[Federal Register Volume 62, Number 143 (Friday, July 25, 1997)]
[Notices]
[Pages 40123-40124]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-19805]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-461]
Illinois Power Company; Clinton Power Station, Unit No. 1
Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (the Commission) is
considering issuance of an exemption from certain requirements of its
regulations to Facility Operating License No. NPF-62, issued to
Illinois Power Company (the licensee), for operation of the Clinton
Power Station, Unit No. 1, located in DeWitt County, Illinois.
Environmental Assessment
Identification of the Proposed Action
The proposed action is in accordance with the licensee's
application dated July 22, 1997, for a temporary, partial exemption
from the requirements contained in General Design Criterion (GDC) 17,
``Electric Power Systems,'' of Appendix A to 10 CFR 50. The requested
exemption would only be effective through and including October 15,
1997, and would permit plant operation with one fully qualified offsite
circuit and one circuit that does not strictly conform to the capacity
and capability requirements of GDC 17.
The Need for the Proposed Action
GDC 17 requires that an onsite and an offsite electric power system
be provided to permit functioning of structures, systems, and
components important to safety. The safety function for each of these
two systems (assuming the other system is not functioning) is to
provide sufficient capacity and capability to assure that (1) specified
acceptable fuel design limits and design conditions of the reactor
coolant pressure boundary are not exceeded as a result of anticipated
operational occurrences, and (2) the core is cooled and containment
integrity and other vital functions are maintained in the event of
postulated accidents.
The Clinton Power Station (CPS) licensing basis assumes two
independent offsite electric power sources that are capable of
supplying power to emergency buses. These consist of 138-kV and 345-kV
offsite circuits. During the current refueling outage at CPS, the
licensee has determined that, for short and intermittent periods of
time, voltage on the 345-kV offsite source has not consistently
remained above the minimum required value conservatively established
for CPS. This is primarily due to the fact that unusually low voltages
are occurring as a result of the current lack of operating generators
in Illinois, coupled with high load demands during peak hours. The
licensee has determined that all practical measures taken to boost
voltage, short of interrupting service to customers, are not sufficient
to maintain required voltage. Further action to restore voltage would
necessitate power interruptions.
Conformance to GDC 17 requires that both offsite sources have
sufficient capacity and capability such that voltage is continuously
maintained above the minimum values conservatively established for the
facility. Due to the intermittent voltage conditions for the 345-kV
system described above, the licensee cannot demonstrate that this
offsite circuit has sufficient capacity and capability at all times.
With this offsite source experiencing intermittent periods of lower
than expected voltage, it would have to be declared inoperable. Plant
startup or continued plant operation is not permitted with one offsite
source inoperable.
The licensee has proposed a temporary, partial exemption to the
requirements of GDC 17 that would only be effective through and
including October 15, 1997. The exemption would temporarily allow plant
operation with one fully qualified offsite circuit and one circuit that
does not strictly conform to the capacity and capability requirements
of GDC 17. Strict compliance with GDC 17 is not necessary to achieve
the underlying purpose of the rule and would impose undue hardship to
the licensee. The licensee has implemented measures to assess when the
345-kV system voltage would be inadequate in the event of a plant trip,
performed an analysis to assess the risk associated with continued
plant operation for the period of time within which the intermittent
condition is likely to occur (i.e., through the end of hot, summer
weather), and established procedures that will restore
[[Page 40124]]
bus voltage within 10 minutes in the event that it is needed.
Environmental Impacts of the Proposed Action
The Commission has completed its evaluation of the proposed action
and concludes that the proposed exemption would not increase the
probability or consequences of accidents previously analyzed and would
not affect facility radiation levels or facility radiological
effluents.
Granting the exemption would not significantly increase the
probability of unavailable offsite power in the event of an accident
and, therefore, would not significantly increase the probability of a
radiological release from CPS. The availability and reliability of the
onsite power sources would not be affected by the exemption. The
availability and reliability of the offsite source having adequate
voltage (i.e., the 138-kV circuit) would also not be affected. Although
there is a slight increase in the probability of having the low-voltage
offsite source unavailable following a plant trip, or both sources
unavailable in the event of a loss of the other offsite source, this
increase is small based on the factors identified, and actions
available to restore offsite voltage.
Electric power would still be available for safety-related
equipment required to mitigate an accident. The proposed change does
not involve an increase in the consequences of an accident, no changes
are being made in the types of any effluents that may be released
offsite, and there is no significant increase in the allowable
individual or cumulative occupational radiation exposure. Accordingly,
the Commission concludes that there are no significant radiological
environmental impacts associated with the proposed action.
With regard to potential nonradiological impacts, the proposed
action involves features located entirely within the restricted area as
defined in 10 CFR Part 20. It does not affect nonradiological plant
effluents and has no other environmental impact. Accordingly, the
Commission concludes that there are no significant nonradiological
environmental impacts associated with the proposed action.
Alternatives to the Proposed Action
Since the Commission has concluded that there is no measurable
environmental impact associated with the proposed action, any
alternatives with equal or greater environmental impact need not be
evaluated. The principal alternative to the proposed action would be to
deny the requested action. Denial of the requested action would
effectively preclude operation of the facility until the intermittent
voltage condition is resolved (i.e., until the end of hot, summer
weather).
Alternative Use of Resources
This action does not involve the use of resources not previously
considered in connection with the Nuclear Regulatory Commission's Final
Environmental Statement dated May 1982, related to the operation of the
Clinton Power Station, Unit No. 1.
Agencies and Persons Consulted
In accordance with its stated policy, on July 22, 1997, the NRC
staff consulted with the Illinois State representative regarding the
environmental impact of the proposed action. The State official had no
comments.
Finding of No Significant Impact
Based upon the foregoing environmental assessment, the Commission
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 this action, see the licensee's
letter dated July 22, 1997, which is available for public inspection at
the Commission's Public Document Room, the Gelman Building, 2120 L
Street, NW., Washington, DC, and at the local public document room
located at the Vespasian Warner Public Library, 310 N. Quincy Street,
Clinton, IL 61727.
Dated at Rockville, Maryland, this 23rd day of July 1997.
For the Nuclear Regulatory Commission.
Gail H. Marcus,
Director, Project Directorate III-3, Division of Reactor Projects III/
IV, Office of Nuclear Reactor Regulation.
[FR Doc. 97-19805 Filed 7-24-97; 8:45 am]
BILLING CODE 7590-01-P
