ML19347C798

AO 50-219/74/8:on 740117,during Surveillance Test,Isolation Condenser Sys Initiation Switches Time Delays Failed to Close within Tech Specs Limt of 15-s.Caused by Design Error & Instrument Drift.Plant Committee Reviewing Occurrence

ML19347C798
Person / Time
Site:	Oyster Creek
Issue date:	01/25/1974
From:	Manning J JERSEY CENTRAL POWER & LIGHT CO.
To:
References
AO-50-219-74-8, NUDOCS 8103040560
Download: ML19347C798 (3)

Text

initis1'Telephona Data cf Repoit Da'ts: 1/2[ 't Occurrcnc3: ,

i 1/17/74

' Initial Written Time of Report Date: 1/25/74 Occurrence: 1055 flegulatory Docht Fi OYSTER CREEK NUCLEAR GENERATING STATION g_ y FORKED RIVER, NEW JERSEY 08731 DN' ~ - '

Abnormal Occurrence Report No. 50-219/74/ 8 IDEtEIFICATION Violation o'f the Technical Specifications, paragraph 2.3.5 ,

OF OCCURRENCE: which requires that isolation condenser system initiation occur with a time delay of <15 seconds after a specified high reacter pressure is reached.

This event is considered to be an abnormal occurrence as de-fined in the Technical Specifications, paragraph 1.15A .

C0hDITIONS PRIOR TO OCCURRENCE: _ Steady State Power Routine Shutdown Hot Standby Operation X Cold Shutdown Load Changes During Refueling Shutdown Routine Power Operation -

Routine Startup Other (Specify)

Operation 1he plant was shutdown with the reactor coolant at <212 F.

DESCRIPTION While performing a routine surveillance test on the reactor

. OF OCCURRENCE:

high pressure-isolation condenser initiation switches, contacts on three out of the four associated time delay relays failed to close within the preset t'ime delay of 15 seconds (after cach pressure switch was tripped and the associated relay deenergized).

1he delay times of these three relays were found to be as follows:

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• Abhirmal OccurrInca Report No. 50-219/74/ 8 Page 2 6K9 - 20 sec.

6K11 - 16.7 sec.

6K12 - 18 sec.

- Each of the involved ' time delay relays was immediately reset to less than 15 seconds.

APPAREhT CAUSE X Design Procedurc 0F OCCURRENCE: Manufacture Unusual Service Condition Installation / Inc. Environmental Construction Component Failure Operator ___ Other (Specify)

Instrument drift has been identified as the cause of these excessive time delays.

. ANALYSIS OF Four pressure. switches in the reactor protection system (RPS)

OCCURRENCE:

activate the isolation condenser system when there is a persis-tent 15 second condition with reactor pressure at or above 1060 psig. Two of these pressure switches with associated time delay relays 6K9 and 6K10 are in one RPS channel, and the other two pressure switches with associated time delay relays 6K11 and 6K12 are in the other RPS channel. liigh pressure signals from two pressure switches, one in each RPS channel, are required to activate the isolation condenser system (coincidence of two RPS channels cach of which is tripped by one of two pressure sensors) . Accordingly, the excessive time delays of these three time delay relays would have resulted in an isolation condenser system initiation delay time greater than 15 seconds had the isolation pressure been reached. There is no evidence, however, to indicate that isolation condenser system initiation would not have taken place with the three time delay relays operating as found. As detailed in Attachment 65 to the FDSAR, at Icast onc

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3 Abnormal Occurrones

/ Report No. 50-219/74/ 8 Page 3 of the isolation condensers is required to act as a means of heat removal during a postulated loss of ' coolant accident.

, The safety significan~ce of the initiation delay time in excess of 15 seconds is being evaluated at this time.

CORRECTIVE Corrective action will be determined following review of this ACTION:

abnormal occurrence by the Plant Operations Review Committee.

FAILURE DATA: Pertinent manufacturer data are listed below:

Manufacturer: Agastat Model: 7022 PDT Range: 5 to 50 seconds Coil: 120V DC Serial Numbers: 6K9 - 1712235 6K11 - 1712237 6K12 - 1712228 t

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