ML20210S627

Ro:On 860918,spurious Safety Injection Occurred Due to Momentary High Steam Flow Signal Concurrent W/Low RCS Average Temp.Cause Not Stated.Unit Stabilized.Corrective Action Taken to Preclude Late Reporting of Unusual Events

ML20210S627
Person / Time
Site:	Diablo Canyon
Issue date:	09/26/1986
From:	Thornberry R PACIFIC GAS & ELECTRIC CO.
To:	Briam W SAN LUIS OBISPO, CA
References
RTR-NUREG-0654, RTR-NUREG-654 NUDOCS 8610080188
Download: ML20210S627 (2)

Text

PACIFIC GAS AND ELECTR,IC C O M PANY

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. DIABLO CANYON POWER PLANT T

ggggggggl PO. Box 56. Avila Beach. Cahfornia 93424 -(805) 595-7351 AC.THORNBEARY M ANT *AANAGER I

September 26, 1986 1

1

. Mr. William Briam, Administrator San Luis Obispo County Administrative Office County Government Center San Luis Obispo, CA 93408

Dear Mr Briam:

Pursuant to NUREG-0654, Revision 1, Appendix 1, the following is a summary report concerning an Unusual Event at the Diablo Canyon Power Plant site.

At 0956 PDT, September 18, 1986, Unit 2 tripped from 100 percent power. A spurious safety injection occurred due to a momentary high steam flow signal

concurrent with a low reactor coolant system average temperature. An Unusual Event was declared by the Shift Foreman at 0956 PDT and emergency notifications were begun.

At 1025 PDT, September 18, 1986, the unit was stabilized and the Unusual Event was concluded. This event has in no way affected the health and safety of the i public and no discharge of radioactive materials was made to the environment.

This report should have been mailed on the first working day following the event.

F PGandE has taken corrective action to preclude any further late unusual event j reports.

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f$f R. C. Thornberry ll RCT:ggd f

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I cc Mr. Benjamin P. Tong, Chief Nuclear Power Plant Planning P. O. Box 9577 I Sacramento, CA 95823 Mr. John B. Martin, Administrator U. S. Nuclear Regulatory Commission, Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596-5368 Mr. George Whiting, Sheriff San Luis Obispo County P. O. Box 32 San Luis Obispo, CA 93401 Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Director, Office of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D. C. 20555 l

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