[Federal Register Volume 65, Number 200 (Monday, October 16, 2000)]
[Notices]
[Pages 61204-61205]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-26473]


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NUCLEAR REGULATORY COMMISSION

[50-461]


AmerGen Energy Company, LLC; Clinton Power Station Environmental 
Assessment and Finding of No Significant Impact

    The U.S. Nuclear Regulatory Commission (the NRC) is considering 
issuance of a license amendment to and exemptions from certain 
requirements of Title 10 of the Code of Federal Regulations (10 CFR) 
Part 50, Section 50.60(a) for Facility Operating License No. NPF-62, 
issued to AmerGen Energy Company, LLC (the licensee), for

[[Page 61205]]

operation of the Clinton Power Station (CPS), located in DeWitt 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.
    The licensee requested in its submittal that the staff exempt CPS 
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 2, 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. 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. It should be noted that, although Code Case N-640 was 
incorporated into the ASME Code recently, an exemption is still needed 
because the proposed P-T limits (excluding Code Cases N-588 and N-640) 
are based on the 1989 edition of the ASME Code.
    The new P/T limits calculated by the methodologies that are subject 
to the exemptions, are requested to be incorporated into the CPS 
Technical Specifications by the associated proposed license amendment.
    The proposed action is in accordance with the licensee's 
application for exemption and amendment dated August 25, 2000, as 
supplemented September 21, 2000.

The Need for the Proposed Action

    The revised P/T limits are desired to allow required reactor vessel 
hydrostatic and leak tests to be performed at a significantly lower 
temperature. These tests are to be performed during the upcoming 
refueling outage scheduled to commence in October, 2000. The lower 
temperature for the tests can reduce refueling outage critical path 
time by reducing or eliminating the heatup time to achieve required 
test conditions.

Environmental Impacts of the Proposed Action

    The Commission has evaluated the proposed action and concludes that 
the exemptions and associated license amendment described above would 
provide an adequate margin of safety against brittle failure of the CPS 
reactor vessel. The lower temperature, is also safer for test 
inspectors due to lower ambient drywell temperature and could result in 
lower radiological dose due to increased inspection effectiveness at 
the lower temperature.
    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 non-radiological impacts, the proposed 
action does not involve any historic sites. It does not affect non-
radiological plant effluents and has no other environmental impact. 
Therefore, there are no significant non-radiological environmental 
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 
Clinton Power Station.

Agencies and Persons Consulted:

    In accordance with its stated policy, on September 28, 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 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 letters dated August 25 and September 21, 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 10th day of October 2000.

    For the Nuclear Regulatory Commission.
Jon B. Hopkins,
 Senior Project Manager, Section 2 Project Directorate III, Division of 
Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 00-26473 Filed 10-13-00; 8:45 am]
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