IR 05000498/1998014
| ML20238F730 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/31/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20238F729 | List: |
| References | |
| 50-498-98-14, 50-499-98-14, NUDOCS 9809040240 | |
| Download: ML20238F730 (12) | |
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ENCLOSURE U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket Nos.:
50-498;50 499 License Nos.:
50-498/98-14;50-499/98-14 Licensee:
STP Nuclear Operating Company Facility:
South Texas Project Electric Generating Station, Units 1 and 2 Location:
FM 521 - 8 miles west of Wadsworth
Wadsworth, Texas
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Dates:
July 6-23,1998 Inspector:
lan Barnes, Technical Assistant Approved By:
Arthur T. Howell 111, Director Division of Reactor Safety ATTACHMENT:
SupplementalInformation
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PDR ADOCK 05000498 G
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EXECUTIVE SUMMARY South Texas Project Electric Generating Station, Units 1 and 2 NRC lospection Report 50-498/98-14; 50-499/98-14 Enoineerina The licensee quality organization has performed comprehensive oversight of
Westinghouse and its subvendors during materials manufacture and steam generator vessel fabrication, and has been proactive in the measures taken to assure compliance with the technical and quality requirements of the licensee specification for replacement steam generators (Section E7.1).
Meaningful evaluation of engineering oversight effectiveness could not be accomplished
due to the limited assessment information contained in the progress and trip reports
..made available for review (Section E7,1).
The current effectiveness of licensee review of vendor technical documents was
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considered good (Section E7.2).
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-2-Report Details
This inspection was the second performed (using Inspection Procedure 50001) in regard to oversight of Unit 1 replacement steam generator design, manufacture, and installation activities.' The primary purpose of the inspection was to complete review of licensee oversight activities in regard to steam generator design and manufacture.-
Summarv of Plant Status
' Units 1 and 2 were at 100 percent power during the onsite inspection period.
lit. Engineering E7 Quality Assurance in Engineering Activities E7.1 Oversiaht of Steam Generator Vendor Enaineerina and Manufacturing Activities a.
Insoection Scope (50001)
The inspector reviewed: (1) Document " South Texas Project Replacement Steam Generator Project independent Oversight," issued October 1,1997; (2) vendor deficiency reports which had been issued to Westinghouse Pensacola Plant; (3) licensee Audit Report 97-088 dated January 12,1998, which documented the audit i
performed at the Equipos Nucleares, S.A. (ENSA) facility in Maliano, Spain; (4) Surveillance Report 98-005 dated March 10,1998, which documented a January 26 through February 6,1998, surveillance at the ENSA facility; (5) a file of vendor inspection reports for Westinghouse Pensacola Plant that had been issued through June 1998; (6) correspondence pertaining to the issue and subsequent lifting of a stop
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work order to Westinghouse; and (7) available documentation regarding engineering
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surveillance activities at Westinghouse Pensacola Plant and Westinghouse Monroeville, b.
Observations and Findinas-The inspector noted that the independent oversight plan provided comprehensive quality management guidance regarding the scope of independent oversight of replacement ste^am generator design, manufacture, and installation. The scope and number of hardware inspections performed at Westinghouse Pensacola Plant by the licensee resident inspectors were considered impressive by the inspector, and were noted to be fully consistent with the guidance of the independent oversight plan. The findings noted during the audit and subsequent surveillance of Equipos Nucleares S.A. were supportive of earlier licensee concerns regarding the effectiveness of Westinghouse oversight of its subvendors. These concerns, coupled with identified engineering and manufacturing
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-3-deficiencies, led to the issue of a stop work order to Westinghouse on November 6, 1997. This stop work order was subsequently lifted on January 29,1998, following the
' development and implementation by Westinghouse of a recovery plan which included:
l historical work reviews in the areas of design, procurement and manufacturing; performance of root cause analyses and development of preventive actions; and verifications performed by the licensee regarding the historical reviews.
The engineering documentation provided to the inspector, with the exception of input given regarding a surveillance performed in April 1998 at Westinghouse, Monroeville, -
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was predominantly engineering progress reports and trip reports reflecting job status at Westinghouse Pensacola Plant. The limited assessment information contained in these
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i documents with respect to technical adequacy of vendor performance precluded i
meaningful evaluation of the effectiveness of engineering oversight activities.
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Conclusions J
The licensee quality organization has performed comprehensive oversight of Westinghouse and its subvendors during materials manufacture and steam generator
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vessel fabrication, and has been proactive in the measures taken to assure compliance with the technical and quality requirements of the licensee specification for replacement steam generators. Meaningful evaluation of engineering oversight effectiveness could not be accomplished, due to the limited assessment information contained in the progress and trip reports made available for review.
I E7.2 Licensee Technical Review of Vendor Documents a.
inspection Scope (50001)
The inspector performed a review of selected Westinghouse Pensacola Plant process documents (including specifications and procedures, welding procedure specifications and supporting procedure qualification records, and quality inspection procedures) that had been reviewed and approved by licensee staff. The review was performed to assess the current effectiveness of licensee and Westinghouse review in assuring conformance to applicable ASME Code requirements and the technical and quality requirements of licensee Specification 4R129NS1014, " Replacement Steam Generators," Revision 1.
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Observations and Findinas i
The inspector noted that, in general, the Westinghouse process documents contained appropriate technical requirements for performance of welding, arc-air gouging, and post-weld heat treatment. Outstanding questions at the completion of the onsite portion of the inspection (i.e., qualification of tube-to-tube sheet Welding Procedure Specification 41641, with respect to tube temperatures attained during performance of
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local post-weld heat treatment of the final vessel shell closure weld; and consistency of i
Procedure DMP-5557, Revision 06, with_ respect to licensee Specification 4R129NS1014, Revision 1, requirements for metal removal following arc-air gouging)
l were appropriately resolved by information provided during in-office review. The provisions for maintaining vessel cleanliness and precluding entry of foreign objects i
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-4-were additionally found to be adequate. No noncompliance with ASME Code requirements or licensee specification requirements were noted during review of the Westinghouse process documents.
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Conclusions Review of current Westinghouse welding, arc-air gouging, post-weld heat treatment, and cleanliness process documents detected no examples of noncompliance with either ASME Code or the technical and quality requirements contained in licensee Specification 4R129NS1014," Replacement Steam Generators," Revision 1. As a result, the current effectiveness of licensee review of vendor technical documents was considered good.
E8 Miscellaneous Engineering issues (92700,92903)
E8.1 (Closed) Violation 50-498/9718-01: Failure to update steam generator specification to reflect approval of use of SA-533, Grade B, Class 2 plate.
The inspector confirmed from review of Specification 4R129NS1014," Replacement Steam Generators," Revision 1, that the specification had been revised to reflect the acceptability of SA-533, Grade B, Class 2 plate. Licensee personnelissued Vendor Deficiency Report 97-021 to Westinghouse as part of the actions taken in response to the violation. Corrective actions taken by Westinghouse included review of 38 released material specifications against the requirements of Specification 4R129NS1014. This review identified that Westinghouse Material Specification A508CO7, Revision F, for small nozzles, specified a SA-508 material class (i.e.,1a) which was not currently permitted by the licensee specification. Review also identified two doiiciencies regarding Material Specification A336CO1, Revision F, for primary nozzle safe end forgings; These deficiencies pertained to the failure to impose the cobalt and hardness limits of the licensee specification. Other Westinghouse specification deficiencies identified during the corrective action review process, in regard to licensee specification requirements, included the identification of: (1) a less restrictive sulfur limit for closure studs and nuts; and (2) a less restrictive carbon limit, ferrite range, and cobalt limit for stainless steel welding materials. The licensee corrective action program is being usea to track resolution of the specification deficiencies.
The inspector additionally verified that: (1) the Westinghouse engineering manager had reemphasized to Westinghouse Pensacola project engineering personnel the importance of thorough review, and the need to satisfy customer technical specifications; and (2) a guideline defining management expectations regarding depth of technical review by South Texas engineers had been issued, and training of review personnel had been accomplished.
E8.2 (Closed) Inspection Followuo item 50-498/9718-02: Compliance of material
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l manufacturers with the requirements of ASTM E23 and E208 during mechanical testing I
of material samples.
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5-At the inspector's request, the licensee obtained from Westinghouse certifications 2 showing the compliance of manufacturers of ferritic pressure boundary materials with the Charpy-V notch impact test requirements of ASTM E23. Information was also obtained regarding the compliance with ASTM E208 of hard facing electrodes used in the preparation of drop weight test specimens.
,The inspector reviewed letters issued by.the National Institute of Standards and
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- Technology (NIST) to the manufacturers of ferritic pressure boundary materials for the South Texas Project, Unit 1, replacement steam generators (i.e., Ansaldo; Creusot Loire; Japan Steel. Works, Muroran Plant; and Kobe Steel), regarding the Charpy-V impact test results obtained from their Charpy-V impact machines using NIST standard specimens. All impact machines were found to comply with the requirements of
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ASTM E23 at the time of manufacture of the South Texas materials. The information provided regarding hard facing electrodes used in the preparation of drop weight specimens demonstrated appropriate compliance with ASTM E208.
. E8.3 (Closed) Reauested Response 50-498:499/97-18: Reported magnetic particle examination data in Ansaldo certification for the upper shell courses did not appear to conform to ASME Section V Code prod amperage requirements.
During review of Ansaldo certification for the upper steam generator shell courses (that was furnished by Westinghouse to the licensee in response to a request from the inspector), the inspector observed that the reported magnetic particle examination data
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appeared to not conform to ASME Section V Code prod amperage requirements.
' Specifically, Article 7, paragraph T 743.2 of ASME Section V Code requires an amperage range of 100-125 amperes per inch of prod spacing be used for ~ conducting magnetic particle examinations of section thicknesses 3/4 inch and,qreater. Ansaldo was required by Westinghouse Drawing 6488E61 to perform a magnetic particle examination of the longitudinal weld joint preparation surfaces, the dressed root of the ~
initial weld prior to completion of the weld from the second side, and the final post weld t heat treated surfaces. During review of Test Report 11581 dated January 15,1997, which pertained to magnetic particle examination of the root of a "J" shell (Item 006,
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Purchase Order ES2891) longitudinal weld seam after grinding, the inspector observed
' that the recorded amperage and prod spacing values were, respectively, -1000 amperes and -180 mm. The maximum amperage permitted by the ASME Section V Code for this prod spacing was calculated by the inspector to be 886 amperes. The use of -1000 amperes for the examination thus appeared to exceed 'ASME Section V Code
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requirements. The inspector reviewed the magnetic particle examination test report for the weld joint preparation surfaces for the "J".shell course and the corresponding test reports for the "H" shell course, and noted the same recorded values for amperage and
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. prod spacing. The transmittal letter to inspection Report 50-498; 499/97-18 subsequently requested the licensee to furnish the corrective actions taken by
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Westinghouse to resolve the potential ASME Code violation.
Westinghouse responded that it was the customary practice at Ansaldo to report the maximum amperage permitted by the procedure when a range was given, even though the operator would correctly set the amperage as a function of prod spacing and material thickness. Certification was provided by Ansaldo, which was signed by the quality assurance manager and the authorized nuclear inspector, attesting to
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performance of the shell barrel magnetic particle examinations in accordance with a
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qualified procedure that had been approved by their Level 111 examiner and demonstrated to the satisfaction of the authorized nuclear inspector. Westinghouse and licensee personnel have confirmed that the magnetic particle procedural test parameters comply with ASME Code requirements. Licensee personnel also witnessed shell course magnetic particle testing in mid-1997 and found that the testing was performed in accordance with established parameters.
Following the NRC inspection, licensee and Westinghouse personnel visited Ansaldo in August 1997. At that time, the adequacy of the magnetic particle machine calibration was verified and a worst-case scenario was investigated. The testing included use of 990 amperes and a 6-inch prod spacing (i.e., lower than the 180 mm average value reported on the Ansaldo certification). This testing demonstrated, as evidenced by the field indicator at the workpiece and the regularity of action of the magnetic powder, no loss of test sensitivity. Known indications in a calibration test block obtained from the j
German State Agency TUV were also satisfactorily detected using these parameters.
Ansaldo additionally committed to record actual values in future testing. The inspector concluded that the licensee and Westinghouse had provided appropriate assurance regarding the adequacy of the magnetic particle examinations performed by Ansaldo.
E8.4 (Closed) Licensea Event Report 50-499/97-002: Greater than 1 percent of steam generator tubes defective. in accordance with Technical Specification 4.4.5.5c, the
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licensee reported that greater than 1 percent of the tubes inspected in Steam
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Generators 2A,2B,20, and 2D during Unit 2 Refueling Outage 2REOS had been identified to be defective.
The inspector ascertained from review of the steam generator tube eddy current
examination results for Unit 2 Refueling Outage 2REO5, that the respective numbers of I
defective tubes in Steam Generators 2A,28,2C, and 2D that had been identified were
' 123,168,146, and 161. These totals represented, respectively,2.54 percent,3.47 I
percent,.3.02 percent, and 3.32 percent of the active tube population in Steam j
Generators 2A,28,2C, and 2D, and thus were reportable under Technical i
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Specification 4.4.5.Sc. All identified defective tubes were removed from service by plugging. An additional two tubes in Steam Generator 2A and one tube in Steam l
Generator 2B were preventively plugged, resulting in a total of 601 tubes that were removed from service during Refueling Outage 2REOS. The majority of the flaw j
indications were axial, originated at the outside diameter surface of the tubing, and were located at tube support plate intersections on the hot-leg side of the steam generators.
The applicable degradation mechanism for these eddy current indications was believed, based on industry data and Unit 1 tube pull results, to be outside diameter stress l
corrosion cracking.
The actions taken by the licensee to increase tubing stress corrosion resistance and minimize steam generator tube degradation were reviewed during a 1993 steam l
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generator tube integrity inspection (NRC Inspection Report 50-498; 499/93-28). The licensee was found to have conformed to industry secondary water chemistry guidelines
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throughout commercial service, and to have maintained overall excellent Unit 2 secondary water chemistry performance. Specific steam generator tube integrity initiatives that have been implemented to minimize degradation have included:
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Thermal stress relief of Rows 1 and 2 low radius U-bends prior to unit operation to minimize the tubing susceptibility to primary water stress corrosion cracking.
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Removal of secondary system copper alloys (other than condenser tube sheets)
prior to unit operation.
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Shot peening of the inside diameter surface of the tubes in the tube sheet expansion transition region in Refueling Outage REO1 (hot-leg side) and Refueling Outage REO2 (cold-leg side), to minimize development of primary water stress corrosion cracking at this location.
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Expansion of 160 tubes in the steam generator preheater section at the "B" and
"D" baffle plate locations, prior to unit operation, in order to minimize tubing wear.
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Reduction of To from an average of ~624 *F to -620 *F in 1995 at the start of Cycle 5.
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Addition of a full flow deaerator prior to unit operation for control of dissolved oxygen.
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Addition of cation condensate polishers to existing full flow mixed bed condensate polishers prior to unit operation.
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Increasing the capacity of the steam generator blowdown system prior to unit i
operation to 1 percent of main steam flow, in order to minimize steam generator I
contaminate levels and reduce the time to recover from chemistry transients.
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Installation of Na monitors prior to unit operation, in order to provide the capability for continuous indication of primary-to-secondary leakage.
The licensee attributed the root causes of the outside diameter stress corrosion cracking to be the selection of mill annealed Inconel 600 tubing for the steam generators and the tube-to-tube support plate crevices created by the use of drilled holes. High reactor coolant system hot leg temperature design values were considered a contributory factor.
The inspector noted that industry operating experience confirms the vulnerability of mill
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annealed inconel 600 to outside diameter stress corrosion cracking, the importance of operating temperature, and the concentration of contaminates that can occur in tight crevices.
l The licensee has subsequently submitted a license amendment for application of voltage-based repair criteria to Unit 2 (in accordance with Generic Letter 95-05) at the tube support plates. A similar amendment was previously approved for Unit 1. The low voltages of the majority of the flaw indications detected during Refueling Outage 2REOS would, if the voltage-based repair criteria had been approved for use, have resulted in a
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significant reduction in required repairs (i.e., only 32 of the 601 total actually plugged).
The inspector concluded that the licensee has progressively implemented comprehensive corrective actions to increase tubing stress corrosion resistance and minimize steam generator tube degradation.
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V. Manuuement Meetinas X1 Exit Meeting Summary The inspector gave an inspection debrief to licensee personnel on July 9,1998, at the completion of the onsite portion of the inspection. This debrief covered the status of the inspection, additional planned reviews, and subjects where additional information was needed. Following further in-office review, the inspector presented the inspection results to licensee staff on July 23,1998, in a telephonic exit meeting. The licensee acknowledged the findings presented. Westinghouse documents were reviewed during the inspection which were identified as containing proprietary information. The specific -
content of the documents that was considered proprietary was not identified. No information was included in the inspection report that was considered proprietary.
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ATTACHMENT SUPPLEMENTAL INFORMATION PARTIAL LIST OF PERSONS CONTACTED j icensee P. Arrington, Licensing Specialist R. Baker, Senior Consulting Engineer, Design Engineering
'J. Blevins, Supervisor, Document Control W. Bullard, Supervisory Health Physicist D. Chamberlain, Consulting Engineer T. Cloninger, Vice President, Nuclear Engineering S. Eldridge, Quality W. Harrison, Senior Consulting Engineer, Nuclear Licensing J. Johnson, Manager, Engineering Quality L. Martin, Vice President, Nuclear Assurance and Licensing M. McBurnett, Director, Nuclear Licensing A. McIntyre Director, Engineering Projects
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W. Mookhoek, Licensing Engineer U. Patil, Senior Consulting Engineer, Design Engineering R. Rehkugler, Director, Quality K. Richards, installation Manager, Steam Generator Replacement K. Silverthorne, Weld Program Supervisor J. Simmons, Radiation Protection Supervisor L. Stinson, Auditor, Procurement Quality
~ B. Sweeney, Licensing Engineer S. Thomas, Manager, Design Engineering S. Timmaraju, Senior Consulting Engineer, Design Engineering T. Walker, Manager, Procurement Quality INSPECTION PROCEDURES USED iP 50001 Steam Generator Replacement inspection IP 92700 Onsite Follow-Up of Written Reports of Nonroutine Events at Power Reactor Facilities IP 92903 Followup-Engineering
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LIST OF ITEMS CLOSED i
50-498/9718-01 VIO Failure to update steam generator specification to reflect approval
of use of SA-533, Grade B, Class 2 plate (Section E8.1).
50-498/9718-02 IFl Compliance of material manufacturers with the requirements of ASTM E23 and E208 during mechanical testing of material samples (Section E8.2).
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c-10-50-498;499/97-18 (1)
Corrective actions taken by Westinghouse to resolve a potential ASME Code violation (Section E8.3).
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Response requested by transmittal letter to inspection Report 50-498;499/97-18.
50-499/97-002 LER Greater than 1 percent of steam generator tubes defective (Section E8.4).
LIST OF DOCUMENTS REVIEWED Licensee Specification 4R129NS1014, " Replacement Steam Generators," Revision 1 Welding Procedure Specification (WPS) 4241, Revision 01, and supporting Procedure Qualification Record (POR) 8505 WPS 4137-1,2,3,4,5,6,7,8,9, and 0, Revision 02, and supporting PORs 3580,3854,3960, 3961, and 3962 WPS 4164-1and -2, Revision 12, and supporting PORs 3598 and 8541 WPS 4142-1, Revision 07 General Welding Specification DMP-5556," Submerged Arc Welding ASME Boiler and Pressure Vessel Code Section IX and Section 111." Revision 10
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Procedure DMP-5524, " Heat Treatment Procedure including Preheat, Interpass, Gouging, Hydrogen Baking and Post Weld Heat Treatment," Revision 50 Procedure DMP-64 0," Heat Treatment Procedure including Preheat, Interpass, Gouging, c
Hydrogen Baking and Post Weld Heat Treatment," Revision 05 Procedure DMP-6181," Post Weld Heat Treatment Steam Generator Upper Assembly and Closure Seam," Revision 14 Specification DMP-5557," General Specification for Manual and Automatic Air Arc Gouging,"
Revision 06 Procedure DMP 5788," Protection and Cleaning of Steam Generator Lower Assembly,"
Revision 05 Procedure DMP-6269," Protection and Cleaning of Steam Generator Upper Assembly,"
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Procedure DMP-5865, " Cleaning for Welding, Cladding and Buttering," Revision 01
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l Quality inspection Procedure 3364, " Cleanliness Requirements for Steam Generator,"
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Revision 11
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Procedure DMP-6255," Foreign Object Control Procedure for a Complete Steam Generator,"
Revision 06 Quality inspection Procedure 3146, " Post Weld Heat Treat Data Sys (SG & PRZ), Revision 09 Quality inspection Procedure 8573, " Ultrasonic Examination of Welds," Revision 17 Vendor inspection reports for Westinghouse, Pensacola that had been issued through June 1998 Vendor deficiency reports that had been issued to Westinghouse, Pensacola Audit Report 97-088 and Surveillance Report 98-005 for Equipos Nucleares S.A., Maliano, Spain Document " South Texas Project Replacement Steam Generator Project Independent Oversight," issued October 1,1997 Engineering documentation including trip reports, progress reports, and input to a surveillance of Westinghouse, Monroeville l
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