ML20010E711

Final Deficiency Rept Re Faulty Welds on Mirror Insulation Support Steel,Initially Reported 810511.Structural Steel Joint Welds Will Be Ground & Properly Prepared for Rewelding & Penetration Welds Will Be Properly Made

ML20010E711
Person / Time
Site:	Bellefonte
Issue date:	08/27/1981
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8109080185
Download: ML20010E711 (2)

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TENNESSEE VALLEY AUTHORITY m

CH ATTANOOGA. TENNESSEE 374ol 400 Chestnut Street Tower II g ' 3\ ~ k2

• August 27, 1981 BLRD-50-438/81-36 BLRD-50-439/81-39 9 Mr. James P. O'Reilly, Director 5 dc&gi log -

Office of Inspection and Enforcement i SEP O 4 Jgg m ;

U.S. Nuclear Regulatory Comission u.s,**"ss% ,,E *'

Region II - Suite 3100 9 101 Marietta Street \

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gf Atlanta, Georgia 30303

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Dear Mr. O'Reilly:

BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - FAULTY WELDS ON MIRROR INSULATION SUPPORT STEEL - BLRD-50-438/81-36, BLRD-50-439/81 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on May 11, 1981 in accordance with 10 CFR 50.55(e) as NCR 1449 This was followed by our first interim report dated June 10, 1981. Enclosed is our final report. We consider 10 CFR Part 21 applicable to this deficiency.

If you have any questions concerning this matter, please get in touch with D. L. Lambert at FTS 857-2581.

Very truly yours, TENNESSEE VALLEY AUTHORITY V

L~. M. Mills, d7 Manager Nuclear Regulation and Safety Enclosure oc: Mr. Victor Stello, Jr., Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 gf[

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8109080185 810827 PDR ADOCK 05000438 S PDR An E tual Opportunity Empir <er

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.. C3 ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 FAULTY WELDS ON MIRROR INSULATION SUPPORT STEEL BLRD-50-438/81-36, BLRD-50-439/81-39 10 CFR 50.55(e)

FINAL REPORT Description of Deficiency The insulation surrounding the reactor vessel is supported by a steel framework supplied by Mirror Insulation. While installing the reactor vessel bottom head insulation support steel, it was discovered that practically all of the weld preparations for field welding and vendor-made welds on these structures were faulty. This condition was caused by the steel supplier's failure to fabricate the support structures in accordance with drawing requirements and the American Welding Society (AWS) code and by inadequate inspection by Babcock and Wilcox (B&W) and their insulator subcontractor (Mirror Insulation).

The weld preparations Vere either not prepared in accordance with the vendor's drawings or were omitted. The vendor welds do not meet the visual acceptance criteria of the AWS D1.1-77 structural steel code. The defects include spatter, are strikes, undercut welds, craters, porosity, and undersize or incomplete welds.

These deficiencies should have been discovered before B&W released the structures for shipment from its subcontractor's (Mirror Insulatien) plant.

B&W also failed to provide TVA's inspector the opportunity to perform source inspection as required by the contract.

Safety Implications If the condition had remained uncorrected and there was a safe shutdown or design basis earthquake, the faulty vendor welds could fail. If these welds were to fail, the insulation support structure could collapse, which could break the incore monitoring piping coming from the bottom of the reactor vessel, resulting in a LOCA.

Corrective Action All vertical welds that were not properly weld prepared and/or welded will have the structural steel joint welds ground and properly prepared before rewelding Penetration welds will be properly made to ensure structural adequacy. After final welding and cleaning, structural steel will be repainted in accordance with specification and drawing requirements, and then inspected to original requirements. TVA will complete these corrective '

actions by January 5, 1982.

To prevent recurrence, Mirror Insulation has added inspections at their support steel supplier's plant, and B&W is increasing their inspections at Mirror Insulation before shipment.

An investigation has been made which has determined tha . there have been no similar deficiencies to date for insulation support steel fabricated for TVA plants preceding Bellefonte. Support steel for the balance of insulation at Bellefonte and TVA plants later than Bellefonte has not yet been fabricated.:

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