ML20207H020

Safety Evaluation Supporting Amend 121 to License NPF-62

ML20207H020
Person / Time
Site:	Clinton
Issue date:	03/08/1999
From:	NRC (Affiliation Not Assigned)
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ML20207H019	List: ML20207H020
References
NUDOCS 9903120225
Download: ML20207H020 (4)

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066 0001 e

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L SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

' RELATED TO AMENDMENT NO.1211O FACILITY OPERATING LICENSE NO. NPF-62 ILLINOIS POWER COMPANY i

CLINTON POWER STATION. UNIT 1

'l DOCKET NO. 50-461

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1.0 INTRODUCTION

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l By letter dated October 5,1998, the licensee for the Clinton Power Station submitted an application to amend the operating license. The proposed amendment would extend the interval

. for the next local leakage rate test (Appendix J, Type C test) for the containment isolation valves (CIVs) in the reactor pressure vessel head spray line, until the seventh refueling outage (RF-7).

The plant is currently in its sixth refueling outage (RF-6). This would require an exception to be taken from the guidelines of Regulatory Guide 1.163, " Performance Dased Containment Leak

. Test Program," dated September 1995, which govem the Primary Containment Leakage Rate Testing Program in accordance with Technical Specification (TS) 5.5.13.

i 2.0 DACKGROUND On September 26,1995, the NRC published a revision to 10 CFR Part 50, Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." The revision added i

Option B, " Performance-Based Requirements," to Appendix J to allow licensees to voluntarily replace the prescriptive testing requirements of Appendix J with testing requirements based on

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both overall and individual component leakage rate performance.

Regulatory Guide 1.163, " Performance-Based Containment Leak Test Program," dated September 1995, was developed as a method acceptable to the NRC staff for implementing Option B. This regulatory guide states that the Nuclear Energy Institute (NEI) guidance document NEl 94-01, Rev. O, " Industry Guideline for implementing Performance-Based Option of 10 CFR Part 50, Appendix J," provides methods ' acceptable to the NRC staff for complying with Option B with four exceptions which are described therein.

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Option B requires that Regulatory Guide 1.163 or another implementation document used by a licensee to develcp a performance-based leakage testing program must be included, by general reference, in the plant TS. The licensee has referenced Regulatory Guide 1.163 in TS 5.5.13.

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-In the case of the CIVs in the reactor pressure vessel head spray line (containment penetration 1MC-042), Regulatory Guide 1.163, through NEl 94-01, allows a nominal 30-month test 1

Interval. It further allows an increasa in the test interval to 60 months if a CIV has shown good pelformance. " Good pelformance" is achieved when the CIV passes its two most recent as-

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found Type C tests.' "As-found" testing means testing before any repa!rs, adjustments, or j

replacements are made.

i There are four CIVs in containment penetration 1 MC-042, designated 1 E12-F061,1 E12-F023, 1E51-FC13, and 1E51-F391. Due to the piping configuration at the penetration, the four valves are tested as a group.' Although the testig history of these valves is excellent, one of the valves,1E12-F023, was adjusted during AF-5 without brat being given an as-found test. At the j

time, which was before Appendix J was revised, there was no requirement for an as-found test.

Thus, this one valve has passed one, but not two, consecutive as-found tests, and has to stay

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on a 30-month test interval. Due to the group-testing configuration, the licensee is seeking -

l relief for the whole penetration, even though only one valve needs it.

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RF-6 has lested more than 2 years and is still on-going. Containment penetration 1MC-042 i

was tested early in the outage, on December 8,1996. Due to a lack of block valves and test, vent, and drain connecti^ns in the penetration, the testing is done by disassembling the head 3

spray piping and install.ng a blind flange. This can readily be done only while the drywell head

' is off and the reactor cavity pool is drained. As the licensee did not expect such a long delay in restarting the plant, the piping has long since been reassembled and the drywell closed up.

Now, the 30-month test interval will expire before the next refueling outage is reached, and the licensee must either retest now or shut down during the next fuel cycle especially to run the test, absent granting of the requested relief. Testing in the normal manner, c!ther now or during j

the next fuel cycle, would require a significant expenditure in time, money, and radiation 3

exposure, without, the licensee asserts, a significant improvement in safety.

3.0 ALTERNATIVES 2

The licensee has considered several attemative approaches to conducting the test without i

disassembling equipment as it normally does; these are detailed in the submittal, and -

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- summarized below.

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1) Applying a freeze seal This approach has several disadvantages. The pipe must be cooled below its brittle I

transition temperature and temporary supports must be installed to keep it immobile during the test. Also, experience has shown that freeze seals do not work well and

- sometimes air will leak past them,~ which could fail a leakage rate test unfairly. Finally, considerable time and expense would be involved.

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2) Flooding the reactor vessel Although this can establish a test boundary to be pressurized for the test, it would s

Include several additional valves not normally included in the test boundary. Their 1

i leakage could potentially make the test appear to fall, aven though the CIVs might leak j

very little. Further, this complex evolution would be time-consuming and expensive.

3) installing a blind flange with the piping in place I

Due to the cramped space with the drywell head in place, and the radiation present, it o

. would be difficult and dangerous to attempt this approach, not to mention costly.

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4.0 EVALUATION l'

First, three of the four CIVs in containment penetration 1MC-042 have passed their last two l

consecutive as found tests and qualify for a 60-month test interval, so they de '1ot, in fact, need j

any relief. Second, the remaining valve, along with the other valves, has an excellent testing history. In RF-4, -5, and -6, the valves never leaked more than 1% of their allowable j

administrative limit, either as-found or as-left. Third, in the one case where valve 1 E12-F023 i

. was adjusted without first being tested in the as found condition, the licensee's records indicate i

that it was scheduled maintenance and testing and there was no indication that the valve was leaking excessively in its as-found state. The as-left leakage rate, as stated before, was less than 1% of the allowable. Finally, the most recent tests for these valves, in RF-6, were as-3 j-found tests and they passed easily, with leakage rates, again, less than 1% of allowable, i.

Based on the above, the staff finds that deferring the leakage rate testing of containment

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- penetration 1MC-042 until RF-7 will not negatively _ impact containment integrity; and therefore, i

the change is acceptable.

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5.0 STATE CONSULTATION

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4 In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of the amendment. ' The State official had no comments.

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6.0 ENVIRONMENTAL CONSIDERATION

L This amendment changes a surveillance requirement of a facility component located within the

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restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in indMdual or cumulative occupational radiation exposure. The Commission has previously j

issued a proposed finding that the amendment involves no significant hazards consideration

' and there has been no public comment on such finding (63 FR 56949). Accbrdingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the

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4 7.0' CONCLUSION The staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by

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operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the

- common defense and security or to the health and safety of the public.

Principal Contributor: J. Pulsipher Date: Nrch 8,1999 i

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