ML19275A636
| ML19275A636 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/27/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Aswell D LOUISIANA POWER & LIGHT CO. |
| References | |
| NUDOCS 7910180041 | |
| Download: ML19275A636 (1) | |
Text
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u UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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REGloN IV 7 ( [
o 611 fiYAN PLAZA DRIVE, SUITE 1000 y
ARLINGTON, TEXAS 76012
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Septs ber 27, 1979 In Reply Refer To:
RTV Docket No.
50-382/IE Bulletin No. 79-24 Louisiana Power and Light Co.
ATTN:
Mr. D. L. Aswell Vice President of Power Production 142 Delaronde Street New Orleans, Louisiana 70174 Gentlemen:
The enclosed IE Bulletin 79-24 is forwarded to you for information.
If you desire additional information regarding this matter, please contact this office.
Sincerely, 9 t/
- _f!
f6 IN
<t Karl V. Sdyfrit Director
Enclosures:
1.
Designated blicants for Operating uicenses 3.
List of IE Bulletins Issued in Last Six Months 1184 244 7910180 O W
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Accession No. 7908220114 SSINS No:
6820 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C 20555 IE Bulletin No. 79 14 Date: September 27, 1979 Page 1 of 2 FROZEN LINES Summary:
On January 3, 1979, an unusual event occurred at Davis-Besse, Unit 1.
The event involved the freezing of the water in a portion of the high pressure coolant injection (ifPCI) 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 not 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 +he outside weather was frozen.
This portion of the line to the BWST is common o both IIPCI pumps. The line has redundant heat tracing (a heated wire to prevent freezing); it is insulated; and it has a low-temperature 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 testing, 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 that the pumps were still operable wit no in"nediate action was taken to thaw DUPLICATE DOCUMENT January 5, 1979, the line was thawed a was successfully completed.
Entire document previously entered into system under:
nuo 7%$Akb/fY 1184 245
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