ML20247D076

Environ Assessment & Finding of No Significant Impact Re Exemption from Requirements of 10CFR50,App J

ML20247D076
Person / Time
Site:	Rancho Seco
Issue date:	03/23/1989
From:	Knighton G Office of Nuclear Reactor Regulation
To:
Shared Package
ML20247D061	List: ML20247D059 ML20247D076
References
NUDOCS 8903300372
Download: ML20247D076 (4)

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UNITED STATES NUCLEAR REGULATORY COMMISSION SACRAMENTO MUNICIPAL UTILITY DISTRICT DOCKET NO. 50-312 ENVIRONMENTAL ASSESSMENT t

AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Comission (the Comission) is considering issuance of an exemption from the requirements of 10 CFR 50, Appendix J to the s

Sacramento Municipal Utility District (SMUD, the licensee) for the Rancho Seco Nuclear Generating Station located in Sacramento County, California.

ENVIRONMENTAL ASSESSMENT Identification of Protosed Action:

The exemption would extend the interval between local leak rate tests of containment penetrations by a maximum of six months. The current interval between local leak rate tests is 24 months as delineated in 10 CFR Part 50, Appendix J. The exemption is in response to a licensee request dated February 15, 1989. Further details regarding the request are contained in a related application for amendment of the plant's Technical Specifications, dated December 30, 1988, as supplemented March 6, 1989.

The Need for the Proposed Action:

Several of the local leak rate tests of containment penetrations can only be performed while the plant is in cold shttdowr. Following a 27-month reactor shutdown during 1986 and 1987, plant preparations for restart comenced in the fall of 1987 in anticipation of reactor criticality that, due to various reasons, was delayed until March 1988. In preparation for the fall 1987 restart and an extended operating period following startup, local leak rate tests were completed during the .sumer of 1987. Since reaching criticality in

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March 1988, the plant has not been in cold shutdown for any appreciable time and the licensee has been unable to complete all the local leak rate tests that, j based on the 24-month interval, are due again in 1989. Rancho Seco is not  !

scheduled to be-in cold shutdown until the next refueling outage, which is J

expected during the fall of 1989. The current 24-month interval for some local i leak rate tests, which necessitates cold shutdown as a prerequisite, may expire prior to the projected refueling date. System perturbations associated with  !

bringing the plant to cold shutdown and the increased potential for problems during 'this transient offset the enhancement in safety resulting from timely completion of local leak rate tests. A one-time extension of the 24-month test  !

requirement appears prudent. 1 l

Environmental Impact of the Proposed Action:

A six month extension of the interval between local leak rate tests is not-i expected to have any impact on the environment. The test history of penetra-tions that may be affected by the extension indicates that the penetration isolation valves are reliable and there is little likelihood that both of the '

redundant valves on each penetration would fail and the failure remain l

undetected during the six month test extension. Furthermore, it is highly unlikely that the need to isolate containment would occur during the period of the six month extension.

Moreover, the proposed change would not involve a significant change in the probability or consequences of any accidents previously evaluated, nor does it involve a new or different kind of accident. The proposed amendment does not otherwise affect routine radiological plant effluents. Therefore, the Connission concludes that there are no significant radiological environmental impacts.

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associated with the proposed amendment. The Commission also concludes that the action will not result in a significant increase in the individual or cummulative occupational radiation exposure.

With regard to potential non-radiological impacts, the proposed exemption involves features located entirely within the restricted area as defined in 10 CFR Part 20. It would not affect non-radiological plant effluents and would have no other environmental impact. Therefore, the Commission concludes that '

there would be no significant non-radiological environmental impacts associated with the proposed exemption.

Alternative to the Proposed Actim Since the Commission has concluded there are no significant environmental effects that would result from the p.oposed action, any alternatives with equal or greater environmental impacts need not be evaluated. The principal alternative would be to deny the requested exemption. Denial of the request would not reduce environmental impacts of plant operation.

Alternative Use of Resources This action would involve no use of resources not previously considered in the Final Environmental Statement (operating license) for Rancho Seco Nuclear Generating Station.

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7 AgenciesandPersonsConsultqj The NRC staff reviewed the iscensee's request and did not consult other agencies or persons.

Finding of No Significant Impact The Commission has determined not.to prepare an environmental impact statemer.t for the proposed exemption.

Based upon the foregoing environmental assessment, we conclude thht the proposed action will not have a significant effect on the quality of the human environment.

For further details with respect to this action, see the licensee's application for the related amendment to the Rancho Seco Technical Specifications, which was submitted by letters dated December 30, 1988 and March 6, 1989. These submittals are available to the public at the Commission's Public Document Room, 2120 L Street, NW, Washington, DC and at.the Martin Luther King Regional Library, 7340 24th Street Bypass, Sacramento, California.

FOR THE NUCLEAR REGULATORY COMMISSION

/Yd' l 4 George . Kn ghto , Director Project Direct rate V Division of Reactor Projects III.

IV, Y and Special Projects Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 23rd day of March,1989

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