, based on the lower 
operating temperatures of a BWR (approximately 546 [deg]F to 558 
[deg]F), and hence the potential slow crack growth rate of the 
remaining flaw left in service, the NRC has concluded that the 
examination should occur during the second refueling outage after the 
EWR application to provide adequate time for any potential measurable 
flaw growth to occur or in the case of an EWR-2A, for crack initiation 
and growth to occur.
    The long-term volumetric inspections for BWRs require modification 
because: (a) For EWR-1A EWRs, the augmented

[[Page 11943]]

inspection requirements are consistent with the conditions of the 
inspection frequencies of Code Case N-770-5. These inspection frequency 
requirements were previously developed by the NRC based on the 
capabilities of the EWR process to address stress corrosion cracking 
while providing significant credit for the use of hydrogen water 
chemistry/noble metal chemical addition controls; and (b) for EWR-1B 
EWRs, the design that would allow a crack to be left in service, should 
not be allowed to go uninspected for the remainder of plant life. 
Therefore, the NRC requires the long-term volumetric inspection of 
these welds at each 10-year inservice inspection interval. The NRC 
notes that this condition is consistent with the NRC condition 
established in Sec.  50.55a for Inspection Item N-1 EWRs (EWR that 
meets stress criteria; however, a crack is present).
    The sixth condition is related to Table 1, Note (1), and the option 
to use an unspecified alternative to determine examination frequencies 
and scope expansion criteria. Note (1) specifies the use of NRC Generic 
Letter 88-01 and includes BWRVIP-75-A as an example of an alternative. 
The NRC has concluded that NRC Generic Letter 88-01 (1988), as 
supplemented by Generic Letter 88-01, Supplement 1 (1992), or BWRVIP-
75-A, are acceptable, subject to the fifth condition, to determine 
examination frequencies and scope expansion criteria. However, Note (1) 
would allow the use of other, unknown alternatives and does not provide 
criteria to ensure alternatives are adequate for this purpose. 
Therefore, to ensure that licensees use an adequate standard to 
determine examination frequencies and scope expansion criteria, the 
sixth condition requires that licensees must not use an alternative 
other than those specified in Note (1).
Code Case N-864 [Supplement 2, 2017 Edition]
    Type: New.
    Title: Reactor Vessel Threads in Flange Examinations, Section XI, 
Division 1.
    Code Case N-864 eliminates the required ASME Code, Section XI 
examination for the reactor vessel threads-in-flange for all inservice 
inspection intervals. The NRC has previously granted alternatives under 
Sec.  50.55a(z) that eliminate the reactor pressure vessel threads-in-
flange examinations (ASME Section XI, Examination Category B-G-1, Item 
No. B6.40) for up to two inservice inspection intervals through the 
NRC's alternative request process. For alternatives that requested 
elimination of the examination for a second consecutive 10-year 
inservice inspection interval, the NRC has been requesting additional 
information on activities performed to ensure that the condition of the 
reactor pressure vessel threads-in-flange receives some level of 
monitoring. These activities typically have included care and 
maintenance of the reactor vessel threads-in-flange (and studs) 
whenever the closure head is removed. The NRC has limited approval of 
such requests to two subsequent inservice inspection intervals because 
the NRC has determined that complete elimination of the examinations 
does not provide adequate protection against long-term degradation of 
the threads-in-flange. The NRC is imposing conditions on the use of 
Code Case N-864 that are consistent with the limits the NRC has placed 
on similar alternatives requests.
    The first condition in Code Case N-864 requires that the reactor 
pressure vessel threads-in-flange examinations (ASME Section XI, 
Examination Category B-G-1, Item No. B6.40) must be performed in at 
least every third 10-year ISI interval. This condition also limits the 
application of Code Case N-864 at facilities that have been authorized 
under Sec.  50.55a(z) to use alternatives that eliminate reactor 
pressure vessel threads-in-flange examinations to ensure that the 
required examination is performed at least every third 10-year 
inservice inspection interval.
    The second condition in Code Case N-864 ensures that sufficient 
monitoring and maintenance activities are performed and documented when 
the code case is applied. As a result of public comments, the NRC 
clarified that performing and documenting the facility's maintenance 
procedures for removal, care, and visual inspection of the reactor head 
closure studs and threads in flange during each refueling outage are 
sufficient to satisfy the second condition.
Code Case N-869 [Supplement 6, 2017 Edition]
    Type: New.
    Title: Evaluation Criteria for Temporary Acceptance of Flaws in 
Class 2 or 3 Piping, Section XI, Division 1.
    Code Case N-869 contains provisions for temporary acceptance of 
flaws, including through-wall flaws in Class 2 or 3 piping including 
elbows, pipe bends, reducers, and branch tees, whose maximum operating 
pressure is greater than 275 psig and does not exceed 600 psig, without 
performing a repair/replacement activity. The code case contains 
provisions regarding the scope, flaw characterization, periodic leakage 
monitoring, flaw evaluation, and augmented examinations. The NRC finds 
that the code case provides reasonable assurance that structural 
integrity of degraded piping will be maintained until the next 
scheduled refueling outage. However, the NRC finds that the augmented 
examination provisions in Section 5 of the code case are unclear and 
need additional clarification.
    When a licensee applies N-869 to disposition a through-wall leak or 
wall thinning in a piping system, Section 5 of the code case requires 
augmented examinations for flaws and significant flaws. The augmented 
examination requirements in N-869 are the same as in Code Case N-513-3.
    In 2018, the NRC found an instance where a licensee misinterpreted 
the provisions in Section 5 of N-513-3 and did not perform the required 
augmented examinations to disposition a through-wall leak in a service 
water system pipe. Other licensees have similarly misinterpreted the 
augmented examination provisions in Section 5 of N-513-3. The NRC found 
that the issue stems from the definition of the terms ``flaw'' and 
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3, 
respectively. The NRC, therefore, imposes two conditions to define 
``flaw'' and ``significant flaw'' as those terms are used in Section 5 
of N-869. Licensees would be required to apply these definitions to 
Section 5 when using the code case.
    The first condition defines a ``flaw'' as a non-through-wall planar 
or nonplanar flaw with a wall thickness less than 87.5 percent of the 
nominal wall thickness of the pipe or the design minimum wall 
thickness. The NRC notes that the pipe wall thickness at the time of 
the plant construction may deviate from the nominal pipe wall thickness 
slightly as part of manufacturing process. The generally accepted 
deviation is 12.5 percent of the nominal pipe wall thickness or the 
design minimum wall thickness.
    The second condition defines ``significant flaw'' as any pipe 
location that does not satisfy the provisions of Section 3 of N-869 or 
if any detected flaw that has a depth greater than 75 percent of the 
pipe wall thickness. The NRC staff notes that the 75 percent wall 
thickness criterion originates from the provisions of IWC/IWD-3643 of 
the ASME Code, Section XI, which prohibit a flaw that exceeds 75 
percent of the pipe wall thickness to remain in service. Under Section 
5 of N-869, a planar flaw that exceeds 75 percent of the pipe wall

[[Page 11944]]

thickness may remain in service; however, the licensee needs to perform 
an augmented examination.
Code Case N-876 [Supplement 2, 2017 Edition]
    Type: New.
    Title: Austenitic Stainless Steel Cladding and Nickel Base Cladding 
Using Ambient Temperature Automatic or Machine Dry Underwater Laser 
Beam Welding (ULBW) Temper Bead Technique, Section XI, Division 1.
    Some irradiated stainless steel reactor vessel internal components 
are susceptible to experiencing irradiation assisted stress corrosion 
cracking. Code Case N-876 provides guidelines for repair welding the 
irradiated stainless steel components inside the reactor vessel. Code 
Case N-876 provides an alternative to the cladding temper bead repair 
rules of Section XI, IWA-4400, which requires preheat and postweld heat 
treatment. This alternative establishes new rules governing ambient 
temperature temper bead cladding repairs using the ULBW process.
    The NRC is imposing two conditions on this code case. The first 
condition that must be applied when performing ULBW on irradiated 
materials provides guidance on what level of neutron irradiation and/or 
helium content would require review and approval by the NRC because of 
the impact of neutron fluence on weldability. The second condition 
limits the depth of the cladding repair due to concerns with the 
fracture toughness of the base metal.
    The technical basis for imposing conditions on the welding of 
irradiated materials are that neutrons can generate helium atoms within 
the metal lattice through transmutation of various isotopes of boron 
and/or nickel. At high temperatures, such as occurs during welding, 
these helium atoms rapidly diffuse though the metal lattice, coalescing 
and forming helium bubbles at the grain boundaries. In sufficient 
concentration, these helium bubbles can cause grain boundary cracking 
that occurs in the fusion zones and heat affected zones during the 
heat-up/cooldown cycle.
    The first condition applies conditions already applicable to Code 
Case N-516-5 ``Underwater Welding Section XI, Division 1,'' that the 
provisions of Sec.  50.55a(b)(2)(xii)(A) and (B) must be met. This 
regulation provides limits on specific levels of neutron irradiation 
and/or helium content, above which welding is prohibited without prior 
NRC review and approval. The NRC is imposing the same condition to uses 
of Code Case N-876.
    The second condition is necessary because the code case does not 
require impact testing of the base metal heat affected zone (HAZ) to 
verify adequate fracture toughness. The code case allows the depth of 
the repair cavity into the ferritic base metal to be up to \1/4\''. 
This would allow welding directly to the base metal; thus, it will 
affect the fracture toughness of the base metal in the HAZ. Therefore, 
the NRC is imposing a condition restricting the use of the code case to 
repairs where at least \1/8\'' of cladding remains. The basis for the 
\1/8\'' limit is that this amount of austenitic material between the 
ferritic base metal and the first weld layer has generally been 
considered to sufficiently limit the heat input to the base metal such 
that deleterious effects on the fracture toughness will not occur; 
therefore, impact testing of the base metal is not necessary. The NRC 
notes that Code Case N-803, which is approved without conditions, 
allows repair of ferritic base material using nonferritic weld filler 
material based on welding procedure qualifications performed using 
tensile tests, side bends, and impact tests, and could be used to 
perform a cladding repair in which excavation into the base metal is 
required.
Code Case N-878 [Supplement 1, 2017 Edition]
    Type: New.
    Title: Alternative to QA Program Requirements of IWA-4142, Section 
XI, Division 1.
    Code Case N-878 provides alternatives to the quality assurance 
requirements in IWA-4142 for procurement of Class 1, 2, or 3 non-welded 
fittings. This code case addresses the testing and certification of 
material used in the manufacture of non-welded fittings, but does not 
address how the licensee must ensure that the procured non-welded 
fittings meet the design and testing requirements of the ASME Code, 
Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3 applications. 
Verification that the Section III requirements for the design and 
testing of these non-welded fittings have been met prior to use is 
essential in ensuring the structural integrity of these Class 1, 2 and 
3 systems is maintained. Therefore, the NRC is imposing conditions for 
the licensee to verify the design and testing activities associated 
with qualification of non-welded fittings required by Section III, NB/
NC/ND-3671.7 that are performed by the fabricator.
    The first condition states for ASME Section III items, the Licensee 
must review the fabricator's design documentation and methods to ensure 
the fittings design is in compliance with the Licensee's design 
specifications, and ASME Section III NB/NC/ND-3671.7 requirements; and 
either (1) supervise and monitor the performance qualification tests of 
the fittings to ensure the design is in compliance with the Licensee's 
design specifications and ASME Section III NB/NC/ND-3671.7, or (2) the 
Licensee or Repair/Replacement Organization conducts qualification 
tests of the fittings or conducts design analyses to ensure the design 
is in compliance with the Licensee's design specifications and ASME 
Section III NB/NC/ND-3671.7. In response to public comments, the NRC 
clarified that for ASME Section III items, this condition applies only 
for those licensees that implemented ASME Code, Section III design 
requirements for their original construction code and/or the licensees 
that have upgraded their original design requirements to ASME Code, 
Section III.
    The second condition states that the Licensees must give the 
Authorized Nuclear Inservice Inspector an opportunity to review the 
design report prior to installation.
Code Case N-880 [Supplement 2, 2017 Edition]
    Type: New.
    Title: Alternative to Procurement Requirements of IWA-4143 for 
Small Nonstandard Welded Fittings, Section XI, Division 1.
    Code Case N-880 provides alternatives to the material procurement 
requirements of IWA-4142 and IWA-4143 for small nonstandard welded 
fittings. This code case does not address how the licensee must ensure 
the procured welded fittings meet the design and testing requirements 
of the ASME Code, Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3 
applications. Verification that the Section III requirements for the 
design and testing of these welded fittings have been met prior to use 
is essential in ensuring the structural integrity of these Class 1, 2 
and 3 systems is maintained. Therefore, the NRC is imposing conditions 
requiring the licensee to verify the design and testing activities 
associated with qualification of welded fittings required by Section 
III, NB/NC/ND-3671.7 that are performed by the fabricator.
    The first condition states for ASME Section III items, the Licensee 
must review the fabricator's design documentation and methods to ensure 
the fittings design is in compliance with the Licensee's design 
specifications, and ASME Section III NB/NC/ND-3671.7 requirements; and 
either: (1) Supervise

[[Page 11945]]

and monitor the performance qualification tests of the fittings to 
ensure the design is in compliance with the Licensee's design 
specifications and ASME Section III NB/NC/ND-3671.7, or (2) the 
Licensee or Repair/Replacement Organization conducts qualification 
tests of the fittings or conducts design analyses to ensure the design 
is in compliance with the Licensee's design specifications and ASME 
Section III NB/NC/ND-3671.7. In response to public comments, the NRC 
clarified that for ASME Section III items, this condition applies only 
for those licensees that implemented ASME Code, Section III design 
requirements for their original construction code and/or the licensees 
that have upgraded their original design requirements to ASME Code, 
Section III.
    The second condition states that the Licensees must give the 
Authorized Nuclear Inservice Inspector an opportunity to review the 
design report prior to installation.
Code Case N-889 [Supplement 7, 2017 Edition]
    Type: New.
    Title: Reference Stress Corrosion Crack Growth Rate Curves for 
Irradiated Austenitic Stainless Steel in Light-Water Reactor 
Environments, Section XI, Division 1.
    Code Case N-889 provides a new crack growth rate (CGR) law for 
irradiation-assisted stress corrosion cracking. The code case is 
applicable to wrought austenitic stainless steels and associated weld 
metals, as well as cast austenitic stainless steels. The proposed CGR 
law requires the user to first calculate irradiated yield stress from 
the dose to the material. There are two yield stress models: One for 
Molybdenum bearing stainless steels and one for stainless steels 
without Molybdenum. Once irradiated yield stress has been determined, 
the user calculates the CGR as a function of applied crack driving 
force and temperature.
    The staff identified three concerns with the technical basis of 
this code case. The first concern relates to the limited CGR data at 
dose levels greater than 20 displacements per atom (dpa). The proposed 
CGR law indicates that the irradiated yield stress (and, consequently, 
the CGR) increases with fluence up to a dose of 20 dpa, at which point 
the irradiated yield's stress ceases to increase appreciably with 
further dose accumulation. While the data at dose levels greater than 
20 dpa does show a plateau behavior in the CGR, the staff's analyses of 
that data suggests that areas of high CGR were averaged over the 
industry calculation of CGR, which increases the uncertainty in the 
high dose CGRs. Therefore, due to the limited data and the associated 
high uncertainty at high fluence, the staff's confidence in CGRs at 
dose levels greater than 20 dpa is low.
    The second concern is the effects of uncertainty in the irradiated 
yield strength value for an individual material-heat. This topic is 
discussed in Section 4.7 of the technical basis report for Code Case N-
889. The NRC also conducted separate analyses. While the results of the 
NRC's findings are generally consistent with the results in Section 
4.7, the interpretation of their significance is not consistent. For 
materials with yield strengths greater than 600 MPa (i.e., more highly-
irradiated materials), the expected CGR for a material with a yield 
strength in the 95th percentile is less than two times the CGR 
predicted by the code case, which is not a significant difference. 
However, for materials with yield strength values less than 250 MPa 
(i.e., unirradiated or minimally irradiated materials), the expected 
CGR for a material in the 95th percentile can be more than five times 
greater than the CGR predicted by the code case. Hence, the NRC's 
concern is that the CGRs for individual low yield strength materials, 
or materials with low fluence, could be significantly underpredicted by 
the code case.
    The final concern is related to the data used in the development of 
the irradiated yield stress model. The methodology for addressing cold 
work in this model was developed in MRP-135, Revision 1, while the 
model itself was developed in MRP-211, Revision 0. The database 
underlying the model included hundreds of yield strength measurements 
on initially annealed and cold-worked Types 304, 316, and 347/348 
stainless steel materials. However, most of the data were for annealed 
Type 304 and cold-worked Type 316 stainless steels. Revision 1 of MRP-
211 contained additional yield strength data, including significantly 
more data for cold-worked Types 304 and 347 stainless steel. The 
authors of the code case, as documented in Section 4.5 of the 
Additional Basis Report dated February 5, 2018, evaluated the code case 
yield stress model with some of this additional data and found 
agreement between the model and the additional data. However, the code 
case authors excluded new data for cold-worked Type 304 and 347 
stainless steel materials. Therefore, the technical basis document for 
Code Case N-889 does not directly address whether cold-worked Type 304 
and 347 (non-Molybdenum bearing) materials are adequately predicted by 
the irradiated yield strength model in the code case. The NRC is 
imposing three conditions on this code case.
    The first condition states that this code case may not be applied 
for neutron exposures greater than 20 dpa. This condition addresses the 
NRC concern that there is sparse data with high uncertainty beyond 20 
dpa. Given that the predicted CGR saturates at higher fluence, this 
condition prevents potential underprediction of the CGR in this fluence 
regime.
    The second condition states that at dose levels below 0.75 dpa, the 
user must use the higher of the Code Case N-889 or the Section XI, 
Nonmandatory Appendix C, C-8520 CGR predictions. This condition 
addresses the NRC concern related to possible underprediction of CGR in 
Code Case N-889 for materials with calculated irradiated yield strength 
less than 250 MPa.
    The final condition states that the irradiated yield stress model 
for cold-worked Molybdenum bearing materials must be used for cold-
worked non-Molybdenum bearing stainless steels (including Type 204 and 
247 stainless steels). This condition addresses the NRC concern that 
data for cold-worked non-Molybdenum bearing steels were not 
appropriately considered during development of Code Case N-889. The NRC 
performed its own evaluation of cold-worked Type 304 and 347 stainless 
steels in the MRP-211 database and found that the yield strength was 
better predicted by the code case's Molybdenum bearing model than with 
the code case's non-Molybdenum bearing model.
Code Case N-890 [Supplement 0, 2019 Edition]
    Type: New.
    Title: Materials Exempted From G-2110(b) Requirements, Section XI, 
Division 1.
    Code Case N-890 provides an alternative to Section XI, G-2110(b) 
which removes the requirement of, ``obtaining fracture toughness data 
for at least three heats,'' for using the static fracture toughness 
curve (Klc) curve for specific materials with a minimum 
specified yield strength at room temperature between 50 kilopound per 
square inch (ksi) and 90 ksi. Code Case N-890 would allow the toughness 
of four ferritic steels (SA-508 Grade 2 Class 2, SA-508 Grade 3 Class 
2, SA-533 Type A Class 2 and SA-533 Type B Class 2) with specified 
minimum yield strength greater than 50 ksi to be characterized by 
Figure G-2110-1 (i.e., the Section XI Klc curve).

[[Page 11946]]

    The NRC identified one technical concern when reviewing the 
technical basis of this code case. The technical basis provided 
appropriate data to justify use of the Klc curve for several 
materials listed in the code case. However, for SA-533 Type B, Class 2 
materials, the NRC observed that in the technical basis document, there 
is no fracture toughness data associated with the weld and heat 
affected zone to support exclusion of the fracture toughness testing 
requirements for these materials.
    As such, the imposed NRC condition requires the user to comply with 
the provisions of Section III, NB-2300 and Section III, G-2110(b) to 
demonstrate the applicability of the ASME Klc curve to SA-
533 Type B, Class 2 material. These provisions require the user to 
generate the necessary toughness data to demonstrate that the ASME 
KIC curve is a conservative representation of the actual 
material toughness.
3. ASME Operation and Maintenance Code Cases (RG 1.192)
Code Case OMN-1, Revision 2 [2020 Edition]
    Type: Reaffirmed.
    Title: Alternative Rules for Preservice and Inservice Testing of 
Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor 
Power Plants.
    The conditions on Code Case OMN-1, Revision 2 [2020 Edition] are 
identical to the conditions on OMN-1, Revision 2 [2017 Edition] that 
were approved by the NRC in Revision 3 of RG 1.192. The OMN-1, Revision 
2 was reaffirmed by the ASME in the 2020 Edition with no change to the 
code case. Therefore, the conditions are retained in Revision 4 of RG 
1.192.
Code Case OMN-3 [2020 Edition]
    Type: Reaffirmed.
    Title: Requirements for Safety Significance Categorization of 
Components Using Risk Insights for Inservice Testing of LWR Power 
Plants.
    The conditions on Code Case OMN-3 [2020 Edition] are identical to 
the conditions on OMN-3 [2017 Edition] that were approved by the NRC in 
Revision 3 of RG 1.192. The OMN-3 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.
Code Case OMN-4 [2020 Edition]
    Type: Reaffirmed.
    Title: Requirements for Risk Insights for Inservice Testing of 
Check Valves at LWR Power Plants.
    The conditions on Code Case OMN-4 [2020 Edition] are identical to 
the conditions on OMN-4 [2017 Edition] that were approved by the NRC in 
Revision 3 of RG 1.192. The OMN-4 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.
Code Case OMN-9 [2020 Edition]
    Type: Reaffirmed.
    Title: Use of a Pump Curve for Testing.
    The conditions on Code Case OMN-9 [2020 Edition] are identical to 
the conditions on OMN-9 [2017 Edition] that were approved by the NRC in 
Revision 3 of RG 1.192. The OMN-9 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.
Code Case OMN-12 [2020 Edition]
    Type: Reaffirmed.
    Title: Alternative Requirements for Inservice Testing Using Risk 
Insights for Pneumatically and Hydraulically Operated Valve Assemblies 
in Light-Water Reactor Power Plants (OM-Code 1998, Subsection ISTC).
    The conditions on Code Case OMN-12 [2020 Edition] are identical to 
the conditions on OMN-12 [2017 Edition] that were approved by the NRC 
in Revision 3 of RG 1.192. The OMN-12 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.
Code Case OMN-19 [2020 Edition]
    Type: Reaffirmed.
    Title: Alternative Upper Limit for the Comprehensive Pump Test.
    The conditions on Code Case OMN-19 [2020 Edition] are identical to 
the conditions on OMN-19 [2017 Edition] that were approved by the NRC 
in Revision 3 of RG 1.192. The OMN-19 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.
Code Case OMN-20 [2020 Edition]
    Type: Reaffirmed.
    Title: Inservice Test Frequency.
    The conditions on Code Case OMN-20 [2020 Edition] are identical to 
the conditions on OMN-20 [2017 Edition] that were approved by the NRC 
in Revision 3 of RG 1.192. The OMN-20 was reaffirmed by the ASME in the 
2020 Edition with no change to the code case. Therefore, the conditions 
are retained in Revision 4 of RG 1.192.

C. ASME Code Cases Not Approved for Use (RG 1.193)

    The ASME code cases that are currently issued by the ASME, but not 
approved for generic use by the NRC, are listed in RG 1.193, ``ASME 
Code Cases not Approved for Use.'' In addition to the ASME code cases 
that the NRC has found to be technically or programmatically 
unacceptable, RG 1.193 includes code cases on reactor designs for high-
temperature gas-cooled reactors and liquid metal reactors, reactor 
designs not currently licensed by the NRC, and certain requirements in 
Section III, Division 2, for submerged spent fuel waste casks, that are 
not endorsed by the NRC. RG 1.193 complements RGs 1.84, 1.147, and 
1.192. It should be noted that the NRC is not adopting any of the code 
cases listed in RG 1.193.

III. Opportunities for Public Participation

    The proposed rule and draft RGs were published in the Federal 
Register on February 2, 2021 (86 FR 7820), for a 60-day comment period. 
The public comment period closed on April 5, 2021.

IV. Public Comment Analysis

    The NRC published the proposed rule and draft regulatory guides for 
public comment in the Federal Register. The NRC received 13 comment 
submissions. A comment submission is a communication or document 
submitted to the NRC by an individual or entity, with one or more 
individual comments addressing a subject or issue. Private citizens 
provided five comment submissions, nuclear industry organizations 
provided five comment submissions, a foreign government entity provided 
one comment submission, an anonymous commenter provided one comment 
submission, and a science advocacy group provided one comment 
submission.
    The comment submissions generally addressed the code cases and 
their proposed conditions, with five comment submissions objecting to 
incorporation of a code case with no conditions in this rulemaking 
activity. The NRC received a number of comments that were outside the 
scope of this rulemaking, such as comments that discuss code cases 
annulled after the publication of the supplements being considered in 
this rulemaking. The latter group out of scope comments will be 
considered in a future rulemaking.
    The public comment submittals are available from the Federal e-
Rulemaking website at https://www.regulations.gov

[[Page 11947]]

under Docket ID NRC-2017-0025. The NRC prepared a summary and analysis 
of public comments received on the 2020 proposed rule and draft 
regulatory guides, which is available as indicated in the 
``Availability of Documents'' section of this document. Responses to 
the public comments, including a summary of how the final rule text or 
guidance changed as a result of the public comments, can be found in 
the public comment analysis.
    For more information about the associated guidance documents, see 
the ``Availability of Guidance'' section of this document.

V. Section-by-Section Analysis

    The following paragraphs in Sec.  50.55a are revised:

Paragraph (a) Introductory Text

    This final rule revises the last sentence to update the contact 
information for the National Archives and Records Administration.

Paragraph (a)(1) Introductory Text

    This final rule corrects a printing error by removing the line 
break after ``telephone:''.

Paragraph (a)(3) Introductory Text

    This final rule adds a reference to new paragraph (a)(3)(iv), which 
indicates that NUREG-2228 is acceptable as specified in the conditions 
when implementing code cases listed in certain NRC regulatory guides.

Paragraph (a)(3)(i)

    This final rule revises the reference to ``NRC Regulatory Guide 
1.84, Revision 38,'' by removing ``Revision 38'' and adding in its 
place ``Revision 39'' and changes the month and year for the document's 
revision date.

Paragraph (a)(3)(ii)

    This final rule revises the reference to ``NRC Regulatory Guide 
1.147, Revision 19'' by removing ``Revision 19'' and adding in its 
place ``Revision 20'' and changes the month and year for the document's 
revision date.

Paragraph (a)(3)(iii)

    This final rule revises the reference to ``NRC Regulatory Guide 
1.192, Revision 3'' by removing ``Revision 3'' and adding in its place 
``Revision 4'' and changes the month and year for the document's 
revision date.

Paragraph (a)(3)(iv)

    This final rule adds new paragraph (a)(3)(iv) to reference NUREG-
2228, ``Weld Residual Stress Finite Element Analysis Validation: Part 
II--Proposed Validation Procedure,'' Published July 2020 (including 
Errata September 22, 2021), which is referenced in RG 1.147, Revision 
20.

Paragraph (b)(1)(ii), Table 1

    This final rule revises the reference to table 1 in the text of the 
paragraph, and designates the table and revises the heading of the 
table to conform to Office of the Federal Register (OFR) codification 
requirements.

Paragraph (b)(2)(xv)(K)(4), Table 2

    This final rule designates the table and revises the heading of the 
table to conform to OFR codification requirements.

Paragraph (b)(3)(iv), Table 3

    This final rule designates the table and revises the heading of the 
table to conform to OFR codification requirements, and capitalizes the 
word ``(Years)'' in two of the three column headings.

VI. Regulatory Flexibility Certification

    As required by the Regulatory Flexibility Act (5 U.S.C. 605(b)), 
the Commission certifies that this rule, if adopted, will not have a 
significant economic impact on a substantial number of small entities. 
This final rule affects only the licensing and operation of nuclear 
power plants. The companies that own these plants do not fall within 
the scope of the definition of ``small entities'' set forth in the 
Regulatory Flexibility Act or the size standards established by the NRC 
(Sec.  2.810).

VII. Regulatory Analysis

    The NRC has prepared a regulatory analysis on this regulation. The 
analysis examines the costs and benefits of the alternatives considered 
by the NRC. The NRC did not receive public comments on the draft 
regulatory analysis. The final regulatory analysis is available as 
indicated in the ``Availability of Documents'' section of this 
document.

VIII. Backfitting and Issue Finality

    The provisions in this final rule allow licensees and applicants to 
voluntarily apply NRC-approved code cases, sometimes with NRC-specified 
conditions. The approved code cases are listed in three RGs that are 
incorporated by reference into Sec.  50.55a. An applicant's or a 
licensee's voluntary application of an approved code case does not 
constitute backfitting, because there is no imposition of a new 
requirement or new position.
    Similarly, voluntary application of an approved code case by a 10 
CFR part 52 applicant or licensee does not represent NRC imposition of 
a requirement or action, and therefore is not inconsistent with any 
issue finality provision in 10 CFR part 52. For these reasons, the NRC 
finds that this final rule does not involve any provisions requiring 
the preparation of a backfit analysis or documentation demonstrating 
that one or more of the issue finality criteria in 10 CFR part 52 are 
met.

IX. Plain Writing

    The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal 
agencies to write documents in a clear, concise, and well-organized 
manner. The NRC has written this document to be consistent with the 
Plain Writing Act as well as the Presidential Memorandum, ``Plain 
Language in Government Writing,'' published June 10, 1998 (63 FR 
31885).

X. Environmental Assessment and Final Finding of No Significant 
Environmental Impact

    The Commission has determined under the National Environmental 
Policy Act of 1969, as amended, and the Commission's regulations in 
subpart A of 10 CFR part 51, that this rule, if adopted, would not be a 
major Federal action significantly affecting the quality of the human 
environment; therefore, an environmental impact statement is not 
required.
    The determination of this environmental assessment is that there 
will be no significant effect on the quality of the human environment 
from this action. The NRC did not receive public comments regarding any 
aspect of this environmental assessment.
    As voluntary alternatives to the ASME Code, NRC-approved code cases 
provide an equivalent level of safety. Therefore, the probability or 
consequences of accidents is not changed. There are also no 
significant, non-radiological impacts associated with this action 
because no changes would be made affecting non-radiological plant 
effluents and because no changes would be made in activities that would 
adversely affect the environment. The determination of this 
environmental assessment is that there will be no significant offsite 
impact to the public from this action.

XI. Paperwork Reduction Act

    This final rule amends collections of information subject to the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). The 
collections of information were approved by the Office of Management 
and Budget, approval number 3150-0011.
    Because the rule will reduce the burden for existing information 
collections, the public burden for the

[[Page 11948]]

information collections is expected to be decreased by 230 hours per 
response. This reduction includes the time for reviewing instructions, 
searching existing data sources, gathering and maintaining the data 
needed, and completing and reviewing the information collection.
    The information collection is being conducted to document the plans 
for and the results of inservice inspection and inservice testing 
programs. The records are generally historical in nature and provide 
data on which future activities can be based. Information will be used 
by the NRC to determine if ASME BPV and OM Code provisions for 
construction, inservice inspection, repairs, and inservice testing are 
being properly implemented in accordance with Sec.  50.55a of the NRC 
regulations, or whether specific enforcement actions are necessary. 
Responses to this collection of information are mandatory under Sec.  
50.55a.
    You may submit comments on any aspect of the information 
collections, including suggestions for reducing the burden, by the 
following methods:
     Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025.
     Mail comments to: FOIA, Library, and Information 
Collections Branch, Office of the Chief Information Officer, Mail Stop: 
T-6 A10M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 
or to the OMB reviewer at: OMB Office of Information and Regulatory 
Affairs (3150-0011) Attn: Desk Officer for the Nuclear Regulatory 
Commission, 725 17th Street NW, Washington, DC 20503; email: 
[email protected].

Public Protection Notification

    The NRC may not conduct or sponsor, and a person is not required to 
respond to, a collection of information unless the document requesting 
or requiring the collection displays a currently valid OMB control 
number.

XII. Congressional Review Act

    This final rule is a rule as defined in the Congressional Review 
Act (5 U.S.C. 801-808). However, the Office of Management and Budget 
has not found it to be a major rule as defined in the Congressional 
Review Act.

XIII. Voluntary Consensus Standards

    The National Technology Transfer and Advancement Act of 1995, 
Public Law 104-113, requires that Federal agencies use technical 
standards that are developed or adopted by voluntary consensus 
standards bodies unless using such a standard is inconsistent with 
applicable law or is otherwise impractical. In this final rule, the NRC 
is continuing to use the ASME BPV and OM code cases, which are ASME-
approved voluntary alternatives to compliance with various provisions 
of the ASME BPV and OM Codes. The NRC's approval of the ASME code cases 
is accomplished by amending the NRC's regulations to incorporate by 
reference the latest revisions of the following, which are the subject 
of this rulemaking, into Sec.  50.55a: RG 1.84, Revision 39; RG 1.147, 
Revision 20; RG 1.192, Revision 4; and NUREG-2228. The RGs list the 
ASME code cases that the NRC has approved for use. The ASME code cases 
are national consensus standards as defined in the National Technology 
Transfer and Advancement Act of 1995 and OMB Circular A-119. The ASME 
code cases constitute voluntary consensus standards, in which all 
interested parties (including the NRC and licensees of nuclear power 
plants) participate.

XIV. Incorporation by Reference-Reasonable Availability to Interested 
Parties

    The NRC is incorporating by reference three NRC RGs that list new 
and revised ASME code cases that the NRC has approved as voluntary 
alternatives to certain provisions of NRC-required editions and addenda 
of the ASME BPV Code and the ASME OM Code. These regulatory guides are 
RG 1.84, Revision 39; RG 1.147, Revision 20; and RG 1.192, Revision 4. 
The NRC is also incorporating by reference NUREG-2228, which is 
referenced in RG 1.147, Revision 20. As described in this document, 
this report pertains to a condition on Code Case N-847.
    The NRC is required by law to obtain approval for incorporation by 
reference from the OFR. The OFR's requirements for incorporation by 
reference are set forth in 1 CFR part 51. The discussion in this 
section complies with the requirement for final rules as set forth in 1 
CFR 51.5(b)(2).
    The NRC considers ``interested parties'' to include all potential 
NRC stakeholders, not only the individuals and entities regulated or 
otherwise subject to the NRC's regulatory oversight. These NRC 
stakeholders are not a homogenous group, so the considerations for 
determining ``reasonable availability'' vary by class of interested 
parties. The NRC identified six classes of interested parties with 
regard to the material to be incorporated by reference in an NRC rule:
     Individuals and small entities regulated or otherwise 
subject to the NRC's regulatory oversight. This class includes 
applicants and potential applicants for licenses and other NRC 
regulatory approvals, and who are subject to the material to be 
incorporated by reference. In this context, ``small entities'' has the 
same meaning as set out in Sec.  2.810.
     Large entities otherwise subject to the NRC's regulatory 
oversight. This class includes applicants and potential applicants for 
licenses and other NRC regulatory approvals, and who are subject to the 
material to be incorporated by reference. In this context, a ``large 
entity'' is one that does not qualify as a ``small entity'' under Sec.  
2.810.
     Non-governmental organizations with institutional 
interests in the matters regulated by the NRC.
     Other Federal agencies, states, local governmental bodies 
(within the meaning of Sec.  2.315(c)).
     Federally-recognized and State-recognized Indian tribes.
     Members of the general public (i.e., individual, 
unaffiliated members of the public who are not regulated or otherwise 
subject to the NRC's regulatory oversight) who need access to the 
materials that the NRC proposes to incorporate by reference in order to 
participate in the rulemaking.
    The NUREG-2228 and three RGs that the NRC is incorporating by 
reference in this final rule are available without cost and can be read 
online or downloaded online. The NUREG-2228 and three RGs can be 
viewed, by appointment, at the NRC Technical Library, which is located 
at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland 
20852; telephone: 301-415-7000; email: [email protected].
    Because access to NUREG-2228 and the three final regulatory guides 
is available in various forms at no cost, the NRC determines that 
NUREG-2228 and the three final regulatory guides, RG 1.84, Revision 39; 
RG 1.147, Revision 20; and RG 1.192, Revision 4, once approved by the 
OFR for incorporation by reference, are reasonably available to all 
interested parties.

[[Page 11949]]



 Table III--Regulatory Guides Incorporated by Reference in 10 CFR 50.55a
------------------------------------------------------------------------
                                                        ADAMS Accession
                    Document title                        No./ Federal
                                                       Register citation
------------------------------------------------------------------------
RG 1.84, Design, Fabrication, and Materials Code Case        ML21181A225
 Acceptability, ASME Section III, Revision 39........
RG 1.147, Inservice Inspection Code Case                     ML21181A222
 Acceptability, ASME Section XI, Division 1, Revision
 20..................................................
RG 1.192, Operation and Maintenance Code Case                ML21181A223
 Acceptability, ASME OM Code, Revision 4.............
------------------------------------------------------------------------


 Table IV--Related Documents Incorporated by Reference in 10 CFR 50.55a
------------------------------------------------------------------------
                                                        ADAMS Accession
                    Document title                        No./ Federal
                                                       Register citation
------------------------------------------------------------------------
NUREG-2228, ``Weld Residual Stress Finite Element            ML20212L592
 Analysis Validation: Part II--Proposed Validation
 Procedure,'' July 2020..............................
------------------------------------------------------------------------

XV. Availability of Guidance

    The NRC is issuing revised guidance, RG 1.193, ``ASME Code Cases 
Not Approved for Use,'' Revision 7, for the implementation of the 
requirements in this final rule. The guidance is available as indicated 
in Section XVI, ``Availability of Documents,'' of this document. You 
may access information and comment submissions related to the guidance 
by searching on https://www.regulations.gov under Docket ID NRC-2017-
0025.
    The regulatory guide lists code cases that the NRC has not approved 
for generic use and will not be incorporated by reference into the 
NRC's regulations.

XVI. Availability of Documents

    The documents identified in the following table are available to 
interested persons through one or more of the following methods, as 
indicated.

------------------------------------------------------------------------
                                                        ADAMS Accession
                                                         No./web link/
                       Document                         Federal Register
                                                            citation
------------------------------------------------------------------------
RG 1.84, Design, Fabrication, and Materials Code Case        ML21181A225
 Acceptability, ASME Section III, Revision 39,
 December 2021.......................................
RG 1.147, Inservice Inspection Code Case                     ML21181A222
 Acceptability, ASME Section XI, Division 1, Revision
 20, December 2021...................................
RG 1.192, Operation and Maintenance Code Case                ML21181A223
 Acceptability, ASME OM Code, Revision 4, December
 2021................................................
RG 1.193, ASME Code Cases Not Approved for Use,              ML21181A224
 Revision 7..........................................
NUREG-2228, ``Weld Residual Stress Finite Element            ML20212L592
 Analysis Validation: Part II-Proposed Validation
 Procedure,'' July 2020..............................
Rulemaking-Proposed Rule-Draft Regulatory Analysis           ML20133K152
 for the American Society of Mechanical Engineers
 Code Cases, RG 1.84, Rev 39; RG 1.147, Rev 20; RG
 1.192 Rev 4.........................................
Rulemaking-Final Rule-Final Regulatory Analysis for          ML21196A096
 the American Society of Mechanical Engineers Code
 Cases, RG 1.84, Rev 39; RG 1.147, Rev 20; RG 1.192
 Rev 4...............................................
NRC Responses to Public Comments.....................        ML21196A100
Proposed Rule-Approval of American Society of                ML20132A241
 Mechanical Engineers Code Cases RG 1.84, Rev 39; RG
 1.147, Rev 20; RG 1.192 Rev 4.......................
Proposed Rule-Approval of American Society of                 86 FR 7820
 Mechanical Engineers Code Cases RG 1.84, Rev 39; RG
 1.147, Rev 20; RG 1.192 Rev 4.......................
Final Rule-Approval of American Society of Mechanical        85 FR 14736
 Engineers Code Cases RG 1.84, Rev 38; RG 1.147, Rev
 19; RG 1.192 Rev 3..................................
------------------------------------------------------------------------

List of Subjects in 10 CFR Part 50

    Antitrust, Classified information, Criminal penalties, Fire 
protection, Incorporation by reference, Intergovernmental relations, 
Nuclear power plants and reactors, Radiation protection, Reactor siting 
criteria, Reporting and recordkeeping requirements.

    For the reasons set out in the preamble and under the authority of 
the Atomic Energy Act of 1954, as amended; the Energy Reorganization 
Act of 1974, as amended; and 5 U.S.C. 552 and 553, the NRC is adopting 
the following amendments to 10 CFR part 50:

PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION 
FACILITIES

0
1. The authority citation for part 50 continues to read as follows:

    Authority: Atomic Energy Act of 1954, secs. 11, 101, 102, 103, 
104, 105, 108, 122, 147, 149, 161, 181, 182, 183, 184, 185, 186, 
187, 189, 223, 234 (42 U.S.C. 2014, 2131, 2132, 2133, 2134, 2135, 
2138, 2152, 2167, 2169, 2201, 2231, 2232, 2233, 2234, 2235, 2236, 
2237, 2239, 2273, 2282); Energy Reorganization Act of 1974, secs. 
201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste 
Policy Act of 1982, sec. 306 (42 U.S.C. 10226); National 
Environmental Policy Act of 1969 (42 U.S.C. 4332); 44 U.S.C. 3504 
note; Sec. 109, Pub. L. 96-295, 94 Stat. 783.


0
2. In Sec.  50.55a:
0
a. Revise the last sentence of paragraph (a) introductory text and 
paragraphs (a)(1) introductory text and (a)(3) introductory text;
0
b. In paragraph (a)(3)(i):
0
i. Remove the text ``Revision 38'' and add in its place the text 
``Revision 39''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the 
text ``issued December 2021'';
0
c. In paragraph (a)(3)(ii):

[[Page 11950]]

0
i. Remove the text ``Revision 19'' and add in its place the text 
``Revision 20''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the 
text ``issued December 2021'';
0
d. In paragraph (a)(3)(iii):
0
i. Remove the text ``Revision 3'' and add in its place the text 
``Revision 4''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the 
text ``issued December 2021'';
0
e. Add paragraph (a)(3)(iv);
0
f. In paragraph (b)(1)(ii), remove the text ``Table I of this section'' 
and add in its place the text ``table 1 to this paragraph (b)(1)(ii)'';
0
g. Designate the table immediately following paragraph (b)(1)(ii) as 
table 1 to paragraph (b)(1)(ii) and revise the heading of the newly 
designated table;
0
h. Designate the table immediately following paragraph (b)(2)(xv)(K)(4) 
as table 2 to paragraph (b)(2)(xv)(K)(4) and revise the heading of the 
newly designated table; and
0
i. Designate the table immediately following paragraph (b)(3)(iv) as 
table 3 to paragraph (b)(3)(iv) and revise the heading and column 
headings of the newly designated table.
    The revisions and addition read as follows:


Sec.  50.55a   Codes and standards.

    (a) * * * For information on the availability of this material at 
NARA, email [email protected] or go to www.archives.gov/federal-register/cfr/ibr-locations.html.
    (1) American Society of Mechanical Engineers (ASME), Three Park 
Avenue, New York, NY 10016; telephone: 1-800-843-2763; https://www.asme.org/Codes/.
* * * * *
    (3) U.S. Nuclear Regulatory Commission (NRC) Public Document Room, 
11555 Rockville Pike, Rockville, Maryland 20852; telephone: 1-800-397-
4209; email: [email protected]; https://www.nrc.gov/reading-rm/doc-collections/reg-guides/. The use of code cases listed in the NRC 
regulatory guides in paragraphs (a)(3)(i) through (iii) of this section 
is acceptable with the specified conditions in those guides when 
implementing the editions and addenda of the ASME BPV Code and ASME OM 
Code incorporated by reference in paragraph (a)(1) of this section. The 
NRC report in paragraph (a)(3)(iv) of this section is acceptable as 
specified in the conditions when implementing code cases listed in the 
NRC regulatory guides in paragraphs (a)(3)(i) through (iii) of this 
section.
* * * * *
    (iv) NUREG-2228. NUREG-2228, ``Weld Residual Stress Finite Element 
Analysis Validation: Part II--Proposed Validation Procedure,'' 
Published July 2020 (including Errata September 22, 2021), which is 
referenced in RG 1.147, Revision 20.
* * * * *
    (b) * * *
    (1) * * *
    (ii) * * *
    Table 1 to Paragraph (b)(1)(ii)--Prohibited Code Provisions
* * * * *
    (2) * * *
    (xv) * * *
    (K) * * *
    (4) * * *
    Table 2 to Paragraph (b)(2)(xv)(K)(4)--Table VIII: S7-1--Modified
* * * * *
    (3) * * *
    (iv) * * *

Table 3 to Paragraph (b)(3)(iv)--Maximum Intervals for Use When Applying
                           Interval Extensions
------------------------------------------------------------------------
                                Maximum interval      Maximum interval
                               between activities    between activities
         Group size           of  member valves in  of each valve in the
                               the groups (years)       group (years)
------------------------------------------------------------------------
 
                              * * * * * * *
------------------------------------------------------------------------

* * * * *

    Dated: January 25, 2022.

    For the Nuclear Regulatory Commission.
Andrea D. Veil,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2022-04374 Filed 3-2-22; 8:45 am]
BILLING CODE 7590-01-P