ML19211A235

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Responds to IE Bulletin 79-24, Frozen Lines. All Lines Are Protected or Will Be Protected Through Use of Cold Weather Log,Heat Trace Thermocouples & Controllers & Electric Heater in Trench Adjacent to Cooling Tower
ML19211A235
Person / Time
Site: Beaver Valley
Issue date: 11/01/1979
From: Woolever E
DUQUESNE LIGHT CO.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-24, NUDOCS 7912170232
Download: ML19211A235 (2)


Text

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November 1, 1979 r

United States Nuclear Regulatory Commission Attention: Boyce H. Grier, Director Region I 631 Park Avenue King of Prussia, Pennsylvania 19406

Reference:

Beaver Valley Power Station, Unit No. 1 Docket No. 50-334 License No. DPR-66 Response To IE Bulletin 79-24

Dear Mr. Grier:

We have reviewed IE Bulletin 79-24 concerning freezing of safety-related process, instrument and sampling lines during extremely cold weather and found that all lines at Beaver Valley Unit 1 are either adequately protected or that provisions are currently being established to preclude line freezing during extremely cold weather. To provide this protection, plant Operations maintains a Cold Weather Log in which is listed all piping and cquipment that requires protection against freezing. Each October, the log is completed and the plant is winterized by either actuating heat trace circuitry, placing localized electric heaters in trenches, or enclosing or covering areas normally exposed to the outside environment. In the past, some problems have been encountered with freezing lines. However, corrective measures were enacted to prevent recurrence and the Cold Weather Log was modified to add these items.

A review of heat trace circuitry on safety-related lines that travel between buildings or are in trenches and are exposed to the outside environment (e.g. Quench Spray Suction Pipe Line 12-QS-1, 2 and LHSI Recirculation Line -

3" SI-35) show that the heat trace thermocouples and controllers are installed outside building penetrations on portions of lines that will be subjected to the worst weather conditions.

1591 186 79121gg M Z

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Beaver Valley Pr ar Station, Unit No. 1 Docket No. 50-334 Response To IE Bulletin 79-24 Page 2 One area where corrective action is being initiated to prevent potential freezing of safety lines is the trench adjacent to the cooling tower containing gaseous waste line 10" - GW-34. The majority of this line is either four (4) feet underground or located inside thc plant auxiliary building with only a <

small section located within the trench. Freezing of this line will completely eliminate overpressure protection on several Category I tanks. To prevent freezing of this line, a localized electric heater has been placed in the trench and the manhole cover will be modified so that it seals tightly and is easily removed.

In summation, we feel we are in compliance with IE Bulletin 79-24 based upon completion of the Cold Weather Log, proper placement of heat trace thermocouples and controllers in areas of safety lines subjected to most severe weather conditions, and installation of an electric heater in the trench adjacent to the cooling tower.

Very truly yours,

. Woolever E.

Vice President Engineering & Construction cc: United States Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, D. C. 20555 1591 187