[Federal Register Volume 59, Number 145 (Friday, July 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18507]
[[Page Unknown]]
[Federal Register: July 29, 1994]
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NUCLEAR REGULATORY COMMISSION
Commonwealth Edison Co.; Zion Nuclear Power Station, Units 1 and
2; Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (the Commission) is
considering issuance of an exemption to Facility Operating License Nos.
DPR-39 and DPR-48, issued to Commonwealth Edison Company (the
licensee), for operation of the Zion Nuclear Power Station, Units 1 and
2, located in Lake County, Illinois.
Environmental Assessment
Identification of Proposed Action
The proposed action would grant an exemption from 10 CFR Part 50,
Appendix J, Section III.D.3, which requires that Type C tests
(containment isolation valve leakage rate tests) be performed during
each reactor shutdown for refueling, but in no case at intervals
greater than 2 years. This requirement applies to valves 1(2)MOV-CC685,
the first isolation valves outside containment in the component cooling
water return line from the reactor coolant pump thermal barriers. It is
these valves that are the subject of this exemption request. This one-
time exemption will allow the Type C leak rate test on valves 1(2)MOV-
CC685 to be deferred until the next refueling outages (September 1995
for Unit 1 and January 1995 for Unit 2).
An amendment request to recognize the exemption was submitted by
the licensee in another letter, also dated June 16, 1994. Both the
amendment and exemption requests were preceded by a Notice of
Enforcement Discretion (NOED) to not enforce compliance with the
Technical Specification requirement to perform Type C tests of 1(2)MOV-
CC685 in accordance with 10 CFR Part 50, Appendix J. The NOED precluded
Unit 2 from being shut down and allowed the startup of Unit 1.
The Need for the Proposed Action
The proposed exemption is needed because valves 1(2)MOV-CC685 have
never been tested per the requirements of 10 CFR Part 50, Appendix J,
Section III.D.3. Continued operation of both units until their next
refueling outage requires the exemption because they will not be in
compliance with the requirements until the tests are performed.
Requiring the licensee to place both units in cold shutdown to do the
tests would result in undue hardship without a compensating increase in
safety. The scope of the test preparations in significant, requiring
removal of the reactor coolant pumps (RCP) from service, draining the
component cooling water (CCW) return line from the RCP thermal
barriers, uncoupling the flange at the CCW outlet from the RCP thermal
barrier and opening test valves to provide a vent path. In addition to
the undesirable thermal cycling of each unit, the licensee estimates
each unit would be shut down for about three weeks, significant
planning and maintenance support would be necessary, and significant
radiation doses to maintenance personnel would be incurred. There would
not be a compensating increase in level of safety that would justify
the extensive amount of work and radiation exposure that would be
incurred by requiring the licensee to perform the Type C leak rate
testing of these two valves prior the units' next refueling outage. The
licensee is proposing performance of the tests during the next
refueling outage for each unit (September 1995 for Unit 1 and January
1995 for Unit 2) which is a time period that is outside of the
schedular requirements of 10 CFR Part 50, Appendix J.
Environmental Impacts of the Proposed Action
The Commission has completed its evaluation and determined that
granting the proposed exemption would not significantly increase the
probability or amount of expected primary containment leakage and that
containment integrity would, thus, be maintained. Although granting the
exemption would mean that the schedular requirements for Type C leak
rate testing in 10 CFR Part 50, Appendix J, would not be met, the
intent of leak rate testing (which is to (1) ensure that the leakage
through the primary containment, and systems and components that
penetrate the primary containment does not exceed the leakage rate
allowed by the Technical Specifications (TS) and associated basis, and
(2) ensure that proper maintenance and repair are being performed
throughout the service life of the containment boundary components)
would still be met due to the substantial barriers to fission product
release which are provided by the intact system piping and associated
valves. In addition, 1(2)MOV-CC9438, which are the valves outside
containment immediately downstream of 1(2)MOV-CC685, have been
satisfactorily tested in accordance with the applicable requirements of
10 CFR Part 50, Appendix J.
The requested schedular exemption is a one time request of short
duration for valves 1(2)MOV-CC685. All other required leak rate tests
have been performed in accordance with the TS and 10 CFR Part 50,
Appendix J. To provide an additional margin of safety during the
upcoming operating cycles and to account for possible leakage through
the valves, Zion will impose an administrative limit for maximum
pathway leakage of 0.4La for both units. The licensee will also
perform periodic visual inspections of the piping from the containment
wall to the subject valves to provide further assurance that no
external leakage exists. The administrative limit for maximum pathway
leakage coupled with the visual inspections of the valves and their
associated piping provide a basis for showing that the probability of
exceeding the off-site does rate limits of 10 CFR Part 100 will not be
increased by deferring completion of the Type C leak rate testing of
1(2)MOV-CC685. In addition, testing has been performed on the valves
that provides a high degree of confidence that leakage through 1(2)MOV-
CC685 would be well within Type C testing limits. This testing
consisted of pressurized air tests of the piping between 1(2)MOV-CC685
and 1(2)MOV-CC9483 and water leakage tests on 1(2)MOV-CC685 in the
accident direction. In both tests, no leakage was observed. Therefore,
the staff has determined that the exemption will not present an undue
risk to the public health and safety.
Consequently, the probability of accidents would not be increased,
nor would the post-accident radiological releases be greater than
previously determined. Neither would the proposed exemption otherwise
affect radiological plant effluents. Therefore, the Commission's staff
concludes that there are no significant radiological environmental
impacts associated with the proposed exemption.
With regard to potential nonradiological impacts, the proposed
exemption involves a change to surveillance and testing requirements.
It does not affect nonradiological plant effluents and has no other
environmental impact. Therefore, the Commission's staff concludes that
there are no significant nonradiological environmental impacts
associated with the proposed exemption.
Alternative to the Proposed Action
Since the Commission has concluded that there are no significant
environmental impacts associated with the proposed action, any
alternatives would have either no or greater environmental impact.
The principal alternative would be to deny the requested exemption.
This would not reduce the environmental impacts attributed to the
facility and would result in a costly shut down of the units for the
purpose of performing the tests.
Alternate Use of Resources
This action does not involve the use of any resources not
previously considered in connection with the Nuclear Regulatory
Commission's Final Environmental Statement, dated December 1972,
related to the operation of the Zion Nuclear Power Station, Units 1 and
2.
Agencies and Persons Consulted
The NRC staff consulted with the Illinois State official regarding
the environmental impact of the proposed action. The State official had
no comments.
Finding of No Significant Impact
The Commission staff has determined not to prepare an environmental
impact statement for the proposed license exemption. Based upon the
foregoing environmental assessment, we conclude that the proposed
action will not have a significant effect on the quality of the human
environment.
For further details with respect to this action, see the request
for exemption dated June 16, 1994, which is available for public
inspection at the Commission's Public Document Room, The Gelman
Building, 2120 L Street, NW., Washington, DC 20555, and at the local
public document room located at Waukegan Public Library, 128 North
County Street, Waukegan, Illinois 60085.
Dated at Rockville, Maryland, this 25th day of July 1994.
For the Nuclear Regulatory Commission.
Robert A. Capra,
Director, Project Directorate III-2, Division of Reactor Projects--III/
IV, Office of Nuclear Reactor Regulation.
[FR Doc. 94-18507 Filed 7-28-94; 8:45 am]
BILLING CODE 7590-01-M
