ML18092A791
| ML18092A791 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/04/1985 |
| From: | Freeman R NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Seyfrit K NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| Shared Package | |
| ML18092A793 | List: |
| References | |
| AEOD-E512, NUDOCS 8509190692 | |
| Download: ML18092A791 (2) | |
Text
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MEMORANDUM FOR:
FROM:
September 4, 1985 Karl V. Seyfrit, Chief Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data Robert G. Freeman, Engineer Reactor Systems Section 2 Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data AEOD/E512
SUBJECT:
ENGINEERING EVALUATION REPORT:
FAILURE OF SAFETY-RELATED PUMPS DUE TO DEBRIS Enclosed is AEOD Engineering Evaluation report entitled, "Failure of Safety-Related Pumps Due to Debris" for your consideration. This evaluation found that due to the design of centrifugal pumps used in high head safety injection (SI) systems for pressurized water reactors (PWRs), these pumps could be susceptible to mechanical problems from abrasive foreign particles in the pumped fluid.
Foreign material having similar characteristics could poten-tially exist inside containment and pass through most existing sump screen designs. A significant finding in this evaluation was the use of hinged-type screen access doors or grates employed in some containment sump designs.
These access doors have the potential to fail open as a result of not being properly secured.
These would result in defeating the safety function of the sump screens which could lead to potential damage and failure of multiple pumps in the emergency core cooling system (ECCS) and block flow through spray orifices in the containment spray (CS) system.
Because of the potential safety implications of degradation and/or possible failure of multiple pumps in the ECCS from debris due to improperly secured containment sump screen doors or grates, it is suggested that IE issue an information notice addressing the safety significance of sump screen integrity and the need for administratively controlling these access openings to the sump.
The information notice should also notify all PWR licensees of the potential undetectable common cause failure of the ECCS due to foreign material contamination of the ECCS borated storage tanks.
Because the Salem event indicates that the high head SI pumps could be suscep-tible to abrasive foreign material in the pumped fluid, it is suggested that the Office of Nuclear Reactor Regulation consider expanding the scope of Generic Issue 38 entitled, "Potential Recirculation System Failure as a Consequence of
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Karl Ingestion of Containment Paint Flakes or Other Fine Debris," to evaluate the potential loss of the high pressure recirculation system during small-break LOCA mitigation for PWRs.
Enclosure:
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