ML20062N318

LER-021/03L-0:on 820714,22B Safety Injection Tank Pressure Found Decreased to 197 Psig on 820427.Caused by Loop Isolator Failure.Isolator Replaced

ML20062N318
Person / Time
Site:	Calvert Cliffs
Issue date:	08/13/1982
From:	Raynor J, Wenderlich R BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20062N311	List: 05000318/LER-1982-021, Forwards LER 82-021/03L-0 ML20062N318
References
LER-82-021-03L-01, LER-82-21-3L-1, NUDOCS 8208230087
Download: ML20062N318 (2)

Text

NRC U. S. NUCLE AR REGULATORY COMMISSION

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(PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION) 10111 7 8 9 lM Lit.ENSE lo I cE CODE Ic IN I 2 l@l 0l 01 -l Ol 14 15 010101 Ol -l 01 25Ol@l LICENSE NUMBEH 26 41LICENSE 1l 11 TYPE il JO l il@l57 CAT $8 l@

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[O l3 l l calibration problem, it was discovered that 22B Safety Injection Tank I l o 14 l l (SIT) pressure had probably decreased to 197 PSIG on 4-27-82, slightly I lo Isl I less than the minimum required 200 PSIG (T.S. 3.5.1). Upon discovery on I 1016 l l 4-27-82, the SIT was immediately repressurized. Follow-up investigation l 1017 I I during the recent outage indicated that pressure had likely been 3 PSIG l l 0 ls i i low. All other SIT's remained operable. Similar events: none. I 80 7 8 9 C E CODE SUBC E COMPONENT CODE SUB DE S E 7

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43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 1110 l I Troubleshootine revealed the cause for this event to be failure of the I li 11 l l Loon's isolator, 2-PY-331A (ACM Model TA-4000). Replaced the isolator. l lil2l l This model isolator is presently being evaluated by the Electric Engi- l 1113l l neering Department for its high failure rate under Facility Change I 1114 I l #81-1027. No other action is deemed necessary at this time. l 7 8 9 80 ST S  % POWER OTHER STATUS DI O RY DISCOVERY DESCRIPTION li15l d h IOl0l0lh! N/A l [C_jhl Troubleshooting i ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7

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PERSONNEL EXPOSURES NOVBER TYPE DESCRIPTION 1 7 l010l0lh d hi N/A I PERSONNE L INJU IES NUMBER DESCRIPTION 8208230087 820813 7

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7 8 9 10 68 69 80 5 NAME OF PREPARER R.' L. Wenderlich/J. W. Ravnor PHONE: 301-269-4776/4713 {

, t LER NO. 82-21/3L DOCKET No. 50-318 LICENSE NO. DPR 69 EVENT DATE 07-14-82

. REPORT DATE 08-13-82 ATTACHMENT EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (CONT'D)

During normal shutdown operation at 1400, while investigating a previous calibra-tion problem, it was determined that 22B Safety Injection Tank (SIT) pressure had probably decreased to 197 PSIG on April 27, 1982, slightly less than the minimum required 200 PSIG (T.S. 3.5.1) . On April 27, 1982, 22B SIT wide range pressure indication had been found to read 193 PSIG, with narrow range reading 213 PSIG. SIT pressure was immediately increased to 200 PSIG by wide range indication. Investigation during the next shutdown revealed that the narrow range indicator had been reading abnormally high. This indication was repaired at 1440 on April 27, 1982. All other SIT's remained operable during this event.

Similar events: none.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (CONT'D)

On April 27. 1982, the troubleshooting of 22B's Safety Injection Pressure Loop was limited to components outside the containment structure due to ALARA consid-eration of the radiation dose rate in the cont.ainment. This limited trouble-shooting revealed that the loop's isolator (2-PY-331A) output' signal was non-repearable. The loop's isolator was replaced. Maintenance request #1-82-2066 was held open to further evaluate the reportability of this event during the unit's next shutdown.

On July'14, 1982, with the unit in Mode 3, entry into the containment was made; wide and narrow range indications were found within nominal. tolerance as com-pared to a calibrated test gauge. However, the test data gathered indicated that on April 27, 1982, 22B Safety Injection Tank pressure had probably been 3 PSIG below the technical specification limit.- The pressure loop isolator was assessed to have been the cause for this event.

This model isolator (AGM, TA 4000) is currently being evaluated by the Electric Engineering Department under Facility Change #81-1027. No further action is

' deemed necessary.at this time.

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