05000269/LER-1983-008, Forwards LER 83-008/01T-0.Detailed Event Analysis Encl

Forwards LER 83-008/01T-0.Detailed Event Analysis Encl

ML20073C443
Person / Time
Site:	Oconee
Issue date:	03/29/1983
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20073C447	List: 05000269/LER-1983-008, Forwards LER 83-008/01T-0.Detailed Event Analysis Encl 05000269/LER-1983-008-01, /01T-0:on 830303,valve & One Independent HPI Train Declared Inoperable When Valve 1HP-25 Failed to Fully Open Electrically.Caused by Component Failure.Valve Operators for HP-24 & 25 Valves Will Be Replaced
References
NUDOCS 8304130161
Download: ML20073C443 (3)

LER-1983-008, Forwards LER 83-008/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2691983008R00 - NRC Website

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March 29, 1983 4 3 Mr. James P. O'Reilly, Regional Administrator

' gg U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Re: Oconee Nuclear Station Docket No.50-269

Dear Sir:

Please find attached Reportable Occurrence Report R0-269/83-08. This report is submitted pursuant to Oconee Nuclear Station Technical Specification 6.6.2.1.a(2) which concerns an operation subject to a limiting condition for operation which was less conservative than the least conservative aspect of the limiting condition for operation established in the Technical Specifica-tions, and describes an incident which is considered to be of no significance with respect to its effect on the health and safety of the public. My letter of March 17, 1983 addressed the delay in preparation of this report.

In that letter, this incident was mistakenly referred to as R0-269/83-07. Please. note this correction.

Very truly yours, fhh l/h/

Ital B. Tucker JCP/php Attachment cc: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555 INP0 Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 Mr. J. C. Bryant NRC Resident Inspector Oconee Nuclear Station Mr. E. L. Conner, Jr.

UO flCI AL COpp Office of Nuclear Reactor Regulation J

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 8304130161 830329 DR ADOCK 05 6

Duke Power Company Oconee Nuclear Station Report Number: R0-269/83-08 Report Date: March 29, 1983 Occurrence Date: March 3, 1983 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence: Failure ot' lHP-25 valve to open fully during functional testing making it and one HPI train inoperable Conditions Prior to Occurrence:

100% Full Power Description of Occurrence: On March 3, 1983, at 1030, valve 1HP-25 failed to open fully from the Control Room during its quarterly Operational Valve Functional Test. Additional attempts were made to electrically open the valve fully. After it failed to open further, 1HP-25 and one independent HPI train were both considered inoperable.

1HP-25 is a high pressure injection suction valve that provides the HPI pumps with suction from the Borated Water Storage Tank (BWST).

Apparent Cause of Occurrence: The valve could not be fully opened from the Control Room because the torque switch on the valve operator tripped repeatedly at a less than fully opened valve position. The torque switch is a device which will de-energize the motor contactor once the torque on the valve stem reaches a given value. The torque switch prevented 1HP-25 from reaching a fully open position. Prior to this incident, the torque switch on 1HP-25 was set at a value of 1 (lowest setting). After 1HP-25 was cycled from the breaker, the torque switch setting was increased from 1 to 2.

This means that now the torque switch on lHP-25 will trip at a higher torque value.

In general, the torque switch is set at the lowest value which will allow the valve to function properly.

1HP-25 is tested once every three months. During its last functional test on December 7, 1982, 1HP-25 failed to open (See R0-269/82-19). After the valve was manually cracked open, it was successfully cycled from the RZ module in the Control Room.

1HP-25 has needed manual assistance before it would function properly during four out of the last nine tests. The reason lHP-25 failed to operate properly on March 3, 1983 cannot be reasonably attributed to a design, manufacturing, construction or installation deficiency. This incident has therefore been assigned a classification of component failure.

Analysis of Occurrence:

1HP-25 is redundant to 1HP-24 and is an ES valve which opens on an ES actuation to line the HPI pump suction up to the BWST. Although 1HP-25 did not reach the fully opened position, it opened approximately to mid-position and would have provided some flow to the BWST outlet header. 1HP-24 was operable at the time 1HP-25 would not fully open. Had an ES actuation occurred, 1HP-24 would ha've opened to provide the HPI pumps _with suction from the BWST.

The health and safety of the public were not compromised.

(ES -Engineered Safeguard)

O Report Number R0-269/83-08 Page 2

Corrective Action

When it was determined that 1HP-25 could not be fdlly opened from the Control Room, Operations opened the valve by hand to its ES position. During the next attempt to cycle the valve, Instrumentation and Electrical (I&E) personnel monitored the current to the valve operator. The torque switch setting was increased from 1 to 2.

Valve operators for valves HP-24, HP-25, LP-17, LP-18, LP-21, and LP-22 will be replaced with environmentally qualified valve operators during the next refueling outage on each unit.

Because of the problems Duke and other utilities have had with.these type valve operators and because some of the original design criteria may be inappropriate, design criteria will be recalculated prior to manufacturing the environmentally qualified valve operators. Dominion Engineering has been contracted to act as Duke's consultant on the valve operator design calculations.

The surveillance frequency on 1HP-25 will be increased to monthly until there are two consecutive monthly tests in which valve performance is satisfactory. At this time, general corrective action for 1, 2, 3HP-24 and 1, 2, 3HP-25 is being formulated, and will be documented in R0-270/83-03, due to the NRC April 14, 1983.

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