[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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