ML19345C690
| ML19345C690 | |
| Person / Time | |
|---|---|
| Issue date: | 09/24/1980 |
| From: | Acosta A Advisory Committee on Reactor Safeguards |
| To: | Plesset M Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1285, NUDOCS 8012080191 | |
| Download: ML19345C690 (1) | |
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PEMORANDUM To:
M.S.Plesset, Chairman Fluid Dynamics Subcomittee From: A.J.Acosta MI.
Re: Pump performance at less than maximum flow Ref:
Memo to M.S.Plesset from J.C.McKinley, July 30,1980 1.
I have reviewed the above reference and attachments at your request. As a preliminary remark it is well known that hydraulically-induced vibrations can be caused by pump operation at flow rates much less than normal.
These vibrations are due to detaiis of the pump internal design and to the inlet piping as well. Such rough running can occur in fully melted flow and the severity may increase with pump cavitation.
2.
I would agree with Mr.McKinley's remark that the pumping system should be designed to be operated safely over the range of flows from small break to LOCA demands.
3.
An open-ended safety requirement for an undefined operating envelope puts component suppliers in a difficult position. Nevertheless certain bounds of flow and suction pressure must be given as goals for safety. Accordingly I would suggest that the Fluid Dynamics Subcommittee review the specifications for the RHR pump motor applications.
It should be noticed that the pump outages referred to in the referen'ce were caused by motor failures; these failures may have been promoted by excessive pump vibration at low flow rates as suggested. Nevertheless it calls attention to the reliability of the motor components as well as that of the hydraulic aspects of the pump operation.
I 4
I would like to draw your attention to a forthcoming EPRI supported program of pump failures and causes in power plants. This is, I think, indicative of the possibility of some generic failures in reactor coolant pump com-ponents. This is intended to be a significant program and it would seem to me to be appropriate for the Fluid Dynamics Committee to review this problem area in a preliminary way at the present time.
I should be glad to provide references to recent EPRI reports if this would be helpful.
AJA:sb 8012080/9/
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