ML20062H695
| ML20062H695 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/27/1980 |
| From: | Pawlicki S Office of Nuclear Reactor Regulation |
| To: | Noonan V Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20062H675 | List: |
| References | |
| NUDOCS 8008210262 | |
| Download: ML20062H695 (2) | |
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fi UNITED STATES f
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NUCLEAR REGULATORY COMMISSION
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WASm8eGTO's, o. c. 20sss a
\\..v f June 27, 1980 MEMORANOUM FOR:
V. S. Noonan, Assistant Director for Materials and Qualifications Engineering Division of Engineering FROM:
- 5. S. Pawlicki. Chief Materials Engineering Branch
SUBJECT:
COMMENTS ON THE DIFFERING PROFESSIONAL OPINION ON SEQUCYAH WELD REPAIR OF PRESSURIZER RELIEF PIPE
REFERENCES:
1.
" Expression of Differing Professional Opinion in the Matter of the Adequacy of Sequoyah Unit One Weld Drawbead Repair of Pressurizer Relief Pipe," J. Halacat: to S. S. Pawlicki, June 16, 1980 2.
"Secuoyan Unit 1 - Pressuri:er Relief Line Repair, Docket No. 50-327," Edward L. Jorcan to D. G. Eisenhut, May 19, 1980 3.
" Tennessee Valley Authority, Sequoyah Nuclear Plant, Unit No.1," 5. S. Pawlicki to L. S. Rubenstein, Decemoer 4,1979 The historical overview of the evaluation of the Secuoyah Unit One weld draw bead repair of pressurizer relief pipe is provided by Joe Halapat: in his memorancum (Ref. 1) expressing a differing professional opinion on the adecuacy of the repair. I have the following comments on that memorandun.
1.
The "m0ckup" used by TVA was not intended 'to duplicate either tne pipe material or the welding procedure used in the straigntening of *ne pres-suri:er relie# pipe. TVA infor ned us at the Maren 13, 1980, meeting that the mockup material was 304 55, while the pipe material is 316 (0.05C),
wnien is normally more resistant to intergranular stress cormsion cracking causec by weld sensiti:ation than 304 Furtner-nore, ne heat input usec to make tne single weld in the mockuo was six times higher than that used on the Secuoyan relief pipe, leading, of course, to more severe sensiti:stion of mockuo material. The primary purpose of the mockup was to experiment with the effectiveness of the straigntening process itself, and very little can be deduced about the condition of the pressuri:er relief pipe from ne examination of the mockup.
2.
The meeting with T/A on March 13, 1980, was attended by exoerts from ne I & E neadcuarters and by the I 1 E Region II resicent inspector. Their opinion was tnat the repair is acceptacle and that "tne less we co on :nis ploe the cetter of# we will be."
In snort, adcitional recairs would only increase sensiti:ation and residual stresses in the piping.
80082102,62
V. 5. Noonan 3.
Tne May 19, 1980, report from the Office of Inspection and Enforcement (Ref. 2) states tnat curing the Maren 13, 1980, meeting to resolve CSS concerns, TVA agreed to perform certain in-situ field tests to verify that tne draw bead welding did not compromise piping integrity. The report c:ncluces that based on the information provided I & E believes TVA's actions were res;cnsive to the staff's concerns and, in view of favoracle test results, rec 0mmends that the issue be considered resolved.
'. The majority opinion remains tha: the weld re; air is acceptable and that the weld area should no: De susceptible to intergranular stress corresion attack. To verify the continuing integrity of tne Secuoyah Pressuri:er relief
- 1:ing we recuired in our memorandum (Ref. 3) that Onese new welcs on the cressuri:er relief piping be incluced in the inservice inscection program for Secuoyah Unt: I and be subject to all the inspection requirements of Sec-den X: of :ne ASME Code throughout :ne service life of the clant.
My recommencatien :: acce:t the Secuoyan Unit I cressuri:er relief cice repair was based en discussions wi n several experts in :nis field, from different NRO Of# ices, anc my Own judgment. It is 00Vicus tnat Joe Halacat: continues 10 have coucts accut ne integrity of the pressuri:er relief pi:e. Qu: ef two recem-mencations ex:ressed in his memorancum (Ref. 1), I vote agains taking Oca:
sam:les from the weld crew bead Secuoyan cressuri:er relief pice; I believe, newever, nat Joe's second recome.endation, that a tnied party inspection De perf rmec, nas some merit, since it may help to remove nis remaining couets.
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- 5. S. Pawlicki Chief Materials Engineering Branch Division of Engineering Office of Nuclear Reacter Regulation cc:
J. nala:at:
- 5. 5. Pawlicki
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