[Federal Register: May 7, 1999 (Volume 64, Number 88)]
[Notices]               
[Page 24683-24684]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07my99-130]

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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-275 and 50-323]

 
Pacific Gas and Electric Company (Diablo Canyon Nuclear Power 
Plant, Units 1 and 2); Exemption

I

    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 Regulations (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 
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.

III

    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

[[Page 24684]]

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 underlying purpose of the rule or is 
not necessary to achieve the underlying purpose of the rule.* * *'' The 
licensee's proposed use of Code Case N-514 will be used as an 
alternative 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 
<ls-thn-eq>110% of the limit defined by the P/T limit curves) would 
provide an adequate margin of safety against brittle fracture failure 
of the reactor 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.

    Dated at Rockville, Maryland, this 3rd day of May 1999.

    For the Nuclear Regulatory Commission.
John A. Zwolinski,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. 99-11515 Filed 5-6-99; 8:45 am]
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