[Federal Register Volume 66, Number 68 (Monday, April 9, 2001)]
[Notices]
[Page 18514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-8630]



[[Page 18514]]

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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-271]


Vermont Yankee Nuclear Power Corporation; Vermont Yankee Nuclear 
Power Station; Environmental Assessment and Finding of No Significant 
Impact

    The U.S. Nuclear Regulatory Commission (NRC) is considering 
issuance of an exemption from certain requirements of Title 10 of the 
Code of Federal Regulations (10 CFR) Part 50, Appendix G for Facility 
Operating License No. DPR-28, issued to Vermont Yankee Nuclear Power 
Corporation (VYNPC, or the licensee) for operation of the Vermont 
Yankee Nuclear Power Station (Vermont Yankee), located in Windham 
County, Vermont.

Environmental Assessment

Identification of the Proposed Action

    Title 10 of the Code of Federal Regulations, 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.
    The proposed action would exempt Vermont Yankee from application of 
specific requirements of 10 CFR part 50, Appendix G, and substitute use 
of ASME Code Case N-640. 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 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 an exemption to apply the Code Case 
would be required by 10 CFR 50.60.
    The proposed action is in accordance with the licensee's 
application for exemption dated December 19, 2000.

The Need for the Proposed Action

    ASME Code Case N-640 is needed to revise the method used to 
determine the reactor coolant system (RCS) 
P-T limits, since 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 Vermont Yankee with these P-T curves without the relief 
provided by ASME Code Case N-640 would unnecessarily require the RPV to 
maintain a high temperature during the pressure tests. Consequently, 
steam leak hazards would continue to be one of the safety concerns for 
personnel conducting inspections in the primary containment. 
Implementation of the proposed P-T curves, as allowed by ASME Code Case 
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 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 this 
Code Case.

Environmental Impacts of the Proposed Action

    The NRC has completed its evaluation of the proposed action and 
concludes that the exemption described above would provide an adequate 
margin of safety against brittle failure of the Vermont Yankee reactor 
vessel.
    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 off site, 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 impacts. 
Therefore, there are no significant nonradiological impacts associated 
with the proposed action.
    Accordingly, the NRC 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 
Vermont Yankee Nuclear Power Station dated December 1974.

Agencies and Persons Consulted

    In accordance with its stated policy, on March 3, 2001, the staff 
consulted with the Vermont State official, William K. Sherman of the 
Department of Public Service, 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 NRC 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 December 19, 2000. Documents may be examined, 
and/or copied for a fee, at the NRC's Public Document Room, located at 
One White Flint North, 11555 Rockville Pike (first floor), Rockville, 
Maryland. 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 2nd day of April 2001.
    For the Nuclear Regulatory Commission.
Robert Pulsifer,
Project Manager, Section 2, Project Directorate I, Division of 
Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 01-8630 Filed 4-6-01; 8:45 am]
BILLING CODE 7590-01-P