ML19260C951

Final Deficiency Rept Re Gulf & Western Preassembled formation.Safety-related Preassembly Formations Will Be Reworked & Rejectable Indications in Welds Will Be Corrected

ML19260C951
Person / Time
Site:	Wolf Creek, Callaway, Sterling
Issue date:	11/28/1979
From:	BECHTEL GROUP, INC., BECHTEL POWER CORP.
To:
Shared Package
ML19260C947	List: ML19260C948 ML19260C951
References
NUDOCS 8002070170
Download: ML19260C951 (5)

Text

FINAL REPORT ON Gulf & Western Preasse= bled Formations For Callaway Plant Unit No.1 (Union Electric)

And Wolf Creek (Kansas Gas and Electric) s Bechtel Power Corporation Gaithersburg November 28, 1979 1937 027 8002070 >!

TABLE OF CONTENTS 1.0 Introfuction 2.0 Description of Deficiency 3.0 Chronology of Events 4.0 Analysis of Safety Inplications 5.0 Corrective Action 6.0 Conclusion e

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1.0 INTRODUCTION

In compliance with 10CFR50.55(e), this report is being issued due to tajectable indications found in welds in preassembled piping formations manufactured by Gulf & Western (G&W), Paola, Kansas. The scope of this report includes preassembled for=ations fabricated, delivered, and in some cases, installed at Union Electric's Callaway Unit One and Kansas Gas & Electric's Wolf C eek Jobsite.

2.0 DESCRIPTION

OF DEFICIENCY This reportable deficiency to the NRC is based on ar investigation of three piping for=ations (For=ation Nu=bers A-18-151, A-47-135, and A-52-135) at the Callaway Jobsite. During this investigation the welds for these formations were found to include imcomplete penetration, incomplete fusion, and slag inclusions. Radiographs for 22 cf 52 welds reviewed on these formations by Bechtel indicate rejectable defects.

Additionally, the radiographs for 31 welds were found to be unacceptable due to i= proper radiographic technique. These 31 welds were reshot and the number of welds rejected for radiographic technique problems was reduced to 16. Si=ilar veld quality and rJ diographic technique defects have been indicated in other for=ations previously delivered to Wolf Creek and Callaway Jobsites.

3.0 CHRONOLOGY OF EVENTS In March, 1979, viscal examinacions of preasse=bly For=ation A-9-111 at Wolf Creek Site indicated concerns regarding weld quality and radiographic techniques employed by G&W. These initial concerns vere followed up in April and May with detailed inspections and audit af preasse=bly for=ations delivered to both SNUPPS jobsites. These audits and inspections indicated substantial noncompliances to specification and ASME Code requirements. These noncompliances involved radiographic technique; (i.e., i= proper film density, multiple penetrameter images, incorrect penetra=eter placements and surface indications inhibiting radiographic interpretation) as well as visible weld discrepancies involving incoglete fusion, surface porosity and ieproper veld profiles. A hold was subsequently placed on installEtion of safety-related preasse=bly formations furnished by G&W.

Between May 17, 1979 and June 28, 1979, a series of meetings took place between Bechtel, SNUPPS, KG&E, UE, and G&W to (1) determine the extent of the weld quality and radiographic technique probie=s and (2) develop a course of remedial and corrective actions. These actions included a 100 percent examination by C&W of all weld radiographs; this avamination completed in early June indicated deficiencies in radiographic technique of between 35 and 50 percent. Further discussions with G6W management resulted in project agree =ent to surface grind and reradiograph, using corrected RT techniques, all preassembly for=ation welds subject to RT arme f eation ; other safety-: elated formations not requiring radiographic avamination; i.e., Class III assemblies 1937 029

~,. - .

Page 2 would also be included in this rework agree =ent. Selected formations not yet installed were returned to C&W in June for rework under strengthened project surveillance. Formations re=aining at the jobsites would be reworked by C&W in the field under site inspection and surveillance. Criteria, procedures, and inspection arrangements governing the rework offort were established over the next several months and actual on-site work initiated at Callaway Site in early October. NRC I/E representatives for the two SNUPPS sites were taformed of the preceding investigation and rework plans. The NRC representatives were informed that a determination regarding report-ability of these deficiencies under 10CFR50.55(e) regulation would be made upon identification of significant veld defects.

On-site rework; i.e., visual inspection, surface grinding and reradio-graphy of the first three assemblies at Callaway Site were ce=pleted in early Nove=ber. After completion and acceptance of the rework effort by G&W and the G6W Authorized Nuclear Inspector, Bechtel, and Daniel /

Union Electric incpection indicated the presence of rejectable weld defects as well as continuing radiographic technique difficulties. The nature of these defects suggest the potential for adverse safety consequences; as a result, these findings were reported on November 2 to the NRC by Union Electric persuant to 10CFR50.55(e) regulations.

Subsequently, G&W has been directed to discontinue all efforts with the exception of five units on the SNUPPS preassemblies located at their Paola, Kansas facility which are in the final stages of co=pletion.

4.0 ANALYSIS OF SAFETY IMPLICATIONS G&W has fabricated 32 safety-related piping forsctions for each of the two SNUPPS Sites (Callaway and Wolf Creek). These 32 preassechlies are part of the following safety-related systems:

A. Auxiliary Feedwater (AL)

3. Chemical and Volume Control (BG)

C. Cc=ponent Cooling Water (EG)

D. High Pressure Coolant Injection (EM)

Each system relies upon at least one of these preassemblies to effect a safe shutdown of the plant concurrent with either a safe shutdown earthquake or a design basis accident. Failure of the welds in certain of these preassemblies could significantly degrade the functionability of critical syste=s to the extent that safe shutdown capability is co= promised.

Due to the potential safety i=p11 cations for safe shutdown, ?.he generic welding proble=s identified in this report are deemed to constitute a significant reportable deficiency pursuant to 10CFR50.55(e).

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Page 3 5.0 CORRfCTIVE ACTION The cause of the proble= vas inadequate control by G&W of welding and NDE operations. Due to G4W's inability to perfor= satisfactorily, the responsibility for rework and reinspection (including NDE) and repairs (where required) of the for=ations has been transferred to the Constructor (Daniel International Corporation) at both jobsites. The rework will be perfor=ed in accordance with the Constructor's Quality Assurance Programs and applicable Codes.

Five preassemblies - four for Callaway (including three preassembled formations previously returned for rework) and one for Wolf Creek, which are at G&W's facility at Paola, Kansas and which require "iniemi effort to co=plete, will be finished by G&W. This work will be perfor=ed by G&W under increased surveillance by Bechtel and will be receipt inspected at each of the SNUPPS jobsites.

6.0 CONCLUSION

All safety-related preassembif formations for both SNUPPS Sites will be reworked. Rejectable indications in the velds of preasse= bled for=ations will be satisfactorily corrected by the Site Constructors.

M 1937 031