ML20082B283
| ML20082B283 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/24/1995 |
| From: | George Thomas DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-10, NUDOCS 9504050084 | |
| Download: ML20082B283 (2) | |
Text
. e go Beaver Va ey Power Station Sh ppingp PA 15077 0004 f
(412) 643-8069 FAX GEORGE S THOMAS March 24, 1995 o.m.on vice presioent u er ower Dmsson U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001
Subject:
Beaver Valley Power Station, Unit No. 2 (BVPS-2)
Docket No. 50-412, License No. NPF-73 Revision to Generic Letter (GL) 89-10 Scope of Valve Testing
Reference:
Duquesne Light Company letter to the NRC, " Response to Generic Letter 89-10, Supplement 6," dated April 29,1994 In the referenced letter, Duquesne Light Company provided information to the NRC in support of a test schedule extension for 37 motor-operated valves in the BVPS-2 GL 89-10 Program. The purpose of this letter is to notify the NRC of a change in our intent to test, under dynamic system conditions, ten of those valves which include both ball and plug designs. Subsequent to the submittal of the referenced letter, the necessity to perform dynamic testing of these valves was evaluated, and it was determined that such testing would not provide any additional infonnation from the test results regarding the operability of these valves or the adequacy of the control switch settings of their motor operators. The basis for this decision is as follows:
1.
It was confirmed with the valve manufacturers that the dynamic effects on the ball valves' ability to stroke is negligible and that differential pressure and flow are not part of the required torque calculation for plug valves.
2.
Two BVPS-2 plug valves were tested in-situ, and h was demonstrated that valve torque was independent of dynamic conditions.
3.
The risk significance of the valves was evaluated and it was determined that the contribution of each valve to the mean core damage frequency is below the 10 threshold value for significance (i.e., they have a low risk significance).
4.
Periodic static testing of the ball and plug valves in accordance with BVPS GL 89-10 program requirements will verify that the valves will continue to j
operate under design basis conditions.
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9504050084 950324 PDR ADOCK 05000412 P
PDR 4
j Beaver Valley Power Station, Unit No. 2 Revision to Generic Letter 89-10 Scope of Valve Testing Page 2 Based on the above actions, the focus of the GL 89-10 Program on gate, globe and butterfly valves, and the lack of information indicating weaknesses in the design qualifications of ball or plug valves, it is our position that it is unnecessary to test these valves under dynamic system conditions. The technical justification for this position will be maintained on site.
Should you have any questions regarding this submittal, please contact Nelson R. Tonet, Manager, Nuclear Safety, at (412) 393-5210.
i Sincerely, l
i dyb "3
George S. Thomas c:
Mr. L. W. Rossbach, Sr. Resident Inspector Mr. T. T. Martin, NRC Region I Administrator Mr. D. S. Brinkman, Sr. Project Manager l
l