ML20150B682

Ro:On 880610,clutch Current Indication Lamp for Control Blade safety-2 Burned Out at Full Power,Dropping Control Blade from 56% Withdrawn to Fully Inserted Position.Clutch Replaced & Lamp Replacement Frequency Increased

ML20150B682
Person / Time
Site:	05000083
Issue date:	06/23/1988
From:	Vernetson W FLORIDA, UNIV. OF, GAINESVILLE, FL
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20150B685	List: ML20150B682 ML20150B696
References
NUDOCS 8807120120
Download: ML20150B682 (2)

Text

_ _ _ _ _ _ _ _ _ _ _ _ _ _

O NUCl. EAR ENGINEERIN@ SCIENCES DEPARTMENT Nuclear Reactor Facility University of Florida m v.-_. _ .m. .

o NUCHAR REACTOR BUUMNG 7Juneo23, 1988 n *

),'..,

[ $ $ [ .$, - ' Clutch Current Indicating Lamp Failure '5S

• Final (14 Day) Report Nuclear Regulatory Commission Suite 2900 101 Marietta Street, N.k.

Atlanta, Georgia 30323 Attention: J. Nelson Grace Regional Adminis trator, Region II Re: University of Florida Training Reactor Facility License : R-56, Docke t No. 50-83 Gen tlemen: .

Pursuan t to the reporting requirements of paragraph 6.6.2(3)(c) of the UFTR Technical Specifications , a description of a potential abnormal occurrence as defined in the UFTR Technical Specifications , ".hapter 1 is described in this 14-day report to include NRC notification, occurrence scenario, evaluation of consequences , corrective action and current s tatus. The potential promptly re-po-table occurrence involved burnout of the clutch current indicating lamp f or control blade Saf ety-2 at full power.

NRC Notif ication The Executive Committee of the Reactor Saf ety Review Subcommittee (RSRS) re-viewed this occurrence on June 13. 1988 and conuluded that it is a potential abnormal occurrence as defined in UFIR Technical Specifications , Chapter 1.

The Executive Committa also concurred with management res tart approval sub-ject to NRC concurrens . The RSRS then ins tructed NRC notification as per Sec-tion 6.6.2 of the UFTR Yn h Spees. This notification was carried out by both telephone to Mr. Paul Ft erickson and a f ollowing telecopy on June 13, 1988 (see Attachnent I).

Initial Event Scenario On Friday, June 10, 1988 at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> af ter approximately 5 1/2 hours of sam-g ple irradiation at f ull power (supporting neutron activation analysis) in pro-co o gress, the Control Blade Saf ety-2 clutch indicating lamp (see marked section

$8@ of Attachnent II; Figure 7-1, Overall UFTR Ins trumentation and Scram Logic gg Diagram) burned out, dropping Control Blade Saf ety-2 f rom 56% withdrawn to the cm fully inserted position. The reactor operator at the controls responded

• O promptly by conducting an unscheduled reactor shutdown per SOP-A.4, Reactor y

wO Shutdown with the reactor secured at 1722 hours0.0199 days <br />0.478 hours <br />0.00285 weeks <br />6.55221e-4 months <br />.

$@ Evaluation of Consequences Str Reactor s taf f and adminis tration including Director '.i.G. Vernetson concluded

$$co there was no compromise to reactor saf ety in this event, nor was there any impact on personnel radiation doses. All control and saf ety sys tems respondeu properly.  % % ,y % % % 2.

m

l

} .

f Nuclear Regulatory Commission June 24, 1988 Page Two i

Based on evaluations of this event, res tart was recommended following replace-h ment and retes t at all clutch indicating lamps including associated required surveillances such as control blade drive and drop tirne checks. Discussion and review of Technical Specification requirements (see Attachment III for applic-able sections of Technical Specifications) indicated that:

1; Congrol Blade Safe:y-2 at the 56% withirawn position-is worth about 132 x 10 A k/k, or N 1.9 dollars of reactivity.

2. A special report is required for an uncontrolled or unanticipated change in reactivity grcater than one dollar (excepting reactor trips from known causes - this event is a gravity drop of one control blade into the reactor as a result of terminating power to the blade drive magnetic clutches , but .not a Reactor Trip as defined in Technical Specifications ;

see Attachment III).

Corrective Action Immediate corrective action consisted of replacing the bucned out clutch cur-rent indicating bulb to include the necessary control blade drive and drop time checks 3 All were successful so the reactor was restored to operating s tatus on June 15, 1988.

Although there are no radiological or saf ety consequences of this event, .such f ailures are to be avoided. Theref ore, since a clutch indicating lamp f ailure occurred last year (at shutdown conditions), the f requency of preventive clutch current indicating lamp replacement will be. increased f rom annual ver-aus semi-annual preventive maintenance. This action is in agreement with pre-vious management evaluations and discussions with the RSRS Executive Committee on June 13, 1988. This actin is expected to reduce significantly the likeli-hood of recurrence of this f ailure event.

Current Status Since res tart on . June 15, 1988, there has been no recurrence of f ailure of any clutch current indicating lamp.

Sincerely, William G. Vernetson Director of Nuclear Facilities WGV/ps At tachmen ts khkuONotiry. (ddCON lob' Da te U

cc: P.I.. Whaley Reactor Saf ety Review Subcommittee D O' D 'N M8 Document Control Desk 4 (meh.kn Er.nu Abh 22, 1991 besies ins far.f f a.a to:wame ;rw.

__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ . _ _ . . _ _ _ _ _ _ _ . _ _ _ _ __._________.__________o