ML20107E710
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J To James P. O'Reilly Directorate of Regulatory Operations i
Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 i.
From:
Jersey Central Power' 4 Light Company Oyster Creek Nuclear Generating Station Docket #50-219 Forked River, New Jersey 08751 1
Subject:
Abnormal Occurrence Report No. 50-219/74/ 2
'!he following is a preliminary report being submitted in compliance with the Technical Specifications P
paragraph 6.6.2.
Preliminary Approval:
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1/9/74
'J. T. Carroll, Jr. V Date cc: Nr. A. Giambusso 4
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9604220053 960213 i
DEKOK95-258-PDR
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g Ayert Date:
1/9/7 Occurrence:
1 1100 l
l OfSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731
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l Abnormal Occurrence keport No. 50-219/74/1
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i Table 3.01.B f and'3,.
Violation of the Technical Specifications,ine high flow l
IDENTIFICATION which specifies that the RB22 Main Stena L OF OCCURRENCE:
sensors actuate at a differential pressure corresponding i
to line flows < 120% of rated.
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His event is considered to be an abnormal occurrence as de-fined in the Technical Specifications 4 paragraph 1.15A CCWDITIOP'S PRIOR TO OCCURRENCE:
X Steady State Power Routine Shutdown Hot Standby Operation Cold Shutdown Load Dianges During Refueling Shutdown Routine Power Operation Routine Startup Other (Specify)
Operation The reactor was operating at approximately 1827 MWt with a recirculation flow of 61X10' #/hr when the surveillance test was conducted.
DESCRIPT!Gi During the routine monthly surveillance testing of the RE22 0F OCCURRENG:
Main Steam Line high flow sensors, it was observed that the i
RB22C and RB22B sensors actuated at a differential pressu:e of 100 psi, one in each of the two safety systems. This is greater than the maximum allowable level of 97.5 psid which
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corresponds to a Main Steam Line flow 120%~ of rated.
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- Abnormal Occurrence h
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Jeppre N3. 50-219/74/l Pasa 2 APPARENT CAUSE Design Procedure OF OCQJpABNG:
Manufacture Unusual' Service Condition fastallation/
Inc. Environmental
~ Construction
- Component F411ure Operator Other (Specify)
The cattse of the failure is under investigation.
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ANALYSIS OF The safety significance of this event is in the loss of OCCURRENCE:
system redundancy. Had a high flow event developed, the redundan
- cts RE22A, B, D, F, G, and H would have
.. isolation function.
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performed 9
CORRECTIVB Each of the two sensors were recalibrated and returned to service as the failures were discovered.
ACTION:
FAILURE DATA:
Manufacturer: Barton Type:
Indicating Differential Pressure Switch Range: 0-200 psid Series:
RB22C - 224-19938 RS228 - 278-77D
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p,e,ared hy:
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,e Jersey Centta PcO'er & Lig7t Company V '- h %
MADISON AVENUE AT PUNCH BOYA. ROAD e MdRRISTOWN.N.J.07960
- 201539-6 es un w r,,e gjj'jj'* Pubiic utiiiiie:corporatiori ceneret men.
January 9, 1974 Fij p
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'Mr. A. Giambusso
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d Deputy Director of Reactor Projects g
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.y kr$['y' f.7 Directorate of Licensing j [.
4 United States Atomic Energy Commission z
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Washington, D. C. 20545
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Dear Mr. Giambusso:
Subj ect:
Oyster Creek Station Docket No. 50-219 Nain Steam Line High Radiation Monitor Failure This letter serves to report the failure of main steam line high radiation monitor RN05A to trip at a level of 10 times background during the quarterly calibration test. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, para-graph 1.15A.
Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a, was made to AEC Region I, Directorate of Regulatory Operations, by telephone on Thursday, December 27, 1973, and by telecopier en Friday, December 28, 1973.
While conducting the quarterly calibration test of the main steam line high radiation monitors, it was observed that the RN05A log count ratemonitorfailedtotripatitsnormalsetpointof1000 cgs.
An attempt was made to determine the actual trip'to the detector point by moving the Cos source, us.ed to introduce the test signal, closer The monitor would not trip regardless of the signal applied.
A half scram was introduced into the reactor protection system and the monitor was removed from service so that it could be bench-checked.
It was observed that the trip would actuate at a level of approximately
'40,000 cps.
It was further observed that subsequent trips occurred interntittently at 1000 cps and 40,000 cps Icvels on a random basis.
The faulty RN05A log count rate monitor assembly was replaced with a spare unit which, when tested, was also found to be defective.
A half scram was introduced into the reactor protection system until the original monitor assembly could be repaired.
Once the repaired unit was
' reinstalled, a successful surveillance test was peiformed. The other three in-service monitors were also satisfactorily tested.
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l Mr. Gianbuss*o O
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- January 9, 1974 The cause of the intermittent failure was traced to a cold sold-ered connection in the high alarm / trip section of the monitor assembly.
The exact location of the failure was not determined but the portion of the circuit involved was narrowed down and after all soldered connectio,ns in-this section were reworked, the problem disappeared.
Pertinent information concerning the monitor assembly is given j
below:
,t Equipment:
RN05A Manufacturer:
General Electric Company Drawing No.:
194X62961 Serial No. :
5,478,616 The purpose of the main steam. line high radiation monitoring system is to is.olate and scram the reactor should gross fuel failures occur causing a sudden release of fission products.
Since the other three monitors were proven operabic, they would have performed the scram and isolation functions associated with a main steam line high radiation condition.
Therefore, the safety significance of this event was a loss of system redundancy.
Since the problem with the monitor trip circuit was found and satisfactorily repaired, corrective action other than continued surveillance is not planned.
A review wil1 be made of all of the surveillance procedures for the main steam line high radiation monitors to ensure that they are sufficient for detecting malfunctions in these units.
3 Enclosed are forty copies of this report.
Very truly yours, h7W l' W Donald A. Ross Manager, Nuclear Generating Stations Cs Enclosures cc:
Mr. J. P.*0'Reilly, Director Directorate of Regulatory Operations O
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