ML19273A991

LER 79-002/01T-0 on 790108:roof Vent Stack Instantaneous Gas Release Rate Above Tech Spec Limit Due to Valve Operator Failure,Causing Loss of Inservice RHR Loop,Rise in Coolant Temp & Gaseous Release Via Core Isolation Cooling Valves

ML19273A991
Person / Time
Site:	Peach Bottom
Issue date:	01/22/1979
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19273A989	List: ML19273A988 ML19273A991
References
LER-79-002-01T-01, LER-79-2-1T-1, NUDOCS 7902010177
Download: ML19273A991 (1)

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TJnit 3 LICENSEE EVE NT REPORT accort No. 3-79-002/lT

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lb 8 60 61 CCCAET NUV0E H W G b ENT O A TE 4 EVENT CESCniPTION AND PROBAOLE CCNSEQUENCES 10

,9 qj Roof vent stack instantaneous re ease rate above Tech. Spec. limit. During I g 3 a maintenance outage coolant vapor leaked from the reactor thru open and l

,g , ; partially dismantled RCIC isolation valves via the MSIV room to the vent l

,, 5 stack. Work on both valves was permissibic since the unit was in cold l shutdown mode. Total release was 1 1/2 hours long with rate in excess of  ;

3 7 l Tech. Spec. for approx. 15 min. (peak 2707, of limit). Consequences minimal I g g  ; because of short duration and content of release (noble gases). I U

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CAUSE DESCniPTION AND CORRECTIVE ACTIONS h i o l Valve operator failure (M016A) caused loss of in. rvice RHR toon. rise in I ii i l coolant temp, and gaseous release via RCIC valves under pin, -, N o- ~o-  !

,, 7 g Shutdown cooling re-established, reactor coolant temp. reduced, thus ending I

,, 3 l release. Operating personnel instructed to limit coolant temo, to 170 ? I i l when release flow path exists. Procedural mods to orovide cuidance. I a 2 n YE THQ CF ^

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nELE ASE.D cr nELE ASE AMOUNT CF ACTIVT TY l1 s y @ l Nmj@l 55.4 Ci Noble Gases ,, u l

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