ML20235S351

Notice of Environ Assessment & Finding of No Significant Impact Re Util 870710 Request for Exemption from Certain Requirements of 10CFR50,App J

ML20235S351
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/05/1987
From:	Thomas C Office of Nuclear Reactor Regulation
To:
Shared Package
ML20235S344	List: ML20235S341 ML20235S351
References
NUDOCS 8710080454
Download: ML20235S351 (4)

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7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT DOCKET NO. 50-213 N0_TICE OF ENVIRONMENTAL ASSESSMENT AND FINDING 0F NO SIGNIFICANT IMPACT The U. S. Nuclear Regulatory Commission (the Commission) is considering issuance of an exemption from the requirements of Appendix J to 10 CFR Part 50 to Connecticut Yankee Atomic Power Company (the licensee) for the Haddam Neck Plant located at the licensee's site in Middlesex County, Connecticut.

ENVIRONMENTAL ASSESSMENT Identification of Proposed Action:

The licensee is requesting an exemption from Paragraph III.A,3 of 10 CFR Part 50 Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." In 1973, Appendix J was issued to establish

. requirements for primary containment leakage testing and inenrporated by reference, ANSI N45.4-1972, " Leakage Rate Testing of Containment Structures for Nuclear Reactors." This Standard requires that containment leakage calculations be performed by using either the point-to-point method or the total time method. The total time method was used the most by the nuclear industry until about 1976.

At this time, licensees who wish to use mass-point must submit an application for exemption from the Appendix J requirement that containment integrated leak rate tests will conform to ANSI N45.4. The exemption proposed g0080454072005 p ADOCK 05000213 PDR

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( 7590-01 by the licensee would be granted until pending changes to Appendix J become effective. The exemption applies only to the method of calculating containment leakage. In the mass-point method, the mass of air in containment is calculated and plotted as a function of time. Leakage is calculated from the slope of the Linear Least Squares.

With the present developments in technology, the mass-point method has gained increasing recognition. In the total time method, a series of leakage rates are calculated on the basis of air mass differences between an initial data point and each individual data point thereafter. If for any reason (such as instrument error, lack of temperature equilibrium, ingassing or outgassing) the initial data point is not accurate, the results of the test will be affected. In the point-to-point method, the leak rates are based on the mass difference between each pair of consecutive points which are then averaged to yield a single leakage rate estimate. Mathematically, this can be shown to be the difference between the air mass at the beginning of the test and the air mass at the end of the test expressed as a percentage of the containment air mass. It follows from the above that the point-to-point method ignores any mass readings during the test and thus the leakage rate is calculated on the basis of the difference in mass between two measurements taken at the beginning and at the end of the test, which are 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> apart.

The licensee's request for exemption and the bases therefore are contained in a letter dated July 10, 1987.

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.( '7590-01 The Need for the Proposed Action:  !

The exemption is needed to allow continued use of the mass-point analysis method at the Haddam Neck Plant.

Environmental Impact of'the Proposed Action: The-proposed exemption will have no incremental' environmental impact relative to current practice because the exemption will allow testing to be conducted in the same manner as it is currently performed.

The error in the total time method creates a higher probability of

-unnecessarily failing a containment integrated leakage rate test (note that the. calculational procedure is'. independent of containment tightness) possibly resulting in increased test frequency, critical path outage time, and exposure to test personnel.

The radiological releases will not be greater than previously determined, nor does the proposed exemption otherwise affect radiological plant effluents, and has no other environmental impact. Therefore, the Comission concludes that there are no significant radiological or non-radiological environmental I

impacts associated with the proposed exemption.

Alternatives to the Proposed Action: It has been concluded that there is no .

measurable impact associated with the proposed exemption; any alternatives to the exemption will have either no environmental impact or greater environmental I

impact.

Alternative Use of Resources: This action does not involve the use of resources beyond the scope of resources used during normal plant operation. .

Agencies and Persons Consulted;_ The Commission's staff reviewed the licensee's request that supports the proposed exemption. The staff did not consult other agencies or persons.

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FINDING 0F NO SIGNIFICANT IMPACT:

Based upon the foregoing 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 exemption.

For further details with respect to this action, see the request for exemption submittal dated July 10, 1987 which is available for public inspection at the Commission's Public Document Room,1717 H Street, N.W., Washington, D.C. 205S5, and at the local public document room located at the Russell' Library, 123 Broad Street, Middletown, Connecticut 06457.

Dated at Bethesda, Maryland, this 5th day of October,1987.

FOR THE NUCLEAR REGULATORY COMMISSION Y0 WW "

Cecil 0. Thomas, Director Integrated Safety Assessment Project Directorate Division of Reactor Projects III/IV/V and Special Projects l

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