ML20038C758

Part 21 Rept Re Loose Terminations on Relays in MSIV Leakage Control Panel.Caused by Lack of Secure Mechanical Fastening of Conductor to Termination Pin on Panel Relay.Ring Lugs Used to Fasten Wires Securely

ML20038C758
Person / Time
Site:	Grand Gulf
Issue date:	12/07/1981
From:	Sherwood G GENERAL ELECTRIC CO.
To:	Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-81-533-000 CAC-110-81, MFN-210-81, PT21-81-533-000, NUDOCS 8112140105
Download: ML20038C758 (3)

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,1 GENER AL h ELECTRIC NUCLEAR POWER SYSTEMS DIVISION GENERAL ELECTRIC COMPANY,175 CURTNER AVE. SAN JOSE. CALIFORNIA 95125 MFN 210-81 MC 682, (408) 925-5040 CAC 110-81 December 7,1981 ,

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U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement kb "# g ' % %D8/A 9' Washington, DC 20555 Y f m g Attention: Richard C. DeYoung, Director Gentlemen:

SUBJECT:

10CFR PART 21, REPORTABLE CONDITION LOOSE TERMINATIONS ON RELAYS IN PANEL AT GRAND GULF SITE This letter advises the NRC of a reportable defect per 10CFR Part 21 as reported to W. Mills of your office Dy Charles A. Cameron, Manager of Safety Evaluation Programs on December 8, 1981. Attached is the report of the defect as it applies to the affected plant, Grand Gulf Unit 1.

General Electric has informed the affected utilities of the defect and has advised them of the appropriate corrective action. General Electric has also identified those plant sites which may have the same defect with their Potter-Brumfield relays and initiated appropriate action.

Very truly yours, ACTING MANAGER FOR G. G. SHERWC00 Glenn G. Sherwood, Manager Nuclear Safety and Licensing Operation GGS:Im/1250 Attachment cc: R. DeYoung, NRC (two extra copies)

J. P. O'Reilly, NRC Region II J. G. Keppler, NRC Region III J. F. McAllister, General Electric L. S. Gifford, General Electric C o!$fjj[6 f PDR \

REPORTABLE CONDITION LOOSE TERMINATIONS ON RELAYS IN MSIV LEAKAGE CONTROL PANEL I. DESCRIPTION OF DEFICIENCY In the process of reshaping wire bundles in a Main Steam Line Isolation Valves (MSIV) Leakage Control panel, some wires were found to fall out of their terminations when a slight force was applied. The condition was identified at the Grand Gulf Unit 1 site and was documented by the plant architect-engineer on both a Quality Action Request and a Nonconformance Report.

The defect was identified only on Potter-Brumfield relays mounted in a panel that is employed in the MSIV Leakage Control System. Of all the panels inspected at the site, there were only two using this type of relay. One panel did not experience the problem due to the use of a positive method of fastening the wires to the relays. The other panel did not have a secure mechanical fastening of the conductor to the termination pin on the relay. This was the cause of the wires having inadequate connections.

1 II. ANALYSIS OF SAFETY IMPLICATION It would be expected that preoperational testing of the MSIV Leakage Control System instrumentation would locate any disconnected wires in the panel in question. However, assuming that such testing did not locate disconnected wires or that the wires became disconnected following testing, the capability of the MSIV Leakage Control System to perform its safety function could be degraded. In the worst case, failure of the MSIV Leakage Control System coupled with excessive valve leakage, could result in excessive flow through an isolation valve. If such a condition exists 6then isolation is required following a severe accident, e.g. , a loss-of-coolant accident, the flow through an isolation valve could conceivably result in release of radioactive steam from the reactor system to the environment.

The condition of the loose conductors on the relays in the MSIV l

leakage control panel was judged reportable under 10CFR Part 21, in that it could result in a decrease in the margin of safety of the plant during this unlikely scenario. This condition is reportable because the defective safety-related equipment was shipped to the site prior to the discovery of the defect. No safety hazard is actually expected, since the affected plants are not operating.

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III. CORRECTIVE ACTIONS TAKEN Corrective actions were taken at the Grand Gulf site for the panels in question. Ring lugs were used to securely fasten the wires to the relays. Approved parts, tools, and procedures were employed to correct the deviation. Also , the current GE manufacturing procedure requires the use of positive termination methods.

General Electric has initiated a program to instruct affected sites utilizing the Potter-Brumfield relay to assure the condition does not exist there or to take any required corrective actions. Field Disposition Instructions (FDI) require relay inspection and the use of ring lugs to secure wires to the Potter-Brumfield relays in cases where the connection is inadequate on the following projects

(" SCHEDULE" is the issue schedule for the FDIs).

PROJECT SCHEDULE Grand Gulf 1 9/25/81 Grand GLif 2 10/2/81 Perry 1 12/4/81

, Perry 2 12/4/81 Clinton 12/18/81 GGS:Im/1251-52 12/8/81

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