ML20215G560
| ML20215G560 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 10/10/1986 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Gallo R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| CON-#486-1158 OL, NUDOCS 8610210003 | |
| Download: ML20215G560 (7) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 F'HILADELPHI A. PA.19101 (215) 841 5020 M. J. COON E Y n uC o."'".'.",'ov C T.O.
October 10, 1986
.LEC TmeC PRODUCTIO= D R. ARTMENT Docket No. 50-352 Inspection Report:
50-352/86-17 Mr. Robert M. Gallo, Chief Projects Branch No.
2, Division of Reactor Projects Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Gallo:
Your letter dated' September 11, 1986 forwarded Inspection Report 50-352/86-17 for Limerick Generating Station.
Appendix A of your letter addresses an item which does not appear to be in full i
compliance with Nuclear Regulatory Commission requirements.
Appendix B identifies a deviation from a commitment in the Final Safety Analysis Report in support of License Condition 2.C.10.
These two items are restated below, followed by our responses.
Violation:
Technical Specification 3.6.3 requires that the containment isolation valves listed in Table 3.6.3-1 be maintained operable at all times.
Power operation may continue with one or more isolation valves inoperable beyond four hours provided that each affected penetration is isolated by use of at least one deactivated automatic valve secured in the isolated position or one closed manual valve.
Contrary to the above, between 2:00 p.m. on July 17 and 6:45 p.m. on July 18, 1986, the reactor was at full power operation, but the outboard isolation valves for containment penetration numbers 55 and 56 were inoperable in that the power supply feeder breakers to the operators for valves HV87-120B and HV87-121B were open and the affected penetrations were not isolated by one deactivated automatic valve secured in the isolated position or one closed manual valve.
This is a Severity Level IV violation (Supplement I).
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Mr. Robert M. Gallo October 10, 1986 Page 2
Response
4 Admission'of Alleged Violation:
i Philadelphia Electric Company acknowledges the violation as stated.
Reason for the Violation:
Personnel error was the reason for Containment penetrations 55 and 56 not being isolated within four hours required by Technical Specification 3.6.3.
The Shift Supervisor (a senior licensed operator) mistakenly authorized taking the valves out-of-service for preventive maintenance after reviewing the Piping and Instrumentation Drawings (P& ids).
The two valves (HV-087-120B and HV-087-121B) are listed as containment isolation valves in the
~
i Technical Specifications; however, they are not indicated on the P& ids as'having an " isolation signal".
The Shift Supervisor did not realize, when approving the Maintenance Request-Form (MRF),
that the valves were listed in the Technical Specifications as isolation valves.
Also, the "TS LCO ITEM" block in Section 1 of l,
the MRP was checked "no" by the maintenance engineer who approved Section 1.
The purpose of this block, which should have been to identify inoperable equipment which may place the station in a Limiting Condition for Operation, had not been clearly defined in the plant's administrative procedure.
Significance of Violation:
The immediate safety significance of the event was minimal because l
other means of isolating the affected penetrations were available.
The redundant isolation valves, HV-087-122 and HV-087-123, which remained in service would have closed upon receipt of an automatic isolation signal.
If these redundant valves would fail to close, the inoperable valves which are in series with these isolation valves could have been closed manually.
In addition, these valves are in closed loop cooling water systems which do not open directly to the containment atmosphere or to the reactor coolant boundary and would require a concomitant failure of the piping inside containment along with a failure of the automatic isolation i
valve to close, in order to effect a release of primary containment atmosphere following an accident.
Corrective Actions Taken and Results Achieved:
Upon discovery by a PECo control room operator on July 18, the safety tagging / blocking on valves HV-087-120B and HV-087-121B were k
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Mr. Robert M. Gallo October 10, 1986 Page 3 j
cleared and the valves were tested and returned to operable status.
Corrective Actions to be Taken to Avoid Future Non-Compliance:
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Letters have been issued to all shift personnel discussing the chilled water isolation valve blocking error and the need to carefully consider Technical Specifications when approving Maintenance Request Forms (MRFs).
Also presented in these letters were several cautions which should be followed when removing equipment from service.
The Nuclear Training Section Coordinator for Limerick Generating Station has been notified of the need for additional review training on containment isolation boundaries, design bases, facility license conditions and operator aids.
This training has been presented during the current License Operator Requalification Cycle which ends October 10, 1986.
Procedure A-26, which provides the administrative controls for the performance of work using MRFs, has been revised to include a checklist to be used by the Shift Supervisor when removing equipment from service.
This procedure revision is currently awaiting Quality Assurance approval.
It is expected that this item will be fully implemented by November, 1986.
Procedure A-26, Appendix'l has been revised to clarify the meaning of the MRP Section I box titled " Tech Spec /LCO".
These two revisions will ensure that primary containment isolation valves are " flagged" when they are to be taken out-of-service for maintenance.
Isolation valve names have been reviewed and modified as necessary to identify that they are primary containment isolation valves.
These modified valve names are being entered into the Computerized History and Maintenance Planning System (CHAMPS) and Permit Manager databases so that they will automatically appear on MRFs and blocking permits.
It is expected that this effort will be completed by January, 1987.
The possibility of adding a special notation in the Limerick P& ids for each primary containment isolation valve is bei'ng evaluated.
Such a notation would assist in the identification of primary containment isolation valves and alert individuals preparing blocking permits for these valves.
Date When Full Compliance Was Achieved:
The primary containment isolation valves HV-087-120B and HV-087-121B were tested and returned to operable status on July 18, 1986.
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Mr. RobDrt M. Gallo October 10, 1986 Page 4 l
Deviation:
Final Safety Analysis Report (FSAR) Subsections 6.2.4.3.1.3.2.10 and 6.2.4.3.1.3.2.11 describe the outboard isolation valves on the supply and return lines for Reactor Enclosure Cooling Water (RECW) and Drywell Chilled Water (DCW) as capable of remote manual closure from the main control room, and state that interim operating procedures exist to effect manual isolation under appropriate conditions.
Limerick License Condition 2.C.10 allows for operation during the-first fuel cycle with the outboard isolation valves in the supply and return lines of RECW and DCW systems not receiving automatic isolation signals.
The condition is based on the implementation of interim operating proceduren to ensure remote manual closure following onset of an accident, as described in a PECo letter to the NRC dated September 21, 1984 and as documented in Supplement 3 to the Limerick Safety Evaluation Report, Subsection 6.2.4.2, dated October, 1984.
Emergency operating procedure T-250, Remote Manual Primary Containment Isolations, provides guidance to remotely close the RECW and DCW outboard isolation valves by lifting leads in the main control room if a leak is suspected to be contributing to releases in the Reactor Enclosure.
Contrary to the above, Electrical Drawing No. E-465, Sheet 1, Schematic for RECW and DCW Motor Operated Valves, depicts valves HV-087-120, HV-087-121, HV-087-124 and HV-087-125 for loops
'A' and
'B' as having shunt trip coils.
Therefore, under design basis accident conditions, these valves would not be capable of remote manual closure from the main control room.
The valve motor loads are shed from, but not automatically sequenced back onto, their respective safeguards buses and would require shutting the valve breakers locally in order to~ restore electrical power to the valves.
Response
Admissicn of Alleged Deviation:
The outboard isolation valves (HV-087-120A, B; HV-087-121A, B; HV-087-124A, B; and HV-087-125A, B) on the supply and return lines of the RECW and DCW systems did have shunt trip coils installed and were not capable of remote manual closure from the main control room in the event of a design basis accident, contrary to FSAR requirements and PECo licensing commitments.
Reason for the Deviation:
The outboard isolation valves were provided in the original plant design to allow remote-manual selection of either the RECW or DCW l
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Mr. Robart M. Gallo October 10,-1986 Page 5 l
system to provide drywell cooling.
These valves were not initially considered to be primary containment isolation valves by l
PECo since they connected to closed cooling water system inside containment which would require only one isolation valve.
During the final stages of licensing of Unit 1, the NRC identified the design as unacceptable since the system did not meet Regulatory Guide 1.141 design requirements for " closed systems" inside containment.
PECo, therefore, committed to the NRC to upgrade these valves to Q-listed, Seismic Category I requirements and to provide diverse isolation signals prior to startup from the first Unit 1 refueling outage.
For the interim period, PECo committed to implement special operating instructions to, ensure appropriate remote manual closure of these valves following a design basis accident.. When these commitments were made, it was not recognized that these valves had shunt trip coils installed which would 4
prevent their remote manual closure from the control room.
Significance of Deviation:
The safety significance of this event is minimal because in the i
event of a design basis accident, the inboard isolation valve on each of these lines would have automatically isolated upon either high drywell pressure or low reactor water level.
In the event of failure of the inboard isolation valve to close, primary containment integrity would not have been jeopardized because the RECW and DCW supply and return lines are water filled and do not 4
open directly to the containment atmosphere or to the reactor coolant boundary.
It would require an additional failure of the piping inside containment, which would allow a complete loss of water inventory in the DCW system, in order to effect a leakage path for the escape of containment atmosphere.
Corrective Actions Taken and Results Achieved:
On August 27, 1986 the shunt trip coils were disabled by disconnecting their terminal blocks at the motor control centers under the control of Temporary Circuit Alteration TCA 0737.
This temporary circuit alteration will remain in effect until a permanent modification is completed.
The implementation of TCA 0737 does not adversely affect the operation of the Class lE motor l
' control center or the operation of the RECW and DCW systems.
Corrective Actions to be Taken to Avoid Future Non-Compliance:
The shunt trip coils for the eight valves will be removed and automatic isolation capability will be added under Modification Design Change Package MDCP 0106, which will be completed during the first refueling outage which is scheduled to begin March 28, 1987.
This modification will provide automatic and diverse
Mr. Robert M. Gallo October.10, 1986 Page 6 i
isolation signals to these valves in accordance with License Condition 2.C.10.
This is believed to be an isolated incident related to the nature of the commitments and the fact that a plant modification was not immediately required for implementation.
Adequate programs are in place to preclude similar events in the future.
Date When Full Compliance Will Be Achieved:
The deviation will be permanently resolved upon implementation of MDCP 0106.
4 If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours,
/
cc:
E. M. Kelly, Senior Resident Site Inspector See Attached Service List
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