[Federal Register Volume 65, Number 182 (Tuesday, September 19, 2000)]
[Notices]
[Pages 56602-56603]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-24020]


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NUCLEAR REGULATORY COMMISSION

Commonwealth Edison Company; Dresden Nuclear Power Station, Units 2 
and 3; Environmental Assessment and Finding of No Significant 
Impact


[Docket Nos. 50-237 and 50-249]

    The U.S. Nuclear Regulatory Commission (NRC) is considering 
issuance of an exemption from certain

[[Page 56603]]

requirements of 10 CFR 50.60(a) for Facility Operating Licenses Nos. 
DPR-19 and DPR-25, issued to Commonwealth Edison Company (ComEd, or the 
licensee) for operation of the Dresden Nuclear Power Station, Units 2 
and 3, located in Grundy County, Illinois.

Environmental Assessment

Identification of the Proposed Action

    10 CFR Part 50, Appendix G, requires that pressure-temperature (P-
T) limits be established for reactor pressure vessels (RPVs) during 
normal operating and hydrostatic or leak rate testing conditions. 
Specifically, 10 CFR Part 50, Appendix G, states, ``The appropriate 
requirements on both the pressure-temperature limits and the minimum 
permissible temperature must be met for all conditions.'' Appendix G of 
10 CFR Part 50 specifies that the requirements for these limits are the 
American Society of Mechanical Engineers (ASME) Boiler and Pressure 
Vessel Code (Code), Section XI, Appendix G Limits.
    To address provisions of amendments to the technical specifications 
(TS) P-T limits, the licensee requested in its submittal dated February 
23, 2000, that the staff exempt ComEd from application of specific 
requirements of 10 CFR Part 50, Section 50.60(a) and Appendix G, and 
substitute use of ASME Code Cases N-588 and N-640.
    Code Case N-588 permits the postulation of a circumferentially-
oriented flaw (in lieu of an axially-oriented flaw) for the evaluation 
of the circumferential welds in RPV P-T limit curves. Code Case N-640 
permits the use of an alternate reference fracture toughness 
(KIC fracture toughness curve instead of KIa 
fracture toughness curve) for reactor vessel materials in determining 
the P-T limits. Since the pressure stresses on a circumferentially-
oriented flaw are lower than the pressure stresses on an axially-
oriented flaw by a factor of two, using Code Case N-588 for 
establishing the P-T limits would be less conservative than the 
methodology currently endorsed by 10 CFR Part 50, Appendix G and, 
therefore, an exemption to apply the Code Case would be required by 10 
CFR 50.60(b). Likewise, since the KIC fracture toughness 
curve shown in ASME Section XI, Appendix A, Figure A-2200-1 (the 
KIC fracture toughness curve) provides greater allowable 
fracture toughness than the corresponding KIa fracture 
toughness curve of ASME Section XI, Appendix G, Figure G-2210-1 (the 
KIa fracture toughness curve), using Code Case N-640 for 
establishing the P-T limits would be less conservative than the 
methodology currently endorsed by 10 CFR Part 50, Appendix G and, 
therefore, an exemption to apply the Code Case would also be required 
by 10 CFR 50.60(b).

The Need for the Proposed Action

    The proposed exemption is needed to allow the licensee to implement
    ASME Code Case N-588 and Code Case N-640 in order to revise the 
method used to determine the reactor coolant system (RCS) P-T limits, 
because continued use of the present curves unnecessarily restricts the 
P-T operating window. Since the RCS P-T operating window is defined by 
the P-T operating and test limit curves developed in accordance with 
the ASME Section XI, Appendix G procedure, continued operation of 
Dresden with these P-T curves without the relief provided by ASME Code 
Case N-640 would unnecessarily require the RPV to maintain a 
temperature exceeding 212 degrees Fahrenheit in a limited operating 
window during the pressure test. Consequently, steam vapor hazards 
would continue to be one of the safety concerns for personnel 
conducting inspections in primary containment. Implementation of the 
proposed P-T curves, as allowed by ASME Code Cases N-588 and N-640, 
does not significantly reduce the margin of safety and would eliminate 
steam vapor hazards by allowing inspections in primary containment to 
be conducted at a lower coolant temperature.
    In the associated exemption, the staff has determined that, 
pursuant to 10 CFR 50.12(a)(2)(ii), the underlying purpose of the 
regulation will continue to be served by the implementation of these 
Code Cases.

Environmental Impacts of the Proposed Action

    The Commission has completed its evaluation of the proposed action 
and concludes that there are no significant adverse environmental 
impacts associated with the proposed action.
    The proposed action will not significantly increase the probability 
or consequences of accidents, no changes are being made in the types of 
any effluents that may be released offsite, and there is no significant 
increase in occupational or public radiation exposure. Therefore, there 
are no significant radiological environmental impacts associated with 
the proposed action.
    With regard to potential nonradiological environmental impacts, the 
proposed action does not involve any historic sites. It does not affect 
nonradiological plant effluents and has no other environmental impact. 
Therefore, there are no significant nonradiological impacts associated 
with the proposed action.
    Accordingly, the Commission concludes that there are no significant 
environmental impacts associated with the proposed action.

Alternatives to the Proposed Action

    As an alternative to the proposed action, the staff considered 
denial of the proposed action (i.e., the ``no-action'' alternative). 
Denial of the application would result in no change in current 
environmental impacts. The environmental impacts of the proposed action 
and the alternative action are similar.

Alternative Use of Resources

    This action does not involve the use of any resources not 
previously considered in the Final Environmental Statement for the 
Dresden Nuclear Power Station, Units 2 and 3, dated November 1973.

Agencies and Persons Consulted

    In accordance with its stated policy, on July 19, 2000, the staff 
consulted with the Illinois State official, Frank Niziolek of the 
Illinois Department of Nuclear Safety, regarding the environmental 
impact of the proposed action. The State official had no comments.

Finding of No Significant Impact

    On the basis of the environmental assessment, the NRC concludes 
that the proposed action will not have a significant effect on the 
quality of the human environment. Accordingly, the Commission has 
determined not to prepare an environmental impact statement for the 
proposed action.
    For further details with respect to the proposed action, see the 
licensee's letter dated February 23, 2000, which is available for 
public inspection at the NRC Public Document Room, The Gelman Building, 
2120 L Street, NW., Washington, DC. Publicly available records will be 
accessible electronically from the ADAMS Public Library component on 
the NRC Web site, http://www.nrc.gov (the Electronic Reading Room).

    Dated at Rockville, Maryland, this 17th day of August 2000.
    For the Nuclear Regulatory Commission.
Anthony J. Mendiola,
Chief, Section 2, Project Directorate III, Division of Licensing 
Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 00-24020 Filed 9-18-00; 8:45 am]
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