ML20086G454

Intervenor Exhibit I-MOSBA-93,consisting of Executive Summary - Vogtle Diesel Operability

ML20086G454
Person / Time
Site:	Vogtle
Issue date:	05/17/1995
From:	AFFILIATION NOT ASSIGNED
To:
References
OLA-3-I-MOSBA93, NUDOCS 9507140370
Download: ML20086G454 (3)

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Dlr7/95 3ppy-Q EXECUTIVE

SUMMARY

- VOGTLE DIESEL OPERABI Backcround and Status 95 JLN -6 P4 :05 On 3/20/90, the 1A diesel started, energized and loaded, but tripped twice before being emergency started and loaded tyf@ 06r3EORftif1fddfan cooling. The Vogtle critique team consisting of D(CTit!93indEftstGfor technical experts believes that the 1A diesel tripped WehWGde of a combination of._ intermittent failures of jacket water switches or inconsistent calibration techniques of these switches during a recent engine overhaul. Subsequent testing has indicated that the 3/20/90 i diesel annunciator indication could be reproduced on a high jacket I water temperature trip. Since 3/20/90, sensor calibration and replacement, extensive logic testing, special pneumatic leak testing, multiple engine starts, and runs under various conditions have been performed to ensure a high stateDiscussions of diesel reliability prior to with the original declaring these engines operable.

equipment manufacturer and review of Vogtle data demonstrate that jacket water temperature switches have proven reliable ca these and similar engines between overhauls.

Recent Reliability Imorovements Vogtle has implemented the following reliability improvements:

1. Calibration procedures have been reviewed with the vendor to ensure that calibrations are consistent, and switch performance q is reliable.

2. Operators have been trained prior to shift relief to ensure that operators realize that an emergency reset will override the high jacket water trip. -

3. The undervoltage start of the diesel has been changed to bypass j non-essential engine trips on Unit 1 to improve overall reliability. This change will be implemented on Unit 2 prior to 4/15/90.

Diesel Reliability In 1989 Vogtle diesels have been more reliable than other nuclear ind t diesels. Vogtle diesels exceed the requirements of the

-t ockou rule.

Safety System Performance (Emercency AC Power--BWR & PWR) g 1987 1986 1989 '

1110 9

US BEST QUARTILE 0.010 0.009 0.012 US MEDIAN 0.017 0.017 0.020 SISTERS 0.027 0.033 0.030

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VOGTLE U1 0.04 0.05 0.006 yms Hsdwe+3 VOGTLE U2 0.006 EXHIBIT

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NUCt. EAR REGULATORY COMMISSf0N So-42Sc(4-3 Docket No. I" 2 5-u * - 10fficial Exh. No.

In' - 93 ,

In the matter of G Pc <+ *L '

Staff IDENTIFIED Apptcant RECEIVED 7 Intervenor 7 REJECTED Conr0 0ff'r Contractor DATE OF' / 7' 4 I Other Witness St.',. Iair / l l

Reporter /" Rho ..

N Exhibitb, paged of 9 Future Reliability Work

.Vogtle will continue to work with the owners group to improve diesel reliability. Appropriate engine enhancements will be scheduled for overhaul periods.

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