ML20205E007
| ML20205E007 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/21/1988 |
| From: | Stefano J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20205E013 | List: |
| References | |
| NUDOCS 8810270278 | |
| Download: ML20205E007 (4) | |
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7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION CONSUMERS POWER COMPANY PALISADES PLANT 00LKET NO. 50-255 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U. S. Nuclear Regulatory Commission (the Commission) is considering issuance of an exereption from the requirements of Appendix J to 10 CFR Part 50 to Consumers Power Company (the licensee) for the Palisades Plant, located in Van Buren County, Michigan.
ENVIRONMENTAL ASSESSMENT Identificatien of Proposed Action:
The licenset requested an exemption from Paragraph III.A.
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 incorporated, 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.
Tne Total Time method was used tSe most by the nuclear industry until about 1976.
'At this time, licensees who wish to use the Mass-Point method of calculating containment integrated leakage must sut,mit 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 woult. Le granted until pending changes to Appendix J are promulgated.
In the Mass-Point method, 32A 2nsu 8268Hp P
.g.
the mass of air in containment is calculated and plotted as a function of time, and 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.
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 reasen (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 percentage of the cc,ntainment 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 and bases for exemption are contained in a letter dated September 9, 1988, as supplemented by letter dated September 16, 1988.
The exemption would permit the licensee to use the Mass-Point method for calculating containment leakage rates as an acceptcble alternative to the Point-to-Point and Total Time methods currently specified in Appendix J.
The Need for the Proposed Action:
The proposed exemption is needed to allow use of the Mass-Point analysis
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method at Palisades Plant and for improved analysis of the test results.
Environmental Impacts of the Proposed Action:
The erraticism of 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.
Radiological releaser will not be greater than previously determined, por does the proposed exemption otherwise affect radiological plant effluents, or have any other environmental impact.
Therefore, the Commission concludes that there are no measurable radiological or nonradiological environmental impacts associated with the proposed exemption.
Alternativo to the Proposed Action:
The Commission has 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 impact.
1 Alternative Use of Resources:
This action does not involve the use of any resources beyond the scope of resources used during normal plant operation, which have been considered
(
previously by the Commission in the Final Environmental Statement dated June 1972.
Agencies and Persons Consulted:
)
The Commission's staff reviewed the licensee's request that supports the proposed exemption.
The staff did not consult othe agencies or persons, l
i
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FINDING OF NO SIGNIFICANT IMPACT Based upon the foregoing environmental assessment, the Comission concludes that.the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the Comission 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 the exemptien dated September 9,1988, as supplemented by letter dated which is available fet public inspection at the Corriission's Septec<be r 16, 1988,
^
s Public Document Room, 2120 L Street, NW., Washington, DC, 20555 and at the Van.
Zoeren Library, Hope College, Holland, liichigan 49423.
Dated at Rockville, Maryland, this 21st day of October 1988.
FOR THE i:UCLEAR REGULATORY COPJ11SS10N icbn '. S fano, Acting 0 r ctor
/ Proje t Di. ecto te Ill-
{Div ion ou R tor Proj s - III IV, Y
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