ML20198J587

Insp Rept 99901326/97-01 on 971027-31.Nonconformance Noted. Major Areas Inspected:Manufacturing Process Control,Control of Special Process & Matl Traceability & Identification

ML20198J587
Person / Time
Issue date:	01/02/1998
From:	NRC (Affiliation Not Assigned)
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Shared Package
ML20198J464	List: ML20198J460 ML20198J516 ML20198J587
References
REF-QA-99901326 99901326-97-01, 99901326-97-1, NUDOCS 9801140167
Download: ML20198J587 (10)

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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION Report No: 99901326/97-01 Organization: AB Sandvik Stes!

Steam Generator Tubing SE-81181 Sandviken '

Sweden

Contact:

Mats Tynell, General Manager 46/26 263873 Nuclear industry Activity: Manufacture of steam generator tubing Dates: October 27-31,1997 Inspectors; lan Dames, Technical Assistant, Division of Reactor Safety Region IV Phillip J. Rush, Materials Engineer Materials and Chemical Engineering Branch Division of Engineering Approved by: Robert A. Gramm, Chief Quality Assurance and Safety Assessment Section Quality Assurance, Vendorinspection and Maintenance Branch Divisi0n of Reactor Controls and Human Factors Enclosure 2 9801140167 990102 PDR, GA999 EFOSW 99901326 ---

PDR

1 INSPECDON

SUMMARY

AB Sandvik Steel (ABSS) holds a current ASME Quality System Certificate for manufacture of ferrous and non-ferrous bars, seamless tubular products, rounds, hollows, billets and ingots, bare electrodes, strip electrodes, bare wire, hot rolled wire, and hot rolled rod. This inspection was performed at the ABSS Tube Mill 68 and supporting facilities and was focused on manufacture of Inconel 690 tubing for the South Texas Project, Unit 1 replacement steam generators.

During this inspection, the inspectors assessed conformance of manufacturing and examination activities to NRC, ASME Code, and customer requirements. Specific subject areas reviewed during the inspection were manufacturing process control, control of special processes, and material',raceability and identification.

The inspection bases were as follows:

• Appendix 0, " Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," to Par 150 of Title 10 of the Code of Federal Reaulations (10 CFR Part 50),

e 10 CFR Part 21, " Reporting of Defects and Noncompliance," and e ABSS's Quality Assurance Manual, Revision 24, dated November 25,1996.

Overall, the results of the inspection indicated that ABSS had estabhshed appropriate program criteria for control of manufacturing and examination activities, with implementation noted generally to be good. The inspectors noted during the inspection, as discussed in Section 3.1 below, that Westinghouse Pensacola Plant (WPP) had not contractually irnposed the requirements of 10 CFR Part 21 on ABSS. WPP had, however, required that all deviations regardless of the time of disclosure or nature of the deviation be reported to WPP for evaluation and disposition. In addition, the inspection identified that ABSS did not conform to certain NRC and customer requirements pertaining to thermal treatment of South Tens Project steam generator tubing. This nonconformance is

! discussed in Section 3.3.1.

2 STATUS OF PREVIOUS INSPECTION FINDINGS This was the first NRC inspection 7f ABSS.

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! 3 INSPECTION FINDINGS AND OTHER COMMENTS 3.1 10 CFR Part 21 Proaram

a. Insoection Scoce i The inspectors reviewed the technical requirements (for South Texas Project, Unit 1 steam generator tubing) contained in Westinghouse Purchase Order 4500022778 and 2

Change Notices 01 through 05, in order to ascertain whether requirements had been - 1 imposed on ABSS with respect to implementing the provisions of 10 CFR Part 21,  :

" Reporting of Defects and Noncornpliance." l

b. Observations an(Findinas The inspectors noted that Change Notice 01, dated February 21,1997, to Purchase.

Order 4500022778 added the statement, " Westinghouse assumes responsibility for 10 CFR Part 21 as applicable," to the purchase order, it was additionally noted during the review that an attachment to the purchase order, Quality Note KA0051 for Inspection Code 51, stipulated that non-U.S. vendors report all deviations regardless of the time of disclosure or nature of the deviahon to WPP for evaluation and disposition. The inspecturs evaluated the five deviation disposition requests that had been submitted to WPP as of the inspection and noted no conditions that would be reportable to the NRC under 10 CFR Part 21.

c. Conclusions The responsibility for 10 CFR Part 21 has been assumed by WPP, with ABSS required to report all deviations for WPP evaluation and disposition.

3.2 Manufacturino Process Control

a. Insoection Scope The inspectors reviewed Soction 9, " Process Control," of the ABSS Quality Assurance Manual, Revision 24; and the technical requirements of Westinghouse Material i

Specification B163C23, Revision D, pertaining to chemistry, mechanical properties, microstructure, hydrostatic testing, cicaning, prohibited materials, and packing. The inspectors also reviewed the ABSS control procedures that had been developed to satisfy the Westinghouse technical requirements, and observed their implementation in the production process. The reviewed rocedures were: Control Procedure 4601,

" Contamination surveillance program," Revision 1; Control Procedure 4611, " Melting and metal working," Revision 0; Control Procedure 4612, " Cleaning processes prior to final pilgering," Revision 0; Control Procedure 4622, " Control of micro inclusions on bars,"

Revision 0; Control Procedure 4631, " Cleaning after final cold pilgering," Revision 4; Control Procedure 4644, " Packing," Revision 2; Control Procedure 4657, " Hydrostatic pressure test," Revision 0; Control Procedure 4668, " Micro tests," Revision 0; Control Procedure 4669, " General and intergranular a: tack test," Revision 0; and Control Procedure 4671, "Intergranular corrosion test," Revision 0.

b. Observations and FindiD21 The inspectors verified that the content of the ABSS control procedures was consistent with the technical requirements of Westinghouse Material Specification B163C23, Revision D. Performance of cleaning processes prior to and 9fter final cold pilgering was found to conform to procedural requirements. . Production personnel were observed, 3-

without exception, to wear gloves during handling of final dimension tubing and exhibited commendable rigor in their efforts to preclude contamination of the tubing surfaces.' The -

inspectors noted from review of a sample of chemistry and mechanical property data that the data conformed to the requirements of Westinghouse Material Specification B163C23, Revision D. The limited heat to-heat variation in tubing composition and mechanical properties were considered by the inspectors to be indicators of good melting and manufacturbg process controls, The inspectors determined from review of metallographic and laboratory data that the carbide morphology, grain size, and resistance to intergranular corrosion conformed to Westinghouse Material Specification B163C23, Revision D, requirements. During this review, the inspectors independently reviewed available specimens to confirm the accuracy of the ABSS photomicrographs. The inspectors were, however, unable to preselect specific specimens for review due to the ABSS practice of discarding specimens after completion of examination.

Observation of hydrostatic testing indicated testing conformed to the test pressure and holding time requirements of Control Procedure 4657, Revision 0, with the operator noted to comply with the procedural criteria for removing recidual water. The inspectors also verified that the demineralized water used for the testing satisfied the chemistry and conductivity requirements of the procedure.

The inspectors noted from review of Control Procedure 4601, Revision 0, that ABSS had attempted to comprehensively define the materials that come into physical contact with final size tubes. The procedure was verified by the inspectors to ap propriately reflect the material prohibitions of Westinghouse Material Specification B163C23, Revision D. The inspectors toured Tube Mill 68 to confirm that the procedure accurately reflectea contact materials. With the exception of one minor discrepancy, the inspectors found that the procedure appropriately described the materials that come into contact with final size tubing. The discrepancy pertained to the omission of the contact of plywood in intermediate storage racks. ABSS immediately issued Revision 1 to Control Procedure 4601 to incorporate the information regarding the intermediate storage racks.

c. Conclusions The procedural controls used for manufacture of the South Texas Project, Unit 1, tubing were consistent with 'he technical requirements of Westinghouse Material Specification 8163C23, Revision D. Overall proceduralimplementation was good, with the limited heat to heat variation in tubing composition and mechanical properties considered to be indicators of good melting and manufacturing process controls, 3.3 Control of Special Processes 3.3.1 Material Heat Treatment

a. _ Inspection Scope I

The inspectors reviewed the tubing heat treatment requirements contained in:

Westinghouse Material Specification B163C23," Thermally Treated Alloy UNS N06690 4

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(Alloy 690) Tubing for South Texas Unit No.1 Replacement steam Generators (Section lil NB, SB 163, Code Case N 20-3)," Revision D; and Section 9.3, " Process Control," of the ABSS Quality Assurance Manual, Revision 24, The inspectors als.

reviewed the ABSS heat treatment procedures that had Deen developed to implement the requirements of Westinghouse Material Specification B163C23 Revision D, and observed their implementation during the production process. The reviewed heat treatment procedures were: Control Procedure 4632, " Final bright annealing," Revision 0; Control Procedure 4636, "Long time th rmal treatment," Revision 1; and Control Procedure 4642,

" Stress relievir,g,' Revision 1.

b. Observations and Findings The inspectors verified that the technical requirements of the ABSS heat treatment procedures were consistent with Westinghouse Material Specification B163C23, Revision D. One discrepancy had been previously identified by ABSS in a Deviation Disposition Request date.1 September 25,1997. The deviation, which had been dispositioned *use-as is" by WPP, identified that the Westinghouse material specification requirement for monitoring the hottest and coldest tubes during bright annealing was not valid for the type of furnace used by ABSS. The inspectors reviewed the furnace design and concurred with the WPP disposition.

The inspectors observed final annealing operations that were being performed on South Texas Project, Unit 1, tubing and noted no departures from procedural requirements with respect to temperature, travel speed, and dew point of the protective hydrogen gas.

During review of a sample of thermal treatment charts for South Texas Project, Unit 1, tubing, the inspectors noted that the temperature printout for the No.1 position consistently showed values (i.e.,690-695 C) during the hold period that were below the minimum specified 715 C. The inspectors ascertained that the No.1 position corresponded with a thermocouple that was the closest to the front end of thc fumace.

This thermocouple was located closer to the end of the furnace than tubing in fumace charges. While assessing the potential significance of the 690-695#C temperatures, with respect to the temperatures reached by tubing at locations closest to the front end of the furnace, the inspectors ivund that ABSS was not fully complying with the load thermocouple requirements of Control Procedure 4636, Revision 1.

Section 2.3 of Control Procedure 4636, Revision 1, states, in part, " . Three load thermocouples are inserted from each fumace end. The thermocouples have three different lengths (16.4,32.8 and 52.5 feet =5,10 and 16 meters) to survey the longitudinal heat distribution. Some are located at the rentre and some are attached to the tube surfaces by stainless steel wire at the surface of the tube bundle in order to survey the heat distribution in cross section . . " The inspectors noted that ABSS was inserting two 10-meter long thermocouples from the front end of the furnace, rather than the required 5-meter and 10-meter long thermocouples. The inspectors determined that the longest tubes in the tube bundle, if uniformly positioned on the furnace car, would extend to approximately 3 meters from each end of the fumace. In response to the notificatir'n by the inspectors of the procedural noncompliance, ABSS included a thermocouple at 5

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5-meters from the front end of the furnace in the next thermal treatment fumace charge j (i.e., Charge 2056). The inspectors noted from review of the fumace chart for.

Charge 2056 that this thermoccuple was the slowest to reach the hold range, taking approximately 30 minutes longer than the previous coldest load thermocoup!e (i.e., l 5 meters from back end of the fumace). Se: tion 4 of Control Procedure 4636, Revision 1, I states, in part, ". . . When the coldest load thermocouple has reached 1319 F (715' 0) the hold time timer, set at 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, is started . . . ." The inspectors concluded from review of j the temperature dats that the potential consequence of not inserting a 5-meters long '

thermocouple from the front end of the fumace was a portion of the tubing length could receive a 9.5 hou' so A in the thermal treatment range, rather than the 10 hors specified by Control Procedure 4636, Revision 1. A deviation disposition request was prepared by ABSS, in response to the inspectors' observations, in order to !nitiate an evaluation of the effects of the nonconforming heat treatment practice on previously thermally treated tubes. The failure to appropriately use the thermal treatment procedure, as required by Criterion IX, " Control r'f Special Processes," of /.ppendix B to 10 CFR Part 50, was identified as Nonconformance 99901326/97-0101.

c. Conclusions The ABSS procedural requirements for performance of bright annealing, thermal treatment, and stress relief of South Texas Project, Unit 1, tubing were consistent with Westinghouse Mate ial Specification B163C23, Revision D. Observed bright annealing operations conformed to the requirements of Control Procedure 4632, Revision 0, with respect to temperature, travel speed, and dew point of the hydrogen protective gas. A nonconformance was identified in regard to the failure to conform to the thermocouple location requirements of Control Precedure 4636, Revision 1, 3.3.2 Nondestructive Examination

a. Insoggtion Scogg The inspectors reviewed the ABSS nondestructive examirrtion procedures that had been developed to satisfy the requirements of Westinghouse Material Specification B163C23, Revision D, and observed their implemernation during the production process. Control Procedure 4651, "In-service inspectability," Revision 1, specified the procedure to be used for assessing the signal-to-noise ratio of the tubing. Control Procedure 4651," Ultrasonic test," Revision 1, and Control Procedure 4652, " Eddy-Currerd tast," Revision 2, defined the respective ultrasonic and eddy current examination requirements for detection of discontinuities in straight tubes prior to thermal treatment. Dimensional requirements for straight tubes were contained in Control Procedure 4653, " Continuous wall thickness measurement," Revision 0, and Control Procedure 4654, " Continuous outside diameter measurement," Revision O. process. Eddy current examination requirements for the final inspection after bending of U-tubes were specified in Control Procedure 4659, " Multi Frequency EC-examination of Dbent tubes (MlZ-18)," Revision 3.

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b. Observations and Findinas The inspectors verified that the eddy current data analysts observed conducting Control Procedure 4659, Revision 3, were appropriately qualified. Records for the qualification of these and other analysts were available and observed to be appropriately approved by inspection oversight authorities. Inspection parameters (e.g., probe type, acquisition equipment, test frequencies) were documented in the ABSS control procedures in accordance with Westinghouse Material Specification B163C23, Revision D; and Section V, Article 8, and Section XI, Appendix IV, of the ASME Boiler and Pressure Vessel Code. The inspectors observed that the tube signal-to-noise ratios for a number of straight tubes examined during the inspection were in excess of the Westinghouse specified minimum value of 15:1. In addition, ABSS made permanent records of these measJrements in HCCordance with Section 6.7.5 of Westinghouse Material Spcification B163C23, Revisim D.

The inspectors noted strengths in the practices employed by the data analysts in evaluating the eddy current data from the inspection of U-bent tubes. Specifically, the enalysts undertook additional conservative measures not required by the analysis guidelines to ensure that tubes did not contain unacceptable discentinuities. These actions included visually confirming the presence o' manufacturing bumish marks (MBMs) during the initial stages of tube production, assessing the root cause of absolute drift response signals, and locating indications on the low frequency channels using signals from the tube support table structure.

The inspectors noted that two different diameter bobbin coil probes,0.520-inches and 0.560-inches, had been used to inspect U-tubes in accordance with Control Procedure 4659, Revision 3. In addition, the assessment of tube signal-to-noise utilized a bobbin coil probe that was a different type to the two sizes used in this control procedure.

The inspectors fudher noted that Westinghouse Material Specification B163C23, Revision D, did not preclude the use of different probes in the production process, and also provided no criteria on allowable orobe wear. ABSS had also not restricted the amount of probe wear. The inspectors considered the absence of probe wear criteria and the use of various probe sizes as potential contributors to inconsistencies in the eddy current data obtained during tube production. Such inconsistencies could complicate the comparison of tube production data with that obtained during preservice inspection of the completed steam generators.

ABSS, in conjunction with the licensee for the South Texas Proget, Unit 1, established a 6 volt criterion to identify tubes with MBM indications that Ic ally reduced wall thickness in excess of the 5 percent limit imposed by Westinghouse Material Specification B163C23, Revision D. The inspectors reviewed the technical bases for the 6 volt criterion and identified that the voltage level for 5 percent through-wall MBM indications was slightly nonct.1servative (5.91 volts versus 6 volts), did not contain any margin for dats scatter due to the uncertainty in the analysis and acquisition of data, and did not take into account the use of bobbin coil probes with different diameters, as discussed previously. Because of these deficiencies, the inspectors concluded that this criterion by itself would not ensure that all MBMs identified during the inspection would have acceptable wall thicknesses in 7-a

the area of the indication. However, the inspectors observed that, based on the extremely limited metal removal that would be anticipated to occur during buffing operations following thermal treatment, the eddy current methodology used for examining MBMs did not appea, to represent other than a minor technical concem.

The inspectors observed scratches on the surface of the finished U-bend tubes.

Section 7.4 of Westinghouse Material Specification B163C23, Revision D, states that,

" tubing shall be . . . free from seams, cracks, tears, laminations, laps, pitting and other injurious imperfections." The ABSS control procedures did not include any specihc guidance for assessing when imperfections, such as the noted scratches, cou;d be considered to be injurious imperfections. During the tube in:.pections in the final stages of

. production, workers were observed attempting to remove these scratches through a manual buffing process. Despite smoothing the scratches slightly during this stage of production, some visible axial imperfections remained in the tubes that were not detected in the final eddy current inspections. The inspectors noted that degradation history for mill annealed Inconel 600 tubing indicates that surface scratches can often be the initiation sites for service induced tube degradation. However, the inspectors concluded that the absence of specific criteria in the ABSS control procedures and in the Westinghouse specification for determining when imperfections were injurious was a technical deficiency rather than a procedural nonconfonnance.

c. Conclusions The ABSS nondestructive examination procedures sad practices were found to be consistent with the requirements specified in Westinghouse Material Specification B163C23, Revision D. The inspectors identified minor technical concerns regarding MBM inspection criterion, maintaining consistency in the eddy current inspection data, and the absence of criteria for classifying what surface imperfections were considered injurious.

3.4 Material Traceability and identification

a. Inspection Scopa The inspectors reviewed the material traceability and identification requirements contained in: Westinghouse Material Specification B163C23, Revision D; Section 8, " Product identification and Traceability," of the ABSS Quality Assurance Manual, Revision 24; and related ABSS control procedures. Personnel practices for maintaining material traceability and identification were also observed at various stages of manufacture production to verify 2 consistency with program requirements. With the exception of activiWs ongoing after final pilgering, the observed ABSS practices for maintaining material traceability and identification were conducted on material not destined for the production of tubing for the South Texas Project replacement steam generators. However, ABSS personnel stated that the material tracenbility and inspection practices observed were the same as those used for the production of steam generator tubing.

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b. Observations and Findinas Control Procedure 4603, *ldentification and traceability," Revision 2, included the general requirements for ensuring that materialidentification is maintained throughout the production process. The procedure, however, did not specifically indicate how identification and traceability are maintained at each stage of the process. The inspectors assessed the practices utilized by personnel at several stages of production thrcugh direct observation and verified the identification of materials between process steps. The inspectors observed 13at the production practices were consistent with the requirements of Section 8 of the ABSS Quality Assurance Manual, Revision 24, and that all materials were appropriately labeled when possible. During stages of production where actuallabeling on the material was not possible (e g., hot rolling, extrusion, pilgering), operators employed practices for tracing the material through the stage of process that should minimize the p9tential for rnislabeling or a loss of materialidentification.

ABSS used a labeling system where material was tracked by a lot identification number.

Lots of material are from a single heat and assigned a unique lot number after cutting round bars into extrusion billets as specified in Control Procedure 4602, " Lot identification," Revision O. After final pilgering, the tubes within a single lot were worked, in general, separately from tubes in other lots during each stage of production. The inspectors observed discenoble breaks between processes from one lot to the next. In instances where lots we e continuously processed, the inspectors noted that production personnel were tracking tubes within each lot and identified the break between tubes in separate lots.

c. CQncluti9At The procedures and practices utilized during the production of tubing appeared adequate for ensuring proper material identification and traceability throughout the process, and wers consistent with the requirements of Section 8 of the ABSS Quality Assurance Manual, Revision 24.

3.5 Entrance and Exit Meetinas At the entrance meeting on October 27,1997, the inspectore discussed the scope of the inspection, outlined the areas to be inspected, and established interfaces with ABSS management. In the exit meeting on October 3',1997, the inspectors discussed their findings and observations. Westinghouse Material Specification B163C23, Revision D, was identified as containing proprietary information. Flo information was included from this document in the inspection report that was considered proprietary. No information was identified by ABSS during the inspection as being considered proprietary.

4 PARTIAL LIST OF PERSONNEL CONTACTED ABSS cornorate ,

Ber1il Larsson, Quality Assurance Mans;ger i 6SSS Prod: ct Center Steam Generator Tubina  ;

Mats Tynell, General Manager G6 tan Bjorkman, Production Manager Per Olof Lund, Quality Assurance Manager .

Hans T6rnblom, Manager, Technique and Development  ;

Benny Pettersson, Manager,' Marketing -

l Jan Erik Bohman, Manager, Nondestructive Examination

• STP Nuclear Ooeratliia comoany H. Gunther Domschke, Quality Assurance Staff Specialist Westinghouse Pensacola Plant James Allen, Senior Quality Assurance Engineer 1 Richard Fremgen, Senior Engineer

, Magnus Larsson, Resident inspector (SAQ)

ITEMS OPENED i

- Dooned 99901326/97 01 01 Para. 3.3.1 NON Inadequate control of thermal treatment V

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