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July 20,1982 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 92596-5368 Attention:
Mr. R. H. Engelken, Regional Administrator
Dear Sir:
Subject:
Docket No. 50-361 30-day Reports Licensee Event Report Nos.82-059, 82-060,82-061 and 82-062 San Onofre Nuclear Generating Station, Unit 2
Reference:
Letter, H. B. Ray (SCE) to R. H. Engel ken (NRC),
dated July 2, 1982 The referenced letter confirmed our prompt notification of your of fice of our f ailure to provide Licensee Event Reports (LER's) within 30 days of the dates upon which the event had occurred.
Pursuant to Technical Specification 6.9.1.13.b, this letter provides the required reports of four (4) instances of entering the Action statements associated with limiting Condition for Operation (LCO) 3.7.5 due to discovery of various inoperable support equipment in the Control Room Emergency Air Cleanup System.
In all cases, compliance with the requirements of the applicable Action statements was achieved.
On April 1, 1982, while in Mode 5, the Control Room Emergency Air Cleanup System, Train A, was removed frcm service to determine the cause of high vibration in the emergency chiller water pump. The Action statement associated with this LCO requires that an inoperable system be restored to operable status within seven days or the remaining operable system be maintained in operation in the recirculation mode. This action was taken on April 8,1982. The pump vibration was determined to be caused by. faulty bearings. The bearings were replaced and the pump restored to service on April 10, 1982.
82080202(X3 820720 PDR ADOCK 05000361 S
PDR pe i
Mr. R. H. Engelken
. July 20, 1982 While in this " degraded mode" the Train A emergency water chiller, E-336, was also found to have a faulty CCW flow control switch on April 7, 1982. The flow control switch was determined to be out of calibration and was recalibrated. The emergency water chiller, E-336, was returned to service on April 14, 1982.
During the 14-day period of Train A inoperability, the Train B Control Room Emergency Air Cleanup System became inoperable on April 11, 1982, when control room fan A-206 was stopped due to the suction damper closing and not responding to open control demands. The applicable Action statement associated with LCO 3.7.5 when-both trains are in-operable requires suspension of all operations involving core alter-ations or positive reactivity changes. The flow controller associated with the inlet damper to fan A-206 was corrected and the fan was returned to service on April 13, 1982.
Subsequently, on April 16, 1982, while still in Mode 5, Train A again became Inoperable when the emergency chiller E-336 was tripped on low flow. The erratic flow switch was replaced and the system returned to operable status on April 17, 1982.
Had an accident requiring Control Room isolation occurred while~any of these instruments were " inoperable" the ability of this Air Cleanup System to maintain Control Room air temperature below 1100 F would have been compromised.
A completed LER form summarizing each event is enclosed. 'If there are any questions regarding the above, please contact me.
Sincerely,
Enclosures:
LER's82-059, 60, 61 and 62.
cc:
A. E. Chaf fee (USNRC Resident inspector, San Onofre Unit 2)
U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information & Program Control Institute of Nuclear Power Operations a