ML18153C221

Application for Amends to Licenses DPR-32 & DPR-37,based on Reanalysis of Main Steam Pipe Scenarios & Impact of Westinghouse-identified ECCS Inconsistencies Between Plant ECCS Configuration & Input Assumptions in LOCA Analysis

ML18153C221
Person / Time
Site:	Surry
Issue date:	05/16/1990
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18153C222	List: ML18153C221 ML18153C223 ML18153C224
References
90-094A, 90-94A, NUDOCS 9005230363
Download: ML18153C221 (3)

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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 16, 1990 United States Nuclear Regulatory Commission Serial No. 90-094A Attention: Document Control Desk NO/ETS:

Washington, D.C. 20555 Docket No. 50-280 50-281 License No. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 RUPTURE OF A MAIN STEAM PIPE PROPOSED OPERATING LICENSE AMENDMENT In a March 6, 1990 letter (Serial number 90-094) we requested a license amendment that would reference our latest analysis of main steam line break (MSLB) scenarios in the operating license. Due to the potential large instrument loop uncertainties for the pressurizer pressure transmitter in a harsh environment a re-analysis was performed without credit for the low pressurizer pressure safety injection function . This analysis confirmed that other sources of automatic safety injection provide adequate protection when required, or that no safety injection is necessary. Since our submittal, we have completed a separate evaluation of the impact of Westinghouse identified ECCS inconsistencies between the plant ECCS configuration and input assumptions in the Westinghouse supplied LOCA analysis. Our evaluation has identified an impact on the MSLB analysis results. The effect of the reduced safety injection flow was a small increase (approximately 3%) in the peak heat flux and a slight decrease (approximately 20 psig) in the reactor coolant system pressure at the time of peak heat flux for the 0.19 sq. ft. per loop break. This submittal provides an updated MSLB analysis which incorporates these results and supercedes the March 6, 1990 submittal in its entirety.

As noted in our March 6, 1990 submittal, it was determined that the probability of malfunction of the low pressurizer pressure safety injection had increased, and hence, an unreviewed safety question existed as defined by 10 CFR 50.59. Accordingly, our re-analysis which shows that low pressurizer pressure safety injection is not required for small steam line breaks is being submitted for NRC approval per 10 CFR 50.59(c);

along with a request for the appropriate license amendment per 10 CFR 50.90.

Attachment 1 is a copy of our re-analysis and Attachment 2 is our proposed amendment to the operating licenses for Surry Units 1 and 2.

e The proposed amendment has been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Corporate Nuclear Safety Staff. It has been determined that the proposed change does not constitute a significant hazard as defined in 10 CFR 50.92. The basis for our determination of no significant hazard is provided as Attachment 3.

Very truly yours, VJJ7sn~

f?c. Stewart or Vice President - Nuclear Attachments

1. Analysis of Small Steamline Break Performance Without Low Pressurizer Pressure Safety Injection, Surry Units 1 and 2

2. Proposed Surry Units 1 and 2 Operating License Amendments

3. Significant Hazards Determination cc: U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station Commissioner Department of Health Room 400 109 Governor Street Richmond, Virginia 23219

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. e COMMONWEALTH OF VIRGINIA )

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COUN1Y OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. L. Wilson who is Assistant Vice President - Nuclear Operations, for W. L. Stewart who is Senior Vice President - Nuclear, of Virginia Electric and Power Company.

He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this /tp day of ____,,.,<---.!-~44--- 19 9o.

My Commission Expires: [~ 3 /.

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Notary Public (SEAL) :

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