ML20100F693
| ML20100F693 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/13/1996 |
| From: | Boulette E BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BECO-LTR-96-007, BECO-LTR-96-7, IEB-95-002, IEB-95-2, NUDOCS 9602220040 | |
| Download: ML20100F693 (3) | |
Text
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s o s a Pilgrim Nuclear Power Station i
Rocky Hill Road Plymouth, Massachusetts 02360 E. T. Boulette, PhD Senior Vice President - Nuclear February 13, 1996 BECo Ltr. #96-007 i
U.S. Nuclear Regulatory Commission Attention: Document Control Desk
. Washington, DC 20555 l
Docket No. 50-293 License No. DPR-35 Pilarim's 120-Day Response to Bulletin 95-02
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References:
(1.)
NRC Bulletin'95-02, "Unexpseted Clogging of a Residual Heat Removal (RHR) Pump l
Strainer While Operating in Suppression Pool Cooling Mode" (2.)
Pilgrim's Response to Bullet!n 95-02 dated November 16,1995 The NRC alerted licensees to potential Residual Heat Removal (RHR) strainer clogging in Reference (1). This letter transmits Pilgrim's 120-day response as required by Reference (1).
l Based on the information provided in this leWr's attachment, Pilgrim has confirmed the RHR i-pump suction strainers are not clogged or nrg aded and the suppression pool is free of debris l
that is or can become suspended and resun in strainer clogging. Hence, the results confirm strainer clogging does not currently jeopardize the operability of safety systems taking suction 1
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from the torus through stra!ners.
This letter closes our commitment to perform RHR pump suction strainer testing to address l
Action 2 of Reference (1).
E.. Boulette, PhD I
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s Boston Edison Company DCC Desk i
Page 2 l
cc:
Mr. R. Eaton, Project Manager Division of Reactor Projects - 1/11 Mail Stop: 14D1 U. S. Nuclear Regulatory Commission 1 White Flint North i
11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region I i
475 Allendale Road King of Prussia, PA 19406 4
Senior Resident inspector Pilgrim Nuclear Power Station
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Attachment to Pilarim Letter #96-007 Overview of the Pilgrim Pump Suction Strainer Test Responding to Bulletin 95-02 1
Test Backaround a
Each RHR pump was operated for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (4-5 turnovers of suppression pool [ torus) water /run) in the suppression poo! (torus) cooling mode in accordance with Temporary Procedure 95-131. Each pump was run separately. This provided data to determine changes in pressure drop across the RHR suction strainer for the pump in use.
As we stated in Reference (2), because the core spray and RHR systems use the same size strainers in similar locations, if the RHR strainers are clean, the core spray strainers can be assumed clean.
HPCI and RCIC strainers can also be assumed clean if the RHR strainers are clean.
This test method confirms that Pilgrim's Emergency Core Cooling System (ECCS) strainers are current!y clean and can be monitored for cleanliness during future operations.
Results and Conclusion The results of the test demonstrated appropriate RHR pump performance with no increase in suction pressure drop during the extended 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> run, thereby indicating there was no strainer clogging or degradation. Furthermore, the suction pressure drop that occurs when the pumps are first started was confirmed to be at or slightly below the predicted values determined by calculations based on a clean strainer. Together, this information indicates that the strainers are clean and that there is no debris in the torus that becomes suspended and deposits on the strainers during extended operation.
The absence of degrading pump suction pressures during the extended run-time indicates fibrous material was not being drawn onto the strainers, indicating torus water is not contaminated with fibrous material in quantities that could affect ECCS pump performance.
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