[Federal Register Volume 85, Number 122 (Wednesday, June 24, 2020)]
[Notices]
[Pages 37965-37968]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-13651]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-254 and 50-265; NRC-2020-0143]
Exelon Generation Company, LLC and MidAmerican Energy Company
Quad Cities Nuclear Power Station, Units 1 and 2
AGENCY: Nuclear Regulatory Commission.
ACTION: Exemption; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued an
exemption in response to a July 22, 2019, request from Exelon
Generation Company, LLC, from certain regulatory requirements in order
to permit exclusion of main steam isolation valve (MSIV) leakage from
the overall integrated leak rate Type A test measurement and MSIV
pathway leakage contributions from the combined leakage rate of all
penetrations and valves subject to Type B and Type C tests.
DATES: The exemption was issued on June 18, 2020.
ADDRESSES: Please refer to Docket ID NRC-2020-0143 when contacting the
NRC about the availability of information regarding this document. You
may obtain publicly-available information related to this document
using any of the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2020-0143. Address
questions about NRC docket IDs in Regulations.gov to Jennifer Borges;
telephone: 301-287-9127; email:
[[Page 37966]]
[email protected]. For technical questions, contact the
individual 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]. The ADAMS accession number for each
document referenced (if it is available in ADAMS) is provided the first
time that it is mentioned in this document.
FOR FURTHER INFORMATION CONTACT: Robert F. Kuntz, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-3733, email: [email protected].
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: June 19, 2020.
For the Nuclear Regulatory Commission.
Russell S. Haskell,
Project Manager, Plant Licensing Branch III, Division of Operating
Reactor Licensing, Office of Nuclear Reactor Regulation.
Attachment--Exemption
NUCLEAR REGULATORY COMMISSION
Docket Nos. 50-254 and 50-265
Exelon Generation Company, LLC and MidAmerican Energy Company Quad
Cities Nuclear Power Station, Units 1 and 2
Exemption
I. Background
Exelon Generation Company, LLC (EGC, the licensee) and
MidAmerican Energy Company are the holders of Facility Operating
License Nos. DPR-29 and DPR-30, which authorize operation of the
Quad Cities Nuclear Power Station (QCNPS), Units 1 and 2. The
licenses provide, among other things, that the facilities are
subject to the rules, regulations, and orders of the U.S. Nuclear
Regulatory Commission (NRC, the Commission) now or hereafter in
effect. The facilities each consist of a boiling, light-water
reactor located in Rock Island County, Illinois.
II. Request/Action
In its letter dated March 5, 2019 (Agencywide Documents and
Access Management System (ADAMS) Accession No. ML19064B369), as
supplemented by letters dated May 23, 2019 (ADAMS Accession No.
ML19143A347), July 22, 2019 (ADAMS Accession No. ML19203A176),
February 24, 2020 (ADAMS Accession No. ML20055E826), and March 31,
2020 (ADAMS Accession No., ML20091H576) EGC requested a permanent
exemption from the Part 50 of Title 10 of the Code of Federal
Regulations (10 CFR), Appendix J, Option B, Section III.A
requirements in order to permit exclusion of main steam isolation
valve (MSIV) leakage from the overall integrated leak rate Type A
test measurement, and from Option B, Section III.B, requirements in
order to permit exclusion of the MSIV pathway leakage contributions
from the combined leakage rate of all penetrations and valves
subject to Type B and Type C tests. The letters also requested
license amendments to revise Technical Specification (TS) 3.6.1.3,
``Primary Containment Isolation Valves (PCIVs),'' Surveillance
Requirement (SR) 3.6.1.3.10 that would increase the single and
combined MSIV leakage rate limits; add a new TS 3.6.2.6, ``Residual
Heat Removal (RHR) Drywell Spray,'' to reflect the crediting of
drywell spray for fission product removal; and revise TS 3.6.4.1,
``Secondary Containment,'' SR 3.6.4.1.1 to address short-duration
conditions during which the secondary containment pressure may not
meet the SR pressure requirement at QCNPS, Units 1 and 2. The
license amendment requests are addressed separately.
Under Part 50 of 10 CFR, paragraph 50.54(o), primary reactor
containments for water-cooled power reactors are subject to the
requirements of Appendix J to 10 CFR part 50. Appendix J specifies
the leakage rate test requirements, schedules, and acceptance
criteria for tests of the leak-tight integrity of the reactor
containment, and systems and components that penetrate the
containment. Option B of 10 CFR 50, Appendix J, ``Performance-Based
Requirements,'' paragraph III.A, ``Type A Test,'' requires, among
other things, that the overall integrated leakage rate must not
exceed the allowable leakage rate (La) with margin, as
specified in the TSs. The overall integrated leakage rate is defined
in 10 CFR part 50, Appendix J, as ``the total leakage rate through
all tested leakage paths, including containment welds, valves,
fittings, and components that penetrate the containment system.''
This includes the contribution through the four main steam (MS)
lines where each line contains two MSIVs in series. Paragraph III.B,
``Type B and C Tests,'' requires, among other things, that the sum
of the leakage rates of Type B and Type C local leakage rate tests
be less than the performance criterion (La) with margin
as specified in the TSs. The allowable leakage rates set in the TSs
ensure that the required dose limits, such as in 10 CFR 50.67,
``Accident source term,'' will not be exceeded.
This requested exemption concerns the MS system, which
penetrates containment. The licensee requested this exemption
because the MS pathway leakage is treated separately from the
remainder of the assumed leakage from primary containment in the
design basis loss of coolant accident (LOCA) analysis. The
radiological consequences of MSIV leakage are modeled as a separate
primary containment release path to the environment that bypasses
secondary containment, and therefore, it is not filtered through the
standby gas treatment system like other containment leakage. The
design basis LOCA dose calculation assumes all MSIV leakage migrates
to the turbine building and then to the environment. By currently
including the MS pathway leakage with the rest of the primary
containment leakage test results, it is being accounted for twice--
once as part of the actual containment leakage and again as part of
the MSIV leakage used in the LOCA dose calculations.
III. Discussion
Pursuant to 10 CFR 50.12, the Commission may, upon application
by any interested person or upon its own initiative, grant
exemptions from the requirements of 10 CFR part 50 when (1) the
exemptions are authorized by law, will not present an undue risk to
public health or safety, and are consistent with the common defense
and security; and (2) when special circumstances as described in 10
CFR 50.12(a)(2)(i)-(vi) are present. The licensee asserted that
special circumstances are present under 10 CFR 50.12(a)(2)(ii)
(stating that the application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule or
is not necessary to achieve the underlying purpose of the rule).
The licensee's exemption request was submitted with license
amendments request to increase the allowable MSIV leakage rate. The
exemption and amendments together will permit an increase in
allowable MSIV leakage rate that is excluded from the overall
integrated leak rate Type A test measurement and excluded from the
combined Type B and Type C test total. The licensee described its
view on the special circumstances associated with the MSIV leakage
path testing in its application dated July 22, 2019.
A. The Exemption Is Authorized by Law
This exemption permits exclusion of the MSIV pathway leakage
contribution from the overall integrated leakage rate Type A test
measurement and from the combined leakage rate of all penetrations
and valves subject to Type B and Type C tests. As stated above, 10
CFR 50.12 allows the NRC to grant exemptions from the requirements
of 10 CFR part 50. The NRC staff has determined that granting of the
licensee's proposed exemption will not result in a violation of the
Atomic Energy Act of 1954, as amended, or the Commission's
regulations. Therefore, the exemption is authorized by law.
B. The Exemption Presents No Undue Risk to Public Health and Safety
Type A tests to measure the containment system overall
integrated leakage rate must be conducted under conditions
representing design basis LOCA containment peak pressure. Type B
pneumatic tests to detect and measure local leakage rates across
pressure retaining, leakage-limiting boundaries, and Type C
pneumatic tests to measure containment isolation valve leakage
rates, must be conducted to ensure the integrity of the overall
containment system as a barrier to fission product release to reduce
the risk from reactor accidents.
In license Amendment Nos. 233 and Amendment 229 (ADAMS Accession
No. ML062070290), the NRC approved the use of the alternative source
term (AST) (as
[[Page 37967]]
prescribed in 10 CFR 50.67) in the calculations of the radiological
dose consequences of design basis accidents (DBAs), including the
design basis LOCA, for QCNPS, Units 1 and 2. The NRC staff safety
evaluation accompanying these amendments acknowledged that once
fission products are dispersed in the primary containment, their
release to the environment is assumed to occur through three
pathways: (1) The leakage of primary containment atmosphere; (2) the
leakage of primary containment atmosphere through MSIVs; and (3) the
leakage from emergency core cooling systems that recirculate
suppression pool water outside of the primary containment. As noted
above, however, leakage through the MSIVs is considered a separate
pathway and is calculated as a separate contributor to the dose
consequence analysis. As such, the inclusion of MSIV leakage as part
of Type A and as part of Type B and C test results is not necessary
to ensure the actual radiological consequences of DBAs remain below
the regulatory limit.
The proposed exemption does not create any new accident
precursors. Therefore, the probability of postulated accidents is
not increased. Also, the consequences of postulated accidents are
not significantly changed from the previously evaluated consequences
associated with the design basis LOCA as described in the AST
amendments. Therefore, there is no undue risk to public health and
safety.
C. The Exemption Is Consistent With the Common Defense and Security
The proposed exemption excludes the MSIV pathway leakage
contribution from the overall integrated leakage rate Type A test
measurement and from the combined leakage rate of all penetrations
and valves subject to Type B and Type C tests. This change to
accounting for leakage rate measurement has no relation to security
issues. Therefore, the exemption is consistent with the common
defense and security.
D. Special Circumstances
Under 10 CFR 50.12(a)(2)(ii) special circumstances include when,
``[a]pplication of the regulation in the particular circumstances
would not serve the underlying purpose of the rule or is not
necessary to achieve the underlying purpose of the rule.''
The test requirements in Appendix J to 10 CFR part 50 ensure
that leakage through containments or systems and components
penetrating containments does not exceed allowable leakage rates
specified in the technical specifications, and integrity of the
containment structure is maintained during its service life. Option
B of Appendix J identifies the performance-based requirements and
criteria for preoperational and subsequent periodic leakage-rate
testing.
The licensee has analyzed the MS pathway leakage separately from
the overall containment integrated leakage; the local leakage across
pressure-containing or leakage-limiting boundaries; and the
containment isolation valve leakage in its dose consequence
analyses. The dose consequences were found to be within the
applicable acceptance criteria in 10 CFR 50.67, ``Accident source
term,'' and the guidance of NRC Regulatory Guide 1.183,
``Alternative Radiological Source Terms for Evaluating Design Basis
Accidents [DBAs] at Nuclear Power Reactors,'' dated July 2000 (ADAMS
Accession No. ML003716792). The staff has reviewed the licensee's
analysis and determined that the dose consequences of implementing
the proposed change are below the applicable acceptance criteria and
the containment leaks will continue to be limited by the QCNPS,
Units 1 and 2, TSs.
Therefore, because the underlying purposes of 10 CFR part 50,
Appendix J, is still achieved, the special circumstances required by
10 CFR 50.12(a)(2)(ii) for the granting of an exemption from 10 CFR
part 50, Appendix J, Option B, Sections lII.A and III.B, exist.
E. Environmental Considerations
The NRC staff determined that the issuance of the requested
exemption meets the provisions of categorical exclusion 10 CFR
51.22(c)(25) because: (i) No significant hazards consideration; (ii)
no significant change in the types or significant increase in the
amounts of any effluents that may be released offsite; (iii) no
significant increase in individual or cumulative public or
occupational radiation exposure; (iv) there is no significant
construction impact; (v) there is no significant increase in the
potential for or consequences from radiological accidents; and (vi)
the requirements from which an exemption is sought involve e.g.,
inspection or surveillance requirements. Therefore, in accordance
with 10 CFR 51.22(b), no environmental impact statement or
environmental assessment need be prepared in connection with the
NRC's issuance of this exemption. The basis for the NRC staff's
determination is provided in the following evaluation of the
requirements in 10 CFR 51.22(c)(25)(i)-(vi).
Requirements in 10 CFR 51.22(c)(25)(i)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(i), the exemption must involve ``no significant hazards
consideration.'' The NRC staff evaluated whether the exemption
involves no significant hazards consideration by using the standards
in 10 CFR 50.92(c), as presented below:
1. Does the requested exemption involve a significant increase
in the probability or consequences of an accident previously
evaluated?
Response: No.
The proposed exemption would permit exclusion of the MSIV
pathway leakage contribution from the overall integrated leakage
rate Type A test measurement and from the sum of the leakage rates
from Type B and Type C tests. The leakage of primary containment
atmosphere through MSIVs is accounted for as a separate contributor
to the design basis LOCA dose consequence analysis. This exemption
will allow the leakage testing to be performed in a manner
consistent with the way MSIV leakage is modeled in the revised
radiological consequence analysis included as part of the related
license amendment requests (LARs) submitted in the letter dated
March 5, 2019 as supplemented by the letters dated March 23, 2019,
February 24, 2020, and March 31, 2020. This change to the leakage
rate measurement does not increase the probability or consequences
of an accident previously evaluated.
Therefore, the exemption does not involve a significant increase
in the probability or consequences of an accident previously
evaluated.
2. Does the requested exemption create the possibility of a new
or different kind of accident from any accident previously
evaluated?
Response: No.
The proposed exemption does not involve a physical modification
to the plant (i.e., no new or different type of equipment will be
installed and there are no physical modifications to existing
equipment associated with the proposed change). Similarly, it does
not physically change any structures, systems, or components
involved in the mitigation of any accidents.
Therefore, the exemption does not create the possibility of a
new or different kind of accident from any accident previously
evaluated.
3. Does the requested exemption involve a significant reduction
in a margin of safety?
Response: No.
The proposed exemption does not alter a design basis or safety
limit nor cause a limit to be exceeded. The proposed exemption allows
the results of the TS required MSIV leakage pathway tests to no longer
be accounted for as part of the overall integrated leakage rate Type A
test measurement and as part of the sum of the local leakage rates from
Type B and Type C tests. This change only affects which leakage rates
are included in the Types A, B, and C results. This exemption will
allow the leakage testing to be performed in a manner consistent with
the way MSIV leakage is modeled in the revised radiological consequence
analysis submitted as part of the related LAR.
Therefore, the exemption does not involve a significant reduction
in a margin of safety.
Based on the evaluation above, the NRC staff has determined that
the proposed exemption involves no significant hazards consideration.
Therefore, the requirements of 10 CFR 51.22(c)(25)(i) are met.
Requirements in 10 CFR 51.22(c)(9)(ii)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(ii), the exemption must result in ``no significant change
in the types or significant increase in the amounts of any effluents
that may be released offsite.'' The proposed exemption allows the
results of the TS-required MSIV leakage pathway tests to be accounted
for only as part of the design basis LOCA
[[Page 37968]]
consequence analysis. This change only affects the total in which the
leakage rates are included and does not change the frequency or
pressure at which the testing must be performed. The underlying purpose
of 10 CFR part 50, Appendix J, is to demonstrate by periodic testing
and visual inspection that the primary reactor containment will be able
to perform its function of providing an essentially leak-tight barrier
against uncontrolled release of radioactivity to the environment. The
inclusion of the MSIV leakage testing results in the design basis LOCA
serves the same purpose as the inclusion in the rate Type A test
measurement and the sum of the leakage rates from Type B and Type C
tests required by Appendix J, Option B, paragraphs III.A and III.B.
Therefore, the proposed exemption will not significantly change the
types of effluents that may be released offsite, or significantly
increase the amount of effluents that may be released offsite.
Therefore, the requirements of 10 CFR 51.22(c)(25)(ii) are met.
Requirements in 10 CFR 51.22(c)(9)(iii)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(iii), the exemption must result in ``no significant
increase in individual or cumulative public or occupational radiation
exposure.'' The proposed exemption permits the exclusion of the MSIV
leakage pathway results from the Type A test measurement and the sum of
the leakage rates from Type B and Type C tests required by Appendix J,
Option B, paragraphs III.A and III.B, and has no impact on, or change
to, fuel or core design. Additionally, the TSs still require that the
MSIV leakage rates be tested and maintained below set limits. As such,
the calculated public and occupational doses will remain essentially
the same. Therefore, the proposed exemption will not significantly
increase individual or cumulative public or occupational radiation
exposure. Therefore, the requirements of 10 CFR 51.22(c)(25)(iii) are
met.
Requirement in 10 CFR 51.22(c)(25)(iv)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(iv), the exemption must result in ``no significant
construction impact.'' The exemption does not propose any changes to
the site, alter the site, or change the operation of the site.
Therefore, there is no significant construction impact. Therefore, the
requirements of 10 CFR 51.22(c)(25)(iv) are met.
Requirement in 10 CFR 51.22(c)(25)(v)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(v), the exemption must involve ``no significant increase
in the potential for or consequences from radiological accidents.'' The
proposed exemption does not remove the requirement to perform leakage
rate testing of the MSIVs. This exemption will allow the leakage
testing to be performed in a manner consistent with the way MSIV
leakage is modeled in the revised radiological consequence analysis
submitted as part of the related LAR. Therefore, this change to the
leakage rate measurement does not result in a significant increase in
the potential for or consequences from radiological accidents.
Therefore, the requirements of 10 CFR 51.22(c)(25)(v) are met.
Requirement in 10 CFR 51.22(c)(25)(vi)
To qualify for a categorical exclusion under 10 CFR
51.22(c)(25)(vi)(C), the exemption must involve inspection or
surveillance requirements. The exemption seeks to permit exclusion of
the MSIV leakage from the overall integrated leak rate Type A test
measurement and the combined leakage rate of all penetrations and
valves subject to Type B and Type C tests required by Appendix J to 10
CFR part 50. Appendix J specifies the leakage rate test requirements,
schedules, and acceptance criteria for tests of the leak-tight
integrity of the reactor containment, and systems and components that
penetrate the containment. Therefore, the exemption involves a
surveillance requirement. Therefore, the requirements of 10 CFR
51.22(c)(25)(vi) are met.
Conclusion
Based on the above, the NRC staff concludes that the proposed
exemption meets the eligibility criteria for the categorical exclusion
set forth in 10 CFR 51.22(c)(25). Therefore, in accordance with 10 CFR
51.22(b), no environmental impact statement or environmental assessment
need be prepared in connection with the NRC's issuance of this
exemption.
IV. Conclusions
Accordingly, the NRC has determined that, pursuant to 10 CFR 50.12,
the exemption is authorized by law, will not present an undue risk to
the public health and safety, and is consistent with the common defense
and security. Also, special circumstances are present. Therefore, the
NRC hereby grants EGC a permanent exemption (1) from the requirements
of 10 CFR part 50, Appendix J, Option B, Section III.A, to allow
exclusion of the MSIV pathway leakage from the overall integrated
leakage rate measured when performing a Type A test; and (2) from the
requirements of 10 CFR part 50, Appendix J, Option B, Section III.B, to
allow exclusion of the MSIV pathway leakage from the combined leakage
rate of all penetrations and valves subject to Types B and C tests for
QCNPS, Units 1 and 2.
This exemption is effective upon issuance.
Dated: 18th day of June 2020.
For the Nuclear Regulatory Commission
Craig G. Erlanger,
Director, Division of Operating Reactor Licensing Office of Nuclear
Reactor Regulation.
[FR Doc. 2020-13651 Filed 6-23-20; 8:45 am]
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