[Federal Register Volume 66, Number 79 (Tuesday, April 24, 2001)]
[Notices]
[Pages 20692-20693]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-10095]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-331]


Nuclear Management Company, LLC; Duane Arnold Energy Center; 
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 10 CFR part 50, 
appendix G, for Facility Operating License No. DPR-49, issued to 
Nuclear Management Company, LLC (NMC, or the licensee) for operation of 
the Duane Arnold Energy Center (DAEC), located in Linn County, Iowa.

Environmental Assessment

Identification of the Proposed Action

    Title 10 of the Code of Federal Regulations (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 October 
16, 2000, that the staff exempt NMC from application of specific 
requirements of 10 CFR part 50, appendix G, and substitute use of ASME 
Code Case N-640. The license amendment request is being addressed as a 
separate action. Code Case N-640 permits the use of an alternate 
reference fracture toughness (K<INF>Ic</INF> fracture toughness curve 
instead of K<INF>Ia</INF> fracture toughness curve) for reactor vessel 
materials in determining the P-T limits. Since the K<INF>Ic</INF> 
fracture toughness curve shown in ASME Section XI, Appendix A, Figure 
A-2200-1 (the K<INF>Ic</INF> fracture toughness curve) provides greater 
allowable fracture toughness than the corresponding K<INF>Ia</INF> 
fracture toughness curve of ASME Section XI, Appendix G, Figure G-2210-
1 (the K<INF>Ia</INF> 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,

[[Page 20693]]

an exemption to apply the Code Case would 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-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 DAEC 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 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 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 this 
Code Case.

Environmental Impacts of the Proposed Action

    The NRC 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 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 Relating 
to the Operation of the Duane Arnold Energy Center,'' dated March 1973.

Agencies and Persons Consulted

    In accordance with its stated policy, on March 26, 2001, the staff 
consulted with the Iowa State official, Mr. D. McGhee of the Department 
of Public Health, 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 October 16, 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 17th day of April 2001.

    For the Nuclear Regulatory Commission.
Carl F. Lyon,
Project Manager, Section 1, Project Directorate III, Division of 
Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 01-10095 Filed 4-23-01; 8:45 am]
BILLING CODE 7590-01-P