ML20206F010

Exemption from Requirements of 10CFR50.60 & 10CFR50,App G,Re Pressure Temp Limits & Min Temp Requirements for Plant,Units 1 & 2.Exemption Related to Application & Suppls ,0205 & 0317 to Allow Use of Code Case N-514

ML20206F010
Person / Time
Site:	Diablo Canyon
Issue date:	05/03/1999
From:	Zwolinski J NRC (Affiliation Not Assigned)
To:	Public Service Enterprise Group
Shared Package
ML20206F014	List: ML20206F010
References
NUDOCS 9905050310
Download: ML20206F010 (3)

Text

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7590-01-P UNITED STATES OF AMERICA NUCLEAR REGUI.ATORY COMMISSION in the Matter of

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PACIFIC GAS AND ELECTRIC COMPANY

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Docket Nos. 50-275

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and 50-323 (Diablo Canyon Nuclear Power Plant,

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Units 1 and 2)

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EXEMPTION 1.

Pacific Gas and Electric Company, et.al. (the licensee) is the holder of Facility Operating License Nos. DPR-80 and DPR-82, which authorize operation of the Diablo Canyon Nuclear Power Plant (DCNPP), Units 1 and 2. The license provides, among other things, that the licensee is subject to all rules, regulations, and Orders of the Commission now or hereafter in effect.

The facility consists of two pressurized-water reactors at the licensee's site located in

- San Luis Obispo County, California.

II.

Section 50.60 of Title 10 of the Code of Federal Reaulations (10 CFR), " Acceptance criteria for fracture prevention measures for lightwater nuclear power reactors for normal operation," paragraph (a) states, in part, that "all light-water nuclear power reactors..... must meet the fracture toughness and material surveillance program requirements for the reactor coolant pressure boundary set forth in appendices G and H to this part." Pressurized water

- reactor licensees have installed cold overpressure mitigation systems / low temperature 9905050310 990503 PDR ADOCK 05000275, P

PDR

.. overpressure protection systems (LTOP) in order to protect the reactor coolant pressure boundary from being operated outside of the boundaries established by the pressure temperature (P/T) limit curves and to provide pressure relief of the reactor coolant pressure boundaries during low temperature overpressurization events.

Ill.

Section 50.12(a) of 10 CFR, " Specific exemption," states that...

The Commission may, upon application by any interested person, or upon its own initiative, grant exemptions from the requirements of the regulations of this part, which are: (1) Authorized by law, will not present an undue risk to the public health and safety, and are consistent with the common defense and security. (2) The Commission will not consider granting an exemption unless special circumstances are present.

Section 50.12(a)(2)(ii) of 10 CFR states that special circumstances are present when

" Application of the regulation in the particular circumstances would not serve the underlyling purpose of the rule or is not necessary to achi. eve the underlying purpose of the rule...." The licensee's proposed use of Code Case N-514 will be used as an attemative method for establishing the setpoints for the LTOP systems. Based on the conservatism that is incorporated into the methods of Appendix G of Section XI to the ASME Code for calculating P/T limit curves, it is concluded that permitting the LTOP setpoints to be established in accordance with the Code Case (e.g., at a level s110% of the limit defined by the P/T limit curves) would provide an adequate margin of safety against brittle fracture failure of the reactor l

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. i pressure vessels. Accordingly, the Commission has determined that special circumstances as defined in 10 CFR 50.12(a)(2)(ii) exist.

IV.

The Commission has determined that, pursuant to 10 CFR 50.12, the exemption is authorized by law, will not present an undue risk to the public health and safety and is consistent with the common defense and security, and is otherwise in the public interest.

Therefore, the Commission hereby grants Pacific Gas and Electric Company an exemption from the requirements of 10 CFR 50.60 and 10 CFR Part 50, Appendix G, to establish LTOP setpoints. The licensee will be allowed to use Code Case N-514 to establish LTOP setpoints to be used in their P/T limit curves.

Pursuant to 10 CFR 51.32, the Commission has determined that granting of this exemption will have no significant effect on the environment (64 FR 23688).

This exemption is effective upon issuance.

FOR THE NUCLEAR REGULATO Y COMMISSION l

John. Zwolinski, Director Division of Licensing Project Management Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 3rd day of May 1999 L

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