ML19275A329
| ML19275A329 | |
| Person / Time | |
|---|---|
| Site: | Marble Hill |
| Issue date: | 09/27/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Coughlin J PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA |
| References | |
| NUDOCS 7910040059 | |
| Download: ML19275A329 (1) | |
Text
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GLEN ELLYN. lLLINOIS 60137 SEP L ' E9 Docket No. 50-546 Docket No. 50-547 Public Service of Indiana ATTN:
Dr. James Coughlin Vice President, Nuclear 1000 East Main Street Plainfield, IN 46168 Gentlemen:
The enclosed IE Bulletin No. 79-24 is forwarded to you for information.
If you desire additional information regardir.g this matter, please contact this office.
Sincerely, b f= A_
JamesG.Ke31[r Director
Enclosure:
IE Bulletin No. 79-24 cc w/ enc 1:
Mr. R. M. Brown, Construction Project Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC LeBoeuf, Lamb, Leiby & MacRae Mr. Dave Martin, Office of the Attorney General f099 ii2 L
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Accession No. 7908220114 SSINS No:
6820 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 September 27, 1979 IE Bulletin No. 79-24 FROZEN LINES Summary:
Or January 3, 1979, an unusual event occurred at Davis-Besse, Unit 1.
The eveat involved the freezing of the water in a portion of the high pressure coolant injection (HPCI) system recirculation line that is common to both high pressure coolant injection pumps.
The line was not thawed until January 5, 1979, and the event was r.ot reported to NRC until March 12, 1979.
In addition, over the past five years, there have been several events involving frozen instrument and sampling lines.
Description of Circumstances:
The condition was discovered on January 3, 1979, while the reactor was operating at approximately 96 percent power.
During a monthly surveillance test of the HPCI pumps, there was no flow through the recirculation line from the pump discharge to the Borated Water Storage Tank (BWST).
Investigation revealed that water in a portion of the line exposed to the outside weather was frozen.
This portion of the line to the BWST is rcmmon to both HPCI pumps.
The line has redundant heat tracing (a heated wire to prevent freezing); it is insulated; and it has a low-temperatute alarm system to warn of freezing conditions.
Water in the line froze apparently because of prolonged sub-freezing temperatures and a defect in the insulation.
There was no apparent malfunction of the heat tracing or temperature alarm circuits, although the temperature sensing elements are located in an area not exposed to the coldest temperature conditions.
This recirculation line serves two purposes:
One is to provide a flow path for surveillance testinr, and the other is to provide a minimum flow path to prevent possible damage to the pump in the event it is operated against a closed discharge valve or a reactor coolant system pressure greater than the maximum discharge pressure of the pump (approximately 1600 psig).
In the initial review of the event on January 3,1979, the licensee concluded that the pumps were still operable with the recirculation line frozen.
Therefore, r
no immediate action was taken to thaw the frozen section of the line.
a January 5, 1979, the line was thawed and the surveillance test of the pumps qwassuccessfullycompleted.
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