ML20198L024
| ML20198L024 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 12/29/1998 |
| From: | Sheron B NRC (Affiliation Not Assigned) |
| To: | DUKE POWER CO. |
| Shared Package | |
| ML20198L028 | List: |
| References | |
| NUDOCS 9901040028 | |
| Download: ML20198L024 (4) | |
Text
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f 7590-01-P
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j UNITED STATES OF AMERICA i
NUCLEAR REGULATORY COMMISSION in the Matter of
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i DUKE ENERGY CORPORATION, ET AL
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Docket Nos. 50-413 and 50-414
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. (Catawba Nuclear Station,.
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Units 1 and 2)
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EXEMPTION t
1.
Duke Energy Corporation, et al. (the licensee) is the holder of Facility Operating License i
i Nos. NPF-35 and NPF-52, for the Catawba Nuclear Station (CNS), Units 1 and 2. The licenses I
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 Cbunty, South Carolina.
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Title 10 of the Code of Federal Reaulations (10 CFR), Part 50, Appendix A, specifies i
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 locat'd as close to the containment as 3
practical. A simple check valve may not be used as the automatic isolation valve.
9901040028 981229 PDR ADOCK 05000413 p
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The Commission may grant an exemption from the requirements of the regulations pursuant to 10 CFR 50.12 if the exemption is authorized g law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. The Commission 4
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.
Ill.
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 -
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isolation valves. From each of these main sum sines, 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
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required to be open by the Technical Specifications (TS) in order issuppi[ steam to the CAPT, ~
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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
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' accident because the motor operators would introduce a new failure mode. Keeping SA-1 and l
SA-4 closed (i.e., meeting GDC-57) during plant operat'on 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 accidant, 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
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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 l
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
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' 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 4
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.
FOR THE NUCLEAR REGULATORY COMMISSION ORIGINAL' SIGNED BY:
Brian W. Sheron, Acting Director Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 29th day of December 1998.
To receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure "N" = No copy l
OFFICE PM:PDll-2:*
lE LA:PDil-2% l SCSB l
SCSB l
D:PDil-2*
NAME P. Tam:en L. Bery - \\(V J. Pulsipher*
C. Berlinger*
H. Berkow DATE-12/15/98 12 /At:/96 ' '
12 /14 /98 12 /14 /98 12/22/98
" OFFICE OGC* -
l D:DRPE*
l ADPR*
l D:t I)ft t,,
l Tech. Ed.*
l' NAME C. Marco J. Zwolinski B. Boger SCdhs(F B.Calure L
DATE 12/17/98 12/22/98 12/22/98
/fdlY/ff 12/15/98 '
G:\\ CATAWBA \\C99561EX.WPD OFFICIAL RECORD COPY
- See previous concurrence i
i 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 1
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.
FOR THE NUCLEAR REGULATORY COMMISSION
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Brian W. Sheron, Acting Director Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 29th day of December 1998.
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