ML20066J428

Exemption from Requirement in Section III.D.1(a) of App J to Allow 10-yr Inservice Insp to Be Scheduled Independently of ILRT 10-yr Svc Periods

ML20066J428
Person / Time
Site:	Sequoyah
Issue date:	01/29/1991
From:	Varga S Office of Nuclear Reactor Regulation
To:
Shared Package
ML20066J435	List: ML20066J428
References
NUDOCS 9101310250
Download: ML20066J428 (5)

Text

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION in the Matter of THE TENNESSEE VALLEY

> Docket No. 50-328 KdTHORITY (Sequoyah Nuclear Plant, Unit 2)

EXEMPTION 1.

The Tennessee Valley Authority (the licensee) is the holder of Facility Operating License No. DPR-79 which authorizes operation of the Sequoyah Nuclear Plant, Unit 2.

This license provides that, among other things, Unit 2 is subject to all rules, regulations, and orders of the Nuclear Regulatory Com-mission (Commission) now or hereafter in effect.

The Sequoyah Nuclear Plant, Unit 2, is one of the two pressurized water reactors located at the licensee's site in Hamilton County, Tennessee.

II.

General Design Criterion (GDC) 52 of Appendix A to 10 CFR Part 50 requires that each reactor containment be designed so that periodic integrated leakage rate testing can be conducted to assure containment isolation integrity.

Section 111.D.1(a) of Appendix J to 10 CFR Part 50 requires that the third Type A test in a 10-year service period shall be conducted when the unit is shut down for the 10-year unit inservice inspection (ISI).

The Type A tests are conducted to measure the primary reactor containment integrated leakage rate. They are also known as the containment integrated leak rate tests.

These tests are required by Appendix J to assure that the containment leakage following a large break loss-of-coolant accident is less -

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than the inaximum allowable leak rate assumed in the accident analysis.

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addition to the Type A tests, Appendix J requires Type B and Type C tests of j

leakage through containment penetrations and containment isolation valves to also assure containment integrity during an accident. This requested exemption does not affect the requirements on (1) the Type B and Type C tests in Appen-dix J or (2) the maximum allowed containment leakage rate in Appendix J and the Unit 2 Technical Specifications.

The containment is required to be operable when the unit is at reactor system conditions above cold shutdown and refueling. The containment is not required for cold shutdown or refueling.

By letter dated August 31, 1990, the licensee requested an exemption from the Type A testing requirements in Section III.D.1(a) of Appendix J.

This is an exemption from conducting the third Type A test in a 10-year service period during the unit shutdown for the 10-year inservice inspection (151). The third Type A test for the first 10-year service period for Unit 2 b wneduled for the Unit 2 Cycle 5 refueling outage in 1992. The licensee contends that, because the 10-year ISI has been extended beyond 1992, the inspection is not required for the Unit 2 Cycle 5 refueling outage and, therefore,.must be i

uncoupled from the third Type A test in each 10-year service period which is-1 l

required by Appendix J.

TVA stated that the third Type A test of the first 10-year service period for Unit 2 is presently scheduled to commence toward the end of the Unit 2 Cycle 5 refueling outage (i.e., May 1992).

It intends to conduct the Unit 2 10-year inservice inspection during the Unit 2 Cycle 6 refueling' outage (i.e.,-

l October-November 1993).

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t l and concludes it is justified on the grounds that the third Type A test within each 10-year service period and the 10-year ISI must be scheduled separately 1

for Unit 2 and the safe operation of Unit 2 does not require that the two tests be conducted in the same outage. The licensee is still required to conduct the Unit 210-year ISI. in accordance with Section XI of the ASME Code.

III.

Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, the exempticns are (1) authorized by lew, (2) vill not present an undue risk to public health and safety, and are (3) consistent with the common defense and secu ri ty. The Commission further determines that special circumstances, as provided in 10 CFR 50.12(a)(2)(ii), are present justifying the exemption --

narcly, that application of the reguletion in these particular circumstances is not necessary to achieve the underlying purpose of the rule in that the Unit 2 containment will continue to provirie a reliable and acceptable means of contain-ment isolation integrity within the leakage requirements of Appendix J and the i

Unit 2 Technical Specifications and the Unit 210-year ISI will still be conducted in accordance with the ASME Code.

When Appendix J was adopted, the end of the 10-year service period and the 10-year inservice inspection outage were contemplated to be cancurrent mile-stones; however, these milestones are unrelated within the meaning of con-tainment integrity because the 10-year ISI is not conducted to assure contain-ment integrity. The Tyra A, B, an' C tests of Appendix J assure containment integrity. The rule did not anticipate extended outages that would extend the 10-year ISI in accordance with the ASME Code. Appendix J requires that the Unit 210-year ISI be rescheduled +o coincide with the Unit 2 Cycle 5 refueling

i 1 4 The 10-year ISI is not related to the integrity of the containment pres-'

i sure boundary. The purpose of the Appendix J test program is to ensure that leakage through the primary reactor containment does not exceed allowable leakage rate values. The purpose of the ISI program is to ensure that struc-tural integrity of Class 1, 2, and 3 components is maintained in accordance with ASME Code requirements. Therefore, the proposed separation has no safety consequences because the requirements on containment integrity in Appendix J and the Unit 2 Technical Specifications, and on structural integrity of ass 1, 2, and 3 components in the ASME Code are not being changed by the proposed exemption.

The 10-year ISI is scheduled for the Unit 2 Cycle 6 refueling outage in 1993 in accordance with Section XI of the American Society of Mechanical Engineers (ASME)Codeandwith10CFR50.55a(g)(4). The first 10-year ISI for Unit 2 is, therefore, scheduled for a future refueling outage other than the upcoming Unit 2 Cycle 5 refueling outage which is scheduled for 1992. The extension of the 10-year ISI is necessary in order for the plant to accumulate sufficient operating time to conduct the 10-year ISI because of the extended 33-month outage of Unit 2 from 1985 to 1988.

In accordance with the prov'sion'.

ofSectionXI,ArticleIWA-2400(c),oftheASMECode,thelicenseeextended the Sequoyah Unit 2 10-year ISI to 1993.

(The Unit 110-year ISI was extended to 1994 because of the similar extended outage from 1985 to 1988.)

The ASME Code allows the 10-year ISI to be postponed if the time the plant has operated is significantly less than the 10-year inspection cycle which is true for Sequoyah because of its extended outage.

The staff has considered the Appendix ( exemption request for uncoupling-the third Type A test of each 10-year service period from the 10-year unit IL

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9 outage. The 10-year inservice inspection for Unit 2 it currently scheduled for 1993 in accordance with Section XI cf the ASME Code. d 10 CFR 50.55a(g)(4).

Performing the 10-year 151 carly and concurrent with the third Type' A test in a 10-year service period is not necessary to-' assure contairment isolation integrity and would;impore a hardship on the licensee with little or no 4

increase in the level of qua'lity or safety at Unit 2.

Accordingly, pursuant to 10 CFR 50.12(a)(2)(ii),' the Commission hereby grants an exemption frcr the requirements of Section III.D.1(a) of Appendix J.

j to 10 CFR Part 50 to the liccnsee for operation of-the Sequoyah Nuclear Plant, Unit 2, as described above. The Commission granted such an exemption for i

Unit 1 in its letter dated September 29,1989.

i Pursuant to 10 CFR 51.32, the-Commission has determined that the issuance of this exemption will have no significant:impace on-the environment. This was noticed in the Federal Register (56 FR3121

, January 28,1991).

1 For further details with respect to this action, see the request for exemption dated August 31, 1990, which is available for public inspection at the C0 scission's Public Document Room, Gelman Building, 2120 L Street, N.W.,

Washington, DC., and at the Chattanooga-Hamilter County Bicentennial Library, 1001 Broad Street, Chattanooga, Tennessee 37402.-

This exen.ption is effective upon issuance.

F0 THE NUCLEAR REGULATORY COMMISSION' k

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even A. Varga, Division of Reactor Pro c s - I/II Office of Nuclear Reactor egulation Dated at Rockville, Maryland this 29th day of January 1991 I

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