[Federal Register Volume 70, Number 55 (Wednesday, March 23, 2005)]
[Notices]
[Pages 14734-14735]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-5679]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-271]
Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear
Operations, Inc. Vermont Yankee Nuclear Power Station; Exemption
1.0 Background
Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear Operations,
Inc. (Entergy or the licensee) are the holders of Facility Operating
License No. DPR-28 which authorizes operation of the Vermont Yankee
Nuclear Power Station (VYNPS). 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 Vernon,
Vermont.
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 which penetrate
the containment. Option B of Appendix J is titled ``Performance-Based
Requirements.'' Option B, section III.A., ``Type A Test,'' requires
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, as specified
in the 10 CFR part 50, Appendix J, Option B, definitions, means the
total leakage rate through all tested leakage paths. The licensee is
requesting a permanent exemption from Option B, section III.A.,
requirements to permit exclusion of the main steam pathway leakage
contributions from the overall integrated leakage rate Type A 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 that the sum of the leakage rates of all Type B and
Type C local leak rate 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 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 main steam pathways). The
proposed exemption would more appropriately permit ALT pathway leakage
to be independently grouped with its unique leakage limits. In this
manner, the VYNPS containment leakage testing program will be made more
consistent with the limiting assumptions used in the associated
accident consequence analyses.
The licensee has analyzed the main steam leakage pathway (with an
increase in leakage from 62 standard cubic feet per hour (scfh) to 124
scfh at
[[Page 14735]]
the calculated peak containment internal pressure (Pa)), the secondary
containment bypass leakage pathways, and the containment leakage
pathway (La) separately in their dose consequence analyses. The
calculated radiological consequences of the combined leakages are
within the criteria of 10 CFR 50.67. The NRC staff reviewed the
licensee's analyses and found them 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 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 part 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. * * *''
The licensee's exemption request was submitted in conjunction with
a TS amendment application to increase the allowable leak rate for the
main steam isolation valves (MSIVs). The proposed amendment will be
issued concurrently with this exemption. The exemption and amendments
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.
The NRC staff has determined that the intent of the rule is not
compromised by the proposed action.
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
part 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 Entergy an exemption from the
requirements of sections III.A and III.B of Option B of Appendix J to
10 CFR part 50 for VYNPS.
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 (69 FR 67612).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 17th day of March 2005.
For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear
Reactor Regulation.
[FR Doc. 05-5679 Filed 3-22-05; 8:45 am]
BILLING CODE 7590-01-P