ML20086L157
| ML20086L157 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/16/1973 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8402070428 | |
| Download: ML20086L157 (2) | |
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PHILADELPHIA ELECTRIC COMPANY P
2301 MARKET STRE ET
-G PHILADELPHIA, PA.19101
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November 16, 1973 to IM Mr. A. Giambusso Deputy Director of Peactor Projects United States Atomic Energy Comnission Directorate of Licensing Washington, D. C. 205h5
Dear Mr. Giambusso:
Reference:
Peach Bottom Atomic Power Station - Unit 2 Facility Operating License DPR-hh Docket No. 50-277
Subject:
Abnornal Occurrence I
On November 6 and November 6,1973, two abnormal occurrences were reported to Fr. Carlson and Mr. Shedlowsky, A.E.C. Region 1 Pegulatory Office.
The recuired Ph-hour notifications were also dispatched on these dates. These reports involved a second failure on the
'K' reactor relief valve bellows and two possible additional hellows failures on reactor relief valves 'E' and
'L'.
In accordance with Section 6.7.2.A of the Technical Specification Arpendix A or DrP-hh for Unit ? Peach Botton Atemic Power Station, t.hese relief valve bellows failure indications are being reported to the Directorate of Licensinr as Abnormal Occurrences.
Investication As stated in the Ph-hour reports, the bellows failure indications on the second and third relief valves occurred between 6:30 a.m. and 8:30 a.n.
on 11/6/73 Since the
'K' relief valve bellows had shown a failure the pre-vious day, plant shutdown operations were implemented in accordance with pararraph 3.6.D.3 of the Technical Specifications. When conditions were approxinately 40 psig primary vessel pressure and reactor power was less than 1%, an inspection of the
'E' and
'L' relief valves was performed. This inspection indicated that the cause of the bellows failure indications was e
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produced by failures in the electrical cabling and electrical connector to
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the pressure switch. No leakage of the bellows was detected. Since the
'K' relief valve had previously failed, no leak test of.this bellows assenbly was performed with the primary coolant systen at pressure. Following this initial inspection, the reactor was shutdown and the primary coolant tempera-0 ture reduced to less than 212 F.
Following plant shutdown, a detailed inspection of the cabling and connectors on all relief valves was performed. This inspection indicated that the cables and connectors were deteriorating because of hi h ambient temperatures E
in the immediate vicinity of the relief valves.
Corrective Action In order to orevent reoccurrence of electrical difficulities associated with the pressure switch which monitors the bellows integrity, new hi h tempera-f ture cabline and connectors are beinF reconnended. Additionally, the pressure switches are to be relocated to an area which is not subject to the high radiant heat load nroduced by the nain stean headers and relief vnives. These modifica-tions, with reneral Flectric and Philadelphia Electric Co. Engineering Depart-i ment approval, will he implemented before returning the, plant to service.
A new relief valve is being provided and installed to replace the
'K' valve. Following reroval, the
'K' valve will be returned to the manu-facturer for analysis and corrective action.
Safety Imolications To date, reactor power level has not exceeded approximately 10%. The operability requirement for the mininum number of relief valves is based on reactor operation at 100% power. The reported failures were primarily instru-I ment indication failures and would not affect the actual operability of the safety valve function of the relief valves. Failure of the one bellows assembly at this tine during the startup test program has no safety significance in that sufficient pressure relief capability was always available.
Very truly yours, Ys M. M. ho(oney q yl,(p f
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Ash.Genl.Superntendent Generation Division MJC:jb cc.
Mr. J. P. O'Feilly Director, Pegion 1 United States Atomic Fnergy Commission 631 Park Avenue King of Prussia, PA 19h06