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To:
James,Pg0'Reilly
.W2F-n k:,4E8 Directorate of Reguintory Operatic..u
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Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 rp<
From:
.._,w Jersey Central Powerband Light Cogany Oyster Creek Nuclear Generating Station Docket #50-219 ForkerRiver, New Jersey 08731 Subject :
Abnomal Occurrence Report No. 73-32 i
'The following is a preliminary report being submitted in compliance with the Tcchnical Specifications, paragraph 6.6,2.
Preliminary Approval:
M 12/20/73 n
J. T. Carrolf, Jr.
Date cc: Mr. A. Ciambusso I
k 9604120114 960213 PDR FOIA DEKOK95-250 PDR
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Preliminary d
Abnor1 mal occurrence Report No. 73-32 SUIVECT:
Failure of the test spool Valve for NSO4A topmperly reset after
% closure test which resulted in a condition which may have caused the EIV Lu close slowcr than norwal should an isolation signal have occurred during the test interval.
This cycnt is considered to be an abnormal occurrence v. defined in the Technical Specifications, paragraph 1.15D, Notification of this event, as required by the Technien) Specifications, para-graph 6.6.2.8, was made to AEC Region I, Directorate of Regulatory Operations, by telephone on %ursday, Decedser 20,1975 at 0900, and by tolecopier at 1500.
SITUATI0y:
It had been observed on DeceWier 17 and 18 that MSIV SO4A was apparently overtravciling during the daily 5% closure exercise, therchy causing pressure transients of 6 psig and 10 ps12, res-poetively. Analysis of the problem indicated that possibly the overtravel was a result of the improper resetting of the test spool valve.
To explore this possibility, reactor pwcr was re-duced to 853 HNt (<40% of rated power) so that further examina-tien of the test spool valve assent:1y could be conducted with reduced possibility of a reactor scriun due to valve closure, and to reduce radiation levels in the work area.
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Pro 11minary Abnormal Occurrence Report Hoo 73-32 Decenher 19, 1973 y
s The St valve clusure test was redone with an instrtment tedini-clan in local observance of.the test,, The sticking condition had tpparently worsened, thereby causing the Mi!V to go approxi-mately 50% closed and then reopen in the normal manner. The technician concluded that the test valve was the cause of the probles.. mus, a situation was created whereby had the valve been required to isolato during the test interval (approximately 2-3 minutes) it is unlikely that it would have met the required closun tiene of $10 seconds, sinco exhatut air from the under-side of the valve operator piston is requind to pass through the test valvo assenbly. Because of the malpositioned valve assembly, the cahaust air would have been restricted, thereby slowing the valve closure time.
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tipun ~ removal and disassenbly of the test spool valyc, it was observed that foreign material resenbling red pentder was found l
on und between the spool and siceve assenhly, although it has f
not bocn conclusively determined that this was the cause of the
- 1ve sticklng. The spool assenbly is being sent to a testing lab for further evaluation.
RfDU! DIAL ACT1(th The test spool valve assembly for NSO4A was replaced. We 5%
closure tost w e repeated satisfactorily, as well as a full closun timing test (6.7 seconds).
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- )ps Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN.N.J. 07960
- 201-539-6111 E6 meg 2 OF TN8
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Puohe Utahties Corporation General er,rs =
20, 1973 M....
December N
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Mr. A. Giambusso i
n i.ttust Deputy Director for Reactor Projects J
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7 2te of Licensing United states Atomic Energy Commission
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Washington, D. C. 20545 N
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Dear Mr. Giambusso:
Subject:
Oyster Creek Station Docket No. 50-219 Damaged Relay The purpose of this letter is to report to you, as a matter of interest, the threatened failure of relay 6K43 in the plant protection system.
This relay is one of two relays which causes operation of the torus to reactor i
building vacuum breaker block valves.
It is a normally energized relay which-maintains closed contacts in the valve circuit for closing the block valves, V-26-18 and V-26-16.
The function of these valves is to assure that the primary containment is not operated at a negative pressure relative to the reactor building.
Should either one of two differential pressure switches trip on the given setpoint of 0.5 psig, its associate relay 6K43 or 6K44 will de-energize with the subsequent opening of the block valves.
On November 21,1973 at 12:41 p.m., smoke was observed emanating from relay 6K43, located in panel 10F in the control room.
The function of the relay was determined, and at 1:05 p.m., an instrument technician, upon instruction from the shift foreman, deenergized the relay to avoid any possibility of damaging adjacent wires and relays. A jumper was then placed across the con-tacts in the valve circuit which again closed the valves. The valves remained open-for approximately one minute, which essentially is the amount of time they are open while performing the normal monthly surveillance test.
hhile the valves were closed in this manner, the redundant pressure switch associated with relay 6K44 would have performed the pressure protection function.
The damaged relay was removed and a new relay of higher voltage was installed. A surveillance test was performed and the system was returned to normal by 3:49 p.m.
Since the incident, the bus voltage has been reduced from the prior 125V AC value to 120V AC.
The damaged relay was removed to the electrical shop for testing; however, the cause of the failure could not be determined.
The relay will be sent to the vendor's testing lab for further evaluation. The relay was a j
S~/~d~3 $ 6 7 $
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Mr. Giambusso December 20, 1973
. General Electric Control Industrial Relay, Serial No. CR120A 02202AA, 300V AC, 10 amp maximum 115V, 60 cycle, coil series A.
During the period when the temporary jumper was installed (1:06 p.m. -
3:30 p.m.), the redundancy of two pressure switches was lost. However, one pressure switch is capable of causing the valves to-open..In addition, a switch ~in the control room could have been used to open the valves should it have been required.
The conditions that would cause the torus to go negative would evolve generally after an extended period of time, following a loss of
^ coolant accident.
Consequently, sufficient time for. action would have been available.. More importantly was the necessity to maintain the primary contain-ment integrity provided by these valves. Consequently, keeping the valves closed rather than. letting them remain open during the repair was justified.
As per prior General Electric recommendations, failed relays will be replaced with ones of a higher voltage rating.
Further action will be considered based upon the vendor's inspection results of the damaged relay.
Enclosed are forty copies of this report-Very truly yours, l
/00 qws-Donald A. Ross t
Manager, Nuclear Generating Stations es cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I I
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