ML20137Z789

Provides Proposed Schedule for Meeting Requirements of 10CFR50.62 Re Reduction of Risk from ATWS Events for light-water Cooled Nuclear Plants.Brief Description of Tentative Design for PWR Listed

ML20137Z789
Person / Time
Site:	Point Beach
Issue date:	09/30/1985
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Butcher E, Harold Denton Office of Nuclear Reactor Regulation
References
CON-NRC-85-102 TAC-53186, TAC-53187, VPNPD-85-440, NUDOCS 8510080369
Download: ML20137Z789 (2)

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,M Wisconsin Electnc mm cowa 23I W. MICHIGAN, P.O. 807 2046. MILWAUKEE, WI 53201 VPNPD-85-440 NRC-85-102 September 30, 1985 Mr. H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555 Attention: Mr. Edward Butcher, Acting Chief Operating Reactors, Branch 3 Gentlemen:

DOCKET NOS. 50-266 AND 50-301 RESPONSE TO FINAL RULE ON 10 CFR 50.62 REQUIREMENTS FOR REDUCTION OF RISK FROM ANTICIPATED TRANSIENTS WITHOUT SCRAM (ATWS)

EVENTS FOR LIGHT-WATER COOLED NUCLEAR POWER PLANTS POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 On June 1, 1984 the Commission approved publication of a final rule, 10 CFR 50.62, regarding the reduction of risk from anticipated transients without scram (ATWS) events for light-water cooled nuclear power plants. Section 50.62(d) of the ATWS rule requires each licensee to develop and submit to the Director of the Office of Nuclear Reactor Regulation a proposed schedule for meeting the requirements of the rule. The purpose of this letter is to provide a proposed schedule for meeting the requirements of the ATWS rule and to provide a brief description of the tentative design being considered to meet the requirements of Section 50.62 (c) (1) as it applies to Point Beach Nuclear Plant.

Section 50.62 (c) (1) of the rule requires each pressurized water reactor (PWR) to have ecuipment from sensor output to final actuation device, that is diverse from the reactor trip system, to automatically initiate the auxiliary feedwater system and to initiate a turbine trip under conditions indicative of an ATWS. In a letter from L. D. Butterfield to C. O. Thomas dated July 25, 1985 (OG-156),

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r Mr. H. R. Denton September 30, 1985 Page 2 the Westinghouse Owners Group (WOG) submitted Topical Report WCAP-10858, "AMSAC Generic Design Package", which presents three conceptual designs which meet this requirement at Westinghouse-designed PWR's. Wisconsin Electric has tentatively decided to use the conceptual design presented in Section 3.0 of WCAP-10858,

" Functional Requirements, ATWS Mitigating System Actuation Circuitry" (LOGIC I: AMSAC Actuation on Low Steam Generator Water Level). In summary, this logic would actuate a turbine trip and auxiliary feedwater flow upon sensing that the steam generator inventory is below the low-low level setpoint.

Redundant steam generator wide-range level transmitters, which are independent (from sensor output to final actuation device) from the narrow-range level transmitters used in the reactor protection system, would be used to provide these signals. The logic would sense conditions indicative of an ATWS event when a loss of heat sink has occurred but will not actuate until after the reactor protection signals should have been generated. The logic equipment would be contained in instrumentation racks diverse from those used for the existing reactor protection system.

The proposed schedule for implementation of the ATWS rule is based in part upon the completion of the Staff's review of l the WOG's AMSAC generic design package. This is to help ensure that the final design to be implemented at Point Beach will adequately meet the requirements of the-rule. A period of approximately eighteen months will be necessary following receipt of the Safety Evaluation Report (SER) to al)ow for detailed design of the system (six months) and procurement of materials (12 months). This is provided that the Staff does not require a plant-specific design review prior to implementation at Point Beach. Wisconsin Electric intends to submit a description of the final design and final implementation schedule within six months of receipt of the SER. The system could then be installed during the first scheduled outage for each unit after this eighteen-month period. Note that this schedule will put the final bnplementation beyond the date requested in Section 50.62(d).

If you have any questions regarding this matter, please contact us.

Very truly your ,

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C. W. Fay Vice President Nuclear Power Copy to NRC Resident Inspector

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