E6-9058. Tennessee Valley Authority; Browns Ferry Nuclear Plant, Unit 1; Environmental Assessment and Finding of No Significant Impact

The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption from Title 10 of the Code of Federal Regulations (10 CFR) Section 50.54(o) and 10 CFR Part 50, Appendix J, for Facility Operating License No. DPR-33, issued to the Tennessee Valley Authority (TVA, the licensee) for operation of the Browns Ferry Nuclear Plant (BFN) Unit 1, located in Limestone County, Alabama. Therefore, as required by 10 CFR 51.21, the NRC is issuing this environmental assessment and finding of no significant impact.

Environmental Assessment

Identification of the Proposed Action

The proposed action would exempt the licensee from requirements to include main steam isolation valve (MSIV) leakage in (a) the overall integrated leakage rate test measurement required by Section III.A of Appendix J, Option B, and (b) the sum of local leak rate test measurements required by Section III.B of Appendix J, Option B.

The proposed action is in accordance with the licensee's application dated July 9, 2004.

The Need for the Proposed Action

The proposed action would reduce the frequency of MSIV rebuilds during outages that are required to achieve the leakage rates specified in the current Technical Specifications (TSs). Section 50.54(o) of 10 CFR part 50 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 that penetrate the containment. Option B, Section III.A requires that the overall integrated leak rate must not exceed the allowable leakage (La) with margin, as specified in the TSs. The overall integrated leak rate, as specified in the 10 CFR part 50, Appendix J definitions, includes the contribution from MSIV leakage. By letter dated July 9, 2004, the licensee requested an 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 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's July 9, 2004, letter also requested an exemption from this requirement, to permit exclusion of the MSIV contribution to the sum of the Type B and Type C tests.

The above-cited requirements of Appendix J require that MSIV leakage measurements be grouped with the leakage measurements of other containment penetrations when containment leakage tests are performed. These requirements are inconsistent with the design of the Browns Ferry facility and the analytical models used to calculate the radiological consequences of design-basis accidents. At BFN, and similar facilities, the leakage from primary containment penetrations, under accident conditions, is collected and treated by the secondary containment system, or would bypass the secondary containment. However, the leakage from MSIVs 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 (i.e., bypass leakage is grouped, leakage into secondary containment is grouped, and ALT leakage is grouped, with specific limits for each group defined in the TSs).

The proposed exemption would permit ALT path leakage to be independently grouped with its unique leakage limits.

Environmental Impacts of the Proposed Action

The NRC staff has completed its safety evaluation of the proposed action and finds that the proposed exemption involves a slight increase in the total amount of radioactive effluent that may be released off site in the event of a design-basis accident. However, the calculated doses remain within the acceptance criteria of 10 CFR part 100 and Standard Review Plan Section 15, and there is no significant increase in occupational or public radiation exposure. The proposed action will not significantly increase the probability or consequences of accidents. The NRC staff, thus, concludes that granting the proposed exemption would result in no significant radiological environmental impact.

The proposed action does not affect nonradiological plant effluents or historical sites, and has no other environmental impact. Therefore, there are no significant nonradiological impacts associated with the proposed exemption.

Accordingly, the NRC concludes that there are no significant environmental impacts associated with the proposed action.

The details of the staff's safety evaluation will be provided in the license amendment that will be issued as part of the letter to the licensee approving the license amendment.

The proposed action will not significantly increase the probability or consequences of accidents. No changes are being made in the types of effluents that may be released off site. There is no significant increase in the amount of any effluent released off site. There is no significant increase in occupational or public radiation exposure. Therefore, there are no significant radiological environmental impacts associated with the proposed action.

With regard to potential nonradiological impacts, the proposed action does not have a potential to affect any historic sites. It does not affect nonradiological plant effluents and has no other environmental impact. Therefore, there are no significant nonradiological environmental impacts associated with the proposed action.

Accordingly, the NRC concludes that there are no significant environmental impacts associated with the proposed action.

Environmental Impacts of the Alternatives to the Proposed Action

As an alternative to the proposed action, the NRC staff considered denial of the proposed action (i.e., the “no-action” alternative). Denial of the application would result in no change in current environmental impacts. The environmental impacts of the proposed action and the alternative action are similar.

Alternative Use of Resources

The action does not involve the use of any different resources than those previously considered in the Final Environmental Statement for the Browns Ferry Nuclear Plant dated September 1, 1972 for BFN Unit 1.

Agencies and Persons Consulted

In accordance with its stated policy, on May 4, 2006, the NRC staff consulted with the Alabama State official, Kirk Whatley of the Office of Radiological Control, regarding the environmental impact of the proposed action. The State official had no comments.

Finding of No Significant Impact

On the basis of the environmental assessment, the NRC concludes that the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the NRC has determined not to prepare an environmental impact statement for the proposed action.

For further details with respect to the proposed action, see the licensee's letter dated July 9, 2004. Documents may be examined, and/or copied for a fee, at the NRC's Public Document Room (PDR), located at One White Flint North, 11555 Rockville Pike (first floor), Rockville, Maryland. Publicly available records will be accessible electronically from the Agencywide Documents Access and Management System (ADAMS) Public Electronic Reading Room on the Internet at the NRC Web site, http://www.nrc.gov/​reading-rm/​adams.html. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS should contact the NRC PDR Reference NRC staff by telephone at 1-800-397-4209 or 301-415-4737, or send an e-mail to [e-mail].

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

For the Nuclear Regulatory Commission.

Margaret H. Chernoff,

Project Manager, Plant Licensing Branch II-2, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation.