ML20086L205

AO 74-18:on 740330,diesel E-4(D) Failed to Start.Caused by Spurious Operation of TD-2 Relay.Diesel Successfully Restarted & Surveillance Test Completed

ML20086L205
Person / Time
Site:	Peach Bottom
Issue date:	04/09/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086L209	List: ML20086L205 ML20086L211
References
AO-74-18, NUDOCS 8402070461
Download: ML20086L205 (2)

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s PHILADELPHIA ELECTRIC COMPANY

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~ ]-(i f April 9,1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545

Subject:

Abnormal Occurrence The f o11owing occurrence was reported to Mr. R. A. Feil, A.E.C.

.Reaion I Reaulatory Oncrations Office on March 31. 1974. Written nnti-fication was made to v.r. James P. O'Reilly, Region I Regulatory Operations Office on April 1, 1974.

In accordance with Section 6.7 2.A of the Technical Specifications, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44, Amendment Number 1 Technical Specification 3 9.A.3 Report No.:

50-277-74-18 Report Date:

April 9,1974 Occurrence Date: March 30, 1974 F aci li ty:-

Peach Bottom Atomic Power Station R. D. #1, Delta, Pennsylvania 17314 Identification of Occurrence:

Diesel start f ailure.

Conditions Prior to Occurrence:

Plant at approximately 30% power.

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April 9,1974 Page 2 i

Description of Occurrence:

During the performance of a routine surveillance test on the E-4(D) diesel, the diesci tripped during the starting sequence. An immediate restart of the dicsci was successful.

Designation of Aoparent Cause of Occurrence:

During the start failure, the " Diesel Fail to Start" annunciator was also actuated. The SDR relay which actuates this annunciator and trips the diesel is energized by a contact of the TD-2 time delay relay.

This time delay relay is designed to shutdown the dicsc1 if engine speed is less than 250 rpm within 10 seconds following the initiation of the starting sequence. The start failure is believed to have been caused by a spurious operation of the TD-2 relay.

Analysis of Occurrence:

Because the diesel was re-started successfully immediately after its initial failure to start, the diesel was only inoperabic for a few minutes. Sufficient dicsci capacity and emergency core cooling systems are availabic to respond to the design basis accident with one diesel generator inoperable. This is recognized in that the Technical Specif t :tien perm;;; :catinued operation.;ith cnc dic:ct inspcrchic for a period of seven days. The short period in which the diesel was inoperabic has no safety implications.

Corrective Action:

Af ter the successful restart of the E-4(D) Diesel, the sur-veillance test was completed. The three other diesels'were also proven operabic. The E-4 diesel circuitry associated with the TD-2 time delay relay was then inspected and checked because a " Diesel Fail to Start" annunciator was again actuated when the diesel was succes ; fully re-started. This investigation proved that the relay time delay was properly set and had not changed.

It also proved that a resistor across the coil circuit of several relays in parallel with the TD-2 relay was not open circuited and of the correct value. No control or circuitry malfunction was identified as a result of this investi-gation. Following this investigation, the E-4(D) diesel was success-fully started four times. No " Diesel Fail to Start" annunciator was actuated during these successf ul starts.

In order to ensure continued starting capability, the E-4(D) diesel was started each day for the next seven days. No f ailure in the diesel starting sequence occurred during this testing.

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Page 3 Failure Data:

No previous diesel start f ailures have occurred.

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Very truly yours,

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M. J. Cooney i

Ass t ocn't Superintendent Generation Division

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Mr. J. P. O'Reilly s'

Director, Region 1 United States Atomic Energy Commission 631 Park Avenue

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