ML17194B708
| ML17194B708 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/07/1983 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Farrar D COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8309080241 | |
| Download: ML17194B708 (4) | |
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Docket No. 50-237 Mr. Dennis L Farrar Director of Nuclear Licensing Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690
Dear Mr. Farrar:
September 7, 1983
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~o_cke.G NRC PDR Local PDR NSIC ORB Reading DCrutchfield HSmith RGi lberl OELD ELJordan JMTaylor ACRS (10)
GHolahan
SUBJECT:
CONFIRMATION OF EXEMPTION FROM REQUIREMENTS OF APPENDIX J TO 10 CFR 50 0 SECTION IV.A Dresden Nuclear Power Station. Unit No. 2 This letter confinns the exemption issued verbally to Commonwealth Edison Company. (CECo) on August 12, 1983, pertaining to Type A leak testing following containment boundary repairs. By telephone and in a supporting letter on August 11 0 1983, CECo requested an exemption from 10 CFR Part 50, Appendix J.Section IV.A for the Dresden Nuclear Po\\1er Station, Unit No. 2, so that a Type A leak test of the Dresden Unit 2 containment need not be performed prior to resuming operation following the repair, by welding, of several small holes in bellows that form part of the containment boundary.
The leaks were in two bellows each located on the drywell side of the two vacuum breakers in ~~rate drywell to torus lines. Two holes on separate convolutes were inadvertently produced in one bellows and one hole in another bellows five.feet away during some welding work nearby on August 10, 1983. The predicted leak rate from the holes at.the design basis accident pressure of 48 psig was calculated to be 6.43 scfm prior to repair~ The repairs were made in conformance with code approved techniques by qualified personnel and the st~ff has high confidence that sound repairs have resulted.
The recent Type A test completed using the design basis accident pressure showed a measured containment integrated leak rate']of 4.94 scfm.
The additional leak rate introduced by the new holes would result in a total leak rate, at the design basis accident pressure. of 11.37 scfm which is less than the allowable limit of 13.7 scfm used for the@esign basis accident calculations. The staff finds the calculated leak rate from these holes to be reasonabJe. Also, based on operating exper~ce to date and infonnation furnished by the licensee, a significant safety
_ m_argin ~nd operating life~ime st111 exist for tb]J repaired bellows.
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NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USGPO: 1981-'335-960
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Mr. Dennis L. Farrar
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Based on the above evaluat;on. you were granted an exemption that deferred conduct of a Type A test (as described in Appendix J, §50) until the next refueling outage.
The recurrence of an almost identical problem withi.n a few weeks causes some concern relative to the effectiveness of the qualify assurance (QA) aspects of thEJ'Eweld1ng operations on adjacent piping. As a result, please provide a report by.October 3, 1981 discussing your assessment of the causes and corrective actions found necessary to the QA and other progrQITls (such as maintenance or repair) as a result of these occurrences.
cc: See next page
- SEE PREVIOUS TISSUE FOR CONCURRENCE Sincerely,
- ro:d.gi.nal s ig11ed 'b~
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- ,*~ ~ ""_j C,:-Jh'f.i~t Darrell.G. Eisenhut. Director Division of Licensing Office ~f Nuclear Reactor Regulation NRG FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY ~
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USGPO: 1981-33$-960
.1; However, there 1s some reduction 1n the 11as 1eata11ed" 1 ffet1me of the bellows and the staff concludes that Type A tests should be carrfed out durfng the next refueling outage 1n accordance with the requfeements in Appendix J of 10 DFR Part 50.
The recurrence of an almost identical problem wfth1n a few weeks causes some concern relatfve to the effectiveness of the quality assurance (QA) aspects of the welding operations on adjacent*pfpfng. As a result. you should provide a report within 30 days discussing your assessment of the causes and corrective actions found necessary to the QA and other programs (such as maintenance or repair) as a result of thfs occurrence.
cc: See next page Sincerely, Darrell G. Eisenhut, Director Dfvisfon of Licensing Office of Nuclear Reactor Regulation OFFICE. *~~*~*j"c' [)'~~1e*r*d -~*~~-*~*~'*f*t~"'" *iit~~~~-~*~~-t........ R~.~.Q.............
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NRCFORM318(10-80)NRCM0240 OFFICIAL RECORD C_OPY USGPO: 1981--'335-ooO
Mr. Dennis L. Farrar cc Isham, Lincoln & Beale Counselors at Law*
One First Natiorial Plaza, 42nd Floor Chicago, Illinois 60603 Mr. Doug Scott Plant Superintendent Rural Route #1 Morris, Illinois... 60450 U. S. Nuclear Regulatory Commission Resident Inspectors Office Dresden Sta ti on RR #1 Morris, Illinois 60450 Chai nnan Board of Supervisors* of Grundy County Grundy County Courthouse Morris, Illinois 60450
- U. S. En vi ronmenta l Protection Agency.
Federal Activities Branch Region V Office
- ATTN:
Regi aria 1 Ra di ati on Representative 230 South Dearborn Street Chicago, Illinois
- 60604 James G. Keppler,--Regional Administrator Nuclear Regulatory Corrmis.sion, Region* III 799 Roosevelt Road Glen Ellyn, Illjnois 60137
- Mr. Gary N. Wright, Manager Nuclear Facility Safety I 11 i noi s Department of Nuclear Safety 1035 Outer Park Drive, 5th Floor Springfield, Illinois 62704
- I