ML20116D992

Ro:On 960711,Safety Channel 2 High Voltage Sensing Circuit Failed.Allowed Reactor to Sit Over Weekend & Planned to Restart

ML20116D992
Person / Time
Site:	05000083
Issue date:	07/12/1996
From:	Vernetson W FLORIDA, UNIV. OF, GAINESVILLE, FL
To:	Ebneter S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20116D986	List: ML20116D985 ML20116D992
References
NUDOCS 9608050037
Download: ML20116D992 (2)

Text

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E' ATTACHMENT I l UNIVERSITY OF-

! FLORIDA Nuclear Reactor Facility 2021

• lear Sciences Center Department of Nuclear Engineering Sciences P.O. Box 118300 -

4 Gainesvtlle, Florida 32611-8300 Tel: (352) 392-1429 i

Fax:(352) 392-3380 July 12,1996 U.S. Nuclear Regulatory Commission . Potential Tech Spec Violation -

Region II Failure in Safety Channel 2 High 101 Marietta Street, N.W., Suite 2900 Voltage Sensing Circuit Atlanta, GA 30323 Attention: Stewart Ebneter, Regional Administrator Re: University of Florida Training Reactor Facility License: R-56, Docket No. 50-83 As per a telephone conversation on July 11,1996 with Mr. Ed McAlpine and again on July 12, 1996 with Mr. Craig Bassett relative to a non-conservative setting in the safety channel 2 high voltage sensing circuit discovered on July 11, 1996, we have concluded this occurrence is a potential reportable occurrence per UFTR Technical Specifications, Section 6.6.2 delinaating requirements for special reports.

De Reactor Safety Review Subcommittee (RSRS) Executive Committee has met and individual members were also contacted earlier and are in agreement with UPTR management reco== Wing NRC notification as per Section 6.6.2 of the UFTR Tech Specs as a pa**1=lly promptly reportable occurrence. ,

Initial evaiuation indicates that the required scram on 10% reduction of safety channal 2 high voltage was active at - 13.6%, somewhat above the 10% required by Tech Specs Section 2.2(5) requiring that Ibe i limiting safety system settings shall be . . . (5) The high voltage applied to Safety Channels 1 and 2  !

neutron chambers shall be 90% or more of the established normal value." The problem apparently occurred sometime after the last quarterly scram checks (Q-1 Surveillance) were conducted on March 27, 1996 and before the latest ones were being conducted on July 10,1996 when a problem was discovered at day's end during the Q-1 Surveillance but not evaluated until July 11 when the 13.6% voltage drop measurement was made. De circuit was reset at 9.1% (conserystive) on July 11,1996 and has been found to be operating properly after the overnight delay. However, the circuit setting has now been measured at an even more conservative 6.3% voltage decrease for the trip so an aging amplifier is being investigated for replacement. Final checks of corrective actions should be completed by July 12,1996 (later today). De reactor will be allowed to sit over the weekend after which it is planned to restart the reactor.

9608050037 9607d4 PDR ADOCK 05000083 S PDR Equal OpportunityIAffirmative Action Institudon

USNRC - Region II Page 2 July 12,19%

The RSRS fxecutive Committee has approved restart subject to successful post adjustment checks and increased frequency of testing of this limiting safety system setting; initially the trip actuation will be checked on a daily basis for two weeks and weekly thereafter for the rest of the quarter before the quarterly frequency will b.e reinstituted.

Sincerely, 1

William G. Vernetson Director of Nuclear Facilities WGV/dms Copies: D. Simpkins

. RSRS Sworn and subscribed this \M day of July,1996.

S hk t i n b. k i och Notary Public MD A. M l

, h""Wconsenson M.nen n. seen e a;e a8 the ==r eina me , ,

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