[Federal Register Volume 84, Number 146 (Tuesday, July 30, 2019)]
[Notices]
[Pages 36961-36963]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-16067]


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

NUCLEAR REGULATORY COMMISSION

[NRC-2016-0233]


Pressurized Water Reactor Control Rod Ejection and Boiling Water 
Reactor Control Rod Drop Accidents

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of reissuance of draft regulatory guide; request for 
comment.

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

SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is reissuing for 
public comment draft regulatory guide (DG), DG-1327, ``Pressurized 
Water Reactor Control Rod Ejection and Boiling Water Reactor Control 
Rod Drop Accidents.'' This DG proposes new guidance for analyzing 
accidents such as a control rod ejection for pressurized water reactors 
and a control rod drop for boiling-water reactors. It defines fuel 
cladding failure thresholds for ductile failure, brittle failure, and 
pellet-clad mechanical interaction and provides radionuclide release 
fractions for use in assessing radiological consequences. It also 
describes analytical limits and guidance for demonstrating compliance 
with regulations governing reactivity limits.

DATES: Submit comments by October 28, 2019. Comments received after 
this date will be considered if it is practical to do so, but the NRC 
is able to ensure consideration only for comments received on or before 
this date. Although a time limit is given, comments and suggestions in 
connection with items for inclusion in guides currently being developed 
or improvements in all published guides are encouraged at any time.

ADDRESSES: You may submit comments by any of the following methods 
(unless this document describes a different method for submitting 
comments on a specific subject):
     Federal Rulemaking Website: Go to https://www.regulations.gov/ and search for Docket ID NRC-2016-0233. Address 
questions about docket IDs in Regulations.gov to Jennifer Borges; 
telephone: 301-287-9127; email: [email protected]. For technical 
questions, contact the individuals listed in the FOR FURTHER 
INFORMATION CONTACT section of this document.
     Mail comments to: Office of Administration, Mail Stop: 
TWFN-7-A60M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, ATTN: Program Management, Announcements and Editing Staff.
    For additional direction on obtaining information and submitting 
comments,

[[Page 36962]]

see ``Obtaining Information and Submitting Comments'' in the 
SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Paul Clifford, Office of Nuclear 
Reactor Regulation, telephone: 301-415-4043, email: 
[email protected] and Edward O'Donnell, Office of Nuclear 
Regulatory Research; telephone: 301-415-3317; email: 
[email protected]. Both are staff of the U.S. Nuclear Regulatory 
Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

    Please refer to Docket ID NRC-2016-0233 when contacting the NRC 
about the availability of information regarding 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-2016-0233.
     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]. The DG is electronically available in 
ADAMS under Accession No. ML16124A200.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

B. Submitting Comments

    Please include Docket ID NRC-2016-0233 in your comment submission. 
The NRC cautions you not to include identifying or contact information 
that you do not want to be publicly disclosed in your comment 
submission. The NRC posts all comment submissions at https://www.regulations.gov as well as enters the comment submissions into 
ADAMS. The NRC does not routinely edit comment submissions to remove 
identifying or contact information.
    If you are requesting or aggregating comments from other persons 
for submission to the NRC, then you should inform those persons not to 
include identifying or contact information that they do not want to be 
publicly disclosed in their comment submission. Your request should 
state that the NRC does not routinely edit comment submissions to 
remove such information before making the comment submissions available 
to the public or entering the comment submissions into ADAMS.

II. Additional Information

    The NRC is reissuing for public comment a DG in the NRC's 
``Regulatory Guide'' series. This series was developed to describe and 
make available to the public information regarding methods that are 
acceptable to the NRC staff for implementing specific parts of the 
NRC's regulations, techniques that the staff uses in evaluating 
specific issues or postulated events, and data that the staff needs in 
its review of applications for permits and licenses.
    The DG, entitled ``Pressurized Water Reactor Control Rod Ejection 
and Boiling Water Reactor Control Rod Drop Accidents,'' is a proposed 
new guide temporarily identified by its task number, DG-1327.
    DG-1327 describes one acceptable method for demonstrating 
compliance with appendix A of part 50 of title 10 of the Code of 
Federal Regulations (10 CFR), General Design Criteria (GDC) 28, 
``Reactivity Limit,'' with respect to a control rod ejection (CRE) for 
pressurized-water reactors (PWRs) and a control rod drop (CRD) for 
boiling-water reactors (BWRs). DG-1327 proposes new guidance for 
analyzing these reactivity-initiated accidents. It defines fuel 
cladding failure thresholds for ductile failure, brittle failure, and 
pellet-clad mechanical interaction and provides radionuclide release 
reactions for use in assessing radiological consequences. It also 
describes analytical limits and guidance for demonstrating compliance 
with regulations governing reactivity limits.
    The draft guide incorporates new empirical data from in-pile, 
prompt power pulse test programs and analyses from several 
international publications on fuel rod performance under reactivity-
initiated accident conditions to provide guidance on acceptable 
analytical methods, assumptions, and limits for evaluating a CRE 
accident for a PWR. The draft guide expands the existing guidance for 
CRE accidents in Regulatory Guide (RG) 1.77, ``Assumptions Used for 
Evaluation a Control Rod Ejection Accident for Pressurized Water 
Reactors.'' However, the NRC intends to maintain RG 1.77.
    The NRC released the draft guide for public comment on November 21, 
2016 (81 FR 83288) with a 60 day comment period that expired on 
February 21, 2017. A public meeting was held at NRC Headquarters on 
January 25, 2017, while the guide was open for public comment. During 
the meeting, the NRC made a commitment to hold a second public meeting 
to discuss the staff's proposed resolution of key comments prior to 
finalization of the guide. Following the January 25, 2017 public 
meeting, the NRC extended the comment period to April 21, 2017 
(February 1, 2017; 82 FR 8958) to allow more time for comment. A second 
public meeting was held at NRC Headquarters on June 5, 2018, to discuss 
resolution of the public comments. To facilitate discussion at the 
meeting, drafts of the guide (ADAMS Accession No. ML18138A459) and a 
table showing the NRC staff's initial resolution of the public comments 
(ADAMS Accession No. ML18138A458) were made publicly available prior to 
the meeting.
    As a result of the written public comments and discussions at the 
public meetings, the NRC made several changes to the draft guide, and 
the NRC's final response to the public comments can be found in ADAMS 
under Accession No. ML18302A107. Among the changes were: (1) Division 
of the analytical methods in the staff regulatory guidance to 
differentiate between PWRs and BWRs, (2) the graphs for cladding 
failure thresholds were extended based on more recent testing, (3) 
addition of an appendix to define acronyms and abbreviations used in 
the guide, (4) addition of an appendix that provides guidance on 
steady-state and transient gap fission product inventories for releases 
following a CRE or CRD accident, and (5) addition of an appendix that 
has alloy-specific cladding hydrogen uptake models.

III. Backfitting and Issue Finality

    DG-1327 describes one acceptable method for demonstrating 
compliance with GDC 28 in 10 CFR part 50, appendix A, with respect to a 
control rod ejection for PWRs and a control rod drop for BWRs. It 
addresses fuel cladding failure thresholds for ductile failure, brittle 
failure, and pellet-clad mechanical interaction, provides radionuclide 
release fractions for use in assessing radiological consequences, and 
describes analytical limits and guidance for demonstrating compliance 
with GDC 28 governing reactivity limits.
    This draft regulatory guide, if finalized, would not constitute 
backfitting as defined in 10 CFR 50.109, ``Backfitting'' (the Backfit 
Rule) and would not otherwise be inconsistent with the issue finality 
provisions in 10

[[Page 36963]]

CFR part 52, ``Licenses, Certifications and Approvals for Nuclear Power 
Plants.'' Existing licensees and applicants of final design 
certification rules will not be required to comply with the positions 
set forth in this draft regulatory guide. Further information on the 
staff's use of the draft regulatory guide, if finalized, is contained 
in the draft regulatory guide under Section D., ``Implementation.''
    Applicants and potential applicants are not, with certain 
exceptions, protected by either the Backfit Rule or any issue finality 
provisions under 10 CFR part 52. Neither the Backfit Rule nor the issue 
finality provisions under 10 CFR part 52--with certain exclusions 
discussed below--were intended to apply to every NRC action which 
substantially changes the expectations of current and future 
applicants. Therefore, the positions in any final draft regulatory 
guide, if imposed on applicants, would not represent backfitting 
(except as discussed below).
    The exceptions to the general principle are applicable whenever a 
10 CFR part 50 operating license applicant references a construction 
permit or a combined license applicant references a 10 CFR part 52 
license (i.e., an early site permit or a manufacturing license) or 
regulatory approval (i.e., a design certification rule or design 
approval). The staff does not, at this time, intend to impose the 
positions represented in the draft regulatory guide in a manner that is 
inconsistent with the Backfit Rule or any issue finality provisions in 
these 10 CFR part 52 licenses and regulatory approvals. If, in the 
future, the staff seeks to impose a position in this regulatory guide 
in a manner that constitutes backfitting under the Backfit Rule or does 
not provide issue finality as described in the applicable issue 
finality provision, then the staff will address the backfitting 
provisions in the Backtit Rule or criteria for avoiding issue finality 
as described in the applicable issue finality provision.

    Dated at Rockville, Maryland, this 24th day of July 2019.

    For the Nuclear Regulatory Commission.
Thomas H. Boyce,
Chief, Regulatory Guidance and Generic Issues Branch, Division of 
Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2019-16067 Filed 7-29-19; 8:45 am]
BILLING CODE 7590-01-P