[Federal Register Volume 64, Number 2 (Tuesday, January 5, 1999)]
[Notices]
[Page 534]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-99]



[[Page 534]]

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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-413 and 50-414]


Duke Energy Corporation, et al., (Catawba Nuclear Station, Units 
1 and 2); Exemption

I

    Duke Energy Corporation, et al. (the licensee) is the holder of 
Facility Operating License Nos. NPF-35 and NPF-52, for the Catawba 
Nuclear Station (CNS), Units 1 and 2. The licenses provide, among other 
things, that the licensee is subject to all rules, regulations, and 
orders of the Commission now or hereafter in effect.
    These facilities consist of two pressurized water reactors located 
at the licensee's site in York County, South Carolina.

II

    Title 10 of the Code of Federal Regulations (10 CFR), Part 50, 
Appendix A, specifies general design criteria for nuclear power plants. 
General Design Criterion (GDC) 57, regarding closed system isolation 
valves, states:

    Each line that penetrates primary reactor containment and is 
neither part of the reactor coolant pressure boundary nor connected 
directly to the containment atmosphere shall have at least one 
containment isolation valve which shall be either automatic, or 
locked closed, or capable of remote manual operation. This valve 
shall be outside containment and located as close to the containment 
as practical. A simple check valve may not be used as the automatic 
isolation valve.

The Commission may grant an exemption from the requirements of the 
regulations pursuant to 10 CFR 50.12 if 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. The Commission 
will not consider granting an exemption unless special circumstances 
are present. Special circumstances are considered to be present under 
10 CFR 50.12(a)(2) where application of the regulation in the 
particular circumstances conflicts with other rules or requirements of 
the Commission or where application of the regulation would not serve 
the underlying purpose of the rule or is not necessary to achieve the 
underlying purpose of the rule.

III

    By letter dated September 2, 1997, the licensee requested an 
exemption from GDC-57 for Containment Penetrations M261 and M393, which 
are main steam penetrations. These lines penetrate the containment and 
are not part of the reactor coolant pressure boundary, nor are they 
connected directly to the containment atmosphere. Outside of the 
containment, these lines branch into various separate, individual lines 
before reaching the respective main steam isolation valves. From each 
of these main steam lines, one branch supplies main steam to the 
turbine-driven auxiliary feedwater pump (CAPT, using the licensee's 
abbreviation).
    Valves SA-1 and SA-4 are manual gate valves located in the Interior 
Doghouse immediately downstream of the respective main steam piping. 
These valves are locked open (with breakaway locks) and are only 
capable of local manual operation. These valves are required to be open 
by the Technical Specifications (TS) in order to supply steam to the 
CAPT, which is part of the engineered safety features. From a 
probabilistic risk assessment perspective, the CAPT is one of the most 
risk-significant safety system components. Adding motor operators to 
SA-1 and SA-4, so that they become automatic or capable of remote 
operation (i.e., meeting GDC-57) would, thus, degrade the reliability 
of the CAPT to mitigate an accident because the motor operators would 
introduce a new failure mode. Keeping SA-1 and SA-4 closed (i.e., 
meeting GDC-57) during plant operation would violate a TS requirement.
    Valves SA-1 and SA-4 can be manually closed, as needed during 
certain accidents, to isolate the steam lines they serve. If SA-1 and 
SA-4 are inaccessible due to post-accident environmental conditions, 
the associated stop check valves can be used to isolate these steam 
lines. The licensee stated that the amount of time needed by operators 
to isolate steam using SA-1 and SA-4, or their associated stop check 
valves, has been factored into the accident analyses and resultant dose 
calculations in the Updated Final Safety Analysis Report.
    Thus, as stated in the staff's safety evaluation, modifying valves 
SA-1 and SA-4 so that they can meet the operational requirement 
specified by GDC-57 would reduce the reliability of the CAPT, violate 
an existing TS, or both. The time needed by operators to manually close 
SA-1 and SA-4, or their associated stop check valves, during an 
accident, has been factored into accident analyses and is bounded by 
the design-basis accident scenarios and consequences. On such bases, 
the staff concludes that literal compliance with the operational aspect 
of GDC-57 is not desirable and the proposed exemption is acceptable.

IV

    Accordingly, the Commission has determined that special 
circumstances are present as defined in 10 CFR 50.12(a)(2)(ii). 
Specifically, the Commission finds that application of GDC-57 with 
respect to Valves SA-1 and SA-4 conflicts with existing TS and is not 
necessary to achieve the underlying purpose of the rule. The underlying 
purpose of GDC-57 is to ensure that reliable means exist to isolate 
this type of line when isolation is needed. As previously discussed, 
Valves SA-1 and SA-4 can be manually closed to isolate their respective 
steam lines. Thus, the design of these valves and the existence of 
appropriate procedures for manually closing these valves provide a 
reliable method of isolating the steam lines when needed. The 
Commission hereby grants the licensee an exemption from the requirement 
of 10 CFR Part 50, Appendix A, GDC-57. Specifically, this exempts the 
licensee from having to lock close Valves SA-1 and SA-4 against TS 
requirements, or having to so modify them that they become automatic, 
or are capable of remote manual operation.
    Pursuant to 10 CFR 51.32, the Commission has determined that 
granting of this exemption will have no significant effect on the 
quality of the human environment (63 FR 71659, dated December 29, 
1998).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 29th day of December 1998.

    For the Nuclear Regulatory Commission.
Brian W. Sheron,
Acting Director, Office of Nuclear Reactor Regulation.
[FR Doc. 99-99 Filed 1-4-99; 8:45 am]
BILLING CODE 7590-01-P