ML20150D596
| ML20150D596 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/11/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20127A683 | List:
|
| References | |
| NUDOCS 8803240376 | |
| Download: ML20150D596 (8) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION s.,
y WASHINGTON, D. C. 20555
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SAFETY EVALUArION BY THE OFFICE OF SPECIAL PROJECTS NRC WELOING CATEGORY - MISCELLANEOUS /0NE OF A KIND TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 1.0 SUB JECT _
NRC Welding Category:
"Miscellaneous /0ne of a Xind" TVA Category:
WELDING TVA Subcategories C010300, WE50908, OA80415, WE50710 WE50813, OP30803, WE50825, WE50119. WE50103, WE50919, WE50911, WE50319,
- WE50719, The employee concerns were evaluated by TVA as potentially safety-related and applicable to the Sequoyah site er as potentially applicable to the Seouoyah site on a generic basis.
TVA established the Welding Project to formulate a program for each nuclear plant site to address the employee concerns rel'.ted to TVA's welding program. Many of the concerns which originated at the Watts Bar Nuclear Plant were determined Lj TVA as possibly being generic, and therefore applicable to all of the TVA nuclear plant sites.
For the Sequoyah site, the TVA Welding Project is divided into two phases.
Phase 1 is a review of the records to determine if there are any problen indicators. Most of the final element reports which are TVA's evaluation of employee concerns with a conron issue (s) were written on the basis nf the Phase 1 efforts.
Phase 2 involved a review of ISI and LER records, an audit by Bechtel of the welding program records, and a physical reinspection of specific weldment populations whose samples were selected on an engineering and logic j
basis.
The NRC staff formed a Welding Task Group with representatives from the Offices of Nuclear Reactor Regulation (NRR)
Inspection and Enforcement (ISE), and Region II.
The Task Groue established an Expert Welding Team through an NRR Technical Assistance contract with Brookhaven National Laboratory (ENL),
BNL provided a Technical Evaluation Report (TER) which summarized the opinions of the Expert Welding Team concerning the various welding issues and the actions taken by TVA as addressed in TVA's Element Report drafts of mid-1986.
The NRC Welding Task Group also performed independent visual, surface and volumetric reinspections of weld:nents at the Seouayah site with help of Region I personnel operating out of the NDE van.
The TER and the inspection Reports were incorporated in the initial Welding SER issued to TVA on November 11, 1986.
This SER is being provided to address in more detail the individual employee concerns and the changes made of the individual employee concerns declared generic to the Sequoyah facility since the initial staff Welding SER.
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$ The staff believes that there are five essential elements which must be functioning for a welding program to be viable. The staff placed each of tne individual employee concerns into one of these essential eierrent categcries.
A miscellaneous category was established to cover those aspects which are not directly related to the TVA welding program, or applicable to the Sequoyah site. These program essential element categories are as follows:
Welding Procedures Welder Qualification / Training Welding inspection Weld Design and Configuration Filler Material Control Hiscellaneous/Cne of a Kind The st'aff's approach has been to group similar employee concerns within an essential element to establish an "issue" or "issues." The staff reasons that the particular issue (s), if valid, and significant, would gererate an aoverse condition in the hardware.
As part of the overall program for reassessing the TVA welding program implemented during plant construction and operations, TVA and the NRC staff conducted reinspections at the Sequoyah site to determine (1) that the licensee's corrective actions for resolving the issues raised by the employee concerns were being satisfactorily implemented, and (2) that the hardware was suitable for service.
NRC staff inspections and evaluations were performed on TVA's record audits program, personnel perfoming TVA's audits and reinspections, and TVA's records.
The employee concerns considered in NRC Essential Eleront "Miscellaneous /0ne of a Kind" are as follows:
TVA FINAL ELEMENT EMPLOYEE REPORT RESPONDING l
CONCERN N0.
TO CONCERN BRIEF DESCRIPTION OF CO M Rn l
EX-85-059-C01 WP-08-SCN WELDS ARE N0' PAINTED AFTER THEY ARE FINALIZED, RESULTS IN RUST IN-85-192-002 WP-08-SCN NUMEROUS UEFAINTED WELDS ON CONCUIT AND PIPING SUPPORTS THROUGHOUT PLANT APE RUSTED IN-85-273-001 WP-08-50N UNPAINTED WELDS ON PIPE SUPPORTS IN-85-451-001 WP-08-SON PAINTERS WERE INSTRUCTED NOT TO PAINT ANY-THING ABOVE 6 FEET Wl-85-030-010 WP-10-SQN WELDING AND NDE 0A PROGRAM NOT !PPLEMENTED IN-85-247-002 WP-13-SON SETTihG OF 50 & 100 AMPS WITH 3/32" RODS IS AN UNSUITABLE WELDING MACHINE.
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. IN-85-303-001 WP-13-SON ALL WELDING MACHINES Sb0ULD HAVE REMOTE SWITCHES SO TUNGSTEN TIP DOES NOT HAVE TO TOUCH BASE METAL TO START WELD. KAY CAUSE TUNGSTEN TO BE LEFT IN WELD WHEN IN-85-127-001 WP-17-SCN BERGEN-PATTERSON HANGER WELDS OF F00R OVALITY ARE ACCEPTED WHILE TVA WELDS OF EETTER QUAllTY ARE REJECTED IP-85-007-003 WP-17-SON VENDOR WELDS ARE OF POORER QUALITY AND WOULD NOT PASS THE SAME ACCEPTANCE STANDARDS AS TVA FIELD WELDS IN-85-657-001 WP-17-SQN EXAMPLE - YUBA HEAT TRANSFER CO.
IN-85-021-003 WP-19-SON STEAMFITTER'S WELDER CERTIFICATION CARDS HAVE BEEN BACKDATED 1 CR 2 WEEKS TO COVER WELDER'S WHOSE CERTIFICATION CARDS WERE NOT RE-STAMPED AFTER 90 DAY IN-85-540-001 WP-19-50N INADE0VATE WELDER CERTIFICATION UPDATE, WELDERS ARE KEPT UPDATE EVEN THOUGH THEY DON'T WELD FOR YEARS IN-85-543-002 WP-19-SON WELDER CERTIFICATION UPDATE PROCEDURE IS INADEQUATE IN-85-612-006 WP-19-SON WELDER CERTIFICATION UPDATE IS INADEQUATE IN-85-965-001 WP-19-SON WELDER CERTIFICATION CARDS ARE BEING BACKDATED IN-86-143-002 WP-19-SQN WELDER'S CERTIFICATION CARD WERE EACKDATED ABOUT 30 DAYS, THIS VAS DONE BECAUSE THE WELDER FAILED TO FAVE HIS CARD UPDATED IN-86-167-005 WP-19-SON WELDER REQUALIFICATIONS PAVE BEEN BACKDATED IN-85-503-001 WP-19-SON INDIVIDUAL DISCIPLINED FOR NOT HAvihG CERTIFICATION UPDATED IN-85-0?l-X05 WP-19-SON WELDER CERTIFICATION CARDS FALS!FIED IN-85-424-X13 WP-19-SQN FALSIFIED WELDER CERTIFICATION CARD IN-85-770-XO7 WP-19-SON FALSIFIED CERTIFICATION CARDS IN-85-778-X07 WP-19-SON FALSIFIED CERTIFICATION CARDS IN-86-167-X06 WP-19-SON WELDER CERTIFICATION CARDS HAVE BEEN FALSIFIED
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., Wi-85-003-001 WP-19-50N FALSIFICATION OF WELDER CERTIFICATION CARD BY CMA.
CONCERN IDENTIFIED BY WELDING UPDATING OFFICE. WELDER WOPKED IN UNIT 2 TUhBINE BUILDING MAY 27 i
Wi-85-003-X02 WP-19-50N WELDER CERT CARD FALSIFIED IN-85-770-003 WP-19-SON INDIVIDUALS POSSESSING INVALID WELDER CERTIFICATION IN-85-612-XO7 WP-19-50N WELDER CERTIFICATION CARD FALSIFIED IN-85-299-003 WP-19-SON EXCESS METAL REMOVED AT BUTT WELDS, EXCESSIVE SHRINKAGE IN-85-532-006 WP-19-SQN OVERS 1ZE HANGER FILLET WELDS l
IN-85-335-002 WP-19-SON WELDERS ON RESTRICTIONS (NOT ALLOWED TO WELD) ARE TOLD TO KEEP CERTIFICATIONS UPDATED WITHOUT USING THE PROCESS IN-85-501-001 WP-19-SON UNUSED BUNDLES OF WELD ROD FRE0VENTLY FOUND IN TRASH CANS IN TURBINE BUILDING OF UNIT 2 Wi-85-084-001 WP-19-50N A WELDER WHOSE CERTIFICATION HAD EXPIRED l
WAS ALLOWED TO CHECK OUT WELD R00 FROM THE R0D SHACK IN-85-725-X14 WP-19-SON WELDER RECERTIFICATION PROGRAM HAD INADE0VATE SUPERVISORY OVERSIGHT.
GOOD WELDERS COULD HAVE MADE OR FINISHED TEST PLATES FOR ANOTHER WELDER IN-85-725-X15 WP-19-50N CONTROL OF WELDER RECERTIFICATION TEST PLATES WAS THADEOUATE: TEST PLATES BEGUN BY ONE WELDER COULD HAVE BEEN COMPLETED BY ANOTHER WELDER Wi-85-055-001 WP-19-SON THE WELDER RECERTIFICATION PROGRAM BEING ADMINISTERED TO WELDERS AT WATTS BAR IS NOT IN ACCORDANCE WITS ASPE CODE REQUIREMENTS Wi-85-056-001 WP-19-SCN WELDER, ARE BEING TESTED ON FLAT PLATE. IN FLAT POSITION FOR WELDING PIPE USING THE T.I.G. AND S.M.A.W. PROCESSES.
THIS DOES NOT CCNFORM TO ASME CODE Wi-85-030-008 WP-19-50N THERE MAY HAVE BEEN THOUSANDS OF WELDS THROUGH CARBO-ZINC PRIMER.
HOWEVER, TVA REPORTS INDICATE THAT ONLY 100-150 WELOS WERE INSPECTED IN THIS MANNER
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2.0 SU WARY OF ISSUES l
The issue involved with the four employee concerns addressed in WP-08-SON is sumarized as follows:
The welds of various steel structures are not being painted. The possibility of weakening of welds due to corrosion, or that sandblasting in preparation for painting may cause unacceptable metal loss with i
attendant loss of strength.
The issue involved with the employee concern addressed in WP-10-SON is summarized as follows:
l The corrective actions specified in TVA Report Number 0AE-80-2, "Review and Evaluation of the OEDC Welding and Construction - Watts Bar and Later Plants" may not have been implemented (at Sequoyah).
The issue involved with the two employee concerns addressed in WP-13-50N is sumarized as follows:
i The welding machines do not have adecuate adjustrents or special features i
which would allow for production of more censistent, good quality welds by avoiding the generation of rejectable defects.
The issues involved with the three employee concerns addressed in WP-17-SON are sumarized as follows:
Vendor welds are rot of the same quality as TVA field welds.
Vendor welds are not inspected in the field.
The 27 employee concerns covered by WP-19-SON were originally assigned a ceceric classification by the TVA Employee Concern Task Group.
These concerns had been investigated by the ERT or NSRS as a specific Watts Bar issue, and some of the concerns referenced Watts Bar or specific features of Watts Bar and were obviously not directly relevant to Sequoyah.
On these bases, the TVA Welding Project took issue with TVA's Employee Concern Procram's original generic classification for these 27 concerns.
The final element report resolved the issues between the groups and TVA determined that the employee concerns in this element report did not have generic applicability but were Watts Bar specific issues.
3.0 EVALUATION The four concerns addressed in WP-08-50N relate to paint not being applied to various carbon steel weldments, their subsecuent rusting and probable loss of strength, and that sand blasting to remove the rust also removes metal
_ (imitating this could also cause some loss of strength).
All of the carbon steel weldments which TVA ano hRC reinspected were painted, and the weldments reinspected included many examples more than six foot above the floor. There are probably isolated, individual instances of carbon steel weldments not i
having been painted. TVA, as a corrective action to deficiencies found in CAR No. 50-CAR-86-00-001, "Protective Coating Program " has initiated a comprehen-sive reinspection program of protective coatings.
Included in this prooram is a 100 percent baseline coating inspection of the level 1 and Level 2 coating areas at SON.
The one concern of WP-10-SCN was about TVA not having applied the results of TVA's Ouality Assurance Evaluation Report 2 (CAE-2) to other plants, specific-ally, the Secuoyah site. The report is specifically noted on the front page "Applies to: Watts Bar and later nuclear plants".
The report is dated September 4.1980, which is after almost all construction had been completed at the Sequoyah site.
Sequoyah is an earlier plant than Watts Bar, and accordingly, this report is not applicable to Sequoyah.
The two concerns addressed in WP-13-SON are about welding machines lacking additional control features and that these missing features could cause weld defects. The TVA and NRC reinspections did not find the type defects which would have been caused by the conditions stated in the concerns.
Regardless of the shortcomings of the machines, welders with proper training and skill can make code acceptable welds with the m.achincs without the additional control features discussed in'the concerns.
The additional centrol features may allow a particular weld to be made easier, however, this is not a code requirement.
There is no basis for further action.
The three concerns addressed in WP-17-SON are about vendor welds being o'f a lower quality than TVA field welds, and that the vendor welds are not inspected in the field.
Concern IN-P5-127-001 relates to Pergen-Patterson hanger welds.
There are no Pergen-Patterson hangers at Sequoyah, and accordingly, this concern is not applicable to Sequoyah.
Concern IN-85-657-001 relates to Yuba Feat Engineering Company's welds not reeting TVA weld stanoards, Yuba has not supplied any equipment to Sequoyah, and accordingly is not applicable to Sequoyah.
Concern IN-85-007-003 specifically rentions Watts Bar in its text, and accordingly, it also is not applicable to Sequoyah.
None of the employee concerns relating to vendor welds appear to be applicable to Seouoyah.
These concerns will be addressed at the Watts Bar site.
The 27 employee concerns listed in WP-19-50N were deemed originally generic by the TVA Employee Concern Task Group. The items were subsequently reviewed by the TVA Welding Project and were detertnined by the TVA Welding Project not to be applicable to Sequoyah.
The basis fcr their action was that either the concerns in their text mention Watts Bar or some particular feature at Watts Bar, or th6t hSRS or ERT investigative reports addressed these concerns as occurring at Watts Bar.
The majority of these concerns (19) are about the dating of welder certification cards or falsification of these cards.
In addition, four of the concerns are about administrative control of the renewal of certification testing for welders, or that this testing was not in accordarce with the code.
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The staff does not necessarily agree with TVA's determination of the generic nonapplicability of these concerns to Sequoyah.
however, the issues involved with these concerns are identical to those addressed in cur Welder Qualification / Training SER. The NRC staff believes that the reinspections performed at Sequoyah demonstrated that the welders made welds acceptable to the code, and accordingly, were cualified.
The types of defects found showed that the acceptance inspections were remiss in accepting undersize welds, uncer-length welds, arc strikes and weld spatter (cleanup).
These defects reflect that j
the original acceptance standards emphasized welder skills, and that the welds be present, and in their proper locations.
Only four defects attributable to poor l
welder skill were found.
These characteristics indicate to the staff that the original acceptance inspections were only of the surveillance type and physical measurements of weld size and length were not perforred.
The engineering analyses performed proved that these defects were insignificant and no weld repairs were necessary. Accordingly, the staff finds that the welders were qualified because they produced acceptable welds, i
The staff dces not necessarily agree with TVA's determination of the generic nonapplicability of these concerns to Sequoyah.
The staff evaluation for the remaining four employee concerns are summarized as follows:
Employee concern IN-85-299-003 is about stainless steel butt joints (probably piping) having excess metal removed and excessive shrinkage. A characteristic of stainless steel is that because of its higher coefficient of expansion compared to carbon steels, it naturally exhitits more shrinkage at its weldments.
The "excess" metal being removed at butt joints is normal surface preparation for ultrasonic examination. This concern does not raise any technical issues of significance.
Employee concern IN-85-501-001 relates to filler material control as unused bundles of weld rod and are frequently found in trash cans.
For the Sequoyah site, filler material control was more rigorous in that rod heaters were recuired for moisture control.
The large number of wolds reinspected by NRC and TVA with no cracks and the five year operating history of the site without weld cracking incidents demcnstrate that filler material control for welding during instructicn and operations was adequate.
Similar issues related to this concern are discussed further in the "Filler Paterial Control" SER.
,I Employee concern IN-85-532-006 it, about a conflict between a weld visual inspection acceptance criteria and a hanger drawing note or the amount fillet weld can be oversize. The hangers involved are not subject to fatigue loacings where excessive weld size could be a detrinent.
Local distortion due to excessive weld size is not a factor when design dimensinns are met. The engineering importance of excessive weld size in this case is moet.
Employee concern Wi-85-030-0C8 relates to original weld acceptance inspections being performed with the welds painted (coated).
The text of the concern asserts that 100-150 welds at Watts Bar were inspected through paint.
Several other concerns on this issue of weld inspections conducted thrcugh paint were addressed in our SER for the Welding Category "WELDING lhSPECTIOW cated
e7;~~ o August 20, 1987.
The staff believes that this issue h'as been satisfactorily addressed for Sequoyah for the reasons stated in the "Welding Inspection SER."
4.0 CONCLUSION
S The staff conclusion stated in the Welding SER dated October 30, 1986 was that the performance of inspections was the area of most concern, and that augmented and accelerated in-service inspections (ISI) were required to provide added assurance. None of the employee concerns categorized in the miscellaneous /one of a kind category have changed this position.
The concerns about carbon steel welds not being painted (WP-08-SQN) were addressed by a large painting reinspection program at Sequoyah.
The applicability of the conclusions of QAE-2 to Sequoyah (WP-10-SQN) was not appropriate because the construction phase of Sequoyah was almost complete when the report was issued.
There are no requirements that welding machines have additional settings or other featurt:s to make the welders job easier; a qualified welder should be able to make acceptable welds with such equipment (WP-13-SQN).
The employee concarns relating to vendor welds were demonstrated as not being applicable to the 3equoyah site (WP-17-SQN).
The concerns addressed in Element Report WP-l'l-SQN were originally determined to be generically applicable to Sequoyah, and subsequently determined by TVA not to be applicable to Sequoyah.
Although nonapplicablity was not specifically demonstrated by TVA for all of the concerns in this element report, the staff believes that the issues raised by these concerns were satisfactoriily addressed elsewhere or were of no
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significance.
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