ML17284A617

Environ Assessment & Finding of No Significant Impact Re Application for Amend That Would Change Max Yield Strength for ECCS Suction Strainer Matls Listed in WNP-2 FSAR

ML17284A617
Person / Time
Site:	Columbia
Issue date:	05/14/1998
From:	Poslusny C NRC (Affiliation Not Assigned)
To:
Shared Package
ML17284A618	List: ML17284A617
References
NUDOCS 9805270082
Download: ML17284A617 (7)

Text

7590-01-P The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of an amendment to Facility Operating License No. NPF-21 issued to Washington Public Power Supply System (the licensee), for operation of WNP-2 located in Benton County, Washington.

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The proposed action would revise the maximum yield strength for emergency core cooling system suction strainer materials listed in the WNP-2 Final Safety Analysis Report (FSAR) ~

The proposed action is in accordance with the licensee's application for amendment dated April 16, 1998, as supplemented by letters dated April28 and May 8, 1998.

The proposed action is needed to support the progression to startup for WNP-2, which is currently in a refueling outage.

During this'outage newly designed suction strainers have been installed in the suppression pool. They are designed to protect ECCS pumps from fibrous.

or other material that could be transported to the suppression pool after a design basis accident such as a loss of coolant accident.

The licensee determined after fabrication of these strainers that the stanless steel material had measured yield strength which exceeded the limitwhich 9805270082 980514 PDR ADOCK 05000397 P

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was specified in the FSAR. Excessive yield strength can make the stainless steel susceptible to stress corrosion cracking (SCC) under certain environmental conditions. The licensee identified this as an unreviewed safety issue and submitted an amendment request which would change the yield strength for the installed strainers.. Approval of this amendment willenable the licensee to change reactor mode and declare the strainers operable while progressing to startup and full power operation.

The Commission has completed its evaluation of the proposed action and, based on the testing and analytical information provided by the licensee, concludes that the increase in yield strength for the specific material used in the suction strainers is acceptable.

The licensee has an effective cleanup system for the suppression pool, which maintains a desired level of water cleanliness sufficient to avoid conditions that would support SCC.

Further, the licensee has conducted a fracture mechanics analysis and has determined that cracking in the surface martensitic structure of the strainers willnot propagate to a critical size and, thus, not jeopardize the strainers'afety related function of protecting the ECCS pumps and spray nozzles.

Also, the licensee's analysis has demonstrated that the strainers have adequate structural integrity to preclude failure when the forces of design basis hydrodynamic loads are applied.

Lastly, a Strauss test using actual strainer material samples demonstrated acceptable stress corrosion cracking resistance.

The staff has concluded that this change willnot increase the probability or consequences of accidents, no changes are being made in the types of any effluents that may be released offsite, and there is no significant increase in the allowable offsite or occupational radiation exposure.

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

With regard to potential nonradiological impacts, the proposed action does not affect nonradiological plant effiuents and has no other environmental impact.

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

Since the Commission has concluded there is no significant environmental impact associated with the proposed action, any alternatives with equal or greater environmental impact need not be evaluated.

As an alternative to the proposed action, the staff considered denial of the proposed action.

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.

This action does not involve the use of any resources not previously considered in the Final Environmental Statement forWNP-2.

In accordance with its stated policy, on May 13, 1998, the staff consulted with the Washington State official, Mr. R. Cowley of the Department of Health, State of Washington Energy Facility Site Evaluation Council, regarding the environmental impact of the proposed action. The State official had no comments.

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A Based upon the environmental assessment, the Commission concludes that the proposed action willnot have a significant effect on the quality of the human environment.

Accordingly, the Commission 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 April 16, 1998, as supplemented by letters dated April28, 1998, and May 8, 1998, which are available for public inspection at the Commission's Public Document Room, The Gelman Building, 2120 L Street, NW., Washington, DC, and at the local public document room located at the Richmond Public Library, 955 Northgate Street, Richland, Washington 99352.

Dated at Rockville, Maryland, this 14th day of May 1998.

FOR THE NUCLEAR REGULATORYCOMMISSiON Chester Poslusny, Senior Project Manager Project Directorate IV-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation

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