ML20204J584
| ML20204J584 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Susquehanna, McGuire, 05000000 |
| Issue date: | 10/12/1988 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rossi C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20204J591 | List: |
| References | |
| AEOD-E807, IEB-88-004, IEB-88-4, NUDOCS 8810250184 | |
| Download: ML20204J584 (2) | |
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FEMORANDUM FOR: Charles E. Rossi Director AE0D/E807 Division of Operational Events Assessment Office of Nuclear Reactor Regulation FROM:
Thomas M. Novak. Director Division of Safety Programs Office for Analysis and Evaluation N
of Operational Data
SUBJECT:
ENGINEERING EVALUATI0t! PEPORT - PUMP DAMAGE DUE TO LOW FLOW CAVITATION
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Enclosed is an AE00 enoineering evaluation report on pump damage due to low flow cavitation recently completed by this office.
This engineering evaluation was ccmpleted in response to item 5 of the actions directed by the E00 to respond to the diagnostic evaluation team report for the McGuire Nucl_ ear Station.
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Our evaluation indicates that operation ef centrifugal pumps at certain flows below the design flows, can create flow recirculation inside the pumps. These internal recirculations induce cavitation, hydraulic pressure pulsation and vibration which can cause damage to the pumps after an extended period of operation at such low flows. The pump damage due to low flow opert lon is a potential generic problem, because the pump mini-f14....r
...c & operating plants were sized solely on fluid temperature rise consideration, and thus the flow rate may not be sufficient to avoid the damage range of internal recircu-lation flow. Also, in some of the emergency core cooling systens and other i
safety-related fluid systems, the recirculation configuration may not have been i
fully considered for pumps designed for a wide range of flows. Our review has identified cases in which major degradation of impellers and casings have occurred to centrifugal pumps running centinuously at low flows.
The enclosed report recognizes that NRR has recently issued Bulletin 88-04 "Potential Safety-Related Pumps Loss" which addresses certain espects of the a
1 low flow problem and requests all licensees to investigate and correct, as applicable, the pump mini-flow design problems in all safety-related systems.
The actions addressed in the bulletin appear specific to the mini-flow design deficiency. However, this study had found that pump damage induced by internal
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recirculation can also be caused by operating pumps at low flow.
In view of this concern, we suggest that NRP review the findings of this report to detemine whether further actions are warranted.
For feedback of the findirgs I
and conclusions of this report, a proposed draft information nctice is enclosed for your consideration.
Df 8910250184 891012 PDR ADOCK 05000369 9 \\
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Charles E. Rossi l l
If you have questions or comments, please do not hesitate to contact me or i
Chuck Hsu (x24443) of my staff. We shall be happy to meet with you or your l
staff to discuss this matter.
e.3 Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated l
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E. Jordan C. Heltemes T. Collins, NRR Distribution:
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