ML20037B521
| ML20037B521 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Oyster Creek  |
| Issue date: | 10/06/1972 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20037B519 | List: |
| References | |
| NUDOCS 8010140639 | |
| Download: ML20037B521 (2) | |
Text
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V' L M AolSoN AVENUE AT PUNCH BOWL Ro Ao e Mo RRISToW.. N. J. 07900 6 5 39.Ct i f October 6,1972 O
4 e
Mr. A. Giambusso h,
Deputy Director for Reactor Projects
_ d.:
I Directorate of Licensing b
United States Ato:ic Energy Commicsion OCT101972> q
'8 $,ygEY Washington, D. C. 20545
{
c Regula! cry
Dear Mr. Cia =busso:
Mail Se:tica C,
i
Subject:
Oyster Creek Station Docket No. 50-219 Inoperable Standby Liquid Control System The purpoce of this letter is to report to you e acident that occurred at Oyster Creek on September 26, 1972 in which it was discovered that the two pumps in the standby liquid control system were inoperable at the same tinc.
At 10:45 a.m. on Septc=ber 25, 1972, the "A" standby liquid control pump was renoved f rom service for replacement of the pump packing.
The pu=p was taken out of service using Technical Specification 3.2.C.3 as the basfs.
It states, "If one standby liquid control system pumping circuit becomes in-operabic during the run mode and specification 3.2.A is cet,
~
the reactor may remain in operation for a peried not to exceed ccven days, provided the pump in the other circuit is demon-otrated daily to be operable".
Specification 3.2.A is met, therefore, the "A" pump breaker was racked out and the pump secured in accordance with plant safety procedures.
The work was not cc: plcted by the end of the day shif t, and the "A" pump was left in an inoperable condition.
At 4 :20 a.m. on Septenber 26, 1972, the "B" liquid control system pump was to be run to comply with Technical Specification 3.2.C.3.
g When the operator depressed the start button, the pump did not start.
An interlock in the starting circuitry prevents two standby liquid control pumps f rom being run simultaneously.
This interlock also prevents the "B" pump from starting when the "A" pump breaker is in the racked out position. The interlock is ccmpoced of a normally closed contact in the starting circuit of each pump.
This contact is operated from a relay in the opposite pump circuit.
If the "A" standby liquid centrol pump is started either from the cq@
contre] : con with the key lock switch or locally fro: the 801ouo(q
Mr. A. Giambusso
' rage II
'Octcber 6, 1972-puch butten station, a relay is picked up which opens the normally closed centact in the "B" standby 11guld control pump starting circuit which prevents thic pu=p from operating with the "A" pump
-running.
The reverse is true if the "B" pu=p is started.
The problem developed when the brcoker for the "A" puup was racked out.
It disabled the pump and at the sacc ti=c it physically removed the contact in the starting circuitry for the "B" pump which simulated an open contact.
This prevented the "B" pump from ntarting.
As soon as the Shift Foreman was aware of the inoperability of both pu=ps, he started a normal shutdewn of the plant.
In the mcentime, he rcccived permission to clear the maintenance safety tagu and rack the "A" pump breaker to its normal positien. He then ran a succecsful operability check en the "B" pump.
The load reduction was stopped and the plant returned to full load.
In order to prevent a recurrence of this event, cperating procedutes have been changed so that operability tests of redundant engineered safeguards system components will be.made immediately following any action that requires one of the systems to be inoperable f or maintenance purposes,
k*e are enclosing forty copies of this letter.
Very truly ycurs, (j11/
1 !C A Ivan R. Finfr ck, VicePresiden{.
IRT/pk
$nclo'sures cc: Mr. J. p. O'Reilly, Director Directorate of Regulatcry Operations, Region 1
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