[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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