ML20128C260
| ML20128C260 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/29/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20128C221 | List: |
| References | |
| NUDOCS 9302030365 | |
| Download: ML20128C260 (3) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION' g
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LAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 75 TO FACILITY OPERATING LICENSE NO. NPF-49 NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
til1LSTONE NUCLEAR P0CER STA110N. UNIT NO. 3 DOCKET N0. 50-423
1.0 INTRODUCTION
The Code of Federal Regulations in 10 CFR Part 50, Appendix J, Sections III.D.2(a) and III.D.3, specifies a periodic testing interval of not greater than 24 months for Type B and Type C containment local leak rate tests (LLRTs).
On January 22, 1991, and February 5, 1991, the licensee (Northeast Nuclear Energy Company) commenced the most recent containment LLRTs in accordance with the above Tyoe B and C periodic testing requirements, respectively, for the Millstone Unit No. 3 during the 1991 refueling outage.
As a result of an unusually long maintenance outage due to the service' water system work and erosion / corrosion work during 1991, and two limited duration outages in 1992, the licensee has rescheduled the next refueling outage from November 1992 to approximately September 1993. Accordingly, by letter dated November 18, 1992, the licensee requested a one-time schedular exemption for the LLRTs from the requirements of 10 CFR Part 50, Appendix J, Sections III.D.2(a) and III.D.3 to accommodate the above schedule change for the next refueling outage.
The request for exemption, if granted, would exceed the required Type B and C test interval by approximately 10 months.
In enother letter, also dated Nuvember 18, 1992, the licensee proposed Technical Specification (TS) changes to reflect the above cited exemption request.
The requested changes wc'.'ld change the Technical Specification surveillance requirements to extend the maximum interval between containment Type B and Type C tests from 'he present 24 months to 34 months for this fuel cycle only.
2.0 EVALUATION At Millstone Unit No. 3, there are 84 Type B penetrations which require Type B testing. Of the 84 penetrations, 80 are electrical penetrations which can be tested at power.
The licensee is conducting Type B testing of these penetrations and plans to complete the testing prior to January-22,1993.
Of the four remaining penetraticns, two penetrations (the equipment hatch and equipment batch manway) were tested on November 16, 1991 and January 28, 1992, respectively. The third penetration, the personnel air lock, is covered under TS Section 3.6.1.3 and is not the subject of this request.
The fuel transfer canal blind flange which was tested (Type B) on March 18, 1991, is the only penetration that cannot be tested at pcwer and will requ re an extension.
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} t There are 68 mechanical penetrations that require Type _C testing;: In Januaryi May and October 1992, while shut down,_ Type C-testing was-satisfactorily performed on 31 penetrations. This represents approximately 45 percent of.the; tctal Type C testing.
The exemption request is only for the remaining-penetrations (37) whose last Type C tests were_perforced during the last; refueling outage.
The licensee indicated that the total Type B and C leak' age as of October 31,:
1992, is 166,161.7 SCCM, which represents approximately 26.6 percent ~ of TS limit of 624,762.67 SCCM -(0.6 L ).
The total Type Bland C' bypass leakage-is 18,552.0 SCCM, which represents approximately 42.4 percent of TS limit,ofi 43,735 SCCM (0.042 L In addi'.1on,._the past LLRT data Hillstone Unit No. 3.).
, in general, has demonstrated good -l(eak rate-tist-Type'B and C)'a results.
Specifically, during the last refueling' outage, the total-Type-B and.
C leakage rate was 233,679.2 SCCH. This value is approximately 37.5 percent of the TS limit. The total bypass Type B and C leakage value was-approximately 17,810 SCCM, which is approximately 40.7 percent of the TS ~
limit The licensee further stated that the:last containment integrated 11eakageirate-test (ILRT) completed on July 7,1989, indicated that the "as-left"-ILRT.
leakage rate (the leakage rate for all potential paths. including Type B and CL penetrations) was 0.29 weight percent per day which is 44.6 percent of the TS limit of 0.65 weight percent per day (L overall leak-tightness of containment a,)d 'its protective. boundaries-is -, thereby de n
maintained. Consequently, the licensee contends that the above-test results 3
are sufficient to justify the:2-year test interval to be exceeded by-approximately 8 to 10 months ~ and will not result in undue risk to-the health or safety of. the public. - Accordingly, the licensee proposed to change the-TS Sections 4.6.1.2.d and 4.6.1.2.e to reflect the above requested exemption.
The. staff agrees with the licensee that the above test results are sufficient-to justify _the 2-year test interval 1to be exceeded one-time by approximately 8 to 10 months.
Furthermore, the_24-month-inter' val requirement for Type B and C-testing containment penetrations is ir. tended to be often enough.to-prevent significant deterioration from occurring and long enough-to permit:thelLLRTs to be performed during' plant outages.
Leak testing of the penetrations during plant shutdown.is preferable b personnel.- Koreover, some pen.ecause of the 1ower radiation expos _ures:to plant-etrations, because-of their intended functions,-
cannot be tested at power operation.
For penetrations that cannottbe tested during power operation or those that, if tested 'during-p1 ant operation would cause a degradation ir, the overall safety-(e.g.,:the closing of a redundant line in a safety.systen),' the increase in confidence of containment ~ integritys c
following a successful test is not significant enough to Justify a plant--
shutdown specifically to perform the LLRTs within a 24-month time period.
The licensee _ committed to perform additional Type C tests during any forced outages of sufficient duration.that may occur before the next refueling outage. The remaining Type'B test,.the fuel transfer canal blind flange,-
cannot be tesod until the'next refueling outage. This is because the' w
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) pool must be drained to access the flange for testing, and in. order to drain the pool certain equipment must be moved over the fuel storage pool. The safety evaluation accompanying License Amendment No. 72 related to charging pump operability stated that "there will be no movement of... heavy loads over s
the storage pool during the time the fuel building exhaust filter system is disconnected." The fuel building exhaustf.11ter will be reconnected at the end of cycle 4 during the next refueling outage, at which time _the Type B test of the fuel transfer canal blind flange can be performed.
On January 29, 1993, the Commission granted the licensee's November 18, 1992 request for a schedular exemption from the requirements of 10 CFR Part 50, Appendix J, Sections III.D.2(a) and III.D.3.
Based on the testing results and the considerations discussed above, the staff concludes that the licensee's proposed TS changes are acceptable.
3.0 STATE CONSULTATIOR In accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 [HyRONMfJTAL CONSID.fRATION The amendment changes surveillance requirements. 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 individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (57-FR 61120). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10-CFR 51.?2(b) no environmental impact statement or environmental assessment need be -
prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(!) 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.
Principal Contributor:
D. Shum Date:
January 29, 1993