Commonwealth Edison Co.; Zion Nuclear Power Station, Units 1 and 2; Environmental Assessment and Finding of No Significant Impact

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]

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