[Federal Register Volume 63, Number 220 (Monday, November 16, 1998)]
[Notices]
[Pages 63754-63755]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30560]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-269, 50-270, and 50-287]
Duke Energy Corporation, Oconee Nuclear Station, Units 1, 2, and
3; Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (the Commission) is
considering issuance of an exemption from the requirements of Title 10
of the Code of Federal Regulations (10 CFR) Section 50.46(b) to the
Duke Energy Corporation (the licensee) for operation of the Oconee
Nuclear Station, Units 1, 2, and 3, located in Oconee County, South
Carolina.
Environmental Assessment
Identification of Proposed Action
The proposed action would exempt the licensee from the provisions
in 10 CFR 50.46(b), with respect to the emergency core cooling
performance requirements during the performance of the proposed Keowee
Emergency Power and Engineered Safeguards Functional (KEP/ESF) Test on
Unit 3.
The emergency core cooling system (ECCS) is designed to assure that
the consequences of the spectrum of loss of coolant accidents (LOCAs),
coincident with a loss of offsite power (LOOP), are within the
performance criteria specified in 10 CFR 50.46(b). As explained in the
licensee's letter dated October 21, 1998, the planned test on Unit 3
could challenge these performance criteria in the extremely unlikely
event that a LOCA and LOOP occurred coincident with the test. The
licensee has chosen to address this issue with an exemption request.
Therefore, pursuant to 10 CFR 50.12, the licensee applied for an
exemption from 10 CFR 50.46.
The Need for the Proposed Action
The proposed action is required to exempt the licensee from the
requirement to maintain an ECCS that is designed to conform to the
criteria in 10 CFR 50.46(b) during the 10-second time interval when the
test is actually being performed during the 24-hour test period. The
action is needed to allow the test to be performed.
As stated in its September 17, 1998, letter, the licensee has
planned a modification that would add voltage and frequency protection
for Oconee loads when supplied from a Keowee hydro unit. The protection
would separate Oconee loads from a Keowee unit if that unit's voltage
or frequency becomes greater than 110 percent or less than 90 percent
of rated value at any time after loading. The planned design would
delay the loading of Oconee loads on the underground power path until
the Keowee unit reaches greater than 90 percent voltage and frequency.
The existing design allows early loading of the underground path Keowee
unit at approximately 60 percent voltage. As a result of considering
the frequency overshoot the Keowee units experience during an emergency
start, and to resolve questions that arose concerning whether the
preferred loading design for the emergency power system is 60 percent
loading or 90 percent loading,
[[Page 63755]]
the Keowee Emergency Power and Engineered Safeguards Functional Test is
planned.
Environmental Impacts of the Proposed Action
The Commission has completed its evaluation of the proposed action
and concludes that exemption from the requirements of 10 CFR 50.46(b)
to allow the licensee to perform the Keowee Emergency Power and
Engineered Safeguards Functional Test to increase the reliability of
the emergency electrical power system is appropriate.
The planned test will be performed with Unit 3 at cold shutdown and
its engineered safeguards (ES) loads on the Standby Bus. The other two
Oconee units will be operating and should not be affected by the test.
However, in the unlikely event that a real LOCA/LOOP were to occur on
either of the operating units during the simulated LOCA/LOOP on Unit 3
(probability, according to the licensee, of approximately 2E-9), the
Oconee emergency power system (EPS) for Oconee Units 1, 2, and 3 could
be in a condition outside its design bases. The EPS may not be capable
of handling the electrical loading of two instantaneous LOCA/LOOP
events without some safety-related equipment being adversely affected.
However, the EPS would be able to handle the electrical loading if the
two events are offset in time by approximately 10 seconds to allow the
first unit's load to reach a steady-state condition prior to starting
of the second unit's emergency loads. Therefore, this 10-second window
of vulnerability causes an infinitesimally small, but non-zero,
increase in the probability of a malfunction of equipment important to
safety and the potential consequences of a LOCA/LOOP event during the
performance of the test.
The exemption 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 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 environmental impacts, the
proposed action does not affect nonradiological plant effluents and has
no other environmental impacts. Accordingly, the Commission concludes
that there are no significant nonradiological impacts associated with
the proposed action.
Alternatives to the Proposed Action
Since the Commission has concluded there is no significant
environmental impact associated with the proposed action, any
alternatives with equal or greater environmental impact need not be
evaluated. As an alternative to the proposed action, the staff
considered denial of the proposed action (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 resources not previously
considered in the ``Final Environmental Statement Related to the
Operation of the Oconee Nuclear Station, Units 1, 2, and 3,'' dated
March 1972.
Agencies and Persons Consulted
In accordance with its stated policy, on November 4, 1998, the
staff consulted with the South Carolina State official, Virgil R. Autry
of the Division of Radioactive Waste Management, Bureau of Land and
Waste Management, Department of Health and Environmental Control,
regarding the environmental impact of the proposed action. The State
official had no comments.
Finding of No Significant Impact
Based on the 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 the proposed action, see the
licensee's letters dated October 21 and September 17, 1998, which are
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 Oconee County Library,
501 West South Broad Street, Walhalla, South Carolina.
Dated at Rockville, Maryland, this 9th of November 1998.
For the Nuclear Regulatory Commission.
Herbert N. Berkow,
Director, Project Directorate II-2, Division of Reactor Projects--I/II,
Office of Nuclear Reactor Regulation.
[FR Doc. 98-30560 Filed 11-13-98; 8:45 am]
BILLING CODE 7590-01-P
