ML20196C649

Forwards Insp Rept 50-346/98-19 on 981014-23.No Violations Noted.Inspectors Reviewed Circumstances Surrounding Events Leading Up to & Following Reactor Trip

ML20196C649
Person / Time
Site:	Davis Besse
Issue date:	11/20/1998
From:	Kozak T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Jeffery Wood CENTERIOR ENERGY
Shared Package
ML20196C654	List: IR 05000346/1998019 ML20196C649
References
50-346-98-19, NUDOCS 9812020079
Download: ML20196C649 (3)

See also: IR 05000346/1998019

Text

_ _ . . _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . . . _ . _ _ _ _ _ _ ,

[ UNITED STATES

[W8? o

g NUCLEAR REGULATORY COMMISSION

8 o REGION 111

3 g 801 WARRENvlLLE ROAD

• LISLE. ILLINOIS 60532-4351

% * * * * * #' November 20. 1998

Mr. John K. Wood

Vice President - Nuclear

Davis-Besse Nuclear Power Station

Centerior Service Company

5501 North State Route 2

Oak Harbor, OH 43449

SUBJECT: DAVIS-BESSE SPECIAL INSPECTION REPORT 50-346/98019

Dear Mr. Wood:

On October 23,1998, the NRC completed a special inspection which was initiated on

October 14 shortly after operators manually tripped the Davis-Besse nuclear reactor. The

inspectors reviewed the circumstances surrounding the events leading up to and following the

reactor trip. The enclosed report presents the results of that inspection.

Prior to the reactor trip, electrical train 2, which is powered from electrical buses D1 and D2,

was considered to be the protected train. Transformer AC, which is the attemate power supply

for buses D1 and D2, had been tagged out-of-service to allow maintenance activities to occur in

the vicinity of the transformer. Work had also been authorized to occur on circuit

breaker AACD1, which is the supply breaker from transformer AC to bus D1. While installing

the breaker back into its cubicle after maintenance activities were completed, a ground

occurred which caused a lockout of buses D1 and D2 and ultimately led to the manual reactor trip. The authorization of work to occur on components associated with a protected train while

the plant is being operated brings into question the effectiveness of your work control

processes and the risk matrix used when evaluating and approving online maintenance work

activities.

Once the lockout occurred, operators communicated effectively and generally executed their

responsibilities conservatively and professionally. Although operators were slow to enter the .

overcooling section of an emergency procedure, overall, the operators performed well during

the event. Procedures were appropriately used, and problems that complicated the event were

properly diagnosed and addressed.

A thorough review of the circumstances surrounding the event was conducted by your staff.

The approach to identifying and resolving equipment problems encountered during the event

was methodical and comprehensive. Equipment anomalies were documented and entered into

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the corrective action program. Engineering personnel support for resolving equipment

I problems was thorough and effective. Troubleshooting and equipment repairs were performed

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professionally. Personnel did not appear to be pressured to complete activities to meet the

restart schedule and all restart issues identified by your staff were addressed properly before

the decision was made to restart the unit.

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9812O20079 981120

PDR ADOCK 05000346

0 PDR ,

_ _ _ _ _ _ _ _ _

.- . - _ - _ . . . _ . - -. - . . . .. -

c.

J. Wood -2- i

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In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter and its

enclosure will be placed in the NRC Public Document Room.

l

Sincerely,

l

Original signed by

Thomas J. Kozak, Chief

Reactor Projects Branch 4

Docket No.: 50-346 1

License No.: NPF-3

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Enclosure: Inspection Report l

50-346/98019(DRP)

cc w/ encl: J. Stetz, Senior Vice President - Nuclear

J. Lash, Plant Manager  !

J. Freels, Manager, Regulatory Affairs

M. O'Reilly, FirstEnergy

State Liaison Officer, State of Ohio

R. Owen, Ohio Department of Health

C. Glazer, State of Ohio Public

Utilities Commission

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DATE 11/s4f98 11/t498

OFFICIAL RECORD COPY

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J. Wood -3-

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Distribution *

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Project Mgr., NRR w/enci- I

J. Caldwell, Rill w/enci

- C. Pederson, Rill w/ encl i

B. Clayton, Rill w/enci

SRI Davis-Besse w/enci -i

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PUBLIC IE-01 w/enci J

Docket File w/enci

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