[Federal Register Volume 60, Number 9 (Friday, January 13, 1995)]
[Notices]
[Pages 3276-3278]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-919]



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[[Page 3277]]

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-237]


Commonwealth Edison Company; Dresden Nuclear Power Station, Unit 
2; Environmental Assessment and Finding of No Significant Impact

    The U.S. Nuclear Regulatory Commission (the Commission) is 
considering issuance of a schedular exemption from the requirements of 
10 CFR Part 50 to Commonwealth Edison Company (ComEd, the licensee) for 
the Dresden Nuclear Power Station, Unit 2, located in Grundy County, 
Illinois.

Environmental Assessment

Identification of Proposed Action

    The proposed action would grant a one-time schedular exemption from 
the requirements of Sections III.D.2(a) and III.D.3 (Type B and Type C 
tests, respectively) of Appendix J to 10 CFR Part 50 relating to the 
primary reactor containment leakage testing for water-cooled reactors. 
The purpose of the tests is to assure that leakage through primary 
reactor containment shall not exceed allowable leakage rate values as 
specified in the Technical Specifications and that periodic 
surveillance is performed.

Need for the Proposed Action

    By letter dated November 23, 1994, the licensee requested, pursuant 
to 10 CFR 50.12(a), a one-time schedular exemption for Dresden, Unit 2, 
from the local leak rate test intervals for certain Type B and C leak 
rate tests required by 10 CFR Part 50, Appendix J, Sections III.D.2(a) 
and III.D.3. The exemption is requested to support the current outage 
schedule and to avoid the potential for an earlier reactor shutdown. If 
a forced outage is imposed to perform testing, it would present undue 
hardship and cost in the form of increased radiological exposure. 
Furthermore, if a forced outage is imposed to perform the required 
testing, an additional plant shutdown and startup will be required. In 
order to rectify these concerns, ComEd proposes to reschedule the 
Dresden, Unit 2, refuel outage from September 1994 to July 16, 1995. 
Increasing the interval between refueling outages will cause Dresden, 
Unit 2, to exceed the Type B and C leak rate testing surveillance 
intervals required for Type B and C leak rate tests which cannot be 
performed during reactor operation.

Environmental Impacts of the Proposed Action

    The proposed action includes exemptions from performing certain 
Type B and C tests for a maximum period of 180 days beyond the required 
Appendix J test intervals. As stated in 10 CFR Part 50, Appendix J, the 
purpose of the primary containment leak rate testing requirements is to 
ensure that leakage rates are maintained within the Technical 
Specification requirements and to assure that proper maintenance and 
repair is performed throughout the service life of the containment 
boundary components. The requested exemption is consistent with the 
intent of 10 CFR 50.12(a), in that it represents a one-time only 
schedular extension of short duration. The required leak tests will 
still be performed to assess compliance with Technical Specification 
requirements, albeit later, and to assure that any required maintenance 
or repair is performed. As noted in Sections III.D.2(a) and III.D.3 of 
Appendix J, it was intended that the testing be performed during 
refueling outages or other convenient intervals. Extending the Appendix 
J intervals by a small amount to reach the next refueling outage will 
not significantly impact the integrity of the containment boundary, and 
therefore, will not significantly impact the consequences of an 
accident or transient in the unlikely event of such an occurrence 
during the 180-day extended period.
    The exemption request is further supported by the information 
provided in the application. ComEd has identified those Type B and C 
volumes which will be leak tested during reactor operation. In 
addition, ComEd has identified those volumes that will be leak tested 
should a forced outage of suitable duration occur prior to July 16, 
1994 (180-day maximum exemption request). These commitments reduce the 
number of volumes which need an exemption and the length of time for 
which an exemption would be required should a forced outage of 
sufficient duration occur. ComEd has also provided the testing 
methodology which will be used if forced outages occur. In order to 
provide an added margin of safety and to account for possible increases 
in the leakage rates of untested volumes during the relatively short 
period of the exemption, Dresden will impose an administrative limit 
for maximum pathway leakage of 80 percent of 0.6L<INF>a for the 
remaining Unit 2 fuel cycle.
    Past Unit 2 local leak rate test data have, in general, 
demonstrated good leak rate test results. The current maximum pathway 
leakage rate for Dresden, Unit 2, as determined through Type B and C 
leak rate testing is 309.46 standard cubic feet per hour (scfh). This 
value is approximately 63 percent of the Technical Specification limit 
of 488.45 scfh (0.6L<INF>a). In addition, the previous outage ``as 
left'' total minimum pathway leakage rate for Type B and C testable 
penetrations was 173.25 scfh. This value is approximately 28 percent of 
the Technical Specification limit of 610.56 scfh (0.75L<INF>a). By 
using the minimum pathway methodology, a conservative measurement of 
the actual leakage expected through a pathway under post-accident 
conditions can be determined. Based on the methodology, the low ``as 
left'' leakage value, and the previous local leak rate test data, it is 
clear that extending the test interval a maximum of 180 days for 
certain volumes will not affect the overall integrity of the 
containment.
    The previous outage ``as left'' Intergrated Leak Rate Test, 
completed on May 14, 1993, indicated that the primary containment 
overall integrated leakage rate, which obtains the summation of all 
potential leakage paths including containment welds, valves, fittings, 
and penetrations, was 493.36 scfh. This value is approximately 80.8 
percent of the limit specified in the Technical Specifications.
    The above data, along with the station-imposed limit for maximum 
pathway leakage, provide a basis for showing that the probability of 
exceeding the offsite dose rates established in 10 CFR Part 100 will 
not be increased by extending the current Type B and C testing 
intervals for a maximum of 180 days. The proposed exemption does not 
affect plant nonradiological effluents and has no other environmental 
impact. Therefore, the Commission concludes there are no measurable 
environmental impacts associated with the proposed exemption.

Alternatives to the Proposed Action

    Since the Commission has concluded there is no measurable 
environmental impact associated with the proposed exemption, any 
alternative with equal or greater environmental impact need not be 
evaluated. The principal alternative to the exemption would be to 
require rigid compliance with the requirements of Sections III.D.2(a) 
and III.D.3 of Appendix J to 10 CFR Part 50. Such action would not 
enhance the protection of the environment and would result in increased 
radiation exposure for the license. [[Page 3278]] 

Alternate Use of Resources

    This action does not involve the use of any resources not 
considered previously in the Final Environmental Statements for 
Dresden, Units 2 and 3, dated November 1973.

Agencies and Persons Consulted

    The staff consulted with the State of Illinois regarding the 
environmental impact of the proposed action. The State had no comments.

Finding of No Significant Impact

    The Commission has determined not to prepare an environmental 
impact statement for the proposed exemption.
    Based upon the foregoing environmental assessment, the NRC staff 
concludes 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 Licensee's 
request for exemption dated November 23, 1994, which is available for 
public inspection at the Commission's Public Document Room, The Gelman 
Building, 2120 L Street, N.W., Washington, D.C., and at the Morris 
Public Library, 604 Liberty Street, Morris, Illinois 60451.

    Dated at Rockville, Maryland, this 9th day of January 1995.

    For the Nuclear Regulatory Commission.
John F. Stang,
Acting Director, Project Directorate III-2, Division of Reactor 
Projects--III/IV Office of Nuclear Reactor Regulation.
[FR Doc. 95-919 Filed 1-12-95; 8:45 am]
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