05000265/LER-1979-012-03, /03L-0 on 790622:nut Inadvertantly Droppoed Into Diesel Generator Winding During Preventive Maint.Outage Time of Generator Extended 20 Minutes Beyond 1.5-h Time Limit. Caused by Personnel Error

/03L-0 on 790622:nut Inadvertantly Droppoed Into Diesel Generator Winding During Preventive Maint.Outage Time of Generator Extended 20 Minutes Beyond 1.5-h Time Limit. Caused by Personnel Error

ML19225B515
Person / Time
Site:	Quad Cities
Issue date:	06/22/1979
From:	Vahrenwald J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19225B502	List: 05000265/LER-1979-012, Forwards LER 79-012/03L-0 05000265/LER-1979-012-03, /03L-0 on 790622:nut Inadvertantly Droppoed Into Diesel Generator Winding During Preventive Maint.Outage Time of Generator Extended 20 Minutes Beyond 1.5-h Time Limit. Caused by Personnel Error
References
LER-79-012-03L-03, LER-79-12-3L-3, NUDOCS 7907250283
Download: ML19225B515 (1)

LER-1979-012, /03L-0 on 790622:nut Inadvertantly Droppoed Into Diesel Generator Winding During Preventive Maint.Outage Time of Generator Extended 20 Minutes Beyond 1.5-h Time Limit. Caused by Personnel Error

Event date:
Report date:
2651979012R03 - NRC Website

text

NRC FORM 366 U. S. NUCLEAR RECULATORY COMMISSION (7 77)

LICENSEE EVENT REPORT CONTROL BLCCK:

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b0 61 DOCK ET NUMB E R 6d 69 EVENT DATE 14 75 REPORT DATE

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2 l While performing the Unit Two Diesel Generator monthly Oreventive maintenance

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l inspection, a nut was inadvertantly dropped into tne diesel generator winding when l

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replacing the brush rigging Cover. The retrieval of the dropped nut extended the g

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The 1/2 diesel generator had been tested prior to taking the Unit' Two l diesel generator out of service. The nut was found prior to starting surveillance l

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,&M Wisconsin Electnc ecw come 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE WI 53201 July 3, 1979 Mr. James Keppler, Regional Director Office of Inspection and Enforcement Region III U. S. NUCLEAR REGULATORY COMMISSION 799 Rooseveit Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

DOCKET NOS. 50-266 AND 50-301 MODIFICATION OF THE RESET CIRCUITS IN THE SAFEGUARDS ACTUATION CIRCUITS LICENSEE EVENT REPORT NO. 79-010/01T-0 POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 Enclosed is Licensee Event Report No. 79-010/01T-0, which, together with this letter, provides a 14 day followup report to our 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> written notification of June 20, 1979. The results of our review of the safeguards actuation circuitry of Point Beach Nuclear Plant indicate a finding that may be reportable in accordance with Technical Specification 15.6.9.2.A.9,

" Performance of structures, systems, or components that requires remedial sction or corrective measures to prevent operation in a manner less conservative than that assumed in t.'.

accident analyses in the safety analysis report or technical specifications bases; or,1iscovery during plant life of conditions not specifically considerad in the safety analysis report or technical specifications that require remedial action or corrective measures to prevent the existence or development of an unsafe condition."

As you know, Mr. A. Schwencer's letter dated November 28, 1978, identified a deficiency in the reset circuitry of the Containment Ventilation Isolation circuits at two other plants. The letter requested that we inves-tigate the reset circuitry used at the Point Beach Nuclear Plant in the Containment Ventilation Isolation and other safeguards circuits.

In our letter to Mr. Denton dated January ~ 16, 1979, we indicated that the safeguards reset circuits at Point Beach had the characteristics mentioned in the November 28 letter and that we would analyze the circuits in detail and modify them where necessary. Further, because of the mechanical characteristics of the containment ventilation valves, we conmitted in LER 79-04 to keep the valves closed during power and hot standby operation. A meeting was held at the Point Beach Nuclear ?lant with Mr. J. T. Beard of your Staff on June 5,1979, at which time circuit configurations, requirements, and modifica-tions were further discussen.

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Mr. James Keppler - Page Two July 3, 1979 We have completed a detailed review of the safeguards actuation circuits at the Point Beach Nuclear Plant. The results of this review indicate that some changes to the circuitry are desirable. Modification requests to effect these changes have been written and are in the review and approval process.

There are four safeguards circuits for which we believe modifications are desirable. These are Safety Injection, Containment Isolation, Containment Ventilation Isolation, and Containment Spray.

The modifications we propose will provide the following circuit characteristics:

1.

MANUAL INPUTS Manual actuation of a safeguards circuit will not be affected by the reset circuitry. Safety Injection has always had this feature. The other three circuits will be modified.

2.

AUTOMATIC INPUTS The Containment Ventilation Isolation circuit will be modified so the reset function will not block an additional automatic signal from activating the circuit. The Safety Injection circuit is designed to sequence a group of protective actions after receipt of an automatic or manual initiation signal.

The Safaty Injection circuit must be reset after initiation in order to operate equipment which was secured or stripped by the safety injection sequence. Should an additional auto-matic signal be generated after reset it is not desirable to resequence che protective actions which have ciready occurred and chance the post accident equipment lineup.

For this reason che Safety Injection circuit will not be modified in this reg:rd. Containment Spray and Containment Isolation do not have multiple automatic inputs and therefore no modifications are necessary.

3.

SEPARATE RESETS FOR EAC'i TRAIN Separate reset switches will be provided for each train for each circuit.

4.

PHYSICAL ACCESS The reset swi ches will be fitted with clear plastic covers.

t This will pavent inadvertent or accidental operation and will require deliberate operator action to reset the safeguards circuits.

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ANNUNCIATION For Containment Isolatico, Containment Ventilation Isolation and Containment Spray, status lights and annunciation will be provided for each circuit in which the reset hold-in feature is retained. The reset hold-in feature may be deleted, eliminating the need for additional lights and annunciation.

Safety. Injection circuits will be provided with status lights and annunciation for each train.

Mr. James Keppler - Page Three July 3, 1979 It is estimated that these modifications will be completed approximately two weeks after final approval of the modification requests and installation procedures. Approvals are expected to require approximately three weeks.

Very truly yours, 9

, %/ y C. W. Fa, Director flaclear Power Department Enclosure

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