ML19256A142

Forwards LER 78-100/03L-0

ML19256A142
Person / Time
Site:	Davis Besse
Issue date:	10/27/1978
From:	Murray T TOLEDO EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19256A143	List: ML19256A142 ML19256A144
References
L78-755, NUDOCS 7811030157
Download: ML19256A142 (2)

Text

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TOLEDO C

._:, EDISON L78-755 October 27, 1978 FILE: RR 2 (NP-33-78-ll8)

Docket No. 50-346 License No. NPF-3 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuc1 car Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

Reportable Occurrence 78-100 Davis-Besse Nuclear Power Station Unit 1 Date of Occurrence: October 1, 1978 Enclosec are three copies of Licensee Event Report 78-100, with a supplemental information sheet, which is being submitted in accordance with Technical Speci-fication 6.9 to provide 30 day writren notification of the subject occurrence.

Yours truly,

'7 2~ , O h-3 Terry D. Murray Station Superintendent Davis-Besse Nuclear Power Station TDM/JRL/lj k Enclosure cc: Dr. Ernst Volgenau, Director Office of Inspection and Enforcement Encl: 30 copies LER 78-100 Mr. William G. Mcdonald, Director Office of Management Information and Program Control Encl: 3 copies LER 78-100 i 7/

787'.930/57 h'

300 MAOl5CN AVENUE TCLEDO. CHIO 43652 THE TOLEVO ED! SON COMPANY ECISON PLAZA

TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-78-ll8 DATE OF OCCURRENCE: October 1, 1978 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Reactor Coolant System (RCS) Unidentified Leakage Exceeded the Allowable Limit (1 GPM)

Conditions Prior to Occurrence: The unit was in Mode 3, with Power (MWT) = 0, and Load (MWE) = 0.

Description of Occurrence: At 0625 hours0.00723 days <br />0.174 hours <br />0.00103 weeks <br />2.378125e-4 months <br /> on October 1, 1978, during routine per-formance of Surveillance Test ST 5042.02, "RCS Water Inventory Balance", the cal-culated value for unidentified leakage exceeded the 1 GPM limit by 0.08 GPM. This placed the unit in the Action Statement of Technical Specification 3.4.6.2.

At C730 hours on October 1,197S, measurement of the Reactor Coolant Pumps This identified stand-scal leakage pipe leak-of f was found to have increased by .54 GPM.

reduced the unidentified leakage to 0.54 GPM, and removed the unit from the Action Statement of Technical Specification 3.4.6.2.

Designation of Anparent Cause of Occurrence: The cause of this occurrence is attri-buted to changes in the amount of seal leak-off.

Analysis of Occurrence: There was no threat to the health 'and safety of the public or unit personnel. The final data showed all leakage specifications to be within allowable limits. Additionally, the revised measurement of Reactor Coolant Pump standpipe leakage accounted for essentially all of the observed increase in total leakage. The small leakages were processed through the norual containment sump.

Corrective Action: Prompt action was initiated to investigate and correct the cause of the increase in RCS leakage. Measurement of the seal leak-off by recording the time to fill a 400 ml cylinder showed an overall increase of This in-Investigation into crease accounted for essentially all of the observed increase.

the possibility of installing more accurate seal leakage indication is continuing per Facility Change Request 78-357.

Failure Data: On March 14, 1978, Reactor Coolant System leakage exceeded 1 GPM as a result of an increase in Reactor Coolant Pump seal leak-off (Licensee Event Rqport NP-33-78-P.).

LER J78-100 NMN