ML20070D706

Forwards Amend Applications 142 & 126 to Licenses NPF-10 & NPF-15,respectively,revising FSAR Section 7.6.1.1.2, Shutdown Cooling Sys Interlocks Design Basis Info

ML20070D706
Person / Time
Site:	San Onofre
Issue date:	07/07/1994
From:	Rosenblum R SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20070D709	List: ML20070D706 ML20070D710 ML20070D713
References
NUDOCS 9407120178
Download: ML20070D706 (2)

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23 PARKER STREET 1RVINE, CALIFORNIA 92718 RICHARD M. ROSENBLUM TELEPHONE m.......- July 7, 1994 m . 4..o U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Docket No. 50-361 and 50-362 Amendmeist Application Nos.142 and 126 Proposed Revision to the Updated Final Safety Analysis (UFSAR)

Section 7.6.1.1.2, " Shutdown Cooling System Interlocks Design Basis Information" San Onofre Nuclear Generating Station Units 2 and 3 Enclosed are Amendment Application Numbers 142 and 126 to Facility Operating Licenses NPF-10 and NPF-15, respectively, for the San Onofre Nuclear Generating Station Units 2 and 3. These amendment applications consist of Proposed Change Number (PCN) 437, and are a request to revise Updated Final Safety Analysis Report (UFSAR) Section 7.6.1.1.2, " Shutdown Cooling System Interlocks Design Basis Information" for San Onofre Units 2 and 3.

Southern California Edison (Edison) proposes modifying the design of the Subcooled Margin Monitor (SMM) calculators in the Qualified Safety Parameter Display System (QSPDS) and the Shutdown Cooling System (SDCS) Open Permissive Interlocks (OPIs). The proposed. design change will significantly increase the accuracy of the pressure sensing instrumentation under harsh environmental conditions, but it will eliminate the diversity of sensors for the SDCS-0PI.

To achieve the desired accuracy for Subcooled Margin Monitoring and Reactor Coolant System (RCS) pressure indication, it will be necessary to replace both the RCS wide-range and the RCS low-range transmitters. The only transmitters available in the industry with the necessary accuracy are Rosemount 1154 Series H transmitters.

Edison committed, in FSAR Q&R 032.23 in 1980, to meet the SDCS-0PI interlock requirements by using diverse process pressure sensors: two Foxboro transmitters (force-balance bellows capsule) and two Rosemount transmitters (oil-filled capacitance cell).

In 1981, the NRC accepted the San Onofre Units 2 and 3 SDCS-0PI design based on Safety Evaluation Report (NUREG-0712) Section 7.6.1, which states that a) there is an independent pressure channel interlocked with each SDCS isolation valve, and b) for each line, each valve is interlocked with a pressure sensor manufactured by different vendors. PCN-437 requests a revision to the UFSAR I Section 7.6.1.1.2 to indicate that the Pressurizer Pressure sensors are no longer required to be provided by different vendors.

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Document Control Desk >' d2-Your approval of this amendment application is requested by December 1, 1994 to support the San Onofre Unit 2 refueling outage which is anticipated to begin in January of 1995.

If you need additional information on this amendment application request, please let me know.

Sincerely, fl. f^ l[ L:n -

Enclosure cc: L. J. Callan, Regional Administrator, NRC Region IV K. E. Perkins, Jr., Director Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 H. Kocol, California Department of Health Services