ML13330A283

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ClarifiesSection IV, Flow Indication & Control, Contained in Util Re Automatic Initiation of Auxiliary Feedwater Sys.Info Concerns Local Control & Indication Capabilities of Automated Auxiliary Feedwater Sys
ML13330A283
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 04/07/1981
From: Baskin K
Southern California Edison Co
To: Crutchfield D
Office of Nuclear Reactor Regulation
References
TAC-44652 NUDOCS 8104140357
Download: ML13330A283 (2)


Text

Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 K. P. BASKIN TELEPHONE MANAGER OF NUCLEAR ENGINEERING,

( 13) 572-1401 SAFETY, AND LICENSING April 7, 1981 C'

Director, Office of Nuclear Reactor Regulation Attention: D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.

20555 Gentlemen:

Subject:

Docket No. 50-206 Automatic Initiation of Auxiliary Feedwater System San Onofre Nuclear Generating Station Unit 1 By letter dated October 16, 1980, the NRC staff was provided with design details of the modifications which are in the process of implementation to provide automation of the auxiliary feedwater system (AFWS) at San Onofre Unit 1. As part of our ongoing review of the information provided to the NRC it was noted that one specific item of information may be misunderstood. The purpose of this letter is to clarify that item as discussed below.

Section IV, "Flow Indication and Control," of Enclosure 1 to our letter dated October 16, 1980 included the following information:

"The four (4) auxiliary feedwater flow control valves are divided into two redundant trains, thus with a single failure in one train, the other train will control the remaining two flow control valves. This allows flow to continue to at least one of the three steam generators. In addition, the valves can be operated locally (and local steam generator level indication is provided)."

The local steam generator level indication referred to in the design details is not located near the flow control valves as might be inferred. The intent of the description was to refer to the existence of local steam generator level indication outside the control room at the auxiliary control A

panel and in the breeze-way area between the containment sphere and the sphere enclosure building.

5 Local control of the flow control valves (though provided) and local steam generator level indication were not included as part of the TMI Short Term Lessons Learned Requirements for automation of the AFWS. The modifications now underway will provide the operators with the capability for remote manual control of these valves so that local manual control would only be required during highly improbable conditions, due to the single failure capabilities of the system. Under these conditions, the local manual control of the flow control valves would have to be coordinated with steam generator level information provided remotely from one of the three available locations.

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D.

April 7, 1981 It is our desire that this information clarifies the local control and indication capabilities of the automated AFWS. If you have any questions or desire additional information, please contact me.

Very truly yours, cc. R. H. Engleken (NRC Office of Inspection and Enforcement, Region V)

Division of Reactor Operations Inspection (NRC Office of Inspection and Enforcement, Washington, D.C.)