ML20009F621

Forwards LER 81-074/03L-0.Detailed Event Analysis Encl

ML20009F621
Person / Time
Site:	McGuire
Issue date:	05/28/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009F622	List: ML20009F621 ML20009F625
References
NUDOCS 8107310360
Download: ML20009F621 (2)

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Mr. James P. O'Reilly, Director f\ J%"

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Re: McGuire Nuclear Station Unit 1 Docket No. 50-369 T/gy j

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-74. This report concerns an inadvertent safety injection. This incident was considered to be of no significance with respect to the health and safety of the public.

Very truly yours,

, /,

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William O. Parker, Jr. .

RWO:pw Attachment cc: Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission Post Office Box 10412 Washington, D. C. 20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Stotion W , i 8107310360 810528 PDRADOCK05000g S

7 McGUIRE NUCLEAR STATION INCIDENT REPORT Report Number: 81-74 Report Date: lby 29, 1981 Occurrence Date: April 29, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence: An inadvertent safety inj;ction vns initiated on Train A when the Train A Solid State Protection System (SSPS) cabinets were re-turned to service without blocking the safety injection signals.

Condition Prior to occurrence: Mode 5, Cold Shutdown Description of Occurrence: On April 29, 1981, modifications were being made to the A Train logic cabinets of the SSPS. When the cabinets were to be returned to normal operation, the appropriate permissive blocks were to be inserted in the SSPS logic, There was some confusion by the technicians about exactly what steps needed te be taken as most of the Train A equipment was tagged out. The " Input Error Inhibit Switch" was placed in the normal position. An immediate safety injection was iniciated on Train A. The control operators took the appropriate steps to re-cover from the safety injection.

Apparent Cause: During the modification work, certain safety injection permissive blocks were cleared from the SSPS Train A logic. When the system was returned to service without the signals blocked, safety injection was initiated.

Analysis of Occurrence: A grocedure was available for restoring the SSPS cabinets to service. (Procedure For Troubleshooting Solid State Protection System (SSPS)

During Critical Operation), but was not being used. The intent of the procedure was followed in that the permissive blocks were attempted to be inserted 1n the logic before the cabinets were returned to service. The safety injection itself had minimal effect on the plant because all of the Train A safety related pumps

, and diesel generator were tagged out. Some ventilation units started and the Train A valves included in Phase A isolation cycled but no significant water volume was transferred.

Safety Analysig: This safety injection had no effect on the plant operation be-cause most of the associated equipment was de-energized and tagged out. The health and safety of the public v're not affected for the same reason. An error of this type could have been significant if more of the associated equipment had been operational and/or the plant had been under a different mode of operation.

Corrective Action: The immediate e,rrective action was to recover from the safety injection. Station management met ith the individuals involved and it was stressed that this type of incident should not be repeated. To prevent a recurrence of the incident, procedures governing work (either testing or maintenance) on the SSPS were rewritten to include specific steps to return the cabinets to service. Each of the steps included a sign off. The steps concerning the permissive block in-sertions included sign offs for a control operator as well as the technician. It was further agreed that no work would be done on the SSPS cabinets without one of the controlling procedures (either a periodic test procedure or the troubleshooting procedure).

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