ML19294A575
| ML19294A575 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 12/19/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Hines E DETROIT EDISON CO. |
| References | |
| NUDOCS 7812280057 | |
| Download: ML19294A575 (1) | |
Text
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NUCLE AR REGULATORY COMMISSION REGION lli
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DEC 191978 Docket No. 50-341 The Detroit Edison Company ATTN:
Mr. Edward Hines, Assistant Vice President and Fbnager Quality Assurance 2000 Second Avenue Detroit, MI 48226 Gentlemen:
The enclosed IE Bulletin No. 78-14 is forwarded to you for infor-mation. No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, bY James G. Keppler Director
Enclosures:
1.
List of IE Bulletins Issued in 1978 cc w/encls:
Central Files Director, NRR/DPM Direcotr, NRR/ DOR PDR Local PDR NS:C TIC Ronald Callen, Michigan Public Service Commission
, Eugene G. Thomas, Jr.,
Attorney 781228coS7
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U.S. NUCLEAR REGU1ATORY COMMISSIOM OFFICE OF INSPECTION AND E::FORCEMENT REGION III Dece ber 19, 1975 IE bulletin NO. 75-14 DE7ER10 RATION OT EUNA-N COMPONENTS IN ASCO SOEENDIDS Description of Circumstances:
Fellowing a reacter scra: at the Monticelle Nuclear Fever Statier er July 27, 1976, one contrel rod was deterrined te have a slev scra insertion tice. Vnfle ceasuring the average contrel red scra: insertien tires (as required by Technical Speef ficatiens), the saac centrol red fai2ed te scrat.
Subsequent investigatier revea2ed that a Euna-N disc in the scra: pilot valve selencid core asse bly had fractured. Stall pieces of the Buna-N taterial vedged between the core asse bly and the valve pilot body. This prevented proper covenent cf the core asse:bly (plunEer), and thus prevented the valve fro: preperly venting control air frc: the scra: valves. A sinflar event occurred during scrat testing en June 5, 1976. On both occasions the control rod f ailed te scra during control red surveillance testing. In these instances, had a scrar occurred during nor:a1 operation of the reactor, the affected rods would have inserted by acticn cf the backup scrat solenedd valves.
The reactor was placed in cold shutdo-i on July 25, 1975. All of the scra pilet scienoid valves and scri backup valves were disasserbied and inspected. Six additional fractured Buna-N discs were found, all in scra pilot sc:enedd valves. Northern States Power Co:pany replaced the plunger Buna-N discs in all 21.2 scra: pilot valves and the 2 backup scra: valves.
a In addition to the Montice31o failures, sici2ar events were recently reported fror the Big Rock Point and Pilgri: facilities. At Big Rock Point, two fafiures were experienced in October while at Pilgri: one faf 3ure was found in July and two in December. A31 of these failures were encountered during surveillance testing.
General E3ectric bad previously issued Service Informatien Letters, SIL 3 28 (March 31,1975) and SIL 125 Kevision 1 (January 30, 1976),
addressing the deterioration through natural aging of Buna-N co penents im CTC sc r p
' h yg p ; e m a g g g,, o ceintenance pr otra: be in scra j
pilot valv
.;una-N discs DUPLICATE DOCUMENT Entire document previously entered into system under:
71/2240230 ANO No. of ages:
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