ML20214W642
| ML20214W642 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 11/14/1986 |
| From: | Hall W PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-86-003, IEB-86-3, SBN-1232, NUDOCS 8612100347 | |
| Download: ML20214W642 (3) | |
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New Hampshire Yankee Division November 14, 1986 SBN-1232 T.F. B7.1.2 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention:
Dr. Thomas E. Murley, Jr.,
Regional Administrator P.efe rences :
(a) Facility Operating License NPF-56, Docket No. 50-443 (b) Construction Permit CPPR-136, Docket No. 50-444 (c)
IE Compliance Bulletin 86-03, " Potential Failure of Multiple ECCS Pumps Due to Single Failure of Air -
Operated Valve in Minimum Flow Recirculation Line,"
dated October 8, 1986 Subj ect: Response to IE Compliance Bulletin 86-03
Dear Sir:
As required by IE Compliance Bulletin 86-03, New Hampshire Yankee (NHY) has reviewed the Seabrook Station ECCS design to determine whether the potential exists for a single failure to disable multiple ECCS pumps as described in the bulletin. The results of this review are provided as.
8612100347 861114 PDR ADOCK 05000443 0
PDR 3j 1
P.O. Box 300. Seabrook, NH 03874. Telephone (603) 474-9574
United States Nuclear Regulatory Commission November 14, 1986 v.
Attention:
Dr. Thomas E. Murley Page 2 To the best of my knowledge and belief, and based on the information contained in Enclosure 1, Seabrook Station does not have a single-failure vulnerability in the minimum flow recirculation line of any ECCS pumps that could cause a failure of more than one ECCS train.
Very truly yours, We Warren J. Hall Regulatory Services Manager Enclos ure cc: Atomic Safety and Licensing Board Service List Original to: United States Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555 STATE OF NEW HAMPSHIRE Rockingham, ss.
November 14, 1986 Then personally appeared before me, the above-named Warren J. Hall who, being duly sworn, did state that he is Regulatory Services Manager of Public Service Company of New Hampshire, that he is duly authorized to execute and file the foregoing information in the name and on the behalf of Public Service Company of New Hampshire, and that the statements therein are true to the best of his knowledge and belief.
Mb 4Wh(
Beverly E. Mlloway, Notary P%ic My Commission Expires: March 6, 1990
i ENCLOSURE I TO SBN-1232 RESPONSE TO IE COMPLIANCE BULLETIN 86-03 In response to IE Compliance Bulletin 86-03, NHY has reviewed the Seabrook Station ECCS design to determine whether the potential exists for a single failure to disable multiple ECCS pumps. The results of this review are as follows.
The Containment Building Spray (CBS) System does not require a minimum flow path, since containment pressure is lower than the shut-off total discharge head of the pump. The worst single failure in the CBS system is the failure of a containment isolation valve (CBS-V-Il or CBS-V-17) to open. This failure will only affect one train.
Each Safety Injection (SI) pump has a single, normally open, motor-operated valve (1-SI-V-89 or -90) in the pump minimum flow path. Beyond the motor-operated valve the flow paths join into a common flow path where there is a single motor-operated valve (1-SI-V-93).
This valve is normally open and is locked opcn in accordance with the locked valve list. The common flow path then returns to the refueling water storage tank (RWST). No single failure or inadvertent closure of a valve will disable both minimum flow paths.
The Residual Heat Removal (RRR) pump minimum flow path for each pump is through the individual RHR heat exchangers and back to the pump suction. Each pump minimum flow path contains a single motor operated valve that opens and closes on low and high flow measured at the pump discharge. The flow path from the pump to the heat exchanger has a single manual valve (1-RIl-V-9 and 1-RH-V-45).
These valves are on the locked valve list. Thus, no single failure or inadvertent operation will disable both RHR pump minimte flow paths.
The minimum flow path for each centrifugal charging pump has a single motor-operated valve (1-CS-V-196 and 1-CS-V-197).
Beyond the motor-operated valves, the individual flow paths join and are routed to the charging pump suction via the seal water return heat exchangers. The motor-operated valves are normally open; upon receipt of an "S" signal, the valves open or close automatically on low or high flow. A single failure of one of these valves will not disable both centrifugal charging pumps. There are four (4) normally open manual valves (1-CS-V-251, -860, -194, and -193) in the common minimum flow path. Inadvertent closure of one of these valves could disable the minimum flow protection; however, valves 1-CS-V-251, -194, and -193 are on the list of valves requiring independent verification and valve 1-CS-V-860 is locked open. When the reactor coolant pumps (RCPs) are running, the closure of one of these valves would be detected by simultaneous low flow alarms on the RCP seal water return flow instruments; at this time, the inadvertent closure of these valves may not be detected, however, these are low pressure modes with a flow path to the charging line and seal injection line available. Control room alarms are available for both low charging flow and low seal injection flow.