ML20024C061

Telecopy Ro:On 830613 & 14,train B Discovered Inoperable & Operability of Standby Gas Treatment Sys Trains Exceeded Tech Specs for Approx 6 H.Caused by Malfunctioning Square Root Converter.Plant Instruction Rev in Progress

ML20024C061
Person / Time
Site:	Browns Ferry
Issue date:	06/29/1983
From:	Coffey J TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8307120219
Download: ML20024C061 (2)

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TRLFCOPY TO NRC U8NRC p June 29, 1983 MTA, ;f0 'a U. S. Nuclear Regulatory Commission O bP Region II 4Y =' O l 101 Marietta Street, NW Suite 3100 Atlanta, Georgia 30303 BFRO-50-259-83035 Reported under Technical Specification 6.7.2.a.2 Telecony : Date: June 28,1983 Time 1515 CDT ,

Telechone : Date: June 28, 1982 Time 1440 CDT Person Contacted: Ross Butcher Date of Occurrence: 6/14/83 Time of Occurrence: 0530 Unit: Common Technical Specification Involved: 3 7.B.4, 4 7.B.3.C, 1.C.1 Conditions Prior to Occurrence Unit 1 was in a refueling outage with all fuel removed from the vessel.

Unit 2 was operating at 87% power, and unit 3 was operating at 100% power.

Identification and Descriotion of Occurrence During routine standby gas treatment system (SBGT) testing, "B" train was discovered inoperable at 2130 on 6/13/83 due to a relative humidity heater not functioning. Required testing on "A" and "C" trains was initiated per Technical Specification 4.7.B.3.C, but not completed at 2330, placing units

. 2 and 3 in a 6-hour LCO per Technical Specification 1.C.1. Testing was completed per plant instructions at about 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> and "A" and "C" trains declared operable. However, during further review of the event on 6/28/83 at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, in preparation of an LER per Technical Specification 6 7 2.b.(2) it was discovered that the flowrates on "A" and "C" train were set per installed instrumentation which was apparently malfunctioning.

This apparently would have resulted in insufficient actual flowrates.

This situation was corrected at approximately 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br /> on 6/14/83 using test instruments. Therefore, between 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> on 6/13/83 and 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br /> on 6/14/83 the operability of all three SBGT trains was in question exceeding the 6-hour LCO of Technical Specification 1.C.1 for about 6-hours.

Annarent Cause of Occurrence Halfunctioning square root converter in one SBGT flow instrument loop (FM-65-71) and the zero ("0") drifting high on the other loops instrument transmitter (FT-65-50).

Other Related Events None 8307120219 830629 OM PDR ADOCK 05000259 S PDR f52L If0 _.

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• ye TRLRCOPY TO NRC June 29, 1983 Corrective Action Taken or Pinnned Flow measurements were verified by test instrumentation as noted in description of occurrence. Pl. ant instructions are being revised to ensure.

that manual dampers on SBGT are not moved without verifying flowrates with test instrumentation.

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J. A. Co f y Acting Power Plant Superintendent Browns Ferry Nuclear Plant i

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