ML20055F809
| ML20055F809 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/03/1990 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rossi C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20055F810 | List: |
| References | |
| AEOD-E90-06, AEOD-E90-6, IEB-88-004, IEB-88-4, NUDOCS 9007190223 | |
| Download: ML20055F809 (3) | |
Text
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JUL 3 4 4
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MEMORANDUM FOR: Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation FROM:
Thomas M.-Novak, Director i
Director of Safety Programs Office of Analysis and Evaluation of Operational Data l
SUBJECT:
ENGINEERING EVALUATION REPORT - POTENTIAL FOR RESIOUAL HEAT REMOVAL SYSTEM PUMP DAMAGE Enclosed is an Engineering Evaluaticn Report concerning potential RHR pump l
deadheading in those RHR systems with the miniflow bypass line connected downstream of the pump discharge check valve. This evaluation was initiated to study the RHR pump deadheading event at Sequoyah~1n December 1989.
The flow path-provided by the miniflow line will be blocked when the check valve is closed.
Such a condition could occur due to adverse pump-to-pump-interaction during miniflow, parallel operation of pumps. The loss of miniflow path will leave a pump without adequate protection against deadheading such that the availability of the_ RHR system could be compromised.
Although Bulletin 88-04 had addressed the pump-to-pump interacti sn problem during miniflow operations, the loss of miniflow path due to closure of the pump discharge check valve had not been specifically addressed. The patential for the adverse pump-to-) ump interaction, which can cause the discharge check valve to close, may not se detected during the surveillance tests of pumps, t
The response to Bulletin 88-04 from Sequoyah did not identify this concern as the response was based on individuel and not dual pump tests.
We have reviewed the kHR system configuration for nineteen additional Westinghouse units; We noted that five of these plants have the same system configuration as that for Sequoyah. Diablo Canyon response to the bulletin t
contains a commitment to install a check valve down stream of the miniflow line, in each of the RHR loop at the next outage.
Sequoyah has al.so made a l
recent commitment to a similar installation.
In the interim both plants i
revised their emergency operating procedures to require securing of one pump,
-following an SI initiation.
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It is suggested that NRR inform licensees of the above potential for ine loss of RHR pum) due to deadheading caused by adverse pump-to-pump inters.ction. A draft of tie proposed information notice is also enclosed for your i
consideration.
1 If you have questions, please do not hesitate to contact me or Chuck Hsu of my staff. We shall be happy to meet with you or your staff to discuss this matter.
OrigW WW Thomas M. Novak, Director i
Division of Safety Programs Office for Ana;ysis and Evaluation.
of Operational Data j
Enclosures:
4 As stated 1
Distribution:
- PDR, JRosenthal MWilliams ICentNN,Nie_Ud,yj EJordan KB1ack ROAB R/F Dross RSavio, ACRS DSP R/F TNovak MTaylor, EDO AE0D R/F LSpessard KRaglin, TTC i
CHsu G7ech PBaranowsky, NRR MChiramal GRubin l
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- See Previous Concurrence: -
ROAB:DSP:AE00 ROAB:DSP:AE0D 0AB:DSP:AE0D
- 1
- AEOD i
l-CHsu:mmk*
MChiramal*
Rosenthal TN5vak 6/06/90 6/06/90 7/ 2.,/90 7/ /90-
NEMORANDUMFOR: Charl:s E. Rossi, Director.
Division of Operational Events Assessment Office of Nuclear Reactor Regulation FROM:
Thomas M. Novak, Director Director of Safety Programs j
Office of Analysis and Evaluation j
of Operational Data
SUBJECT:
ENGINEERING EVALUATION REPORT - POTENT FOR 1
RESIDUAL llEAT REMOVAL SYSTEM PUMP DAM iE Enclosed is an Engineering Evaluation Report conce ing the potential pump deadheading for the RHR system with the miniflow ypass line connected down-stream of the pump discharge check valve.. The ow path provided by the miniflow line would be blocked when the check alve is closed.
Such a condition could occur due to adverse pump-to-pump intel ction during miniflow, sarallel operation of pumps. The loss of miniflow pyth may leave the pump. wit 1out adequate protection against deadhead %g sufh that the-availability of the RHR j
system could be compromised.
Although Bulletin 88-04 has addressed e pump-to-pump interaction problem i
during miniflow operations, the loss f miniflow path due to closure of the pump discharge check valve has not en specifically addressed. The potential for the adverse pump-to-sump inter ction, which can cause the discharge check valve to close, may not >e detec d during the surveillance tests r,f pumps.
In view of this concern, it is suggested that NRR issue an information notice to inform iicensees of the po ential for loss of RHR pump due to deadheading caused by adverse pump-to-p p interaction.. A draft of the proposed inti)rmation j
notice is also enclosed fo your consideration, if you have questions, p ease do not hesitate to contact me or Chuck Hsu of sty staff. We shall be hap y to meet with you or your staff to discuss this matter.
Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation i
of Operational Data.
Enclosures:
As stated Distribut on:
AEOD R/F SRuoin KBlack KRaglin, TTC HFaulkner, IP Central ile CHsu GZech MWilliams TNovak DSP R/
MChiramal Plam MTaylor, EDO Dross ROAB F
LSpessard JRosenthal RSavio, ACRS-EJordan PDR R0A :DSP:ALOD ROAB:DSP:AEOD AC:R0 P: OD D:DSP:AE00 CH :nnk:as,4 MChiramal Plam TNova k:
i e,
6/t/90 6/le/90 6/pg/90 6/ /90 L
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