ML20149H161
| ML20149H161 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 07/23/1997 |
| From: | Marcus G NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20149H164 | List: |
| References | |
| NUDOCS 9707240244 | |
| Download: ML20149H161 (5) | |
Text
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7590-01-P f
UNITED STATES NUCLEAR REGULATORY COMMISSION l
ILLINOIS POWER COMPANY DOCKET NO. 50-461 l-CLINTON POWER STATION. UNIT NO. 1 1-ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT i.
a The U.S. Nuclear Regulatory Commission (the Commission) is considering_
issuance of an exemption from certain requirements of its regulations to i
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 j'
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DeWitt County, Illinois.
ENVIRONMENTAL ASSESSMENT
. Identification of the Proposed Action:
i 1
The proposed action is in accordance with the licensee's application
[7 dated iluly 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 exesaption would only be effective 4
3 l
through and' including.0ctober 15, 1997, and would permit plant operation with-
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'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 Pronosed 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 h
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capacity and capability to assure that (1) specified acceptable fuel design
' limits and design conditions of the reactor coolant pressure boundary are not
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exceeded as a result of anticipated operational occurrences, and (2) the core
.1 is cooled and containment integrity and other vital functions are maintained i
in the event of postulated accidents.
l The Clinton Power Station (CPS) licensing basis assumes two independent J
offsite electric power sources that are capable of supplying power to emergency l
buses. These consist of 138-kV and 345-kV offsite circuits. During the i
current refueling outage at CPS, the licensee has determined that, for short i
l 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 l
intemittent 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 i
declared inoperable.
Plant startup or continued plant operation is not i
permitted with one offsite source inoperable.
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. e 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 l
l 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 i
l' 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 i
l 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 bus voltage within 10 minutes in the event that it is needed.
Environmental'Imoacts of the Proposed Action:
The Comission has completed its evaluation of the proposed action and concludes that the proposed exemption would not increase the probability or I
consequences of accidents previously analyzed and would not affect facility radiation levels or facility radiological effluents.
i Granting the exemption would not significantly increase the probability i
of unavailable offsite power in the event of an accident and, therefore, would j
not significantly increase the probability of a radiological release from CPS.
j The availability and reliability of the onsite power cources would not be.
affected by the exemption. The availability and reliability of the offsite l
l 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 j
i the low-voltage offsite source unavailable following a plant trip, or both L
, t.
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l 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 l
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 environmenta'l 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 bapact. Accordingly, the Commission concludes that there are no significant nonradiological environmental impacts asso:iated 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 l
l 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.,
i until the end of hot, summer weather).
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- l Alternative Use of Resources
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This action does not involve the use of resources not previously j
considered in connection with the Nuclear Regulatory Comission's Final Environmental Statement ' dated May 1982, related to the operation of the l
Clinton Power Station, Unit No. 1.
Aaencies and Persons Consulted:
L 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.
i FINDING OF NO SIGNIFICANT IMPACT
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Based upon the foregoing environmental assessment, the Comission concludes that the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the Comission has determined not to prepare an environmental impact statement for the proposed action.
.For further details with respect to this _ action, see the itcensee's
_ letter dated July 22, 1997, which is available for public inspection at the
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Comission'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.
4 FOR THE NUCLEAR REGULATORY COMMISSION w
Gail H. Marcus, Director Project Directorate III-3 L
Division of Reactor Projects III/IV l
Office of Nuclear Reactor Regulation i
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