IR 05000440/1999006

Insp Rept 50-440/99-06 on 990303-04 & 0412-16.No Violations Noted.Major Areas Inspected:Inservice Insp Efforts & Overlay Repairs of N4C Feedwater Nozzle

ML20206H405
Person / Time
Site:	Perry
Issue date:	05/06/1999
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20206H400	List: IR 05000440/1999006 ML20206H398
References
50-440-99-06, 50-440-99-6, NUDOCS 9905110200
Download: ML20206H405 (10)

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. l U.S. NUCLEAR REGULATORY COMMISSION REGION lll Docket No.: 50-440

- License No: NPF-58

, Report No.: 50-440/99006(DRS)

Licensee: Cleveland Electric Illuminating Company Facility: Perry Nuclear Power Plant, Unit 1 Location: Post Office Box 5000 Cleveland, OH 44101 Dates: March 3-4, April 12-16,1999 inspector: Jerome Schapker, Reactor Engineer Approved by: John M. Jacobson, Chief Mechanical Engineering Branch Division of Reactor Safety (

9905110200 PDR 990506 7'

0 ADOCK 05000440 PDR

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EXECUTIVE SUMMARY Perry Nuclear Power Plant, Unit 1 NRC Inspection Report 50-440/99006(DRS)

This inspection focused on inservice inspection efforts and overlay repair of the N4C feedwater nozzle. The report covers a five-day on-site inspection and a three-day inspection at the Electric

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Power Research Institute Nondestructive Examination Center by one regional inspector, e inservice inspection activities were effectively implemented and in accordance with the licensee program and ASME requirements. The inservice inspection program reflected a strong commitment to safety through the examinations of welds susceptible to intergranular stress corrosion cracking using procedures and personnel qualified by Performance Demonstration Initiative. (Section M1.1).

• A strong inservice inspection program with active oversight of contract personnel was demonstrated by the licensee's independent evaluation of contractor-identified nondestructive examination indications and the pro-active reevaluation of feedwater nozzle flaws. (Section M1.1)

e Preparation for the weld overlay of the N4C reactor vessel feedwater nozzle to safe-end weld was well done through the use of a weld mock-up with identical nozzle and biological shield configurations. (Section E l l

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Report Details 11. Maintenance M1 Conduct of Maintenance M1.1 Observation of inservice Inspection (ISI) Activities Inspection Scoce (73753. 73755)

The inspector observed inservice inspection work-in-progress, interviewed personnel, reviewed data associated with General Electric Nuclear Energy inspection Services (GE), and observed personnel performing the following activities:

e Magnet;c particle and ultrasonic examinations (UT) of feedwater piping welds 1N27-0047 and 1N27-0048 e Enhanced visual examinations of the inside surfaces of the reactor pressure vessel e Automated ultrasonic examination of reactor vessel to N4A nozzle weld using the General Electric Reactor inspection System (GERIS)

e Automated ultrasonic examination (Tomoscan/Tomoview) of the N4C-KB and N4E-KB feedwater nozzle safe-end welds data stored on optical discs e Mock-up overlay welding of feedwater nozzle safe-end to nozzle weld e Ultrasonic equipment calibration prior and post performance of examination I Observations and Findinas Licensee and contractor personnel adhered to procedural requirements and demonstrated the knowledge and skills necessary for the examinations observed. The inspector noted that a licensee Level I!! examiner had been assigned to provide active j oversight of contractor Level 111 personnel. The licensee personnel made independent evaluations of indications found during ISI examinations and compared their results with the flaw dispositions made by the Level lli contractor in accordance with the recommendations in Generic Letter (GL) 88-01, the licensee performed augmented inspections of the reactor vessel coolant nozzle to safe-end welds which are all dissimilar metal welds that contain an inconel 182 buttering. During ,

Refueling Outage (RFO) 2, a shallow flaw was detected in feedwater nozzle to safe-end !

weld N4C-KB.' The flaw was sized and evaluated in accordance with ASME Section XI, l Article IWB-3600. In RFO-3, the intergranular stress corrosion cracking (IGSCC) '

susceptible safe-end welds were treated with Mechanical Stress improvement Process (MSIP) and received pre-MSIP and post-MSIP UT examination with no change in flaw siz ;

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In 1996, the Hope Creek Generating Station experienced a through-wall flaw in one of their Core Spray nozzle to safe-end welds. The extent of this flaw had not been identified previously with the analysis techniques applied at the time. The GE Smart System (Tomoscan) had been used to examine the weld in 1992 and 1995 and had not reported any flaws. A retrospective evaluation of the data by GE determined that the flaw was present in the 1995 data. This prompted GE and other ISI vendors to pursue )

better data analysis procedures and softwar The licensee applied this background to dissimilar metal welds previously analyzed using Tomoscan. The same UT data (stored on optical disc) was analyzed using the new (Tomoview) software. The re-evaluation of N4C-KB feedwater nozzle to safe-end weld data showed a pre-existing flaw to have changed slightly in length and significantly in the i through wall dimension. The flaw depth was determined to be 0.75 inches, rather than the 0.25 inches previously reported in the last U )

The licensee employed the services of the Electric Power Research Institute (EPRI) l Nondestructive Examination Center to perform an independent review of GE's re-evaluation of the N4C-KB using the new Tomoview software. The inspector observed i their evaluation at EPRI and determined that the Tomoview software appeared to more accurately sized the flaw. This assessment was based on previous experience in

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evaluating IGSCC type flaws. The additional complexity of dissimilar metal welds '

(changes in sound velocity, grain structure, etc) for UT examination makes the sizing of flaws very difficult. There have not been any Performance Demonstration Initiative (PDI)

procedures developed for dissimilar metal welds to date. It was the inspector's observation that the new Tomoview was a considerable improvement which enhances the analyst's ability to size flaw The licensee re-examined the N4C-KB weld during the current outage and concluded {

the flaw sizing had not changed from the previous UT examination data. Analysis of the UT data with the Tomoview software confirmed the flaw sizing was consistent with the re-analyzed data observed at EPRI. The licensee elected to repair the safe-end to i nozzle weld with an overlay weld. (Reference paragraph E2.1)

For feedwater system piping welds 1N27-0047 and 0048, the magnetic particle examinations were performed in accordance with procedural requirements. No indications were identifie During ultrasonic equipment system calibration in preparation for a UT of feedwater line weld nos.1N27-0047,1N27-0048,1N27-0037,1N27-0008,1N27-0035 and 1N27-0037,

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the GE personnel used the proper refracted angle of transducer, verified the amplitude linearity of the machine, and established the distance amplitude correction curve in accordance with the appropriate procedure. For the UT, the inspector verified that the scanning parameters were appropriate and that the correct acceptance criteria were used for indication evaluationss Weld locations were clearly identified with an etched identification number. No relevant Indications were detected. The licensee supplies the ISI examiners with previous outage data reports with the assigned ISI task, appropriate j drawings and procedure I

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l l The UT of the reactor vessel to nozzle weld N4A was performed with the General j Electric Reactor Inspection System (GERIS) automated ultrasonic inspection syste i For this examination, the inspector verified that scan parameters, which included scanning speeds, scanning level gain settings, and transducer frequencies were in accordance with the GE Procedure No. UT-702V2, Revision Visual inspections (VT) of reactor vessel internals were completed using an underwater video camera. The inspector reviewed portions of the tapes of the feedwater spargers, sparger end bracket welds, and sparger T-box and arm welds. The licensee's VT Level lil ISI engineer had previously reviewed this activity, demonstrating active contractor oversight. Pictures were very clear due to effective lighting and high resolution cameras. The enhanced visual examinations inside the reactor pressure '

vessel were of good quality and coverage. The inspector reviewed the VT video tapes l l

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and verified that no degraded welds or newly damaged components were obsewe Previously damaged components such as feedwater sparger J-tubes, which had minor dents at the openings, had not changed from previous inspection ASME Section XI, Appendix Vill, requires demonstration of the effectiveness of UT ISI l

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procedures, equipment, and personnel. To date, Appendix Vill has not been mandated by the NRC; however, the licensee proactively elected to perform applicable ISI ultrasonic examinations using PDI procedures and personnel for IGSCC susceptible j welds. These exams were demonstrated to the Authorized Nuclear Inservice Inspector !

(ANil) as required by ASME IWA-224 I Conclusions Inservice inspection activities were effectively implemented in accordance with the !

licensee's program and ASME requirements. The inservice inspection program reflected a strong commitment to safety through the examinations of welds susceptible to IGSCC using procedures and personnel qualified by Performance Demonstration Initiative. A strong inservice inspection program with active oversight of contract personnel was also demonstrated by the licensee's independent evaluation of contractor-identified nondestructive examination indications and the pro-active reevaluation of feedwater nozzle flaw M3 Maintenance Procedures and Documentation M3.1 Inservice insoection Procedures Insoection Scooe (73051. 73052)

The inspector reviewed and evaluated the following ISI documents, program procedures and ISI personnel certifications for compliance with technical specifications, ASME Code, NRC requirements and American Society for Nondestructive Testing SNT-TC-1 A recommendations:

• PNPP [ Perry Nuclear Power Plant] Procedure No. NDE-002, Revision 4,

" Ultrasonic Examination (UT) Instrument Linearity Verification"

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e e PNPP Procedure No. NDE-018, Revision 6," Ultrasonic Examination of Stainless Steel Piping Welds for IGSCC" e PNPP Procedure No. NDE-008, Revision 6. " Ultrasonic Examination of Pipe We!ds" e GE Procedure No. UT-503, Revision 8," Automatic UT of Shroud Assembly Welds" e GE Procedure No. UT-300V3, Revision 0, " Manual UT Examination of Reactor Vessel Assembly Welds" l e GE Procedure No. UT-PER-702V2, Revision 0, " Procedure for GERIS 2000 l

Ultrasonic OD Examination of RPV Assembly Welds" e GE Procedure No. UT209, Revision 5, " Automatic UT of Similar and Dissimilar Metal Welds, including Nozzle to Safe-End Welds" e GE Procedure No. UT 105, Revision 1, " Manual UT of Dissimilar Metal Nozzle Safe-End Welds" e GE Procedure No. UT-233, Revision 1, " Automatic UT Data Analysis of Piping Welds in Accordance With Performance Demonstration Initiative" e GE Procedure No. UT 232, Revision 0, " Automatic UT and Tomoview Analysis of Weld Overlay Austenitic Piping Welds in Accordance With PDl" e ISI Personnel Certifications for all NDE personnel observed performing NDE work j b. Observations and Findinos i The licensee's VT and UT examination data reports and evaluation documentation I complied with ASME Code Section XI requirements. The inspector reviewed the PDI procedures for compliance to current ASME Code requirements, including demonstration to the ANil. All code requirements appear to have been me The inspector reviewed GE personnel qualification and certification records and determined that they met the SNT-TC-1 A Recommended Practice and the ASME Code, 1989 Edition,Section XI requirements. These certifications had been reviewed and accepted by the ANi All observed ISI examination procedures were approved and accepted by the ANil. The NRC inspector also reviewed the ISI procedures used for the examinations observed, and determined that the procedures met the required ASME Section XI and Section V requirement p

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. Conclusions

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The ISI documents, procedures and personnel certifications reviewed during this inspection complied with ASME Code requirements and no victations or dev!ations were identified. The inspector considered the ISI plan particularly well organized and documente Ill. Enaineerina E2 Engineering Support of Facilities and Equipment E Observation of Reactor Vessel Feedwater Nozzle N4C Overlav Weld Reoair Preoaration Insoection Scope (73753)

The inspector reviewed and evaluated the following engineering support documents, related to dispositions of recordable Indications resulting from nondestructive ISI examinations of the feedwater nozzl Observations and Findinas As a result of the UT examination re-analysis, the licensee issued condition report No. 99-0417, dated February 24,1999. The condition report identified that reevaluation ,

of UT data taken during RFO-5 (using the Tomoview UT analysis software) for the N4C feedwater nozzle safe-end to nozzle weld the flaw sizing was undersized for depth. The flaw depth was sized as 0.25 inches in depth during RFO-5 (1996) and resized using improved software as 0.75 inches in dept An operability determination No.- 99-0417 was performed by the licensee to determine that the reevaluated flaw size for the N4C nozzle could reduce the safety factor (to catastrophic failure)if the flaw propagated to the point that structural integrity of the nozzle was compromised. GE performed an engineering analysis of the reevaluated flaw size for the N4C nozzle utilizing ASME Code Section XI, paragraph IWB-3641 and Generic Letter (GL) 91-18 guidance. The analysis concluded that the projected flaw size, at the time of plant shutdown for RF-07 (March 27,1999), met the ASME Code and GL 91-18 requirements / guidance (Reference GENE-B13-02010-00-10, dated February 26, 1999).

The licensee purchased a detailed mock-up and contracted the services of Welding Services incorporated (WSI) to perform weld training and procedure demonstration prior to performing the overlay weld repair on the N4C feedwater nozzle. This mock up was a cut out section of the reactor vessel, nczzle and biological shield representative of the actual physical restrictions and parts where the repair was to be performed. Observations of welding on the mock-up demonstrated the quality of the welding procedure. The applicable Procedure Qualification Record and the Weld Procedure Specification for the overlay repair, and the qualification records for the welding operators were qualified in accordance with ASME Code Section IX. The overlay will be applied over the dissimilar metal weld without removal of the embedded flaw. The weld process will employ a tempering weld in the area of the P-1 base metal. The repair plan complied with

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applicable requirements of ASME Code Case N-504 and the recommendation in NUREG-0313, Revision 2, and GL 88-01. The weld overlay was designed as a full structural overlay (.425 inches). The completed weld overlay weld will be machined to a flat surface to assure inspectibility using ultrasonic examination technique Conclusions The licensee's evaluation of the resized feedwater nozzle flaw adequately justified operability up to the current refueling outage. Preparation for the weld overlay of the N4C reactor vessel feedwater nozzle to safe-end weld was well done through the use of a weld mock-up with identical nozzle and biological shield configuration )

V. Manaaement Meetinas I

X1 Exit Meeting Summary  !

On April 16,1999, the inspector conducted a final exit with licensee representatives and summarized the scope and findings of the inspection. At the exit the inspector questioned licensee personnel as to the potential for proprietary information within the inspection report material discussed at the exits. No proprietary information was identifie i

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PARTIAL LIST OF PERSONS CONTACTED

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Licensee T. Henderson, Regulatory Assurance Supervisor B. Luthanem, Regulatory Assurance- l L. Myer, Vice President, Nuclear )

R. Rogoski, Senior Welding Engineer l R. Schrauder, Director - PNED '

. S. Seman, Lead ISI Engineer S. Stegel, Level lil, NDE C. Wirtz, ISI Program Manager  !

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J. Briggs, IWI Level lli )

J. Hayden, Senior NDE Specialist l H. Schlortt, Lill UT l Electria. Power Research Institute J. Landrum, Project Manager 4 C. Latiolais, Project Manager  !

S. Walker, Program Manager Factory Mutual System

T. Laps, Authorized Nuclear Inservice Inspector U. S. Nuclear Reaulatory Commission C. Lipa, Senior Resident inspector l

INSPECTION PROCEDURES USED !

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.lP 73753: Inservice inspection, Observation of Work Activities IP 73755: Inservice inspection, Review of NDE Data IP 73052: Inservice inspection, Review of Procedures IP 73051: Inservice inspection, Review of Pregram

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LIST OF ACRONYMS USED

' ANil Authorized Nuclear Inservice Inspector GE ' General Electric Nuclear Energy GERIS GE Reactor inspection System GL Genedc Lener IGSCC Intergranular Stress Corrosion Cracking ISI Inservice inspection MSIP Mechanical Stress Improvement Process l MT Magnetic Particle Examination PDI Performance Demonstration Initiative PNPP Perry Nuclear Power Plant UT Ultrasonic Examination VT Visual Examination i

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