ML19343C213

LER 76-017/01P-0:on 760701,oxygen Concentration in Torus Reached Indicted Level of 5.4% Which Exceeded Tech Specs Limit.Caused by Erratic Behavior of Torus Oxygen Analyzer Following Calibr

ML19343C213
Person / Time
Site:	Oyster Creek
Issue date:	07/14/1976
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
LER-76-017-01P, LER-76-17-1P, NUDOCS 8103020132
Download: ML19343C213 (3)

Text

l'OENSEE EVENT REPORT

. . r -

CONTROL OLOCK-l l l l l l l (pLEASE PnlNT ALL ?.CoutRED INFCnMAsiorJ e 1 6 Na tictra Nountra vs tv

'] lNl.1l0lClPl1j l 0 l 0 l-l 0l 0l 0l 0 l 0l-l 0 l 0j l 4 l 1 l 1l 1l 1l 30

[0l1l 32 7 09 14 16 25 26 31 cattcony tvY rNN occvri NOUDin [Vitel DAtt Rrront OAfg QCON'T l l l [T j y l0 l 5 l 0l-l 0l 2l 1 l 9l l 0l 7l 0l 1l 7l 6l 60 69 74 l0l7l1l4l7[61 73 bu 7 o 57 58 69_ 60 G1 IVENT DESCA:PTION

@ l The oxyr'en concentration in the torus was permitted to reach an indicated level of l 7 00 03

$ [5.4*6 which exceeded the Technical Specification limit hv 0.4*6. Steps were initiated l 7 09 Da D l im,cdiately to purne the torus to less than 5*. oxygen. (50- 219/ 76 1 P) J 7 09 UO nI en l

7 o9 na I _j 7 oo ,,me ou t et c E covrcNtNT co0r sur u uNa vuuros 8 lS I B l y lxixlxlxi xi xl 17 12 LO_)

43 lxl9l9l9147 44 W 48 7 89 1C 11 CAUSE DESCR.PTION

@ [ De event was due to the erratic behavior of the torus oxygen analy:cr following l 7 83 69 l calibration. The erratic operation was amplified by a gas sample flow adjustment j 0

7 G9 09 1- l which caused the indicated oxygen icyc1 to drop to 2'6. Le true oxygen Icyc1 in j 7 89 60 FA04tIV ME THOD Or

$7Af97  % POWE R OTHER STATUS OSCObtnv DGCOvinv OtSC8 PTON l 0l 9l 2l l l Calibration of Torus Oxygen Analy crj 1

7 8 9 d 10 12 13 NA l 44

[BJ 45 4G gio

'ACN t$ CON T E N T C8 GELfASE AMOUNT OF ACTfv1fY LOCATON Of AFLEASE Dit t ALf D 7 0 9 W Wl 10 11 NA I 44 l

45 NA 00 l

PERSONNEL EXPOSURES nut.1 Pin TYFE CES0n@ ION NA 1

7 09 l 0j 0l 4 11 Wl 12 13 ,

UO l

PERSONNEL INJUA!ES .

PrJUE;E R OCSOnpfCN l

$ l 0l 0l d11 12l 7 09 NA 00 Prebable Consequences NA l DE l 00 7 89 LOSS OR DAMAGE TO FACLUY e

Tvrt OE SCfbPf CN D2 y NA l l 00 7 89 10 PtJ0t.lCITY NA l l 1 l ~ 00 7 09 ADOlllONAL FACTORS - Cause Description - Continued b ! the torus was discovered 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> later when the analy:cr was recalibrated. 7gl 7 uo l

8l 7 09 80 1

gg aid A. Ross, Manager

.cnne,rinc srneinm_sucir,r PHONE. 201-539-6111 ~, ...

Jersey central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07900

• 201-533-6111

.. .. . ., v.a cemeat g',y),y], Pubhe utihti.;4rporation bibrS E OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731

~

Licensee Event Report Reportable Occurrence No. 50-219/76-17-1P Report Date July 14, 1976 Occurrence Date July 1, 1976 Idcr.ification of Occurrence Violation of the Technical Specifications, paragraph 3.5 A.5, when the indicated oxygen concentraticn in the torus exceed the 5*6 limit. This event is considered to be a reportabic occurrence as defined in the Technical Specifications, paragraph 6.9.2.a.2.

Conditions Prior to Occurrence The major plant parameters at the time of the occurrence were as follows:

Power: Reactor,1768 FMt Generator, 585 FMe (3) ~

Flow: P.ecirculation, 58.5 x 10 6 lb/hr Feedwater, 6.58 x 10 6 lb/hr Stack Gas: 9500 pei/see Description of Occurrence On Thursday, July 1,1976, at approximately 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br />, following a calibration of the torus oxygen analyzer, it was observed that the torus oxygen concentration as indicated by the analyzer was 5.4's. Steps were initiated immediately to purge the torus to less than St, and by 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br />, the oxygen concentration was reduced to 4.St,. The sequence of events which led to the violation were ~ -

as follows: --

On Wednesday, June 30, 1976, on the 4 to 12 midnight shift, the torus oxygen analyzer failed. down scale. Maintenance per s.nel were contacted On theand 12 the midnight analyzer was repaired, calibrated and retu aed to service.

e s, ~ - -

7 - , - -

e .- .

. . . s Reportabic Occurrence No. 50-219/76-17-IP July 14, 1976 Page 2 to 8 shift, the torus oxygen analyzer began to behave erratically. The Group Shift Supervisor on duty at the time made an adjustment in the gas sample flow rate in an effort to correct the erratic behavior. The flow adjustment caused a change in the calibration of the analyzer and amplified its erratic behavior.

The calibration change caused the indicated oxygen concentration to drop to the 2% level. It remained at this level for a nine hour period until 0930 of the 8 a.m. to 4 p.m. shift when another calibration was performed which revealed the high 02 concentration.

Apparent Cause of Occurrence Because of the change in sample flow and the subsequent distorted analyzer operation, the slow ascent over the 5% oxygen limit was not realized.

Analysis of Occurrence Containment inerting requirements are based upon assumed zirconium metal / water reactions producing hydrogen gas in the containment during a design bases loss of coolant accident. It is postulated that by maintaining less than 5%

oxygen in the containment, an explosive mixture of oxygen and hydrogen will not result. The safety significance of this event is considered minimal since any hydrogen produced would be released into the drywell atmosphere which at the time of the occurrence was .3% 02 . Since during a design bases LOCA all the drywell gases are forced into the torus, an oxygen concentration less than 5'6 would have resulted in the torus shortly after the start of the LOCA.

Corrective Action On July 1,1976, the torus atmosphere was purged with nitgogen until the analyzer indicated a concentration of 3.8%. Periodic torus purging will be continued to maintain acceptable oxygen concentration. The torus 02 analyzer was calibrated and returned to service. In addition, the drywell 02 analyzer was temporarily connected to the torus sample flow as a cross check with the torus 02 analyzer, and both analyzers were in close agreement. A grab sample was obtained and sent to an independent laboratory for analysis. The laboratory analysis indicated correct analyzer calibration. To prevent recurrence, the following recommendations will be put into effect: (1) a caution tag will be affixed to the oxygen analyzer cautioning against changes in sample flow rate; and (2) operation of the analyzer will be reviewed in the Operator Training Program.

, Failure Data N/A .

__