ML20211D418
| ML20211D418 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/10/1986 |
| From: | Youngblood B Office of Nuclear Reactor Regulation |
| To: | White S TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8606120915 | |
| Download: ML20211D418 (5) | |
Text
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Docket hos.: 50-327 and 50-328 10 JUN 1985 Mr. S. A. White Manager of Nuclear Power Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
Dear Mr. White:
Subject:
Request for Additional Information - Sequoyah Nuclear Plant Phase II Welding Project Reports The NRC staff has been reviewing your Sequoyah Nuclear Plant Phase II Welding Project reports. The reports need further amplification and clari-fication on some technical aspects before we can complete our review. contains our questions on these technical aspects. We request that you provide your reply by June 16, 1986. We will provide you with additional questions after we complete our review of the 19 WP-XX-SQN reports.
Sincerely, Ok B. J. Youngblood, Director PWR Project Directorate #4 Division of PWR Licensing-A
Enclosure:
As stated cc: See next page i
l DISTRIBUTION:.
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' Docket File.:
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JPartlow PMasters local PDR BGrimes CHartbower PRC System Edordan WMunse NSIC HThompson RStout PWR#4 Rdg (3)
WLong ESullivan MDuncan CRossi TKenyon BJYoungblood Rdg R8allard BDLiaw CStahle CCzajkowski DESmi 11
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9606120915 860610 DR ADOCK 050 37
m Mr. S. A. White P
Tennessee Valley Authority Sequoyah Nuclear Plant cc:
Herbert S. Sanger, Jr., Esq.
Tennessee Department of Public General Counsel Health i
Tennessee Valley Authority ATTN:
Director, Bureau of 400 West Sumit Hill Drive, E 11B 33 Environmental Health Services Knoxville, Tennessee 37902 Cordell Hull Building Nashville, Tennessee 37219 Mr. K. W. Whitt Mr. Michael H. Mobley, Director Tennessee Valley Authority Division of Radiological Health 400 West Sumit Hill Drive, E3A8 T.E.R.R.A. Building Knoxville, Tennessee 37902 150 9th Avenue North Nashville, Tennessee 37203 Mr. Bob Faas
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Westinghouse Electric Corp.
County Judge P.O. Box 355 Hamilton County Courthouse Pittsburgh, Pennsylvania 15230 Chattanooga, Tennessee 37402 Mr. Jerry Wills Tennessee Valley Authority
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k SN 133B Lookout Place Chattanooga, Tennessee 37402-2001 Mr. Donald L. Williams, Jr.
Tennessee Valley Authority 400 West Sumit Hill Drive, W10885 i
Knoxville, Tennessee 37902 Resident Inspector /Sequoyah NPS c/o U.S. Nuclear Regulatory Comission 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 Regional Administrator, Region II U.S. Nuclear Regulatory Comission, 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 w
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ATTACHMENT 1 DOCKET NUMBERS 50-328/327 4
SEQUOYAH NUCLEAR PLANT WELDING PROJECT REPORTS 1.
In 2.0 APTECH ENGINEERING REPORT (Supplemental Infomation), Page 3, 8th l
line, it is stated that "In the case of the feedwater lug, no engineering evaluation was requested by the plant." Why was installing the missing welds l
to drawing requirements chosen as the means of resolving a missing weld problem rather than performing an engineering evaluation as had been done with a very similar problem? Demonstrate that code requirements were met without installing the missing welds.
2.
The tem " separated weld" is used in 2.0 APTECH ENGINEERING REPORT (Supple-mental Information), Page 3, 12th line. Define the basis for your assessment of this weld failure as being due to operating transients and not having been j
due to poor weld quality or cracking during fabrication.
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3.
In the APTECH ENGINEERING REPORT, the Table titled, "NOI DESCRIPTIONS -
l SEQUOYAH NUCLEAR PLANT UNIT 1", NOI Number 500201, under Disposition and Addi-tional Coments it is stated; ".... clean weld area per SQM-17, paint and p
reexamine." Explain how code requirements were met with the examination i
I f.
following painting.
4.
In the APTECH ENGINEERING REPORT, Table 4-1 lists 5 Licensing Event Reports l
concerned with welds. Provide the number of LERs evaluated in this search.
j Were any failure analyses conducted of the welds covered by these LERs? If so, please provide them.
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5.
Were there ever other than E7018 carbon / low alloy steel shielded metal arc welding electrodes on the Sequoyah site, such as E8018C37 Demonstrate that in-correct electrodes were not used on any weldment.
6.
For the Bechtel Audit, what were the total number of welders and inspectors in the populations from which the audit samples were taken? Provide separate totals for the Office of Construction and Nuclear Operations.
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7.
The TVA Reinspection checked the relative magnetism for all weids, austenitic L
and ferritic. What was the procedure for this inspection method? Provide l
justification for different levels of magnetism and their acceptance criteria, particularly " weakly magnetic".
8.
Cracks were not listed as one of the attributes in the tables of the TVA Reinspection Report. Were any cracks found during the TVA Reinspection? Also, porosity was not an attribute listed in the STRUCTURAL WELDS table. What was the rejection rate for porosity in the structural welds in the TVA Reinspection?
4 9.
In 4.4.1, page 8 line 21, of the five welds which were ground, were the l
manufacturer's minimum wall thickness requirements encroached upon? If so, to
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what extent?
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l 10.
In 4.4.1, page 10, line 1 the rough condition of two welds found during the reinspection is discussed. Provide information that justifies the statement, "The indepth investigation of the welder and inspector qualification revealed no indications of inadequacy of the welder or inspector capabilities." What was done to demonstrate that this level of workmanship by this welder and/or judgement by this inspector were not repeated elsewhere at Sequoyah?
11.
In 4.4.1, page 11, in the table titled " PIPING WELD 5",
the rejection rate when expressed in terms of the percentage of welds rejected is 56% (184/333).
Even allowing for some rejected welds counted more than once because of more than one rejectable attribute, the rejection rate is very high. a) What is the root cause of this high rejection rate of originally inspected and accepted welds? b) Is there any basis for concluding that there is a connection between the employee concerns expressing doubt about inspectors capabilities or that harassment and intimidation of inspectors occurred? c) With respect to question a), address in particular the attribute underfill, which has very specific code requirements. d) The arc strike / weld spatter rejection rate was 31%. What is the root cause for this high rejection rate? e) What were the original inspection criteria for these weld attributes? f) What were the reinspection criteria for these attributes? g) What is the justification for elimination of inspecting arc strikes for cracks in G-29C?
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f 12.
In 4.4.1, page 11 and 4.4.2, page 13, in the tables titled " PIPING WELDS" and " STRUCTURAL WELDS" respectively, expressing weld rejection rates based upon the attribute inches is misleading. There was only a finite number of welds inspected, and a qualified craftsman should be capable of making welds which meet all of the attributes in all of the inches submitted to inspection.
For these tables, please rearrange the data as follows:
)
PIPE WELDS TYPE OF WELD NO. OF WELDS REINSPECTED NO. OF WELDS REJECTED Socket Welds Office of Const.
Nuclear Ops.
Butt Welds Office of Const.
Nuclear Ops.
Other (specify)
Office of Const.
Nuclear Ops.
Total Welds Office of Const.
Nuclear Ops.
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l STRUCTURAL WELDS TYPE OF WELD NO. OF QLCS REINSPECTED NO. OF WELDS REJECTED Fillet weld Office of Const.
Nuclear Ops.
Butt Weld Office of Const.
Nuclear Ops.
Other (specify)
Office of Const.
Nuclear Ops.
13.
In the TVA Reinspection Report, a cceparison is made between original in-spection results and the reinspection results for piping welds.
If such a comparison can be made in a quantitative manner for structural welds, please present the data.
- 14. Referring to the Legend for Table 4.2, in the Final Resolution column, define the meaning of the letter codes in parentheses.
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- 15. There are some employee concerns abcut various structures not being in accordance with the as built drawings.
Did the TVA reinspection address this issue? If so, report the deviatious from the as built drawings found. Report the deviations in configuration as to type of deviation, the rate of a type of deviation compared to the number in the' reinspection population, and if such deviations resulted in not meeting code requirements.
)
- 16. Table 4.3 shows that a total of 50 structures were reinspected in the TVA reinspection program. However, Table 4.4 shows only 31 structures as having been reinspected.
Explain the discrepancy.
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