[Federal Register Volume 71, Number 191 (Tuesday, October 3, 2006)]
[Notices]
[Pages 58440-58442]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-16270]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-259]


Tennessee Valley Authority; Browns Ferry Nuclear Plant, Unit 1; 
Exemption

1.0 Background

    The Tennessee Valley Authority (TVA, the licensee) is the holder of 
Facility Operating License No. DPR-33, which authorizes operation of 
the Browns Ferry Nuclear Plant, Unit 1 (BFN-1). The license provides, 
among other things, that the facility is subject to all rules, 
regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC, 
the Commission) now or hereafter in effect.
    The BFN-1 facility consists of a boiling water reactor (BWR) 
located in Limestone County, Alabama.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), 50.54(o), 
requires that primary reactor containments for water-cooled power 
reactors 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 which penetrate 
the containment. Appendix J, Option B, Section III.A requires that the 
overall integrated leak rate must not exceed the allowable leakage with 
margin, as specified in the Technical Specifications (TSs). The overall 
integrated leak rate, as specified in the 10 CFR part 50, Appendix J 
definitions, includes the contribution from main steam isolation valve 
(MSIV) leakage. By letter dated July 9, 2004, the licensee requested 
exemption from Option B, Section III.A, requirements to permit 
exclusion of MSIV leakage from the overall integrated leak rate test 
measurement.
    Option B, Section III.B of 10 CFR part 50, Appendix J, requires 
that the sum of the leakage rates of all Type B and Type C local leak 
rate tests be less than the performance criterion with margin, as 
specified in the TSs. The licensee also requests exemption from this 
requirement, to permit exclusion of the MSIV contribution to the sum of 
the 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)

[[Page 58441]]

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) special circumstances are present. Section 
50.12(a)(2)(ii) of 10 CFR states that special circumstances are present 
when ``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.'' In addition, Sec.  
50.12(a)(2)(iii) of 10 CFR states that special circumstances are 
present when ``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.''
    Testing in accordance with 10 CFR part 50, Appendix J, ensures that 
primary containment leakage following a design basis loss-of-coolant 
accident will be within the allowable leakage limits specified in the 
TSs and assumed in the safety analyses for determining radiological 
consequences. For BFN-1, the containment integrated leakage rate test 
currently includes leakage through closed MSIVs. However, the MSIV 
leakage effluent has a different pathway to the environment compared to 
other containment penetrations. It is not directed into the secondary 
containment and filtered through the standby gas treatment system as is 
other containment leakage. Instead, the MSIV leakage is directed 
through the main steam drain piping into the condenser and is released 
to the environment as an unfiltered ground level effluent. The licensee 
analyzed the MSIV leakage pathway for the increased leakage (from less 
than or equal to 11.5 standard cubic feet per hour (scfh) per valve to 
less than or equal to 100 scfh per valve, with combined leakage for all 
four main steam lines less than or equal to 150 scfh), and the 
containment leakage pathway separately in a dose consequences analysis. 
The calculated radiological consequences of the combined leakages were 
found to be within the criteria of 10 CFR part 100 and 10 CFR part 50, 
Appendix A, General Design Criterion 19. The NRC staff reviewed the 
licensee's analyses and found them acceptable, as described in the 
safety evaluation associated with Amendment No. 251, dated September 
27, 2004. In approving Amendment No. 251, the NRC staff added license 
condition 2.C(15):

    The licensee is required to confirm that the conclusions made in 
TVA's letter dated September 17, 2004 [Agencywide Documents Access 
and Management System Accession No. ML042730342], for the turbine 
building remain acceptable using seismic demand accelerations based 
on dynamic seismic analysis prior to the restart of Unit 1.

    In approving these exemptions, the NRC staff notes that the 
licensee must satisfy license condition 2.C(15).
    By separating the MSIV leakage acceptance criteria from the overall 
integrated leak rate test criteria, and from the Type B and C leakage 
sum limitation, the BFN-1 containment leakage testing program will be 
made more consistent with the limiting assumptions used in the 
associated accident consequences analyses. It will also allow 
additional operational flexibility by, in effect, increasing the total 
containment leakage rate limit while remaining within the applicable 
dose consequence guidelines and requirements. The licensee's exemption 
request was submitted in conjunction with a proposed amendment to the 
TSs to increase the allowable leak rate for MSIVs, which is being 
evaluated by the NRC staff separately. The amendment associated with 
this exemption will revise TS Surveillance Requirement (SR) 3.6.1.3.10 
to limit the maximum allowable MSIV leakage through each individual 
valve to 100 scfh and combined MSIV leakage to 150 scfh. The requested 
exemption from Appendix J requirements for MSIV leakage will allow BFN-
1 to operate with the proposed TS increased allowable MSIV leakage 
rates with reduced radiological exposure to plant personnel for 
maintaining MSIV leakage limits. The licensee's exemption request and 
proposed changes to the TSs together would implement the recommendation 
of BWR Owners Group Topical Report NEDC-31858, ``BWR Report for 
Increasing MSIV Leakage Rate Limits and Elimination of Leakage Control 
Systems,'' which was approved by the NRC staff in a safety evaluation 
dated March 3, 1999. Therefore, the NRC staff finds the proposed 
exemptions from Appendix J to separate MSIV leakage from other 
containment leakage to be acceptable.

Authorized by Law

    This proposed exemptions would permit exclusion of MSIV leakage 
from the overall integrated leak rate test measurement and permit 
exclusion of the MSIV contribution to the sum of the Type B and Type C 
local leak rate 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 the licensee's proposed 
exemptions will not result in a violation of the Atomic Energy Act of 
1954, as amended, or the Commission's regulations. Therefore, the 
exemptions are authorized by law.

No Undue Risk to Public Health and Safety

    The underlying purpose of 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 (DBAs). The proposed changes require the use of 
the main steam piping and the condenser to process MSIV leakage. This 
additional function does not compromise the reliability of these 
systems. They will continue to function as intended and not be subject 
to a failure of a different kind than previously considered. Since no 
new accident precursors are created by permitting the exclusion of MSIV 
leakage from the overall integrated leak rate test measurement and 
permitting the exclusion of the MSIV contribution to the sum of the 
Type B and Type C local leak rate tests, the probability of postulated 
accidents is not increased. The allowable leak rate specified for the 
MSIVs is used to quantify a maximum amount of leakage assumed to bypass 
containment. Sufficient margin relative to the regulatory limits is 
maintained even when conservative assumptions and methods are utilized. 
Also, the proposed change does not involve changes to the structures, 
systems, or components which would affect the probability of an 
accident previously evaluated in the BFN-1 updated final safety 
analysis report. Thus, 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 exemptions would permit exclusion of MSIV leakage from 
the overall integrated leak rate test measurement and permit exclusion 
of the MSIV contribution to the sum of the Type B and Type C local leak 
rate tests. This change to the operation of the plant has no relation 
to security issues. Therefore, the common defense and security are not 
impacted by these exemptions.

Special Circumstances

    Section 50.12(a)(2)(ii) of 10 CFR states that special circumstances 
are present when ``Application of the regulation in the particular 
circumstances would not serve the underlying purpose of the rule

[[Page 58442]]

or is not necessary to achieve the underlying purpose of the rule.'' 
The NRC staff examined the licensee's rationale to support the 
exemption request and concluded that it would meet the underlying 
purpose of Appendix J, Option B, Sections III.A and III.B. The 
underlying purpose of 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 DBAs. Including 
the MSIV leakage in the test acceptance criteria is not necessary to 
achieve the underlying purpose of the rule because MSIV leakage is not 
directed into the secondary containment. Also, TS SR 3.6.1.3.10 
specifies a specific leak rate limit to assure operation of BFN-1 
remains within the bounds of the DBA analysis. Therefore, the 
underlying purpose of the rule continues to be met.
    In addition, Sec.  50.12(a)(2)(iii) of 10 CFR states that special 
circumstances are present when ``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.'' The 
licensee's exemption request and proposed changes to the TSs together 
would implement the recommendation of Topical Report NEDC-31858. The 
special circumstances associated with MSIV leakage testing are fully 
described in the topical report. These circumstances include 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 
exemption from Appendix J requirements for MSIV leakage rates is 
required so that BFN-1 can operate with the proposed TS increased 
allowable MSIV leakage rates. This results in reduced radiological 
exposure to plant personnel, greater MSIV reliability, and significant 
monetary benefit to TVA as a result of reduced plant outage durations.
    Therefore, since the underlying purpose of 10 CFR part 50, Appendix 
J, is achieved and the circumstances described in NEDC-31858 are met, 
the special circumstances required by 10 CFR 50.12(a)(2)(ii) and 
50.12(a)(2)(iii) for the granting of an exemption from 10 CFR part 50, 
Appendix J exist.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), 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 TVA an exemption from the 
requirements of 10 CFR Part 50, Appendix J, Option B, Sections III.A 
and III.B with respect to MSIV leakage, for BFN-1.
    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 (71 FR 33777).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 26th day of September 2006.

    For the Nuclear Regulatory Commission.
Catherine Haney,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. E6-16270 Filed 10-2-06; 8:45 am]
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