ML17266A224

LER 80-029/01T-0:on 800611,at 100% Power,Ground Occurred in Circuit of Valve HVC-14-6 Causing Valve to Fail Closed. Caused by Steam Condensing on Valve Solenoid W/Moisture Invading Terminal Box.Solenoid & Terminal Board Replaced

ML17266A224
Person / Time
Site:	Saint Lucie
Issue date:	06/25/1980
From:	Schoppman M FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17208A785	List: ML17208A784 ML17266A224
References
LER-80-029-01T, LER-80-29-1T, NUDOCS 8007080290
Download: ML17266A224 (2)

Text

NRC FORM S&8 V S NUCLEAR REGULATORY COMMISSION P TTI LICEiqISEE EVENT REPORT I

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'EPORTABLE OCCURRENCE 33~0-29 LICENSEE EVENT REPORT PAGE TWO ADDITIONAL EVENT DESCRIPTION AND PROBABLE CONSE UENCES Following loss of CCM to reactor coolant pump seals, the reactor was manually tripped, reactor coolant pumps were tripped, and a natural circulation cooldown was begun. The S/D margin required by Technical Specifications increases by 1".. Im d', tely wh n one or more RCP's is lost or turned off, and the shutdown margin calculation indicated that the RCS was 28 ppm below the requirements of echnic'al Specication 3.4.1. Emergency boration immediately restored shutdown margin. (Th'.s did not affect the health and safety of the public because the requireme,.ts assume one CEA stuck.out, while at this time all rods were on bottom. Furthermore, the required margin is for more restrictive end of cycle conditions).

The failed valve was jumpered open about 1', hours after its failure. The other isolation valve in the same line was operable, and seal cooling was desirable ta avoid further seal damage; Fhc Action (cooldo~m) of-T-.S.

3.6.3.1.d was in progress, and the CCH valve could have been .closed manually if necessary.

The plant was placed on shutdown cooling in about 8', hours, which then permitted inspection. Although no significant seal leakage was noted, previous experience and vendor recommendations indicate seal inspection is prudent due to the heat sensitive nature of portions of the seals.

ADDITIONAL CAUSE DESCRIPTION AND CORRECTIVE ACTIONS To reduce the probability of future losses of CCM .to RCPs, the blovrdown line which was the source of steam that initiated the event has been modified to replace flanged (leaking) joints with welded joints, and terminals in the terminal box have been spliced to reduce susceptibility to moisture. In addition a plant modification has been made to provide Novas a backup to air to RCP CCll isolation valves and to provide for pneumatic 6verride of the isolation valve on loss of solenoid. Additionally, the manual jacl ing device is being made more accessible and usable. Any use of these modifications will be under strict administrative controls.