ML20205T027

Rev 1 to Special Rept 86-01:on 860306,during Surveillance Testing,Emergency Diesel Generator a Intentionally Secured W/O Loading at Least 50% of Continuous Rating.Maint Insp for Adjustment of Plunger Bolt Evaluated

ML20205T027
Person / Time
Site:	Callaway
Issue date:	04/15/1986
From:	Randolph G UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
86-01, 86-1, ULNRC-1294, NUDOCS 8606130031
Download: ML20205T027 (5)

Text

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y :=j/ & s hM6 d2 UNION ELECTRIC COMPANY

" April 15, 1986 FRTCRITY sourgy s 5 ky I g[y j [

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Mr. James G. Keppler [

Regional Administrator L- a y -

Office of Inspection & Enforcement NLbd '

U.S. Nuclear Regulatory Commission L -

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Region III HL g -

799 Roosevelt Road Glen Ellyn, IL 60137 ULNRC-1294

Dear Mr. Keppler:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 FACILITY OPERATING LICENSE NPF-30 SPECIAL REPORT 86-01 REVISION 1 DIESEL GENERATOR FAILURE DURING AN INVALID TEST The enclosed revision to Special Report 86-01 (March 31, 1986, ULNRC-1280) is submitted to provide clarification of the events which occurred as a result of a diesel generator output breaker plunger bolt being out of adjustment.

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G. L. Randol h Manager, Callaway Plant

/ /drs Enclosure I cc: Distribution attached kh S

APR 171986' Mciling Address:P.O. Box 620 Fulton,MO65251 1I 160l

cc distribution for ULNRC-1294 Mr. James G. Keppler Manager, Electric Department Regional Administrator Missouri Public Service Commission Office of Inspection & Enforcement P.'O. Box 360 U.S. Nuclear Regulatory Commission Jefferson City, MO 65102 Region III 799 Roosevelt Road Mr. O. Maynard Glen Ellyn, IL 60137 Kansas Gas and Electric Company P. O. Box 208 American Nuclear Insurers Wichita, KS 62701 c/o Dottie Sherman, Library The Exchange Suite 245 Records Center 270 Farmington Avenue Institute of Nuclear Power Operations Farmington, CT 06032 Suite 1500 1100 circle 75 Parkway Mr. J. H. Smith Atlanta, GA 30339 Bechtel Power Corporation SNUPPS Project Mr. Paul O'Connor 15740 Shady Grove Road Office of Nuclear Reactor Regulation Gaithersburg, MD 20877-1454 U. S. Nuclear Regulatory Commission Mail Stop P-316 Mr. Nicholas A. Petrick 7920 Norfolk Avenue Executive Director, SNUPPS Bethesda, MD 20014 5 Choke Cherry Road Rockville, MD 20850 Mr. Merlin Williams Supt. of Regulatory Quality &

NRC Resident Inspector Administrative Services D. F. Schnell (400) Kansas Gas and Electric Company R. J. Schukai (470). P. O. Box 309 S. E. Miltenberger Burlington, KS 66839 J. F. McLaughlin J. E. Davis (Z40LER)

(Z40LER) (w/c)

D. W. Capone /R. P. Wendling (470)

, F. D. Field (470) l A. P. Neuhalfen A. C. Passwater/D. E. Shafer/D. J. Walker (470) l G. A. Hughes

{ Z40.01 (QA Record) l J. M. Price l D. E. Young M. E. Taylor r

H. Wuertenbaecher, Jr. (100) l S. L. Auston (470)(NSRB)

! J. D. Schnack l

GLR Chrono 3456-0021.6 3456-0260 240ULNRC G56.37 N. Date (Sandra Auston) (470) l l

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SPECIAL REPORT 86-01 REVISION 1 DIESEL GENERATOR FAILURE DURING AN INVALID TEST Surveillance Procedure ISP-SA-2413A, Diesel Generator and Sequencer Testing (Train A), was in progress on 3/6/86 to satisfy various 18 month Technical Specification (T/S) surveillance requirements. The plant had entered Mode 5, Cold Shutdown, on 3/4/86. During performance of the

"' A' Train Blackout Without SIS (Safety Injection Signal)" portion of ,

ISP-SA-2413A, the 'A' emergency diesel generator (D/G) was intentionally l secured without loading to at least 50% of continuous rating. The D/G ,

was secured to investigate a failure of the load sequencer to properly ]

sequence the required emergency loads onto the 4.16 kV safety-related  :

bus (NB01) energized by 'A' D/G. j Since the successful D/G start was terminated intentionally without )

loading to at least 50% of continuous rating, it is not considered a i valid test or failure in accordance with Regulatory Position C.2.e(4) of j Regulatory Guide 1.108, Revision 1, August 1977. The D/G testing frequency established by T/S Table 4.8-1 is therefore not affected by this incident and this Special Report is being submitted as required for all D/G failures, valid or nonvalid, per T/S 4.8.1.1.3. It is noted that the D/G could have been manually loaded and a valid test completed had the operators not intentionally secured the D/G for troubleshooting )

of the load sequencer. I l

Starts of the D/G's have been tracked since the completion of Preoperational Testing on 5/11/84. The starting history of the.D/G's as of the date of this report is summarized as follows:

Number of Number of 1 Number of Failures During Failures During )

D/G Valid Tests Valid Tests Invalid Tests j A 31 1* 5#

B 27 0 15

• Reference Special Report 84-02. 1

1. Reference Special Reports 85-01, 85-02, 85-07, and 86-01.

$ Reference Special Report 85-05. l The following is a summary of the events applicable to this incident.

The "'A' Train Blackout Without SIS" portion of l ISP-SA-2413A began at approximately 2018 on 3/6/86.

- Loads shed off bus NB01 as required when the test signal (blackout without SIS) was initiated.

- 'A' D/G successfully started and attained the required voltage and frequency.

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SPECIAL REPORT 86-01 REVISION 1 Page 2

'A' D/G output breaker closed.

- Only 'A' Centrifugal Charging Pump and 'A' Component Cooling Water Pump sequenced onto bus NB01 and were powered by the 'A' D/G.

- Testing activities were halted and troubleshooting initiated.

- Troubleshooting of the 'A' D/G output breaker identified that the plunger bolt (which actuates certain stationary contacts when the breaker closes) was out of adjustment.

Consequently, the stationary contact did not sustain a signal to the load sequencer. The condition also prevented synchronizing of the D/G with offsite power by not allowing a synchronizing check relay to pick up.

Note: The stationary contact was momentarily actuated by the plunger bolt due to the force of the breaker closing, causing the Centrifugal Charging Pump (CCP)

(a time zero sequenced load) to start. The stationary contact failed to remain closed due to the plunger bolt being out of~ adjustment, so the remaining loads failed to sequence onto the bus.

The Component Cooling Water Pump (CCW) was started by a CCP-CCW interlock approximately one second after the start of the CCP. Had the stationary contact remained actuated, this interlock would have been defeated and the CCW pump would have started at sequencer step one (five seconds following start of the sequencer).

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- Temporary adjustments were made such that the synchronizing check relay picked up. The D/G was paralleled with offsite power and the loads were transferred off the D/G. The D/G output breaker was opened, and the D/G' secured and declared inoperable at approximately 2350 on 3/6/86.

- The plunger bolt was.found to be out of adjustment by approximately 3/32 of an inch. It was adjusted within tolerance per Electrical Preventive Maintenance Procedure MPE-ZZ-QS005, Cleaning, Inspection, and Lubrication of 13.8 kV and 4.16 kV Breakers, at 0210 on 3/7/86.

The "'A' Train Blackout Without SIS" portion of ISP-SA-2413A was again commenced at approximately 2040 on 3/7/86 and completed satisfactorily.

'A' D/G was declared operable at 2222 on 3/7/86.

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SPECIAL REPORT 86-01 REVISION 1 L Page 3 Verification of proper adjustment of the plunger bolt for 'A' D/G output breaker was last performed on 5/20/85 during an 18 month preventive maintenance inspection. The cause of the plunger bolt being out of adjustment is unknown. This type of problem has not been a frequently experienced occurrence associated with the D/G output breakers; however, due to the significance of the plunger bolt / stationary contacts function, a preventive maintenance inspection for proper adjustment of the plunger bolt will be evaluated for increased frequency for 'A' and 'B' D/G output breakers.

4 This incident occurred while the plant was in Mode 5. In this mode, T/S 3.8.1.2 requires only one diesel generator to be operable.

'B' D/G was operable while 'A' D/G was out of service for testing and inoperable due to the output breaker plunger bolt. Performance of ISP-SA-2413B, Diesel Generator and Sequencer Testing (Train B), began

, following completion of ISP-SA-2413A. On 3/10/86 the load sequencer for for 'B' train functioned satisfactorily when the breaker closed during the "'B' Train Blackout Without SIS" portion of ISP-SA-2413B.

Surveillance tests are currently performed at least once per 31 days for each D/G. This is in conformance with the schedule of Regulatory Position C.2.d of Regulatory Guide 1.108, Revision 1, August 1977, and Technical Specification Table 4.8-1 which require the test interval to be not more than 31 days if the number of failures in the last 100 valid tests is one or zero.

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