[Federal Register Volume 75, Number 64 (Monday, April 5, 2010)]
[Notices]
[Pages 17169-17170]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-7601]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-331; NRC-2010-0107]
Nextera Energy Duane Arnold, LLC, Duane Arnold Energy Center;
Exemption
1.0 Background
NextEra Energy Duane Arnold, LLC, formerly FPL Energy Duane Arnold,
LLC (the licensee) is the holder of Facility Operating License No. DPR-
49, which authorizes operation of the Duane Arnold Energy Center (Duane
Arnold). The facility consists of a boiling-water reactor located in
Linn County in the State of Iowa. The licensee was authorized to change
its name by Amendment No. 275, dated November 13, 2009, to the Facility
Operating License. The license provides, among other things, that the
facility is subject to all rules, regulations, and orders of the
Nuclear Regulatory Commission (NRC, the Commission) now or hereafter in
effect. In a letter dated March 4, 2009, FPL Energy Duane Arnold, LLC
requested exemption from certain requirements of 10 CFR part 50,
Appendix J.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR), Appendix J
specifies the leakage test requirements, schedules, and acceptance
criteria for tests of the leak-tight integrity of the primary reactor
containment and systems and components which penetrate the containment.
Option B of Appendix J is entitled ``Performance-Based Requirements.''
Option B, Section 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 Technical
Specifications (TSs).
The overall integrated leak 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
from main steam isolation valve (MSIV) leakage. The licensee has
requested exemption from Option B, Section III.A requirements to permit
exclusion of MSIV leakage from the overall integrated leak rate test
measurement. Main steam leakage includes leakage through all four main
steam lines and the main steam drain line.
Option B, Section III.B of 10 CFR part 50, Appendix J, ``Type B and
C Tests,'' requires, among other things, that the sum of the leakage
rates at accident pressure of Type B tests and pathway leakage rates
from Type C tests be less than the performance criterion (La) with
margin, as specified in the TSs. The licensee also requests exemption
from this requirement, to permit exclusion of the main steam pathway
leakage contributions from the sum of the leakage rates from Type B and
Type C tests.
The licensee requests this exemption because the main steam pathway
leakage is treated separately from the remainder of the assumed leakage
from primary containment in the design basis loss-of-coolant accident
(DBA LOCA) analysis. The MSIV leakage effluent has a different pathway
to the environment, when compared to a typical containment penetration.
The licensee has analyzed the MSIV and main steam pathway leakage
separately from the overall containment integrated leakage, local
leakage across pressure retaining, leakage limiting boundaries, and
containment isolation valve leakage in its dose consequence analysis.
By currently including the main steam pathway leakage in with the rest
of the primary containment leakage actual test results, it is
essentially being accounted for twice in the dose analysis.
In summary, by application dated March 4, 2009, the licensee
requested an exemption for the Duane Arnold Energy Center (Duane
Arnold). The proposed change will exempt Duane Arnold from certain
requirements of Appendix J to 10 CFR part 50. Specifically, the
licensee is requesting a permanent exemption to permit exclusion of the
main steam pathway leakage contributions from the overall integrated
leakage rate (Type A) test measurement and from the sum of the leakage
rates from local leakage rate (Type B and Type C) tests.
3.0 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 are present. Special circumstances are
present whenever, according to 10 CFR 50.12(a)(2)(ii), ``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 * * *.''
Authorized by Law
The exemption would permit exclusion of the main steam pathway
leakage contributions from the overall integrated leakage rate (Type A)
test
[[Page 17170]]
measurement and from the sum of the leakage rates from local leakage
rate (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, Appendix J. 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.
No Undue Risk to Public Health and Safety
The underlying purposes of 10 CFR part 50, Appendix J is to assure
that containment leak-tight integrity is maintained (a) as tight as
reasonably achievable, and (b) sufficiently tight so as to limit
effluent release to values bounded by the analyses of radiological
consequences of design-basis accidents.
In License Amendments 237 (regarding secondary containment
OPERABILITY during movement of irradiated fuel and core alterations,
dated April 16, 2001) and Amendment 240 (regarding Alternative Source
Term (AST), dated July 31, 2001), the NRC approved the use of the AST
(10 CFR 50.67) in the calculations of the radiological dose
consequences of design basis accidents (DBAs) for the Duane Arnold
Energy Center. The reactor design basis accident of concern is the
design basis loss-of-coolant accident (LOCA). The NRC Staff Safety
Evaluation accompanying Amendment 240 accepted that the main steam
pathway leakage is treated separately from the remainder of the assumed
leakage from primary containment in the LOCA analysis and once
dispersed in the primary containment, the release to the environment is
assumed to occur through three pathways: (1) The leakage of primary
containment atmosphere (i.e., design leakage); (2) the leakage of
primary containment atmosphere via design leakage through main steam
isolation valves (MSIVs); and (3) the leakage from emergency core
cooling systems (ECCS) that recirculate suppression pool water outside
of the primary containment (i.e., design leakage). Since Amendment 237
was specifically for the Fuel Handling Accident (FHA), which occurs
during refueling when primary containment is not required, the main
steam pathway leakage is not part of the release pathway for this
reactor accident. Thus, no new accident precursors are created by
exempting Duane Arnold from certain requirements of Appendix J to 10
CFR part 50.
Further, based on the above the determination that no new accident
precursors are created by the proposed exemption, the probability of
postulated accidents is not increased. Additionally, based on the above
based on the way the main steam pathway leakage has previously been
evaluated and accepted in the Duane Arnold radiological dose analysis
for DBAs separately from the overall leakage associated with the
primary containment boundary (Type A) and local leakage rate total
(Type B and C), the consequences of postulated accidents are not
increased. Therefore, there is no undue risk, since risk is probability
multiplied by consequences, to public health and safety.
Consistent With Common Defense and Security
The exemption would permit exclusion of the main steam pathway
leakage contributions from the overall integrated leakage rate (Type A)
test measurement and from the sum of the leakage rates from local
leakage rate (Type B and Type C) tests. This change to accounting for
leakage rate measurement has no relation to security issues. Therefore,
the common defense and security is not impacted by this exemption.
Special Circumstances
Special circumstances, in accordance with 10 CFR 50.12(a)(2), are
present whenever 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
underlying purpose of 10 CFR part 50, Appendix J, Option B, Paragraphs
III.A and III.B is to ensure the actual radiological consequences of
reactor accidents remain below those previously evaluated and accepted,
as demonstrated by the actual, periodic measurement of containment
leakage (Type A) and local leakage rate measurement (Type B and C).
Although Type A, and Type B and C, leakage tests are defined as a
measurement of those leakages, inclusion of the main steam pathway
leakage results in double counting at the Duane Arnold Energy Center,
once as a part of the actual containment leakage and again as part of
main steam pathway leakage used in dose calculations. This is because
Duane Arnold's revised design-basis radiological consequence analysis,
reviewed and approved in Amendments 237 and 240 to Duane Arnold's
operating license, address MSIV leakage as individual factors,
exclusive of primary containment leakage. Therefore, requiring
inclusion of main steam pathway leakage in the Type A, and Type B and
C, leakage is not necessary to achieve the underlying purpose of the
rule.
Because compliance with 10 CFR part 50, Appendix J, Option B,
Paragraphs III.A and III.B is not necessary to achieve the underlying
purposes of the requirements, the special circumstances required by 10
CFR 50.12(a)(2), for the granting of an exemption from 10 CFR Part 50,
Appendix J, Option B, Paragraphs III.A and III.B exist.
4.0 Conclusion
Accordingly, the Commission 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 Commission hereby grants to NextEra Energy Duane Arnold,
LLC a permanent exemption from the requirements of 10 CFR part 50,
Appendix J, Option B, Paragraphs III.A and III.B for the Duane Arnold
Energy Center.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment [75 FR 13318; dated March 19, 2010].
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 29th day of March 2010.
For the Nuclear Regulatory Commission.
Robert A. Nelson,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. 2010-7601 Filed 4-2-10; 8:45 am]
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