ML19254C996
| ML19254C996 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 09/27/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | John Miller GEORGIA POWER CO. |
| References | |
| NUDOCS 7910190264 | |
| Download: ML19254C996 (2) | |
Text
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
E REGION 11
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S 101 MARIETTA ST., N.W., SulTE 3100 ATLANTA, GEORGIA 30303 In Reply Refer To:
SEP 2 71979 RII;JP0 50-321 N 50-366 j
Georgia Power Company Attn:
J. H. Miller, Jr.
Executive Vice President 270 Peachtree Street Atlanta, Georgia 30303 Gentlemen:
The enclosed Bulletin 79-24 is forwarded to you for action. Written responses are required.
If you desire additional information regard.r.g this matter, please contact this office.
Sincerely, r
)
James P. O'Reill Director
Enclosure:
1.
Designated Applicants for Operating Licenses e
1190 019 L6i 7910190
SEP 2 71979 Georgia Power Company.
cc w/ encl:
M. Manry, Plant Manager Post Office Box 442 Baxley, Gec,rgia 31513 C. E. Belflower Site QA Supervisor Post Office Box 442 Baxley, Georgia 31513 1190 020 O
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 FR0 ZEN 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 (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 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 throrgh the. recirculation line from the pump discharge to the Borated Water Sturage 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 common to both HPCI pumps.
The line has redundant heat tracing (a heated wire to prevent freezing); it is insulated; and it has a low-temperature alarm sys'.em to warn of freezing couditions.
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 January 3, 1979, the licensee concluded that the pumps were still operable with the recirculation line fro 7en
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no immediate action was taken to thaw th January 5, 1979, the line was thawed and was'successfully completed.
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