ML20080Q263
| ML20080Q263 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/27/1983 |
| From: | Johnson B CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8310120331 | |
| Download: ML20080Q263 (2) | |
Text
.e fi Consumers Power Company General offices: 1945 West Parnall Road, Jackson, MI 49201. (517) 788-0550 September 27, 1983 James G Keppler, Administrator Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - REQUEST FOR WITHDRAWL OF LICENSEE EVENT REPORTS83-037 AND 83-042 Licensee Event Reports83-037 and 83-042 transmitted information regarding the loss of both automatic and manual control to CV-0737A. the auxiliary feedwater control valve for the "A" steam generator. Per design, the loss of automatic and manual control of CV-0737A caused it to fail full open. Given this condition, each LER stated that the resultant mismatch in control valve position between CV-0737A (full open) and CV-0736A, the auxiliary feedwater control valve for the "B" steam generator, (normally in the throttled position) created the potential inability to adequately feed the "B" steam generator with the auxiliary feedwater pumps. This was the premise by which we concluded that requirements of Technical Specification 3.5 were exceeded.
Each occurrence was conservatively reported per Technical Specification 6.9.2.a(2).
Further investigation has resulted in information which mitigates the safety significance of these occurrences. The fact that both CV-0737A and CV-0736A would normally control flow at approximately 150 gpm was misinterpreted as a In
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requirement to feed each steam generator with this minimum flow.
actuality, there is no minimum required flow to either steam generator, only a minimum total flow to both. Therefore, all statements regarding a potential inability to feed the "B" steam generator at a given minimum flow rate are incorrect.
f.The percevided mismatch in control valve position and the resultant auxiliary feedwater flow rate to the steam generators, discussed in each LER, has also
/ been clarified. With CV-0737A f ailed full open per design, the controller for
/
CV-0736A would initially sense reduced flow. CV-0737A would then rapidly open to the extent necessary to pass approximately 150 gpm. The overall result is a near balance in flow to each steam generator.
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JGKepplsr, Adcinistrcter 2
Palisades Plant REQUEST FOR WITHDRAWL OF LERS83-037 & 83-042 September 27, 1983 Additionally, the condition with CV-0737A failed full open and CV-0736A controlling at 150 gpm was analyzed with respect to runout of the motor driven auxiliary feedwater pump. Data from a test completed on December 14, 1981 indicates that although the operating limit of 112 amps for the pump motor would be exceeded under the postulated conditions, the overcurrent trip setting of 132 amps would not be exceeded. Should the motor driven auxiliary feedwater pump trip, however, the steam driven pump would still auto start and provide the required feedwater flow.
In LER 83-037, the cause was attributed to a faulty rack mounted circuit board which had been installed to replace the original circuit board. When the original circuit board was re-installed, control was regained. Subsequent investigation has revealed that the spare circuit board, which was believed to be defective, was found to be defect free. Therefore, the problem with the spare circuit board, when installed, remains unknown.
We have concluded that additional occurrences involving loss of control of either auxiliary feedwater control valve (CV-0737A, CV-0736A) in a manner similar to that described in the referenced LERs will not be required to be reported to the NRC.
It is our request that LER 83-037 and LER 83-042 be withdrawn based upon the information contained herein.
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Brian D Johnson Staff Licensing Engineer CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement NRC Resident Inspector - Palisades OC0983-0016AA-NLO2