ML13324A497

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Forwards Risk Assessment of Loss of Control Room Habitability,Per SEP Topic II-1.C.Failure of Control Room HVAC Sys Coincident W/Radiological Event or Offsite Accident Would Create Very Low Hazard to Control Room Operation Crew
ML13324A497
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 11/14/1984
From: Medford M
SOUTHERN CALIFORNIA EDISON CO.
To: Zowlinski J
Office of Nuclear Reactor Regulation
Shared Package
ML13324A495 List:
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-02-01.C, TASK-2-1.C, TASK-3.D.3.4, TASK-RR, TASK-TM TAC-44128, NUDOCS 8411200339
Download: ML13324A497 (2)


Text

Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M.O. MEDFORD TELEPHONE MANAGER. NUCLEAR LICENSING November 14, 1984 (213) 572-1749 Director, Office of Nuclear Reactor Regulation Attention:

3. A. Zowlinski, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.

20555 Gentlemen:

Subject:

Docket No. 50-206 SEP Topic II-l.C, Offsite Hazards NUREG-0737, Item III.D.3.4, Control Room Habitability San Onofre Nuclear Generating Station Unit 1

References:

1. Letter, M. 0. Medford, SCE, to D. M. Crutchfield, NRC, Systematic Evaluation Program Integrated Assessment, February 24, 1984
2. Letter, D. M. Crutchfield, NRC, to R. Dietch, SCE, Order Confirming Licensee Commitments on Post-TMI Related Issues (Generic Letters 82-05 and 82-10), March 14, 1983 Reference 1 provided our schedule to perform a risk assessment of possible control room HVAC upgrades in order to resolve the subject SEP topic. The assessment is also part of our response to the subject NUREG-0737 requirement, as required by Reference 2. To this end, this letter provides the results of our assessment and our plans to determine the final upgrades to the San Onofre Unit 1 control room HVAC and habitability systems.

A risk assessment of the loss of control room habitability (enclosed) has been performed for the San Onofre Unit 1 control room. This assessment demonstrates that, utilizing the NRC's benefit criteria for risk reduction, the value/safety impact analysis results in the conclusion that no modifications to the current control room HVAC and habitability systems are appropriate. This assessment is based upon the determination that the failure of the control room HVAC system, coincident with a radiological event or offsite accident that would create a hazard to the control room operations crew, is very low.

Notwithstanding this risk assessment, we will perform a review of upgrades that can reasonably be implemented to enhance the reliability of the control room HVAC. This review will be completed on a one to two month 8411200339 841114 PDR ADOCK 05000206 P

PDR

Mr. J.

November 14, 1984 schedule and it is anticipated that the results will be ready for discussion with members of the NRC staff during the Integrated Assessment. Based upon that discussion agreement on the final upgrade plan will be reached.

If you have any questions, please let me know.

Very truly yours, Enclosure