ML20235T133

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

ML20235T133
Person / Time
Site:	Millstone
Issue date:	10/05/1987
From:	Thomas C Office of Nuclear Reactor Regulation
To:
Shared Package
ML20235T067	List: ML20235T064 ML20235T133
References
NUDOCS 8710090270
Download: ML20235T133 (4)

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7590-01 j

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l UNITED STATES NUCLEAR REGULATORY COMMISSION I

NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET N0. 50-245 NOTICE OF ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT

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The U. S. Nuclear Regulatory Commission (the Commission) is considering I

issuance of an exemption from the requirements of Appendix J to 10 CFR Part 50 to Northeast Nuclear Energy Company (the licensee) for the Millstone Nuclear l

Station, Unit No. 1, located at the licensee's site in New London County, Connecticut.

ENVIRONMENTAL ASSESSMENT l

Identificatic, 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 j

requirements for primary containment leakage testing and incorporated by reference, ANSI N45.4-1972, " Leakage Rate Testing of Containment Structures

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for Nuclear Reactors." This standard requires that containment leakage calculations be performed by using either the point-to-point method or the l

total time method. The total time method was used the most by the nuclear I

industry until about 1976.

8710090270 871005 PDR ADOCK 05000245 P

PDR

a i 7590-01 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 by the licensee i

would be granted until pending changes to Appendix J become effective. The j

1 exemption applies only to the method of calculating containment leakage.

In the l

mass-point method, the mass of air in containment is calculated and plotted as

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a function of time and leakage is calculated from the slope of the linear least l

squa res.

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With the present developments in technology, the mass-point method has gained increasing recognition.

The superiority of the mass-point method becomes apparent when it is compared with the two other methods.

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 I

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 I

beginning of the test and the air mass at the end of the test expressed as a percent-age 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 calcu-1cted on the basis of the difference in mass between two measurements taken at the I

beginning anct 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.

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

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The Need for the Proposed Action:

The exemption is needed to allow continued use of the mass-point analysis method at Millstone Unit No. 1.

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 erraticism of the total time method creates a higher probability of l

l 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.

Thus, 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 Commission concludes that there are no significant radiological or non-radiological environmental impacts l

associated vith the proposed exemption.

Alternative to the Proposed Action:

It has been concluded that there is no measurable impact associated with the proposed exemption; any alternatives to 1

the exemption will have either no environmental impact or greater environmental l

impact.

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

1 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.

4 FINDING OF NO SIGNIFICANT IMPACT:

Based upon the foregeing environmental assessment, the Commission concluded 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 l

Commission's Public Document Room, 1717 H Street, N.W., Washington, D.C. 20555, and at the local public document room located at the Waterford Public Library, Rope I

I Ferry Road, Route 156, Waterford, Connecticut 06385.

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

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FOR THE NULCEAR REGULATORY COMMISSION l

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'A. 0 JWe Cecil 0. Thomas, Director Integrated Safety Assessment Project Directorate l

Division of Reactor Projects III/IV/V and Special Projects 1

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