ML20046C679

Exemption from Requirements in Section III.A.6(b) of App J to 10CFR50 Re Accelerated Test Frequency

ML20046C679
Person / Time
Site:	Sequoyah
Issue date:	07/23/1993
From:	Varga S Office of Nuclear Reactor Regulation
To:	TENNESSEE VALLEY AUTHORITY
Shared Package
ML20046C680	List: ML20046C679
References
NUDOCS 9308110356
Download: ML20046C679 (6)

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION j

t In the Matter of

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TENNESSEE VALLEY AUTHORITY

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Docket No. 50-328 i

i (Sequoyah Nuclear Plant, Unit 2)

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EXEMPTION

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1.

i The Tennessee Valley Authority (TVA) is the holder of Facility Operating j

License No. DPR-79, which authorizes operation of the Sequoyah Nuclear Plant, Unit 2 (the facility,' Unit 2).

The facility consists of a-pressurized water reactor located on TVA's Sequoyah site in Hamilton County, Tennessee.

y The license provides, among other things, that the facility is subject to all t

rules, regulations, and orders of the Nuclear Regulatory Commission (the

-i Commission) now or hereafter in effect.

II.

Section III.A.6(b) of Appendix J to 10 CFR Part 50 requires that if two-consecutive Type A tests fail to meet the applicable acceptance criteria, a Type A test shall be conducted at each refueling outage.

This increased testing frequency would continue until two consecutive Type A tests meet the.

acceptance' criteria, after which time the normal retest. frequency of three Type' A tests at approximately equal intervals within each 10-year service j

period would resume.

The approximately equal intervals are defined in i

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Surveillance Requirement 4.6.1.2.a of the Sequoyah Technical Specifications (TSs) 2.s 40 10 months.

Type A tests are tests of the primary reactor containment to measure the expected overall integrated leakage-rate of the containment for the loss-of-coolant accident conditions.

The action would exempt the licensee from the provisions in Section Ill.A.6(b) of Appendix J with respect to the requirement to accelerate the i

Type A frequency if there have been two consecutive failures of Appendix J containment Type A tests.

If two consecutive Type A tests fail to f

meet the acceptance criteria of 0.75 La, a Type A test must be performed at each refueling outage until two consecutive Type A tests meet the acceptance criteria.

Thereafter, the test frequency in Section !!I.D of Appendix J, which requires performing three Type A tests at approximately equal intervals during each 10-year service period, may resume.

The exemption would relax the f

acceleration of the Type A test frequency and the requirement to perform a i

Type A test during the Unit 2 Cycle 6 refueling outage scheduled for fall of 1993.

If this exemption is granted, the next scheduled Type A test would be t

performed during the Cycle 7 refueling outage currently scheduled for April i

1995.

4 The applicable acceptance criteria per 10 CFR 50, Appendix J. Section i

III.A.5.(b)(2) is 0,75 times the allowable leakage (La), which results in a f

limit of 0.1875 percent-per-day. At Unit 2, the licensee conducted Type A 1

tests during the pre-operational testing in 1981, and refueling outages in l

November 1984 (Cycle 2), March 1989 (Cycle 3), and April 1992 (Cycle 5). The cause of the Cycle 2 and Cycle 3 Type A leak tests exceeding the acceptance criteria of 0.75 La was packing leakage from two outboard roct valves on two I

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3 containment pressure sensing lines.

Repairs were performed and, after due consideration, the staff granted an exemption from performing a test i

during Cycle 4 by letter dated August 27, 1990.

As a result of the Type A test performed during the Cycle 5 refueling outage, the measured leakage rate was again found to exceed the acceptance criteria of 0.75 La.

This failure resulted when the leakage from the local leak rate test of valve 2-FCV-61-191 (which is attached to glycol Penetration X-47A) was added into the result of the Type A test that was performed during the outage.

The leakage was caused by a small nut that was found under the i

valve stem nut on the outboard valve, which prevented the valve from going ~

fully closed.

(lhe nut was from unrelated work in the vicinity of the valve).

following removal of the loose nut, lubrication of the valve stem, and cycling of the valve several times, the local leak test was re-performed.

No measured f

leakage was found.

It could not be determined which action, removal of the foreign material that prevented full valve closure or sticking of the ' valve stem (or both), corrected the problem.

Corrective measures that have been adopted to prevent recurrence of the problem include a monthly inspection of the glycol valves for foreign material and monthly lubrication of the valve stems.

The history of the results of Type A tests conducted at Unit 2 is summarized as follows:

As-found 0.75 La 1.0 La l

Type A Tests teak Rate Limit Limit Performed (X pec day)

(% per day)

(% per day)

Status Preop Test 0.14 0.18/5 0.25 pass Cycle 2 (1984) 0.22 0.1875 0.25 fail Cycle 3 (1989) 0.22 0,1875 0.25 fail Cycle 5 (1992) 0.42 0.1875 0.25 fail

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The staff has reviewed the licensee's submittal and agrees with the licensee that the root cause of the previous Type A test failures was excessive leakage from a single component in the pressurization boundary, and that a general containment leakage problem does not exist. Once the component was repaired, the retest confirmed the adequacy of the repair.

In addition, corrective actions have been implemented to prevent future test failures, and the corrective actions taken on the two previous Type A test failures have been effective since they are unrelated to the leakage through Penetrat on X-47A.

The staff agrees with the licensee that failures of this type are random and that the leakage that caused the 1992 test failure can best be addressed though the alternative corrective actions rather than increasing the-frequency of performing a Type A test.

Therefore, the staff concludes that performing future Type A testing on an accelerated schedule would serve no technical purpose and the requested exemption has no significant impact on containment integrity.

Pursuant to 10 CFR 50.12(a)(2)(ii), the staff agrees that application of the regulation is not necessary to achieve the underlying purpose of the rule and that the requested exemption should be granted.

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Ill.

Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), 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 further determines that special circumstances, as provided in 10 CFR 50.12(a)(2)(ii), are present justifying the exemption; i

namely, that the application of the regulation in the particular circumstances for Unit T in U e Cycle 6 refueling outage would not serve, and is not

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5 necessary, to achieve the underlying purpose of the rule.

The application of 1

I the regulation is not necessary to assure the integrity of the containment in j

the event of a postulated design basis loss-of-coolant accident.

i Accordingly, the Commission hereby grants an exemption from Section j

i llI. A.6(b) of Appendix J to 10 CFR Part 50 for Sequoyah Unit 2.

j Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this Exemption will have no significant impact on the environment

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(55 FR 21602).

t For further details with respect to this action, see the request for I

exemption dated January'7,1993, which is available for public inspection at l

the Commission's Public Document Room, Gelman Building, 2120 L Street, N.W.,

j Washington, D.C., and at the Chattanooga-Hamilton County Library, 1001 Broad Street, Chattanooga, Tennessee 37402, i

This exemption is effective upon issuance.

6 FOR THE NUCLEAR REGULATORY COMMISSION i

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Division of Reactor Proje

+s - 1/II Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 23rd day.of. July 1993 o

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5 necessary, to achieve the underlying purpose of the rule.

The application of the regulation is not necessary to assure the integrity of the containment in the event of a postulated design basis loss-of-coolant accident.

Accordingly, the Commission hereby grants an exemption from Section III.A.6(b) of Appendix J to 10 CFR Part 50 for Sequoyah Unit 2.

Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this Exemption will have no significant impact on the enviror. ment (55 FR 21602).

For further details with respect to this action, see the request for exemption dated January 7,1993, which is available for public inspection at the Commission's Public Document Room, Gelman Building, 2120 L Street, N.W.,

Washington, D.C., and at the Chattanooga-Hamilton County Library, 1001 Broad Street, Chattanooga, Tennessee 37402..

This exemption is effective upon issuance.

FOR THE NUCLEAR REGULATORY COMMISSION original signed by:

Steven A. Varga, Director Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 23rd day of July 1993 OGC on_Let ter Onl y n,

M OFFICE PDII-4/LA PDIl-4/PM r PDIIq4/D AhfRII DRPE:Q NAME MSandersIh.f DLaBarge Ffh o'n Gl[ bas h

DATE h/(p/93 f/6/93 7 /02/93

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DOCUMENT NAME: SQN\\85310,LlR

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