NUREG-0123, Safety Evaluation Supporting Amend 99 to License DPR-6

Safety Evaluation Supporting Amend 99 to License DPR-6

ML20245H249
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	07/31/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20245H227	List: NUREG-0123, Safety Evaluation Supporting Amend 99 to License DPR-6
References
RTR-NUREG-0123, RTR-NUREG-123 NUDOCS 8908160379
Download: ML20245H249 (3)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 7n

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 99 TO FACILITY OPERATING LICENSE NO. DPR-6 CONSUMERS POWER COMPANY BIG ROCK POINT PLANT DOCKET NO. 50-155

1.0 INTRODUCTION

By letters dated May 25, 1989 and June 30, 1989, Consumers Power Company.(the licensee) requested an a:nendment to the Technical Specifications (TS) appended to Facility Operating License No. DPR-6 for the Big Rock Point Plant. The proposed-amendment would change Sections 3.7(d), (e) and (f) to depict the  !

requirements of 10 CFR Part 50, Appendix J and NUREG -0123, Standard Technical Specifications for General Electric Boiling Water Reactors. This change removes the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> duration requirement to reduce the impact of diurnal effects by using an NRC approved " Total Tine" or Point-to-Point method described in ANSI N45.4-1972 and Bechtel Topical Report BN-TOP-1, Rev. 1.

The June 30 submittal corrected an inadvertent textual error in the proposed TS '

change and did not alter the action noticed in the Federal Register on June 28, 1989 or after the initial documentation.

2.0 DISCUSSION Big Rock Point has experienced diurnal effects during past integrated leak rate test (ILRT) when the test length spanned 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> causing the containment sphere to experience heating and cooling through the daylight to night time hours because of the Big Rock Point containment design. The Big Rock Point containment is a large (130 ft, diameter) sphere constructed of 3/4 inch plate steel. The exterior is covered by a thin layer of mastic and paint as a protector to the outside environs but provides minimal insulating value. This design inherently results in variation in containment temperatures due to variations in windspeed, i temperature, and percent overcast conditions. With the plant located on the '

shore of northern Lake Michigan, these variations can be very extreme during the summer months due to " lake-effect" cooling after dark.

Both the " Total Time" and Point-to-Point methods could allow a reduced duration to minimize the diurnal effects, upon subsequent NRC approval of the specific methodology. A leakage rate and upper bound 95% confidence limit can be accurately determined using these methods. ANSI N45.4-1972 allows a reduction in test length if those responsible for the acceptance of the containment structure are satisfied that an accurate test can be determined during a shorter test period. At this time only the methodology discussed in the Bechtel Topical Report, BN-TOP-1, Rev. 1, has been approved by the NRC.

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~2-This change also incorporates requirements of 10 CFR Part 50, Appendix J regarding test pressure, test intervals, and acceptance criteria.

i Section 3.7(d) has been modified to reflect the test frequency requirements of 1 10 CFR Part 50, Appendix J and the Standard Technical Specifications (STS).

This paragraph also requires that the test conform to the criteria specified in i Appendix J which explicitly addresses maintenance and the methods for inclusion  !

of pre-maintenance leakage rates into the overall containment acceptance criteria. The requirement for the twenty-four hour duration has been removed. l' Section (e) had contained the test frequency requirements which are now contained

_ in paragraph (d). Paragraph (e) will now contain leakage rate acceptance criteria and retest requirements in conformance with Appendix J and the STS.

Section (f) had contained retest requirements following ILRT failure. These are now addressed in Section (e). Paragraph (f) now includes the verification and accuracy requirements as specified by 10 CFR Part 50, Appendix J. Verification requirements did appear in paragraph (d) of the previous revision of the Big i Rock Point Technical Specifications but did not completely reflect the 10 CFR Part 50, Appendix J guidance.

3.0 EVALUATION We have reviewed the technical support furnished by the licensee for each of its proposed changes. Our evaluation for each of them follows in the same order in which they are listed in Section 2.0, Discussion above.

Paragraph (d) will now reflect the test frequency requirements of 10 CFR Part 50, Appridix J. Although this does not differ with the current Technical Specification, it now includes the tolerance band contained in NUREG-0123.

Explicit in thu maragraph is a requirement that methods used to perform the ILRT shall conform to the criteria specified in 10 CFR Part 50, Appendix J.

The twenty-four hour duration restriction has been removed. The NRC staff finds that Appendix J and the endorsed industry standards do permit integrated leak rate test durations of less than twenty-four hours providing the method described in Bechtel Topical Report BN-TOP-1, Rev. 1 is used. The recent change to 10 CFR Part 50, Appendix J (effective date 11/15/88) only requires a duration of at least twenty-four hours when the Mass Point method described in Standard ANSI /ANS 56.8-1987 is used. Appendix J endorsed American National Standards Institute N45.4-1972, " Leakage Rate Testing of Containment Structures for Nuclear Reactors" when utilizing the Total time or Point to Point methods. N45.4-1972 requires a twenty-four hour duration unless it can be demonstrated to the satisfaction of those responsible for acceptance of the containment structure that the leakage rate can be accurately determined during a shorter test period.

NRC review has concluded that the Bechtel Topical Report BF-TOP-1, Rev. 1, using the " Total Time" method is an acceptable method of implementing a shorter curation leakage test. Other methods utilizing a shorter duration have not been reviewed and approved for use at Big Rock Point.

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Previous paragraph (d) also placed limited restrictions on " repairs" which 2 has been removed. This is-justified since 10 CFR Part 50, Appendix J, Section III.A.(a) & (b) provides the requirements concerning maintenance of containment boundary components to insure that the containment can be tested in as close to the "as is" condition as practical.

Paragraph (e) contains the retest requirements-specified in 10 CFR Part 50, Appendix J, Section III.A.6.(a) & (b). Paragraph (d) and (f) of the previous Big Rock Point Technical Specification provided these retest requirements; thus, this change only restructures these requirements to provide clearer guidance.

Verification test and accuracy requirements previously discussed in paragraph I (d) of the Big Rock Point Technical Specification were outdated and did not fully represent the requirements of Appendix J. Paragraph (f) now requires the supplemental test requirements as specified in 10 CFR Part 50, Appendix J, q Section III.A.3.(b). j

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The staff finds that the proposed TS changes conform to the requirements of 10 l CFR Part 50, Appendix J and are acceptable.

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4.0 ENVIRONMENTAL CONSIDERATION

This amendment involves a change in the installation or use of a facility i component located within the restricted area as defined in 10 CFR Part 20 and a change to the surveillance requirement. The staff 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 3 there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that'this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this 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 environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

5.0 CONCLUSION

We have 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 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.

Date: July 31, 1989 Principal Contributor: Robert M. Pulsifer

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