[Federal Register Volume 71, Number 215 (Tuesday, November 7, 2006)]
[Notices]
[Pages 65137-65138]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-18711]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-298]


Nebraska Public Power District, Cooper Nuclear Station; Exemption

1.0 Background

    Nebraska Public Power District (NPPD or the licensee) are the 
holders 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 all 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), section 
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. Option B of Appendix J is titled, ``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 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 main steam 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 main steam isolation valve (MSIV) leakage is directed through the 
main steam drain piping into the condenser and is released into the 
environment as an unfiltered ground level effluent.
    In summary, the licensee analyzed the MSIV leakage pathway and the 
containment leakage pathways separately in a dose consequences 
analysis. The calculated radiological consequences of the combined 
leakage were found to be within the criteria of 10 CFR part 100 and 
General Design Criterion (GDC) 19. The NRC staff reviewed the 
licensee's analyses and found them acceptable as described in a safety 
evaluation dated September 1, 2004. By separating the MSIV leakage 
acceptance criteria from the overall integrated leak rate test 
criterion, and from the Type B and C leakage sum limitation, the CNS 
containment leakage testing will be made more consistent with the 
limiting assumptions used in the associated accident consequences 
analyses.

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 and 
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):
    (i) Application of the regulation in the particular circumstances 
conflicts with other rules or requirements of the Commission; or
    (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; or
    (iii) Compliance would result in undue hardship or other costs that 
are significantly in excess of those contemplated when the regulation 
was adopted, or that are significantly in excess of those incurred by 
others similarly situated; or

[[Page 65138]]

    (iv) The exemption would result in benefit to the public health and 
safety that compensates for any decrease in safety that may result from 
the grant of the exemption; or
    (v) The exemption would provide only temporary relief from the 
applicable regulation and the licensee or applicant has made good faith 
efforts to comply with the regulation; or
    (vi) There is present any other material circumstance not 
considered when the regulation was adopted for which it would be in the 
public interest to grant an exemption. If such condition is relied on 
exclusively for satisfying paragraph (a)(2) of this section, the 
exemption may not be granted until the Executive Director for 
Operations has consulted with the Commission.
    The licensee's exemption request was submitted in conjunction with 
a TS amendment application to increase the allowable leak rate for the 
MSIVs. The proposed amendment will be issued concurrently with this 
exemption. The exemption and amendment together would implement the 
recommendations of Topical Report NEDC-31858, ``BWR Report for 
Increasing MSIV Leakage Rate Limits and Elimination of Leakage Control 
Systems.'' The topical report was evaluated by the NRC staff and 
accepted in a safety evaluation dated March 3, 1999. The special 
circumstances associated with MSIV leakage testing are fully described 
in the topical report. These circumstances relate to the monetary costs 
and personnel radiation exposure involved with maintaining MSIV leakage 
limits more restrictive than necessary to meet offsite dose criteria 
and control room habitability criteria.
    The underlying purpose of the rule which implements Appendix J 
(i.e., 10 CFR 50.54(o)) 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. 
Based on the above, no new accident precursors are created by the 
exemption, thus, the probability of postulated accidents is not 
increased. Also, based on the above, the consequences of postulated 
accidents are not increased. As such, the NRC staff has determined that 
the intent of the rule is not compromised by the proposed exemption.
    The proposed exemption would permit exclusion of the main steam 
pathway leakage contributions from the overall integrated leakage rate 
Type A test measurement. This change has no relation to security 
issues. Therefore, the common defense and security is not impacted by 
this exemption.
    Based on the foregoing, the separation of the main steam pathways 
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 be acceptable.

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 from the 
requirements of Sections III.A and III.B of Option B of Appendix J to 
10 CFR part 50 for CNS.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (71 FR 61074).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 30th day of October 2006.

    For the Nuclear Regulatory Commission.
Catherine Haney,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
 [FR Doc. E6-18711 Filed 11-6-06; 8:45 am]
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