[Federal Register Volume 74, Number 181 (Monday, September 21, 2009)]
[Notices]
[Pages 48103-48104]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-22600]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-298; NRC-2009-0398]


Nebraska Public Power District; Cooper Nuclear Station; Exemption

1.0 Background

    Nebraska Public Power District (NPPD or the licensee) is the holder 
of Facility Operating License No. DPR-46 which authorizes operation of 
the Cooper Nuclear Station (CNS). The license provides, among other 
things, that the facility is subject to the rules, regulations, and 
orders of the Nuclear Regulatory Commission (NRC, the Commission) now 
or hereafter in effect.
    The facility consists of a boiling-water reactor located in Nemaha 
County, Nebraska.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), Part 50, 
paragraph 50.54(o), requires primary reactor containments for water-
cooled power reactors to be subject to the requirements of Appendix J 
to 10 CFR Part 50. 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 
that penetrate the containment. Appendix J, Option B, ``Performance-
Based Requirements,'' 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 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 and 
the MS inboard drain line (penetration X-8). The MS Pathway includes 
leakage from the MS line penetrations plus the MS inboard 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.
    By application dated October 13, 2008, as supplemented by letters 
dated April 8, May 29, June 12, and September 1, 2009, the licensee 
requested exemption from Option B, Section III.A requirements in order 
to permit exclusion of MS Pathway leakage from the overall integrated 
leak rate test measurement. The licensee also requested exemption from 
Option B, Section III.B requirements in order to permit exclusion of 
the MS Pathway leakage contributions from the sum of the leakage rates 
from Type B and Type C tests. The licensee's application included a 
license amendment request to revise the radiological assessment 
calculation methodology for the design basis loss-of-coolant accident 
at CNS through application of the alternative source term, in 
accordance with the provisions of 10 CFR 50.67 and 50.90, and to revise 
the TSs accordingly.
    The NRC previously granted a license amendment (Amendment No. 226, 
dated October 31, 2006) and an exemption (letter to licensee dated 
October 30, 2006) from (1) Option B, Section III.A requirements in 
order to permit exclusion of MS isolation valve (MSIV) leakage from the 
overall integrated leakage rate measured when performing a Type A test, 
and (2) Option B, Section III.B requirements in order to permit 
exclusion of the MSIV leakage from the combined leakage rate of the 
penetrations and valves subject to Type B and Type C tests. The only 
difference in the current exemption request is the inclusion of the 
leakage contribution from the MS inboard drain line with the MSIV 
leakage in the MS Pathway.
    The MS leakage effluent has a different pathway to the environment, 
when compared to a typical containment penetration. It is not directed 
into the secondary containment and filtered through the standby gas 
treatment system as is other containment leakage. Instead, the MS 
leakage is collected and treated via an alternative leakage treatment 
(ALT) path having different mitigation characteristics.
    In performing accident analyses, it is appropriate to group various 
leakage effluents according to the treatment they receive before being 
released to the environment (e.g., from MS pathways). The proposed 
exemption would more appropriately permit ALT pathway leakage to be 
independently grouped with its unique leakage limits. In this manner, 
the CNS containment leakage testing program will be more consistent 
with the limiting assumptions used in the associated accident 
consequence analyses.
    The licensee has analyzed the MS 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 analyses. Specifically, 
the alternative source term design-basis accident analyses use the MS 
piping, MS drain lines, and main condenser as an alternate means for MS 
Pathway leakage treatment. The dose consequences were found to be 
within the acceptance criteria of 10 CFR 50.67, ``Accident source 
term,'' and the guidance of NRC Regulatory Guide

[[Page 48104]]

1.183, ``Alternative Radiological Source Terms for Evaluating Design 
Basis Accidents at Nuclear Power Reactors,'' dated July 2000.
    Therefore, the separation of the MS Pathway from the other 
containment leakage pathways is warranted because a separate 
radiological consequence term has been provided for these pathways. The 
revised design-basis radiological consequences analyses address these 
pathways as individual factors, exclusive of the primary containment 
leakage. Therefore, the NRC staff finds the proposed exemption from 
Appendix J, to separate MS leakage from other containment leakage, to 
be acceptable.

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. The licensee's exemption 
request was submitted with a license amendment request to use the 
alternative source term methodology for use in calculating the dose 
consequences of the design-basis loss-of-coolant accident analysis. The 
NRC staff will issue the proposed amendment in conjunction with the 
exemption. The exemption and amendment together would implement the 
alternative source term methodology. The special circumstances 
associated with the MS Pathway leakage testing are fully described in 
the licensee's application dated October 13, 2008, as supplemented by 
letters dated April 8, May 29, June 12, and September 1, 2009, and 
discussed below.

Authorized by Law

    This exemption would permit exclusion of the MS 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. 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.

No Undue Risk to Public Health and Safety

    The underlying purposes of 10 CFR Part 50, Appendix J, Option B, 
Sections III.A and III.B are to ensure 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. 
Based on the above, no new accident precursors are created by exclusion 
of the MS 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, thus, the probability of postulated 
accidents is not increased. Also, based on the above, the consequences 
of postulated accidents are not increased. Therefore, there is no undue 
risk to public health and safety.

Consistent With Common Defense and Security

    The proposed exemption would exclude the MS 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. This change to the operation of the plant has no relation to 
security issues. Therefore, the common defense and security is not 
impacted by this exemption.

Special Circumstances

    Special circumstances include, in part, the special circumstances 
defined in 10 CFR 50.12(a)(2)(ii), which states, ``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, is to ensure 
that containment leak-tight integrity is maintained as tight as 
reasonably achievable and sufficiently tight so as to limit effluent 
release to values bounded by the analyses of radiological consequences 
of design-basis accidents. The intent of the rule is not compromised by 
the licensee's proposed action because the containment leak rates will 
continue to be limited by CNS's TSs. The proposed action will 
appropriately permit ALT pathway leakage to be independently grouped 
with its unique leakage limits and maintain the accident dose analyses 
consequences within the acceptance criteria of 10 CFR 50.67.
    Therefore, since the underlying purposes of 10 CFR Part 50, 
Appendix J, is 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 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 NPPD an exemption (1) from the 
requirements of 10 CFR Part 50, Appendix J, Option B, Section III.A, to 
allow exclusion of the MS 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 MS Pathway leakage from the combined leakage 
rate of all penetrations and valves subject to Type B and C tests for 
CNS.
    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 (74 FR 47030; September 14, 2009).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 14th day of September 2009.

    For the Nuclear Regulatory Commission.
Joseph G. Giitter,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. E9-22600 Filed 9-18-09; 8:45 am]
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