ML17264A921

Requests Exemption from Requirements of 10CFR50.60, Acceptance Criteria for Fracture Prevention for Lightwater Nuclear Power Reactors for Normal Operations. Request Being Made to Apply Guidance in ASME Code Case N-514

ML17264A921
Person / Time
Site:	Ginna
Issue date:	06/12/1997
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	Vissing G NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17264A920	List: ML17264A919 ML17264A921
References
NUDOCS 9706180465
Download: ML17264A921 (4)

Text

AND ROCHESTER GAS AND EIECTRIC CORPORATION e 89 EASTAYENUE, ROCHESTER, N. Y Iddd9 0001 AREA CC6E716 Sd6-2700 ROBERT C. MECREDY Vice President Nvctear Operations June 12, 1997 U.S. Nuclear Regulatory Commission Document Control Desk Attn: Guy Vissing Project Directorate I-1 Washington, D.C. 20555

Subject:

Request for Exemption from 10CFR50.60, "Acceptance Criteria for Fracture Prevention for Light Water Nuclear Power Reactors for Normal Operation" R.E. Ginna Nuclear Power Plant Docket No. 50-244

Dear Mr. Vissing:

The purpose of this letter is to seek exemption from the requirements of 10CFR50.60, "Acceptance Criteria for Fracture Prevention for Lightwater Nuclear Power Reactors for Normal Operation", as described in Attachment 1. This request for exemption is being made to apply the guidance in American Society of Mechanical Engineers (ASME) Code Case N-514, "Low Temperature Overpressure Protection", in lieu of those specified by 10CFR50, Appendix G. RG&E requests your action on this item by September 16, 1997, refueling outage so that it scheduled could for be incorporated October 1997.

prior to our next Very truly yours, Robert C. Mec edy REJ5464 xc: Mr. Guy Vissing (Mai);"-Stop 14B2)

Project Directorate X-1 Washington, D.C. 20555 N

U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Inspector 9706180465 970618 pDR AencK eseD0244 P

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Attachment 1 Rochester Gas and Electric (RG&E) requests exemption from the requirements of 10CFR50.60 in accordance with the guidance specified in 10CFR50.12(a)(2) to apply the requirements specified in ASME Code Case N-514.

To prevent transients that would result in pressure increases greater than the 10CFR50, Appendix G Pressure Temperature (P/T) limits while at low temperatures, RG&E has installed a low temperature overpressure overprotection (LTOP) system. The pressure actuation setpoint has been established such that transient occurred, the LTOP system would prevent the pressure in if a the reactor vessel from exceeding the P/T limits of 10CFR50, Appendix G. The pressure actuation setpoint must, also be high enough to prevent the inadvertent actuation of the LTOP system as a result of normal operating pressure surges. Application of the various instrumentation and calculational uncertainties has resulted in an LTOP actuation setpoint that establishes an operating window that is too narrow to permit reasonable system makeup and pressure control.

To allow for an increased operating band, RG&E requests to use ASME Code Case N-514, which designates the allowable pressure as 1104 of that specified by 10CFR50 Appendix G. ASME Code Case N-514 is consistent with guidelines developed by the ASME Working Group on Operating Plant Criteria to define pressure limits during LTOP events that avoid certain unnecessary operational restrictions, provide adequate margins against failure of the reactor pressure vessel, and reduce the potential for unnecessary actuation of pressure-relieving devices used for LTOP. The content of this code case has been incorporated into Appendix G of Section XI of the ASME Code published in the 1993 Addenda to Section XI and has been incorporated into the latest draft of Regulatory Guide 1.147 (Draft DG 1050, dated May 1997).

It is RG&E's position that circumstances are present such per 10CFR50.12(a)(2)(ii), special that "Application of the regulation in the particular circum nces would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule..." The underlying purpose of 10CFR50.60, Appendix G is to establish fracture toughness requirements for pressure retaining components of the reactor coolant pressure boundary to provide adequate margins of safety during normal operations. This appendix requires that the rea'ctor vessel be operated with P/T limits as conservative as those obtained by following Appendix G of the ASME Code. Since the Code Case N-514 has been incorporated as part of Appendix G of the ASME Section XI Code, use of the code case requirements meets the conservatism of the Appendix G.

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