ML19256F329

Submits Commitment of Compliance to NRC 791023 Interim Position Re Containment Purge & Vent Valve Operation. Commitment Is Adequate for NRC Determination That OL Need Not to Be Modified,Suspended or Revoked

ML19256F329
Person / Time
Site:	Davis Besse
Issue date:	12/13/1979
From:	Crouse R TOLEDO EDISON CO.
To:	Reid R Office of Nuclear Reactor Regulation
References
NUDOCS 7912180505
Download: ML19256F329 (3)

Text

.D.e g>&* TOLEDO Docket No. 50-346 License No. NPF-3 Serial No. 564 December 13, 1979 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Mr. Robert W. Reid, Chief Operating Reactors Branch No. 4 Division of Operating Reactors

Dear Mr. Reid:

This letter is in response to your letter dated October 23, 1979 requesting Toledo Edison commitment to the NRC interim position for containment purge and vent valve operation at Davis-Besse Nuclear Power Station Unit 1. The attachment to the above letter lists three (3) items to be compiled with. The following is the description of compliance with the respective items or exception thereto.

Item 1: During modes 1, 2, 3 and 4, the containment purging and venting is limited by technical specifications to an accumulated time of 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> within the last 365 days.

This purging and venting is achieved by manually opening the purge and exhaust valves. In further compliance with the NRC position, Toledo Edison will limit all purging and venting times to as low as achievable.

Item 2a: Toledo Edison is presently pursuing with the valve vendor, an analytical method to verify valve operability under design basis accident - LOCA conditions. This analysis will be in accordance with the guidelines stated in your September 27, 1979 letter. If required, this analysis will also determine the position to which the valve opening should be limited to ensure that the critical valve parts will not be damaged by DBA-LOCA loads and that the valve will tend to close when the fluid-dynamic forces are introduced. The valve supplier has informed us that such a determination will be completed in coincidence with the analysis committted to in our letter Serial No. 557 dated November 13, 1979. However, some preliminary koby S

THE TCLECO EDISCN CCMPANY EOiSCN PLAZA 3C0 MAOISCN AVENUE TOLECO. OkO 43552

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vender torque calculations perforced on our valves indicate that the aerodynamic torques with valves at less than 65 degrees open (90 degrees being full open) conditions are approximately half of the full open conditions. It is the valve manufacturer's engineering judgement that the resultant loads in critical valve components will also be reduced by the same magnitude thus enhancing the capability of these valves to withstand LOCA generated forces.

Pursuant to the above, Toledo Edison will restrict the valve position to less than 65 open (90 being full open) in modes 1, 2, 3 and 4.

Due to expected component delivery schedules, the system to achieve this restriction will be installed during the spring refueling outage currently scheduled to start in March, 1980. Until this modification is complete Davis-Besse will limit purging and venting times to as low as operationally achievable.

Item 2b: The containment purge and exhaust valves are isolated by the Safety Features Actuation System (SFAS) at Davis-Besse Unit 1 (DB-1). As described in Section 7.3.1.1.3.

of the DB-1 Final Safety Analysis Report, whenever the containment purge and vent valves are open,an SFAS valve closure signal cannot be physically bypassed or overridden to prevent closure of the containment purge and vent valves in the event of high containment radiation, high containment pressure or low reactor coolant system pressure.

We believe that the above reeponse is adequate for your staff to determine that the DB-1 operating license, NPF-3, need not be modified, suspended or revoked.

Yours very truly, R. P. Crouse Vice President Nuclear RPC:SCJ db b/2-3 1609 103

• 'N e SUBMITTAL IN RESPONSE TO A 10 CFR 50.54(f)

REQUEST OF OCTOBER 23, 1979 FOR DAVIS-BESSE NUCLEAR POWER STATION UNIT 1 FACILITY OPERATING LICENSE NO. NPF-3 This letter is submitted in conformance with 10 CFR 50.54(f) relating to Mr. Robert W. Reid's letter of October 23, 1979. This letter addresses

" Containment Purging and Venting During Normal Operation."

By Asrld _

General'Supcrintendent, Power Engineering and Construction For R. P. Crouse Vice President, Nuclear Sworn to and subscribed before me the thirteenth day of December, 1979.

Y, M, sm

/ ,, FRED W. GERN*AIN Netary Putte - State 'sf Chio My Ccmmiss;on Em'es Cct. 20 h'82 1609 104