02-18521. Dominion Nuclear Connecticut, Inc., Millstone Nuclear Power Station, Unit No. 3; Environmental Assessment and Finding of No Significant Impact

The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an amendment to Title 10 of the Code of Federal Regulations (10 CFR) Part 50 for Facility Operating License No. NPF-49 issued to Dominion Nuclear Connecticut, Inc. (the licensee), for operation of the Millstone Nuclear Power Station, Unit No. 3 (MP3), located in Waterford, Connecticut. 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 revise the Final Safety Analysis Report (FSAR) description of the Supplementary Leakage Collection and Release System (SLCRS) operation after a postulated accident. As a result, this revision modifies the licensing basis for the post-accident operation of the SLCRS.

The proposed action is in accordance with the licensee's application dated June 6, 1998, as supplemented by letters dated April 5, 1999; April 7, April 19, July 31, and September 28, 2000; March 19, June 11, September 21, and December 20, 2001.

The Need for the Proposed Action

The proposed action is necessary because the SLCRS is used to maintain a negative pressure relative to atmospheric in the secondary containment by collecting air from the enclosure building and connecting areas, filtering it to remove iodine, and discharging the filtered air to the atmosphere. The licensee has identified potential release pathways from secondary containment to the environment that could bypass the SLCRS filter following a design-basis accident due to non-nuclear safety-grade (NNS) exhaust fan operation after the accident. These additional pathways are not included in the current design-basis accident dose analyses as documented in the MP3 FSAR, therefore making them non-conservative. The proposed action would include the additional pathway in the current design-basis accident dose analyses.

Environmental Impacts of the Proposed Action

The NRC has completed its evaluation of the proposed action and concludes that issuance of the proposed amendment would not have a significant environmental impact. The proposed changes to the FSAR provide documentation of a combination of events not previously included in the FSAR. Based on the licensee's use of acceptable methodologies and assumptions, and staff confirmation of the licensee's dose results, the staff has determined that the licensee's revised design-basis accident radiological consequences analyses for the Loss of Coolant Accident (LOCA) and rod ejection accident, which take into account additional SLCRS bypass release pathways, are acceptable. The analyses show that the radiological consequences of a postulated design-basis LOCA are within 10 CFR part 100 dose limits for offsite doses and 10 CFR part 50, appendix A, General Design Criterion 19, dose limits with regard to control room habitability.

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, and 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 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 resource than those previously considered in the Final Environmental Statement for MP3, dated December 1984.

Agencies and Persons Consulted

On June 12, 2002, the staff consulted with the Connecticut State official, Mr. Michael Firsick of the Connecticut Department of Environmental Protection, 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 June 6, 1998, as supplemented by letters dated April 5, 1999; April 7, April 19, July 31, and September 28, 2000; March 19, June 11, September 21, and December 20, 2001. 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 staff by telephone at 1-800-397-4209 or 301-415-4737, or by e-mail to [e-mail].

Dated at Rockville, Maryland, this 10th day of July 2002.

For the Nuclear Regulatory Commission

Victor Nerses,

Sr. Project Manager, Section 2, Project Directorate I, Division of Licensing Project Management, Office of Nuclear Reactor Regulation.