ML13316B742

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Responds to IE Bulletin 80-04, Analysis of PWR Main Steam Line Break W/Continued Feedwater Addition. Scoping Studies Will Be Completed by 800513.Studies Include Effect of Auxiliary Feedwater Runout & Impact of Other Energy Sources
ML13316B742
Person / Time
Site: San Onofre 
Issue date: 05/12/1980
From: Ottoson H
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
IEB-80-04, IEB-80-4, TAC-44652, TAC-46652, NUDOCS 8007290883
Download: ML13316B742 (2)


Text

Southern California Edison Company P.O. BOX 800 2244 WALNUV GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 May 12, 1980 U. S. Nuclear Regulatory Commission Attention: R. H. Engelken, Director Office of Inspection and Enforcement Region V Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, California 94596 Gentlemen:

Subject:

Docket No. 50-206 IE Bulletin No. 80-04, Analysis of a PWR Main Steam Line Break With Continued Feedwater Addition San Onofre Nuclear Generating Station Unit 1 By letter dated February 8, 1980, you forwarded IE Bulletin No. 80-04 for action. IE Bulletin No. 80-04 specifically requests the following actions to be taken by licensees.

1.

Review the containment pressure response analysis to determine if the potential for containment overpressure for a main steam line break inside containment included the impact of runout flow from the auxiliary feed water system and the impact of other energy sources, such as continuation of feedwater or condensate flow.

2.

Review your analysis of the reactivity increase which results from a main steam line break inside or outside containment. This review should con sider the reactor cooldown rate, and the potential for the reactor to return to power with the most reactive control rod in..the fully withdrawn position.

3.

If the potential for containment overpressure exists or the reactor return to power response worsens, provide a proposed corrective action and a schedule for completion of the corrective action. If the unit is operating, provide a description of any interim action that will be taken until the proposed corrective action is completed.

4.

Within 90 days of the date of this Bulletin, complete the review and evaluation required by this Bulletin and provide a written response describing your reviews and actions taken in response to each item.

In response to IE Bulletin No. 80-04, the following information is submitted.

The information has been organized to correspond to the enumeration of actions to be taken by licensees listed above.

Mr. R. H. Engelken, Di tor May 12, 1980

1. By letter dated December 21, 1979, you requested we submit an analysis of the.impact of early initiation of auxiliary feedwater flow with a failure to limit flow to the affected steam generator to determine if the poten tial for containment overpressure exists following a main steam line break. By letter dated January 16, 1980, we indicated that the informa tion requested would be submitted by October 1, 1980. Your letter dated April 3, 1980 requested we submit, in a timely manner, an assessement of the safety impact of automatically initiating AFWS flow on the safety analysis for San Onofre Unit 1 to allow sufficient time for the NRC staff to complete their review and issue a safety evaluation prior to June 1, 1980. Our letter dated April 29, 1980 indicated that revised scoping studies to assess the safety impact of automatically initiating AFWS flow on the main steam line break containment pressure response are expected to be completed by May 16, 1980. The scoping studies will include the effect of auxiliary feedwater runout flow as well as the impact of other energy sources such as the addition of main feedwater or condensate flow due to the response of the feedwater control valves during the tran sient. However, our April 29, 1980 letter indicated that the complete analytical results requested by your December 21, 1979 letter can not be submitted until October 1, 1980.
2.

In conjunction with the scoping studies discussed above, a review of the San Onofre Unit 1 main steam line break core response analysis is being conducted. The review will consider all of the aspects identified in Item 2 of your request. The results of the review will be provided by May 16, 1980.

3.

As part of our responses to Items 1 and 2 above, we will provide proposed corrective actions, a schedule for completion of the corrective actions, and a description of any interim actions, if necessary.

4.

The actions.being taken in response to each item of IE Bulletin No. 80-04 are discussed above.

If you have any questions or desire further information, please contact me.

Very t y yours, H. L. Ottoson Manager of Nuclear Operations cc:

NRC Office of Inspection and Enforcement (Washington, D.C.)