ML19289C406
| ML19289C406 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/05/1979 |
| From: | Murray T TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| L79-024, L79-24, NUDOCS 7901120142 | |
| Download: ML19289C406 (3) | |
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6 Z TOLEDO G EDISDN L79-024 January 5, 1979 FILE: RR 2 (NF-32-77-12)
Docket No. 50-346 License No. NPF-3 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 1
Dear Mr. Keppler:
Attached are ttree copies of the Supplemental Information Sheet of Licensee Event The revision is indicated by a "1" Report NP-32-77-12, which has been revised.
in the left margin.
therefore, please There has been no change to the Licensee Event Report Form; retain the Licensee Event Report Fom and replace the Supplemental Infomation Sheet only, with the attached revised copics.
Yours truly, Terry D. Murray Station Superintendent Davis-Besse Nuclear Power Station TDM/SNB/ljk Attachment Dr. Ernst Volgenau, Director cc:
Office of Inspection and Enforcement Enc 1:
30 copies Mr. William G. Mcdonald, Director Office of Management Information and Program Control Enc 1:
3 copies
'\\/
79011201 Q S
4
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THE TOLEDO EO:SCN COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO, OHIO 43S52 5
99
TOLEDO EDISON COMPA'iY DA"IT-EESS.E NUCLEAR POWER STATION U' LIT ONE SUPPLE" ENTAL INFORMATION FOR LER NP-32-77-12 DATE OF EVENT: August 5, 1977 FACILITY: Davis-Besse Unit 1 Reduction of Allowable Pressurizer Relief Actuations IDENTIFICATION OF OCCURRENCE:
C The unit was in Mode 3, with Power (MWT) = 0, and Conditions Prior to Occurrence:
Load (NWE) = 0.
During Hot Functional Testing, the pressurizer electro-Description of Occurrence:
magnetic power relief valve was opened and severe movement of the discharge piping Supports were added to the eight inch commen discharge line and heat Subsecuent testing verified the discharge pipe movement to be was observed.
i tracing was added.
An initial thermal / structural analysis of the piping within acceptabla limits.
stresses allowed 20 cycles of relief valve discharge combined with fise plant heatups 1
and cooldowns, as long as the piping temperature was maintained at least 4600F by t The Babcock and Wilcox design criteria is 8800 lifetime electromatic relief valve acteations, 28S code relief valve actuations and 240 heatups and cooldowns.
heat tracing.
This report is being submitted in accordance with Technical Specification 6.9.1.81.
l Toledo Edison Company received the final report by Teledyne On November 17, 1978, Based on the more detailed Engineering Services on the thermal cycling limitations.
analysis, the total allowable number of valve actuations allowed is 650 with piping temperature above 400 F and 25 with piping temperature below 4000F.
The cause of this occurrence is a Designation of Aoparent Cause of Occurrence:
The design deficiency in the pressurizer electromagnetic relief valve piping.
stresses which result with the present piping configuration are too large to allow the full criteria of 8800 electromagnetic relief valve design cycles and 288 code relief valve actuations.
There was no danger to the health and saf ety of the public Analysis of Occurrence: Valve discharges to date are well below the lifetime cyles.
or to unit personnel.
Valve discharge limits noted above have been imposed upon the Corrective Action:
PT 5164.03, " Pressurizer Relief Valve Heat Trace Test",
facility. A Periodic Test, Actuations will be logged in will monitor daily the discharge piping te=perature.
As of December 7,1978, the unit had used only 80 of the 650 I
the Transient File.
allowed ? 4000F actuations and 17 of the 25 di400 F actuations.
TOLEDO EDISON Co?!PANY DAVIS-BESSF NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLD!E!TTAL INFOR>IATION FOR LER NP-32-77-12 Corrective Action Continued: Further analysis of the piping configuration is being These modifications will perfomed to determine the piping i:.odifications required.
1 be completed during the first refueling outage if possible.
No previous design deficiencies of Reactor Coolant System piping 1
Failure Data:
configurations have been reported.