ML20245J012

Safety Evaluation Accepting Extension of Surveillance Intervals

ML20245J012
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	08/14/1989
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20245H969	List: ML20245H965 ML20245J008 ML20245J012
References
NUDOCS 8908170425
Download: ML20245J012 (4)

Text

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UNITED STATES y y 3.'f j.

NUCLEAR REGULATORY COMMISSION f

W ASHINGTON, D. C. 20555

h' Gfl g.. '...,,e SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FACILITY OPERATION LICENSE NO. DPR-61 CONNECTICUT YANKEE ATOMIC POWER COMPANY i

HADDAM NECK PLANT DOCKET NO. 50-213 INTRODUCTION l

By letter deted April 26, 1989, Connecticut Yankee Atomic Power Company (CYAPC0/ Licensee) requested a schedular exemption from the requirements of 10 CFR 50, Appendix J. Sections III.A.6.(b), " Additional Requirements-Type A Test,"

III.D.2(a), " Type B test" and III.D.3. " Type C test." CYAPC0 has proposed to extend the test. period for the Type A, B and C test till the refueling outage scheduled to begin September 5, 1989. This would be approximately a 6 month extension for the Type A test and approximately a 2 month extension for the Type B and C tests. These exemptions are necessary to prevent a midcycle shutdown to perform the Type A, B and C test, j

DISCUSSION I)

Section III.A.6.(b) of 10 CFR 50, Appendix J, requires that:

"If two consecutive periodic Type A tests fail to meet the applicable ecceptance criteria in III.A.S.(b), notwithstanding the periodic retest schedule of III.D., a Type A test shall be performed at each plant shutdown for refueling or approximately every 18 months, whichever occurs first, until two consecutive Type A tests meet the acceptance criteria in III.A.5(b), after which time the retest schedule specified in III.D. may I

be resumed."

Because of two consecutive failures of the Type A test, CYAPCO conducted a Type A penalty test on September 27, 1987, and failed the "as-found" acceptance criteria. According to the provisions of Section III.A.6.(b),

the next scheduled test should occur on April 27, 1989. CYAPCO's next refueling outage is scheduled for September 5,1989, and the integrated leak rate test (ILRT) itself will not start until October 1989. The start date for the outage is due to the extension of the 1937 refueling outage into April of 1988 to repair the core barrel and thermal shield. The 1989 l

ILRT retest date would exceed Appendix J's 18-month requirement by j

approximately 6 months.

1 8908170423 g999y4 DR ADOCK 03000213 FDC

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. A review of the 1987 Type A test results indicates that the "as-left" condition of the containment satisfactorily met the requirements of Appendix J.

However, as in 1986, the 1987 "as-found" ILRT did not meet the acceptance requirements and was deemed a failure. The cause for the 1986 and 1987 "as-found" ILRT failures was due to excessive Type C leakages.

2)

Section III.D.2.(a) of 10 CFR 50, Appendix J, requires that:

" Type B tests, except tests for air locks, shall be performed during reactor shutdown for refueling or other convenient intervals but in no case at intervals greater than 2 years."

CYAPCO's Type B local leak rate test (LLRT) leakage has historically not been a source of significant "as-found" leakage (less than 50 lbm/ day).

The exemption is necessary to prevent a midcycle shutdown and allow the test to be performed during the 1989 refueling outage.

3)

Section III.D.3 of 10 CFR 50, Appendix J, requires that:

" Type C tests shall be performed during each reactor shutdown for refueling but in no case at intervals greater than 2 years."

CYAPC0 requests a schedular exemption be granted because the next scheduled refueling outage will exceed the provision of this requirement July 18, 1989. '

Currently this testing would be required by by approximately 2 months.

CYAPCO's Type C LLRT test program continues to undergo significant changes and improvements.

CYAPCO contends that these efforts to reduce Type C leakage are sufficient to allow the 2-year test interval to be exceeded by approximately 2 months and still meet the intent of Appendix J.

EVALUATION By letter dated April 26, 1989 CYAPCO requested a schedular exemption from the requirements of 10 CFR 50, Appendix J, Type A, B and C test, so as to extend the testing period for these tests to the next refueling outage. This request for exemption, if granted, would exceed the Type A test period by approximately 6 months and the Type B and C period by approximately 2 months. The evaluation of the Type A, B and C test are provided below:

Type A Test The Haddam Neck Plant has failed three consecutive "as found" integrated leak rate tests. After the second failure in 1986, CYAPC0 was required by Appendix J to increase the testing frequency for the ILRT from three times in 10 years to once per outage until two consecutive "as found" tests are acceptable. Therefore, this will be Haddam Neck's fifth ILRT since 1980.

In addition CYAPCO perfomed e full pressure ILRT during the 1987 outage for the first time since the preoperational test in 1968. CYAPC0 has agreed to continue the full pressurc ILRTs. The NRC staff believes the full pressure ILRTs will provide more accurate leak rate data than the previous lower pressure ILRTs which required the leak rates to be extrapolated to the full pressure.

4 CYAPCD has stated that the cause for the "as found" ILRT failures has been due

- exclusively to Type C leakages. As such CYAPC0 has increased its efforts to minimize Type C leakage. These efforts have included:

1).

Improving test procedures and methods, 2)

Making modifications to penetrations of poor performers, 3)

Making modifications to Service Water System to limit silt, 4)-

Conducting supplemental Type C test, and 5)

Pursuing an enhanced testing and maintenance program to identify, test, repair and reduce containment leakage.

CYAPC0 in their submittal dated April 26, 1989 provided a list of the corrective actions performed to date.

The NRC staff has reviewed CYAPCO's submittal and concluded that it would be acceptable to extend the Type A test period for approximately 6 months. The NRC staff's conclusion is based on the following:

1)

The "as found" failure of the ILRT has been due to excessive Type C leakage. As such CYAPC0 has taken aggressive actions to improve the Type C leakages. The NRC staff has reviewed these actions and agrees these actions should improve leakage through historically poor penetrations and provide CYAPC0 a method to detect and focus its attention on future bad performers.

2)

During the last refueling outage unexpected core barrel and thermal shield repairs extended the outage several months. During this time of approximately 6 months plent components were not exposed to the normal operating temperature, pressure and radiation conditions. The time interval of 18 months specified in Appendix J was based, in part, on the expected degradation of components exposed to the environment resulting from a full 18 months of nonnal pltat operations. The total exposure time for the containment to normal plant operation environment at Haddam Neck Plant will be about 15 months.

Therefore, the staff would expect that the containment integrity will be maintained during the extension of the test period.

Type B and C Test 1

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The staff has reviewed the information provided in CYAPCO's letter dated April 26, 1989 and has concluded that it would be acceptable to extend the required Type B and C test approximately 2 months. The NRC staff's conclusion that the Type B and C test for Haddam Neck Plant can be extended for approximately 2 months without presenting a significant safety concern is based on the following:

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l 1)

During the last refueling outage unexpected core barrel and thermal shield repairs extended the outage several months. During this time of approximately six months plant components were not exposed to the nomal operatino j

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temperature, pressure, and radiation conditions. The time interval of 24 months specified in Appendix.J for Type B and C. tests was based, in part, on the expected degradation of components exposed to the environment resulting from a full 24 months of normal plant operations. The total exposure time for the containment penetrations to the normal plant operating environment at Haddam Neck will be about 20 months, including the time period involved in the extension.

2)

CYAPC0 has taken aggressive actions to improve Type C leakage. Type B leakege has historically not been a problem at the Haddam Neck site. ' As noted above,.these actions should decrease leakage through historically poor penetrations and provide CYAPC0 a method to detect and focus its attention on future bad performers.

3)

The 24 month interval requirement for Type B and C penetrations is intended to be often enough to prevent significant deterioration from occurring and long enough to permit the LLRTs to be performed during plant outages.

Leak testing of the penetrations during plant shutdown is preferable because of_ the lower radiation exposures to plant personnel.

Moreover, some penetrations, because of their intended functions, cannot be tested at power operation.

For penetrations that cannot be tested during power operation or those that, if tested during plant operation would cause a degradation in the overall safety (e.g., the closing of a redundant line in a safety system), the increase in confidence of containment integrity fcilowing a successful test is not significant enough to justify a plant shutdown specifically to perform the LLRTs within a 24 montt time period.

Based on the above review, the staff concludes that extending the surveillance intervals as described is acceptable.

Dated:

August 1.4,19B9 Principal Contributor:

A. Wang

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