ML20236D235

Exemption from Requirements of App J to 10CFR50,Paragraph III.A.3 to Allow Use of Mass Point Method as Provided in Ansi/Ans 56.8-1981 to Calculate Containment Leakage

ML20236D235
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/15/1987
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	CONNECTICUT YANKEE ATOMIC POWER CO.
Shared Package
ML20236D226	List: ML20236D224 ML20236D235 ML20236D242
References
NUDOCS 8710280081
Download: ML20236D235 (5)

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UNITED' STATES OF AMERICA I I

NUCLEAR REGULATORY COMMISSION J d

In the Matter of ~ )

CONNECTICUT. YANKEE ATOMIC Docket No. 50-213 POWER COMPANY. ) .

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Haddam Neck Plant )

'I EXEMPTION '

. I. t The Connecticut Yankee Atomic power Company (CYAPC0, the Licensee) is the holder.of Operating License No. DPR-61 which authorizes operation of the Haddam '

Neck Plant (the facility) at the steady-state power levels not in excess of 1825 megawatts thermal. The license provides, among other things, that the  !

Haddam Neck Plant'is subject to all rules, regulations, and Orders of the i Conmission now'or hereafter in effect.  !

The plant is a single-unit pressurized water reactor at the licensee's i

site located in Middlesex County, Connecticut.

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The Code of Federal Regulations,10 CFR 50.54(o), specifies that primary reactor containments for vater-cooled power reactors shall comply with Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." Paragraph III.A.3 of Appendix J incorporates by reference the American National Standard (ANSI) N45.4-1972, " Leakage Rate Testing of Containment Structures for Nuclear Reactors." This standard requires that 8710280001 B71015 PDR P

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1 containment leakage: calculations-for Containment Integrated Leakage Rate Tests. .l

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. (CILRTs). be performed usin[:. either the Point-to-Point method or the Total Time method.  !'

A'more recent standard, ANSI /ANS 56.8-1981, " Containment System Leakage- }

Testing," which was' intended to replace ANSI N45.4-1972, specifies the use of-the Mass Point method to the exclusion of ~the two older methods. l A' proposed '!

revision to Appendix J, which has.been published for public comment (51 FR 39538, dated October 29,.1986), refers to a proposed Regulatory Guide (MS 021-5, Cetober 1986), which endorses, with certain exceptions, the ANSI /ANS 56.8-1981 standard.

Pending approval of the revision to Appendix J, which would permit the Mass Point

' analysis, licensees'who wish to use the Mass Point technique must submit an ap' plication for. exemption from the requirement that Appendix J test calculations j for CILRTs will conform with ANSI N45.4-1972. 1 l l III.

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By letter datad July:10, 1987, the licensee requested an exemption from 10 CFR Part 50, Appendix J. Paragraph III.A.3, which requires that all CILRTs be performed in accordance with ANSI N45.4-1972, " Leakage Rate Testing of Containment Structures for Nuclear Reactors." ANSI N45.4-1972 requires that leakage calculations be performed using either the Total Time method or the Point-to-Point method. The licensee has stated in support of the application

- for exemption from Appendix J that the Mass Point method is a more accurate method of calculating containment leakage. l l

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I It has been recognized by the professional communit) :: hat the Mau Point method is superior to the two other methods, Point-to-Point and Total Time, which are referenced in ANSI N45.4-1972 and endorsed by the present

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regulations. The Mass Point method calculates the air nass at each point in l time, and plots it against time. A linear repression lin, is plotted through the mass-time points using a least square fit. The slope-of this line is the leakage rate.

Draf t Regulatory Guide MS 021-5, which was published for comment in 1 October 1986, endorses, with exceptions, the ANSI /ANS 56.8-1981 standard and j

the Mass Point Method.

In addition to the method of calculation, consideration of the length of the test should also be included in the overall program. In accordance with 3

Section 7.6 of ANSI N45.4-1972, a test duration less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is only allowed if approved by the NRC staff, and the only currently approved ,

i methodology for such a test is contained in Bechtel Topical Report BN-TOP-), j Revision 1, " Testing Criteria for Integrated Leakage Rate Testing of Primary Containment Structures for Nuclear Power Plants," dated November 1, 1972. l This approach only allows use of the Tntal Time method. Therefore, tre staff will condition the exemption to require a minimum test duration of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the Mass Point method is used.

The licensee's letter also submitted information to identify the special circumstances for granting this exemptinn for the Haddam Neck Plant pursuant to 10 CFR 50.12. The purpose of Appendix J to 10 CFR Part 50 is to assure that containment leak-tight integrity can be verified periodically throughout the service lifetime so es to maintain containment leakage within the limit

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7590-01' l specified in the plant. technical specifications. The underlying purpose of

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the rule specifying particular methods for calculating ' leakage rates is to assure- that accurate and conservative methods are used to assess the results of containment leak rate tests. As set forth above, the Mass Point method has been a widely used method providing accurate results and the staff has determined that this method of calculating leakage satisfies the purpose' of the rule. i Based on the above discussion, the licensee's proposed exemption from paragraph III.A.3 of Appendix J, to allow we of the Mass Point method as  !

i requested in the submittal dated July 10, 1987, is acceptable with the condition of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> minimum test duration, until such provision of Appendix'J is modified. Thereafter, the licensee shall comply with the provisions of such rule (or may renew its request for exemption). The exemption applies. i only to the. method of calculating leakage by use of the Mass Point method and ,

not to any other aspects of the tests.

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4 Accordingly, the Commission has determined that, pursuant to 10 CFR Part l i

50.12, this exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. The Commission has further determined that special circumstances, as set forth in 10 CFR 50.12(1)(2)(11), are present justifying the exemption, namely that application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. Accordingly, the Commission hereby grants an exemption as described in Section III above from l

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.l paragraph III.A.3 of Appendix J to the extent that the Mass Point method may be used for containment leakage ~ rate calculations, provided it is used with a minimum test duration of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The exemption is granted until such

-provision'of Appendix J is modified.. Thereafter, the licensee shall comply with.the provisions of such rule. The exemption-applies only to the method of i calculating leakage by use of the Mass Point method and not any other aspects 'I 1

of the tests. 'l Pursuant to 10 CFR 51.32, the Commission has determined that-the granting-of this' exemption will have no significant impact on the environment (52 FR 38026 , October 13,1987).

This exemption is effective upon issuance.

FOR THE NUCLEAR REGULATORY COMMISSION 3

l nn . 6h . 1 e or .i Division of Reactor Proj 'ts III, IV, V l and Special Projects l Dated at Bethesda, Maryland this l15th day of October,1987 l

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