ML20054C839
| ML20054C839 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/05/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20054C836 | List: |
| References | |
| NUDOCS 8204220016 | |
| Download: ML20054C839 (2) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION WASHINGTON D. C. 20555 5
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- .e SAFETY EVALUATION BY THE OFFICE OF NUCLEAR R'EACTOR REGULATION RELATED TO AMENDMENT NO. 5 5 TO FACILITY OPERATING LICENSE N0'. DPR-42 AND AMENDMENT NO. 4 9 TO FACILITY OPERATING LICENSE NO. DPR-60 NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-282 AND 50-306 INTRODUCTION By letter, dated February 1,1982 Northern States Power Company (the licensee) requested a change to the Technical Specifications-(TS) of Appendix A of operating license Nos. OPR-42 and DPR-60. The proposed change revises the allowable leakage rate for the airlock doors of thevcontainment building at the Prairie Island Nuclear Generating Plant Units 1 'and 2.
Specifically, the proposed TS permits an increase in the allowable l' akage rate for the e
overall airlock door tests of the containment building for Units 1 and 2 from 409 scc / min to 1500 sec/ min at 46 psig.
Table TS 4.1-1 of Amendments 53 and 47, issued on December 30, 1981, was misnumbered "page 3 of 5".
It should have read "page 4 of 5".
DISCUSSION AND EVALUATION The existing TS 4.4. A.S.c states that for airlocks, the leakage shall be.
less than the design leakage reported in " Supplement No. 1 to Unit 1 Reactor Containment Building Integrated Leak Rate Test June 1973 dated June 6, 1974." The design leakage in this report is 256 sec/ min at 10 psig for airlock door intergasket tests and 409 sec/ min at 46 psig for the overall airlock test. The licensee proposes to change TS'4.4.A.5.c to read "For airlocks, the leakage shall be less than 256 scc / min at 10 psig for door intergasket tests 'and 1500 scc / min at 46 psig for overall. airlock tests."
The difference between the proposed and the existing TS is an increase in the leakage rat.e from 409 to 1500 sec/ min at 46 psig for the overall, airlock test. Orginally, the allowable leakage limit of 409 sec/ min was based on the sealing capability of the original seal material which consisted of silicon rubber. This silicon rubber has been replaced in Unit 1 sith a Grafoil seal which is qualified for the potential radiation dose of the 1
design basis accident conditions recommended in NUREGs 0578 and'0737.
The Unit 2 airlock will' also be modified during tne 1982 refueling outage.
Alth'ough Grafoil seals can withstand a higher radiation dose for accident conditions, they do not have a low leakage sealing capability equivalent to the silicon rubber seals. This difference in sealing capability resulted i
in this re' quest by the licensee for a license amendment.
l G204220016 820305 i
PDR ADOCK 05000282 P
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We agree with the licensee that a comfortable margin still exists if the allowable leak rate is increased to 1500 sec/ min for the overall airl'ock tests, since this is still well below the allowable tota,1 leakage 'for Type B and C tests of 10 CFR Part 50 Appendix J.
Appendix J of 10 CFR
.Part' 50 allows total leakage at a rate not to exceed 154,800 sec/ min for the total Type B and C leakage tests which includes the leakage of the '
airlock doors. This proposed TS does not in any way change this' total leakage rate requirement which the licensee must meet.
In addition by permitting this change the licensee will be required to reduce the leakage rate at other containment building leak paths that are subjected to the.
Type B and C tests so that the total leakage rate from the containment building does not exceed the ~ allowable value (i.e. 154,800 sec/ min at 46 psig) of 10 CFR Part 50 Appendix J.
Based on the above evaluation we find that the proposed TS which changes the allowable leak rate for the overall airlock tests will not alter the existing level of protection to the public. On this basis we find the licensee's proposed TS acceptable.
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I Environmental Consideration We have determined that the amendments do not authorize a change in effluent types or total amounts-nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental. impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with.the issuance of these amendments.
Conclusion We have concluded, based on the considerations discussed above, that:
((l) because the amendments do not involve a.significant increase in the probability or consequences of accidents previously considered
'and do not involve a significant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health _ and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be. conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical l
to the common defense and security or. to the health and safety of l
the public.
Date: MAR 5 1982 Principal Contributor:
D. C. Dilanni
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