ML19275A684
| ML19275A684 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 09/27/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Andognini C BALTIMORE GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7910180115 | |
| Download: ML19275A684 (1) | |
Text
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o UNITED STATES 8 "' 3 e j
NUCLEAR REGULATORY COMMISSION 3 ^-
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KING OF PRUSSIA, PENNSYLVANIA 19406 Docket No. 50-293 SEp 27 gg Boston Edison Company M/C Nuclear ATTN:
Mr. G. Carl Andognini, Manager Nuclear Operations Department 800 Boylston Street Boston, Massachusetts 02199 Gentlemen:
The enclosed Bulletin 79-24 is forwarded to you for actien. Written responses are required.
If you c'esire additional information regara;ng this matter, please contact this office.
Sincerely, w
d [ier 4A yce H. Gr
- Director
Enclosures:
1.
List of IE Bulletins Isst.ad in the Last Six Months cc w/encls:
P. J. McGuire, Pilgrim Station Manager A. Z. Roisman, Natural Resources Defense Council 1185 005 7910180 f
ENCLOSURE 1 Accession No. 7908220114 SSINS No:
6820 UNITh.
- ATES NUCLEAR REG M. CAY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 79-24 Date:
September 27, 1979 Page 1 of 2
- '0 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 ret:irculation 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 Circumstanc 3:
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 ficw 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 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 system to warn of freezing conditicas.
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 p :p in thu event it is operated :yainst a closed discharge valve or a reactor cociant system pressure greater than the maximum discharge pressure of the pump (approximately 1600 psig).
In the initial review of the event on '-
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+ha m ancaa concluded that the pumps were still operable wit no immediate action was taken to thaw January 5, 1979, the line was thawed i was successfully completed.
DUPLICATE DOCUMENT Entire document previously entered into system under:
7.?.a f E v. c. m t 1185 006 anO No. of pages: