ML20235Y456
| ML20235Y456 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/14/1987 |
| From: | Long R GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| PNS-87-0105, PNS-87-105, NUDOCS 8710200366 | |
| Download: ML20235Y456 (3) | |
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USNRC-DS GPU Nuclear Corporation Nuclear e oU 20 A 9 5-9
" , f4i*s$tl#8 3t Middletown, Pennsylvania 17057 0191 717 944 7621 j
TELEX 84 2386 I
Writer's Direct Dial Number:
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October 14, 1987
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PNS-87-0105 l
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U.S. Nuclear Regulatory Commission
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Document Control Desk
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Washington, DC 20555
Dear Sir:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 Safety Limit Violation By letter dated September 20, 1987, GPU Nuclear detailed the safety limit violation which occurred at the Oyster Creek Nuclear Generating station on September 11, 1987.
The cover letter to that submittal specified operator error 'as the cause of the violation. This letter is being written to supplement the root cause analysis provided and further delineate why the operator error occurred.-
The safety limit which was violated requires at least two recirculation loops to be operable (i.e., suction valve and discharge valve open) at all times unless the reactor vessel head is off and the reactor is flooded to a level above the Main Steam nozzles. The plant had B and C recirculation loops operable.
A, D, and E recirculation loops had their respective discharge valves shut.
Due to an imminent loss of cooling water to the Recirculation l
Pumps (RCP), the operator commenced securing RCPs B and C.
In accordance with the normal operating procedure when the plant is at power, he started closing the loop discharge valve prior to de-energizing the pump.
In this off-normal plant configuration, this sequence of actions caused a violation of the safety limit due to personnel error.
The root cause of the personnel error was that the operator failed to implement the procedure for securing RCPs on a loss of RBLCW. Abnormal Operating Procedure 2000-ABN-3200.19 "RBCCW Failure Response" specifies that the RCPs are to be secured and the recirculation suction and discharge valves verified open (to prevent violation of the safety limit). Had the operator implemented this procedure, the safety limit violation would not have occurred. As committed in our September 20, 1987 letter, the importance of adherence to approved procedures will be stressed to the operators prior to plant restart.
8710200366 873014 PDR ADOCK 05000219 G
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4 GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
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PNS-87-0105' October 14, 1987 Procedure 2000-ABN-3200.19 was reviewed for clarification and a few minor revisions were issued.
As committed in our letter of. September 20, 1987, training on this procedure and.its new revisions will be completed prior to restart.
During this event, the operator did not consult 2000-ABN-3200.19 prior to closing the recirculation discharge valve. Consulting an abnormal or emergency procedure prior to taking requisite immediate. actions is not required during an emergency.
Operators are trained to implement memorized immediate actions and then consult the procedure to verify the completeness of 1
those actions which were taken.
A contributory cause to this event was that the training of operators on recirculation pump securing, like the operating procedure, had been structured towards normal operating conditions. As stated in our September 20, 1987-letter, GPUN believes that the sense of urgency to secure the RCP associated with the impending loss of.the RCP cooling source, Reactor Building CIosed Cooling Water (RBCCW), was uppermost'in -the operator's mind when the violation occurred.
In this event, the operator reacted instinctively to execute the practice.which was routine-to him without appropriate consideration of the existing plant conditions or recirculation loop availability.
Had his " hands on" training at the Basic Principles Simulator or the Full Scale Simulator more stringently challenged him on off-normal recirculation pump operations, the proper action may have been taken.
Similarly, if he had been drilled more completely on the RBCCW failure response procedure, his " instinctive" response may have been the correct one for the existing off-normal conditions.
Operating Procedure 301, which includes normal recirculation pump securing, was revised to more appropriately place a caution statement immediately preceding the section on RCP securing.
Training on the Basis Principles Simulator and the Full Scope Simulator was modified to specifically include RCP operations from off-normal conditions. As committed in our September 20, 1987 letter, training on Procedure 301 and its revision, and training on the Basis Principles Simulator will be completed prior to restart. The modified training on the Full Scope Simulator has been initiated and is projected for completion by November 30, 1987.
Finally, a contributory cause to this event was the safety limit itself.
Subsequent to the 1979 event when the safety limit was submitted and approved, GPUN determined that one loop, not two, is required to provide adequate communication between the core and annulus region for a worst case analysis.
Had a Technical Specification Change Request been submitted to more appropriately define the recirculation loop requirements as a one loop Limiting Condition for Operation vice a two loop safety limit, the actual significance of this event would have been more clearly reflected in the Technical Specifications.
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' PNS-87-0105 October 14, ?987 l
As committed in our September 20, 1987 letter, a Technical Specification l
Change Request is being evaluated' for submittal to more appropriately define the significance of isolating a fourth-recirculation loop. Additionally, a review of the Technical Specifications has been initiated to determine if any other specific items could be more appropriately defined. And finally, as a member.of the Boiling Water Reactor Owner's Group, GPUN is participating in a long term Technical Specification upgrade program where many utilities are sharing experience and knowledge to improve Technical Specifications
'throughout the industry as a whole..
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If any further information is required, please contact Mr. John' Rogers of nty i
staff at (609)971-4893.
Very truly yours, R. L. Long l
Vice President & Director Planning & Nuclear Safety RLL/JR/dmd(0385A) -
cc: T. E. Murley L. H. Bettenhausen W. T. Russell S. Collins W. Bateman B. Boger A. Dromerick, Jr.
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