ML20126F121

RO 50-213/75-1:on 750326,packing Gland Leak Rate Exceeded Tech Specs & Valve Steam Leak Offline Pressurized Enough to Lift Sys Valve,Relieving Pressure to Containment Sump.Caused by Inner Set of Packing Failure on Letdown Isolation Valve

ML20126F121
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	04/01/1975
From:	Hartley F CONNECTICUT YANKEE ATOMIC POWER CO.
To:
References
RO-50-213-75-1, NUDOCS 8103090035
Download: ML20126F121 (2)

Text

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ABUDr. MAL OCCUW.D;CE REPORT Report Nu ter: 50-213/75-1 P.eport Date: 4-1-75 Occurrence Da_t_e_: 3-26-75 Facility: Haddam Neck Plant Identifice. tion of Occurrence: Reactor Coolant Syste:, Packing gland leak.

Conditions Prior to Occurrence: Steady State Power Description of 0;currentt.

Velves in the reactor coolant system, two (2) inches or greater in size, have a du:.1 velve ste. ps;t.ing arrangercent with a valve stem leak off system connected to the valve betueen the tro sets of p5cking, to direct leahage from th2 inncr e

packing cl nd to a drain collection tcnk via a cooler. At 0530 on lurch 20, 1975.

a high terperatore alarm has received at the outlet of the valve stem leakoff ccoler.

Tctal renter coolant system leakage at 0500 was calculated to ' . v.3 GCi. An u.;

intestinction to find the cause of the alarm i. s initiated. At 1303 an clar rectived in the mir control roon. for the volur.e control tank level 'Tc.ta ef Chenge High" folicwed shortly by an alarm frca. the conteinment radiation maitrit ;

sy s t c.1. An increase in the containment sump level was cbscrved and at 1302 On orderly rer ctor plant shut dov.n was co:rcenced. At 1315 the leak rate to the reactor contain =r.t for 15 minutes indicated 4 GMt. This exceeds thc allocult Te i ics.i Sg .ificalico lii.its for reactor operation. 'A containsec.t entr3 un rade and reswied that the valve stear leak off line had Laen pressurized tc the point of causing the valve sten leakoff system relief valve to lift and relieve the pressurc to the containment sump. The plant and reactor was shut dorm, the systen coaled drn and depressurized to 309'F ard 550 PSIG. LD-F07-203 was rcpxked while in its back seat position. The plant was hected up and returned to power.

Cesignaticn of Arnarent Caure of Occurrence:

The apparent cause of the above occurrence was d?ternired to be a failure of the int.cr set of puking cn tha letde in isoiation vaive LD-MSV-20D allowing a rentcr coaient syst; e lcnage in cuess of that ello..es by the str. tion T:.chnici S;ecifications for Reactor Operation.

Anel:. sis cf Ocy_qrence:

All reactor conlant leck:ge was directed either to the norral collecticn tcuk or to the recctor contain.<ent. Both of which are designed to contain recctor coolant syst o le;kaJe end since no radio-cctivity was released to the environment, we conclude tnrt the public health and safety was not compromised as a result of this occurrence.

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ASf;0PE L OCCURREf;CE REfDRT - Haddam tieck Plant 213/75-1

orrective Action

Both the inner and outer sets of packing on LD-l'0V-200 were replaced with new packing. A containment inspection was conducted to check the other system valves for excessive leakof f and misadjustr.:ent. LD-MOV-200 operability was checked satisfactory.

v/ {p >.:A 4Q Plant Superin h dent 7

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