IAEA-EBP-IGSCC-08LIMITED DISTRIBUTION

22-05-01

MINUTES OFTHE SECOND MEETING OF THE

PROGRAMME’S WORKING GROUP 1ON IMPROVEMENTS IN IN-SERVICEINSPECTION PERFORMANCE AND

QUALIFICATION

UNIVERSITY OF KYIV, KYIV, UKRAINE5-8 FEBRUARY 2001

EXTRABUDGETARY PROGRAMME ON MITIGATION OF INTERGRANULARSTRESS CORROSION CRACKING IN RBMK REACTORS

INTERNATIONAL ATOMIC ENERGY AGENCY

CONTENTS

1. INTRODUCTION .................................................................................................................. 2

2. MEETING SUMMARY......................................................................................................... 2

2.1. STATUS OF WORKING GROUP 1 TASKS................................................................. 2

2.2. TRAINING COURSE AT LENINGRAD PLANT ......................................................... 3

2.3. TRAINING COURSE ON AUTOMATED ULTRASONIC INSPECTION.................. 4

2.4. OUTLINE OF THE FINAL REPORT FOR WORKING GROUP 1.............................. 4

2.5. REQUESTED INPUT TO WORKING GROUP 2 AND WORKING GROUP 3.......... 4

3. CORRECTIVE ACTIONS AND COMMITTMENTS.......................................................... 5

Appendix I. LIST OF PARTICIPANTS..................................................................................... 8

Appendix II. SIZING PROCEDURE DEVELOPED BY IGNALINA PLANT ...................... 11

Appendix III. OUTLINE FOR QUALIFICATION DOSSIER................................................. 45

Appendix IV. TRAINING COURSE ON AUTOMATED UT, TECNATOM........................ 46

Appendix V. FINAL REPORT OUTLINE. ............................................................................. 48

Appendix VI. SYLLABUS FOR TRAINING COURSE ON SIZING. ................................... 49

Appendix VII. IAEA UT QUALIFICATION PILOT STUDY FOR WWER-1000

REACTOR................................................................................................................................ 51

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1. INTRODUCTION

The second meeting of Working Group 1 on Improvements in In-Service InspectionPerformance and Qualification was held at the Institute of Post Diploma Training, NationalTaras Shevchenko University of Kyiv, 5-8 February, 2001. The objective of the meeting wasto review the progress of the working group against the project plan and schedule that wasagreed to during the first meeting in July 2000 at Kursk, IAEA-EBP-IGSCC-02. The meetingachieved its objective and a detailed plan to produce a qualification procedure was developed.The meeting participants agreed to and committed themselves to a substantial scope of workto complete the adaptation of procedures, development of a qualification procedure andconduct of an initial set of trials.

A list of meeting participants is provided in Appendix I. A summary of the meeting isprovided below:

2. MEETING SUMMARY

R. Havel opened the meeting and provided an overview of the progress of the wholeIAEA Extrabudgetary Programme on Mitigation of Intergranular Stress Corrosion Cracking inRBMK Reactors. After the overview, the Working Group members agreed to the followingspecific agenda items:�� review the status of Working Group 1 Task Groups;�� discuss specific logistics and details for the Training Seminar at Leningrad plant;�� discuss specific logistics and details for the Training Seminar on Automated Ultrasonic

Inspection offered by Tecnatom;�� complete an outline for the Final Report for Working Group 1;�� discuss requested input to Working Group 2 and Working Group 3;�� agree upon corrective actions necessary to complete the project.�

2.1. STATUS OF WORKING GROUP 1 TASKS

J. Saburov provided a brief review of progress for Task Group 1. The major points ofthe discussion are listed below:

�� The Working Group successfully completed a seminar in September that provided anoverview of the manual inspection methodology that is used in western nuclear powerplants for detection of IGSCC, sizing of IGSCC and inspection of weld overlay. Theparticipants at the seminar received copies of sizing and weld overlay procedures and anotebook containing all training materials. As agreed during the first Working Groupmeeting the procedures that were presented at the seminar will form the basis of plantspecific procedures to be developed by the participants from Lithuania, Russia andUkraine. This will apply to the sizing and weld overlay procedures. After reviewing thedetection procedure provided during the training course at Smolensk plant, Russia andLithuania decided that the current procedure MCU–5-99 was adequate. NDE specialists atthe Ignalina plant and Chernobyl plant did want to continue training in the detectionmethods presented at Smolensk plant. It was felt that the detection methods presentedprovide potential alternative methodology that would be useful.

�� Ignalina plant provided members of the working group a sizing procedure that had beenadapted from the material presented at Smolensk plant. J. Saburov requested that members

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of the Working Group review the procedure and provide their comments by March 1st.The procedure is provided in Appendix II including comments by M. Davis.

�� Members of the Working Group committed to complete this action as requested. Ignalinaplant plans to use the procedure during the upcoming plant outage in May 2001. T. Taylorwill provide a translated version to the English speaking members of the Working Group.

�� There was significant interest in adapting the weld overlay procedure. NIKIET indicatedthat it had not been able to complete adaptation of the procedure, however, N. Timofeevcommitted to complete the adaptation by December 2001. After discussion that the date ofDecember seemed too late, J. Saburov and N. Timofeev agreed to determine a target dateconsistent with the work plan.

�� Russian participants indicated that there was interest in developing a detection procedurethrough the anticorrosive coating on RBMK piping. NIKIET indicated that there is aseparate effort to develop this procedure in Russia outside the IAEA program.

N. Timofeev provided a brief review of the progress from Task Group 2. The majorpoints of the discussion are listed below.

�� NIKIET indicated that there had been some work completed to review currentqualification documents, however, NIKIET indicated that it had no funding to produce anywritten report and no report was provided to the Working Group.

�� After discussion of a path forward, the Working Group agreed to adapt the basic outlinepresented in the IAEA report “Methodology for Qualification of In-Service Inspection forWWER Nuclear Power Plants”; IAEA EBP WWER–11. The Working Group recognizedthat while the title of the document indicated WWER’s, the basic methodology could beeasily adapted for the 300mm RBMK reactor piping that is of specific interest to theWorking Group. B. Dikstra led the Working Group through a discussion that produced adetailed outline for a qualification procedure that could be used to conduct the trials thatare part of the Working Group project plan. The outline for the qualification procedure isprovided in Appendix III. A list of the commitments made by the Working Groupmembers to support this procedure development is provided in Section 3 of this report.

2.2. TRAINING COURSE AT LENINGRAD PLANT

During the 2nd Steering Committee meeting, NIKIET raised a concern that samples usedduring the seminars that were planned as part of Working Group 1’s project plan did notaddress specific RBMK geometries. During the Steering Committee meeting it was agreedthat if NIKIET could provide some samples, these samples would be used at the trainingseminar in Leningrad plant.

N. Timofeev indicated at the Working Group meeting that NIKIET had selected somesamples and would provide these samples for the training seminar in Leningrad plant. N.Timofeev then proposed that a blind trial of the sizing methodology be conducted at theLeningrad plant. After discussion the Working Group decided that it was not appropriate forblind trials to be conducted at a training seminar. Blind trials for the methodology will beconducted during the pilot study trials as agreed to, at the first Working Group meeting.

During the Working Group meeting there was discussion about providing calibrationblock materials for the detection procedure at the seminar at Leningrad plant. During thediscussion it was noted that the A321 steel is basically the same as the Russian austenitic

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steel. T. Taylor agreed to check on the availability of pipe material and if possible makecalibration blocks of A321 steel

The Working Group then discussed equipment logistics for the seminar. J. Saburovpointed out that it would be a significant risk and burden for specialists from countries outsideRussia to bring expensive manual ultrasonic instruments into Russia. It was agreed at theWorking Group that NDE specialists would bring transducers and cables and that R. Haveland J. Saburov would contact Leningrad power plant to determine what equipment existed atthe power plant for training. This action would be completed during the week of February12th.

2.3. TRAINING COURSE ON AUTOMATED ULTRASONIC INSPECTION

The Working Group discussed logistics and details for the seminar on automatic ultrasonicinspection proposed by Tecnatom. The major points of discussion are provided below. �� The Working Group agreed that a written objective and training syllabus should be

developed that describes the role that this seminar plays in helping plant safety andachieving the objectives of the Working Group.

�� Tecnatom indicated that the seminar is best limited to a total of six representatives. TheWorking Group agreed that the criteria for attendees should be as follows;

a) senior plant in-service inspection engineers, b) if possible specialists that had previous training should be given priority, c) specialists that had training in signal analysis should be given priority, d) engineers that develop ultrasonic inspection procedures should be given priority. The following proposal was made for participants:�� Lithuania; one participant from Ignalina plant.�� Russia; one participant each from Kursk, Leningrad and Smolensk plants. It was agreed

that NIKIET and GAN would decide on nominating one participant among themselves.�� Ukraine; one participant from Chernobyl power plant.

The best dates for the seminar from Tecnatom’s viewpoint are the week of June 4th orJune 11th. However, June is not necessarily the best date for participants from RBMK plantsbecause of plant outages. Once the exact seminar participants are determined the dates for theseminar will be finalized.

2.4. OUTLINE OF THE FINAL REPORT FOR WORKING GROUP 1

The outline for the Working Group 1 final report was agreed upon and it is provided inAppendix V.

2.5. REQUESTED INPUT TO WORKING GROUP 2 AND WORKING GROUP 3

Working Group 1 received requests from Working Group 2 regarding a target flaw sizeand from Working Group 3 regarding a methodology and the scope and schedule for in-service inspection of welds that received treatment such as mechanical stress improvement orweld overlay. The Working Group discussed these requests and results are summarized below.

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�� There was considerable discussion regarding a target flaw size. Current Russianregulations require detection of flaws that are 1.5mm in through wall depth and 10mm inlength. This flaw size is quite small and discussion during the meeting pointed out thatwhile flaws in this size range can be detected present data from PISC and other studiesindicate that false call rates associated with detecting small flaws can be very high. TheWorking Group agreed that a more realistic target flaw size for ultrasonic methodology isa flaw size of 4mm through wall depth and 60mm in length. The Working Group felt thatacceptable detection and false call rates could be demonstrated for this larger flaw size. T.Taylor will present this discussion to Working Group 2 during the meeting in March.

�� Concerning the input to Working Group 3, it was felt that Working Group 1 could provideinput regarding the methodology of welds that have received treatment such as mechanicalstress improvement or weld overlay. However, the Working Group felt that WorkingGroup 2 was more appropriate for helping determine scope and schedule. N. Timofeevindicated that the current requirements for welds that have been repaired by a weldingprocess are as follows:100% of all welds repaired by a welding process are inspected afterone year. After that each weld is inspected after 35,000 to 45,000 hours of operation.

�� During the discussion of input to Working Group 3 the group felt that it was important tomake Working Group 3 aware that mechanical stress improvement process (MSIP), isvery likely to make any existing defects difficult or impossible to detect and that actionshave been assigned to assemble any data on this available from Western work ondetectability of IGSCC in the presence of compressive stress. T. Taylor will discuss thisissue with J. Lance.

3. CORRECTIVE ACTIONS AND COMMITTMENTS

A list of the corrective actions necessary to complete the work planned, commitmentsmade by the Working Group members to support the work and other action items required toachieve the objectives of the Working Group are summarized next.

Entire Working Group�� Review the sizing procedure submitted by J. Saburov and provide any comments in

writing by March 1st

�� Review Working Group 1 meeting minutes and provide comments to R. Havel as soon aspractical.

�� Working Group members who have agreed to provide input to the Technical Specificationwill provide that input to N. Timofeev by March 1st. See the individual list below forspecific member commitments.

�� Working Group Members who have agreed to provide input to the QualificationProcedure will provide that input by April 1st. See the individual list below for specificmember commitments.

�� Review drafts of the Technical Specification and Qualification Procedure. Writtencomments on these documents will be provided at least two weeks before the nextWorking Group meeting.

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J. Saburov�� Compile the comments on the sizing procedure and send the list to Working Group

Members with suggested resolutions.�� Provide a copy of the Russian detection procedure to T. Taylor for translation by February

16th.�� Work with R. Havel to determine what UT equipment exists at Leningrad power plant and

what needs to be brought.

I. Korobskaya�� Provide input to Technical Specification on “Code Requirements”�� Provide input to Technical Specification on “Quality Assurance Requirements”

N. Timofeev�� Provide the following input to the Technical Specification• Component Criteria• NDT Methods• Inspection Conditions (N. Timofeev will ask power plants for assistance in this• effort)• Criteria for Flaws to be Detected�� Provide any experimental data available in support of the detection procedure by� 23rd March.�� Work with B. Dikstra in developing the Technical Justification. This input will include a

discussion on Essential Variables, Procedure Variables, Equipment Variables and thephysical reasoning for the procedures (detection and sizing).

�� Assist in developing input for the Qualification Procedure trials in the pilot studyregarding time allotted for examinations. This input acknowledges that radiation dose mayplace limitations on the amount of time an inspector has for manual examination of welds.

�� Adapt the weld overlay procedure by December 2001.�� Help ensure that the same people who attend the seminar at Leningrad in March will

attend the sizing seminar in August. I. Kadenko�� Lead the Qualification Body activity for the trials. S. Kostenko�� Assist I. Kadenko in Qualification Body activities B. Dikstra�� Produce a first draft of the Technical Justification with a view to developing this further

with assistance from N. Timofeev.�� Provide a list of inputs required for the Technical Specification by 1 March.�� Assist in providing input for scheduling the trials to be conducted in the pilot study�� Provide in cooperation with Nikolai Timofeev input for updating the Working Group 1� Workplan for Task 2

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T. Taylor�� Develop the draft meeting minutes by February 16th

�� Provide input on “Inspection Effectiveness” for Technical Specification�� Provide the following input for the Qualification Procedure: • Description of Practical Trials • Evaluation Criteria�� Provide Translation of the Sizing procedure and Detection procedure to B. Dikstra and� J. Sanchez by February 23rd.�� Provide translation of the Technical Specification and Technical Justification within two

weeks after receiving the documents�� Enquiry whether EPRI has any data on detection of IGSCC after treatment by mechanical

stress improvement.�� Establish the syllabus and for the Sizing seminar in Moscow in August by the end of

February, Appendix VI. J. Sanchez�� Provide a written description of the objective and training syllabus for the proposed

seminar on automated ultrasonic inspection that describes the role that this seminar playsin helping plant safety and achieving the objectives of the Working Group.

M. Trelinski�� Enquiry whether Ontario Hydro has any data on detection of IGSCC after treatment by

mechanical stress improvement.�� Check with M. Davis on the possibility of providing a demonstration of the sizing

procedure at the seminar that will be conducted at Leningrad. If the demonstration ispossible, work with N. Timofeev, J. Saburov and T. Taylor concerning logistics thespecific objective.

A. Miasniankin�� Provide the input on component criteria for the Technical Specification to N. Timofeev. R. Havel�� Work with J. Saburov to determine what UT equipment exists at Leningrad power plant� and what needs to be brought.�� Circulate a list of titles from a previous IAEA workshop at Slavuvitch

The next meeting of Working Group 1 is scheduled for May 22nd to 24th in Moscow.However, the Working Group agreed that before IAEA sends out invitations for the meetingthe Working Group will provide R. Havel with a completed draft of items each member of theWorking Group has committed to complete.

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Appendix I.LIST OF PARTICIPANTS

USAMr. Tom TaylorPacific Northwest National Laboratory (PNNL)2400 StevensMail Stop K5-26Richland, WA99352 USATel.: +1 509 375 4331Fax: +1 509 375 6736E-mail: tt.taylor@pnl.gov

UNITED KINGDOMMr. Barry J. DikstraMitsui Babcock Energy LimitedHigh StreetRenfrewPA4 8UWScotlandUnited KingdomTel.: +44 141 885 3962Fax: +44 141 885 3370E-mail: BDIKSTRA@MitsuiBabcock.com

CANADAMr. Michael TrelinskiPrecision Ultrasound42 Millstone CrescentWhitby, Ontario L1R 1T4CanadaTel.:+1 905-922-3052, -619-3831E-mail: michael.trelinski@sympatico.ca

LITHUANIAMr. Juri SaburovIgnalina NPP (INPP)Visaginas4761 LithuaniaTel.: +370 66 286 68Fax: +370 66 28818, 60188E-mail: saburov@mail.iae.lt

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RUSSIAMr. Alexander I. Miasniankin(present Thursday 8.2.2001 only)Kursk NPPKursk regionKurchatov307239 RussiaTel.: +7 07131 5 43 75Fax: +7 07131 4 18 19; +7 07131 49600E-mail: krutogina@kunpp.kursknet.ru

Mr. Nikolai V. TimofeevNIKIET/ EDC RDIPEP.O.Box 788Moscow101000 RussiaTel.: +7 095 263 7442Fax: +7 095 975 2019, 263 7442E-mail: chim@entek.ru

Ms. Irina N. KorobskayaGosatomnadzorTaganskaya str.34Moscow109147 RussiaTel.: +7 095 911 60 46Fax: +7 095 912 40 41E-mail: kin@crusader.gan.ru

SPAINMr. Jose L. SanchezTecnatom, s.a.Avda. Montes de Oca, 1San Sebastian de los ReyesMadrid28709 SpainTel.: +34 91 659 8671Fax: +34 91 659 8677E-mail: jlsanchez@tecnatom.es

UKRAINEMr. Sergei P. KostenkoNuclear Regulatory DepartmentArsenalna str. 9/11Kiev01011 UkraineTel.: +380 44 254 3517Fax: +380 44 254 33 11E-mail: kostenko@hq.nra.kiev.ua

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UKRAINEMr. Ihor M. KadenkoNondestructive Examination Training andCertification FacilityP.O.Box 267Kiev-3001030 UkraineTel.: +380 44 221 0280; 221 3117Fax: +380 44 221 3116E-mail: ndef@uninet.kiev.ua;

ndef@mail.univ.kiev.ua

Ms. N. SakhnoNondestructive Examination Trainingand Certification FacilityP.O.Box 267Kiev-3001030 UkraineTel.: +380 44 221 0280; 221 3117Fax: +380 44 221 3116E-mail: ndef@uninet.kiev.ua;

ndef@mail.univ.kiev.uaIAEA

Mr. Radim HavelNSNIWagramer Str. 5P.O. Box 100Vienna1400 AustriaTel.: +43 1 2600 22013Fax: +43 1 2600 29649E-mail: R.Havel@iaea.org

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Appendix II.SIZING PROCEDURE DEVELOPED BY IGNALINA PLANT

Document.pdf

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M. Davis comments to J. Saburov (Ignalina plant), on the procedure titled “Sizing offlaws such as IGSCC detected in the heat affected zone of welds on 300mm diameteraustenitic piping”. The procedure revision provided in this Appendix takes these commentsinto account already.

Mr. Juri SaburovIgnalina NPP (INPP)Visaginas4761 Lithuania

Dear Mr. Saburov,

I have reviewed the procedure titled “Sizing of flaws such as IGSCC detected in theheat-affected zone of welds on 300mm diameter austenitic piping” that staff from Ignalinaplant have developed from material presented in a training seminar on Advanced UltrasonicTesting For Detection, Characterization and Repair of IGSCC, IGSCC Flaw Sizing and WeldOverlay Examination at Desnogorsk, Russia. This seminar was conducted as part of theInternational Atomic Energy Agency Extra budgetary Program on Mitigation of IntergranularStress Corrosion Cracking (IGSCC) in RBMK Reactors.

After reviewing the procedure I find that it is a very adaptation of the training materialpresented at the seminar. My review of the procedure resulted in the following comments.

Comment 1.0

Paragraph 4.0. page 3, states that “experts shall have additional training on austeniticsteel examination and specific methods used in this procedure”. The paragraph does not statehow much additional training each inspector must have. I recommend adding an additionalstatement similar to the one suggested below:

The sizing experts shall have documented Advanced Flaw Sizing Training. Recommendminimum of 40 hours.

Comment 2.0

Section 6.3 contains a requirement that cable resistance should not exceed 50 Ohm/m.This requirement was not specified in the original procedure and I do not think a requirementfor resistance is relevant. What should be specified is a requirement for the impedance of thecable. I would suggest a 50 Ohm cable impedance requirement.

Comment 3.0

Paragraph 8.1, page 12, states that the surface waviness of the examination area shall notexceed 0.015mm (at least I assume mm). Please confirm that this is 0.15mm (the Russianversion of the procedure uses 0.015 but no units). This specification seems very conservative– in your experience is this specification realistic? This comment does not require resolution;rather it is a caution against developing procedure specifications that cannot be realisticallymet given plant conditions.

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Comment 4.0

Paragraph 9.4, page 13, the next to paragraph states:

“About changes of material thickness, weld geometry and discontinuity orientation it ispossible to consider on the base of distance between signals B and C. If the above indicatedparameters are constant, the distance between signals B and C should be constant.”

I would suggest the following change:

“Changes in material thickness, weld geometry and discontinuity orientation will changethe distance (in screen divisions) between signals B and C. If the distance between signals Band C (in screen divisions) changes by more than 10%; then size estimates using SIGMA cannot be relied upon and the TAU signal should be used.”

Comment 5.0

Paragraph 9.5, page 12, states that HALT method is applied to determine discontinuitydepth (height) up to 60 % of wall thickness.

I have found that the HALT method may actually be applied to flaws with through walldepths greater than 40% for pipe in the 12 to 16mm thickness range.

It would also be appropriate to and a note in the procedure that when using the HALTMethod CE 1 and CE 2 signals may be present and are not used for this sizing method.

Comment 6.0

Paragraph 10.1, page 15, the third paragraph on this page states: “Is measured andrecorded the width of waveform envelope B (CE-1) for notches 20 %, 40 %, 60 % and 80 %depth.”

I would recommend the following change:

“The width of the waveform envelope B (CE-1) (commonly called echo-dynanic) ismeasured and recorded for notches 20%, 40%, 60% and 80% depth”

Comment 7.0

Section10.2.2, page 16, the second paragraph states:

“Measure and record distance between a signal of shear wave from the corner of notch(B) and signal of diffraction wave from the top of notch (A) for notches 20%, 40 % and 60 %depth of calibration block thickness.”

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I would recommend the following change:

“Measure and record the distance (IN SCREEN DIVISIONS) between a signal of shearwave from the corner of notch (B) and signal of diffraction wave from the top of notch (A) fornotches 20 %, 40 % and 60 % depth of calibration block thickness.”

Comment 8.0

Section 10.4 does not identify the HALT acronym. I would suggest the followingchange to the section title:

10.4 HALT method - High Angle Longitudinal wave Technique

The description of calibration could be improved by making the following change. Iwould suggest the following change:

�� Obtain the peak signal from the side drilled hole at depth 2 mm and adjust by delaycontrol to 1 horizontal scale division of UT scope.

�

�� Obtain the peak signal from the side drilled hole at the8 mm and adjust by sweep range(sound velocity) to depth 8 mm to 4 horizontal scale division or the maximum depthneeded for the sizing examination.

�

�� Alternate between the depth 2 mm to 1 screen division and depth 8 mm to 4 screendivision.

NOTE: This calibration technique will establish a linear range from 2mm to 8mm, such thatlinearity is established between depths of 2 mm and 8 mm.Also, spreading the 2 mm hole to 2 divisions and the 8 mm hole to 8 divisions will greatlyexpand the screen range such that peaking the signals from the holes or a crack tip signal willbe difficult.

Another comment would be to have side drilled hole at 3 mm depth intervals to a maximumdepth of 15 mm.

Comment 9.0

In my opinion, chart that is presented in figure 9, page 20, is excellent. If my commentabove in 9.5 is used then modify the flow chart for HALT to show 40% rather than 60%.

Comment 10.0

In the version of the sizing procedure that was distributed, the sections of the sizingprocedure describing the MOST and HALT and HALT techniques are numbered as 11.3. Iwould recommend an editorial change to make the numbering consecutive.

As stated above, I think that the staff at Ignalina have dome an excellent job in adaptingthe training material presented at Desnogorsk, Russia. It would be my pleasure to sign as aASNT UT Level III reviewer for this Flaw Sizing procedure.

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Sincerely, Concurrence of Review,

J. Mark Davis Tom Taylor & Mike Trelinski

ASNT UT Level IIICERTIFICATION NUMBER JM-1098

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Appendix III.OUTLINE FOR QUALIFICATION DOSSIER

1.0 IntroductionThis section will describe the purpose of the document and the scope, which is limited

to 300mm primary circulation piping.

2.0 Technical SpecificationThis section will describe the detailed scope of the qualification and will address the

following topics.�� Code requirements�� Component addressed by qualification�� NDT methods�� Inspection conditions�� Flaw parameters to be measured�� Inspection effectives�� QA requirements

3.0 Inspection ProcedureThis section will contain the two procedures that will be part of the pilot study;

Detection (Russian procedure MCU-5-99) and Sizing.

4.0 Qualification ProcedureThis section will describe the basic process used for qualification and address the

following topics.�� The technical justification will contain section on essential variable analysis and the basis

in physics for the procedure.�� Description of the Practical Trials�� Evaluation Criteria

5.0 Evaluation of qualification resultsThis section will describe how and who will conduct the qualification pilot study. I.

Kadenko has agreed to lead this effort.

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Appendix IV.TRAINING COURSE ON AUTOMATED UT, TECNATOM

OBJECTIVES

1. To demonstrate improvements upon inspection technology used to detect and assesscracking in piping before and after repair

2. To describe applicability of automatic UT piping inspection system 3. To provide knowing on automated ultrasonic examination capabilities versus manual

�� Reliability of results�� Data recording�� Defect characterization�� Dose reduction�� Limits of applicability (access, geometry, constraints…)

The proposed Seminar will contribute to achieve the main goals of the Working Group 1,as will provide:�� Transferring of advanced automated UT testing techniques�� Equipment being currently used for application of ENIQ Methodology in RBMK´s

austenitic steel piping inspection�� Test samples with real cracks

Criteria for attendees to the Seminar should be:

�� senior plant in-service inspection engineers�� specialists having been previously trained�� engineers that develop ultrasonic inspection procedures

SYLLABUS

DAY 1 MONDAY

I. Introduction�� Goals of the Seminar�� Summary of IGSCC phenomena�� UT techniques and Procedures to be applied�� Test blocks description

II. Equipment description�� Scanners�� Data Acquisition System�� Data Analysis System

DAY 2 TUESDAY

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III. Automated UT inspection�� Set up and calibration�� Acquisition on test specimens with realistic defects

DAY 3 WEDNESDAY

�� Results Analysis�� Detection�� Sizing�� Retests�� Conclusions

DAY 4 THURSDAY

IV. Checking of results by manual inspection

�� Manual inspection by currently developed procedure�� Manual vs. automated

DAY 5 FRIDAY

�� Technical Meeting and Conclusions

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Appendix V.FINAL REPORT OUTLINE

1.0 Background 2.0 Overview of Working Group 1.0 Project Plan and Objectives 3.0 Review of Current Inspection Needs 4.0 Description of Qualification Approach 5.0 Technical Specification 6.0 In-Service Inspection Procedures Addressed by Working Group�� Detection�� Sizing�� Weld overlay 7.0 Training Program�� Description the training seminars conducted as part of this project. 8.0 Qualification Pilot Study�� Procedure Review�� Technical Justification�� Specification of Practical Trials�� Evaluation Criteria�� Evaluation of Trial Results 9.0 Description of the Results of the Pilot Study 10.0 Conclusions and Recommendations 11.0 Appendices – Procedures, Seminar Material, Technical Justification

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Appendix VI.SYLLABUS FOR TRAINING COURSE ON SIZING

AUGUST 20 MONDAY

�� Welcome and introductions�� Registration and over view of the IGSCC Course�� Brief review of US Experience in IGSCC Sizing

�� Inaccuracy of dB Drop Method�� Round Robin Results�� Results of EPRI Study to identify sizing results�� Initial Results of US Sizing trials

�� Current US Qualification Requirements for Sizing�

AUGUST 21 TUESDAY�

�� ID Creeping Wave Technique for Sizing of IGSCC�� Wave Physics�� Calibration techniques�� Characterization techniques

�� Practical Exercises in Sizing�

AUGUST 22 WEDNESDAY�

�� Tip Diffraction Techniques for Sizing�� Wave Physics�� Calibration techniques�� Transducer Selection for Tip diffraction

�� Practical Exercises in Sizing with Tip Diffraction�

AUGUST 23 THURSDAY�

�� Bi-Modal Techniques Sizing�� Wave Physics�� Calibration techniques�� Transducer Selection for

�� Practical Exercises in Sizing with Bi-Modal Technique�

AUGUST 24 FRIDAY�

�� Refracted Longitudinal Techniques for Sizing�� Wave Physics�� Calibration techniques�� Transducer Selection for

�� Practical Exercises in Sizing with Longitudinal Technique�

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AUGUST 25 SATURDAY�

�� IGSCC Sizing Workshop�� Laboratory Exercises

�

AUGUST 27 MONDAY

�� IGSCC Sizing Workshop�� Laboratory Exercises

�

AUGUST 28 TUESDAY�

�� Written and Practical Performance Examination�� Group 1 Written Examinations�� Group 2 Practical Examinations

�

AUGUST 29 WEDNESDAY�

�� Written and Practical Performance Examination�� Group 2 Written Examinations�� Group 1 Practical Examinations

�

�� Course review and critique�� Review of examination�� Pack equipment

�

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Appendix VII.IAEA UT QUALIFICATION PILOT STUDY FOR WWER-1000

REACTOR

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PILOT STUDYTECHNICAL SPECIFICATION

For the Ultrasonic Examination of the Kozloduy Unit 5,Reactor Pressure Vessel Weld 3

In-Service Inspection

Prepared by

EPRI

EPRI WO-6321IAEA Project RER /4/020

February, 2000

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SUMMARY

Countries operating WWER (Water Water Energetic Reactor) nuclear power plantshave recognized the importance that a well organized and defined in-service inspection (ISI)plan has in the continued safe operation of their nuclear power plants. In many instances it isacknowledged there is a lack of a systematic approach to demonstrating ISI capabilities. Plantoperators do not possess sufficient information on design margins, operative damagemechanisms, loadings, component geometry, and materials, to develop a technically soundand economical ISI qualification program. This difficulty is made more complex by the lackof acceptance standards, codes, and criteria for performing ISI and evaluating ISI findings.

At the request of member states operating WWER Nuclear Power Plants, theInternational Atomic Energy Agency (IAEA) organized the preparation of a report“Methodology for qualification of in-service inspection systems for WWER Nuclear PowerPlants.” This report was prepared in the framework of the Extrabudgetary Programme on theSafety of WWER and RBMK Nuclear Power Plants and published in March 1998. Followingpublication the member states further requested the IAEA set up a pilot study to investigatethe practical aspects of using the guidelines contained within the IAEA report.

Started during1998, the pilot study is a major part of the TC regional project RER/4/020on Advanced NDT of Primary Circuit Components of WWER Nuclear Power Plants and is animportant step to the general application of the guidelines for other components and nuclearplants. A key feature of the pilot study is that it is based upon a real component, which willbring together actual data, and procedures that ultimately may be used at the pilot plant. Withthis in mind it is important to state the purpose of the pilot study is to evaluate themethodology contained in the IAEA guidelines “Methodology for qualification of in-serviceinspection systems for WWER Nuclear Power Plants” and not to endorse or qualify anyspecific organization or ISI program. Consequently the aim of this document is to provideuseful examples of the information that may be required in order to develop an ISIqualification program.

The pilot study component is a circumferential weld of a reactor pressure vessel (RPV)in a Water Water Energetic Reactor-1000 system (WWER-1000), located at the KozloduyNuclear Power Plant (NPP) in Bulgaria. The NPP is owned and operated by the NationalElectric Company. The design of the nuclear steam supply system of the NPP was by OKBGidropress of Russia.

The fundamental approach of the pilot study will be to use actual data to specify realisticreliability requirements for in-service inspection. It is anticipated that to understand andmeasure the NDE methods capability to meet these requirements that practical trials combinedwith a technical justification will constitute a technically strong case to meet the ISIobjectives.

The Technical Specification is mostly based on data derived from relevant inputinformation supplied by the project “team members.” These include;

The Bulgarian Nuclear Regulator, The NPP as Licensee, The NPP Main Designer, TheIn-service Inspection Organization, and the Independent Qualification Body (IQB). In somecases the information was supplemented by expert opinion obtained during IAEA regional

54

workshops held in Zagreb (January 1999) and technical meeting held in Sofia (May 1999).Under contract to IAEA, EPRI (Electric Power Research Institute) assembled the informationusing the framework of the IAEA guideline titles

�� Code requirements (ISI)�� Component / areas including the following essential information

�� Dimensions and Weld Geometry�� Material Specifications and Welding Procedures�� Weld repairs�� Surface condition

�� NDT-Method�� Inspection Conditions

�� Access restrictions�� Environmental Factors

�� Expected / postulated flaws�� Flaw parameters to be measured�� Inspection effectiveness�� QA requirements.

One of the most important contributions to the Technical Specification is a reportspecifically commissioned for the pilot study from the main designer of the WWER-1000.Within the report the results of calculations for the target depth [a] of sub-surface ellipticalcracks in weld No 3 of a WWER-1000 RPV are given based on a plant specific analysis of theKozloduy, Unit 5, RPV. Because the results are only applicable to the Kozloduy, Unit 5, RPVthey are not included in the technical specification. Furthermore it is the responsibility of eachNPP to determine such information and to obtain the necessary approval from the regulatorybody having jurisdiction at the NPP on the methodology used to determine these values.Likewise it is the responsibility of the NPP operator and appropriate regulatory authority toagree upon the required inspection effectiveness. This item should remain open until the targetflaw size is established and agreed upon. As part of this pilot study, a detailed evaluation ofthe calculations of the main designer was performed. This evaluation resulted in arecommendation that the target flaw size and the inspection reliability be revised to reflectplant specific conditions such as fluence, cladding effects, and heating of the ECCS water.The specific details of this analysis are contained in the OKB Gidropress report. Consequentlythe technical specification has confined itself to the describing the ISI performance reliabilityobjectives in the following manner:

RELIABILITY

�� A very high level of ISI reliability should be established through the combinationof Technical Justification and practical trials to show the NDT system is capable ofdetection, characterization and size estimation of flaws equal to or greater than thetarget flaw size.

�

�� A reasonable level of ISI reliability should also be established through thecombination of Technical Justification and practical trials which shows the NDTsystem is capable of detection, characterization and size estimation of flaws lessthan the target flaw size.

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For the future it is planned that the information agreed upon and the team processestablished to develop this information will be used as examples in a good practices guidelinedocument for ISI planning which will also incorporate the lessons learned from this pilotstudy.

INTRODUCTION

In 1990 the International Atomic Energy Agency (IAEA) initiated a project to assistcountries of Central and Eastern Europe and the former Soviet Union in evaluating the safetyof their first generation WWER-440/230 nuclear power plants. In 1992 the program wasextended to include RBMK, WWER-440/213 and WWER-1000 plants [1].

The capability and effectiveness of in-service inspection (ISI) have been identified andranked, in the framework of the IAEA’s Extrabudgetary Programme activities, as one of themost important (Category III) safety issues for WWER plants [1].

Due to the high safety significance of WWER in-service inspection and also taking intoconsideration the requests and suggestions from several WWER operating countries, theIAEA organized the preparation of the report “Methodology for qualification of in-serviceinspection systems for WWER nuclear power plants” [1].

The report provides several qualification principles defining the administrativeframework needed for the practical implementation of the methodology, along with adescription of the process of qualification of an inspection system according to thatmethodology. Included are recommendations on the minimum technical documentation andrelated prerequisites as well as several specific requirements with regard to the NDTprocedures, equipment and personnel to be qualified and to the test specimens to be used inpractical trials. Furthermore the guideline suggests an appropriate distribution ofresponsibilities, among all the parties involved in a qualification process [1].

During 1997, as the first activity of the TC regional project RER/4/020 on AdvancedNDT of Primary Circuit Components of WWER NPPs, the IAEA held a regional workshop inZagreb, Croatia to discuss the “Basic elements of ISI Programme Planning andImplementation.” In response to suggestions from the participating countries, a pilot study onthe application of the IAEA report using a real power plant component was organized.

The objective of the pilot study is to test these methods and is an important step to thegeneral application of the guidelines to other components and other plants. It is expected thatthrough the lessons learned the pilot study will be incorporated into a Good Practicesguideline document for ISI Programme planning and will if required, providerecommendations for revisions to the IAEA report - Methodology for Qualification of In-service Inspection Systems for WWER Nuclear Power Plants.

There are 20 units from the WWER-1000 type of reactor in operation and 7 underconstruction in the region. In order to make the pilot study deal with realistic issues it waspreferable that wherever practical actual data and information from an operating WWER 1000Nuclear Power Plant would be used. In response, personnel from the National Electric

56

Company of Bulgaria agreed to provide the necessary input information from the KozloduyUnit 5 NPP.

As in other Countries, the motivation for this work lies in the desire for a systematicapproach to demonstrating ISI capabilities in nuclear power plants. In many instances, plantoperators do not possess sufficient information on design margins, operative damagemechanisms, loadings, component geometry, and materials, to develop a technically soundand economical ISI qualification program. This difficulty is made more complex by the lackof acceptance standards, codes, and criteria for performing ISI and evaluating ISI findings.Accordingly the pilot study by following the IAEA guidelines provides an opportunity fororganizations wishing to implement a systematic approach to deal with such issues.

A project team led by the IAEA was set up with members representing, The NuclearPower Plant, The Nuclear Regulator, The Main Designer, The Independent QualificationBody, and the In-Service Inspection Company, provided the relevant Input Information.Because an Independent Qualification Body does not formally exist in Bulgaria personnelfrom the Bulgarian Nuclear Regulator and the Bulgarian Academy of Sciences simulated thisrole. To facilitate the assembly of the information and to provide expert assistance during theproject including the preparation of this document the IAEA placed a contract with EPRI(Electric Power Research Institute).

Assembly of the information started in 1998 and a draft technical specification wasissued to the project members and others for review during the early part of 1999. Commentsreceived have been considered and where possible incorporated into this document. It isexpected the technical specification will be the first of a number of documents, which providea practical insight into the use of the Methodology for Qualification of In-service InspectionSystems for WWER Nuclear Power Plants.

In consideration of the available time, financial resources, availability of establishedqualification organizations and in some cases the technical precedents that were anticipated, itwas resolved the pilot study should be considered a simulation of the qualification of an NDTsystem (equipment, procedures, personnel) for ISI. It should also be noted the purpose of thepilot study is not to endorse or qualify any specific organization or ISI program and mostimportantly the information should only be used as examples of the information that may berequired in order to develop an ISI program.

TECHNICAL SPECIFICATION

1. SCOPE

This Technical Specification has been prepared as part of a pilot study to investigate thepractical aspects of using the guidelines contained within the IAEA report IAEA-EBP-WWER-11 “Methodology for Qualification of In-service Inspection Systems for WWERNuclear Power Plants,” March 1998 [1].

The pilot study component is weld Nr.3 of the Kozloduy Unit 5 Reactor Pressure Vessel(RPV) Nuclear Power Plant (NPP) located in Kozloduy, Bulgaria This is a Water WaterEnergetic Reactor-1000 system (WWER-1000), owned and operated by the National Electric

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Company of Bulgaria. The design of the nuclear steam supply system of the NPP was by OKBGidropress of Russia

The technical specification summarizes the relevant input information to specify therequirements for the reliability of in-service inspection (ISI) for the component. The format ofthe document includes those items under the heading– “Qualification Dossier -TechnicalSpecification.” illustrated in figure 1.

�� Code requirements (ISI)�� Component / areas including the following essential information

�� Dimensions and Weld Geometry�� Material Specifications and Welding Procedures�� Weld repairs�� Surface condition

�� NDT-Method�� Inspection Conditions

�� Access restrictions�� Environmental Factors

�� Expected / Postulated flaws�� Inspection effectiveness

�� Flaw parameters to be measured�� QA requirements.

2. ISI CODE REQUIREMENTS

Regulations set forth in the Bulgarian Act on the Use of Atomic Energy for PeacefulPurposes require the owner of a Nuclear Power Plant to carry out periodic In ServiceInspection (ISI) of safety related components in accordance with specified requirements.

The Reactor Pressure Vessel (RPV) is classified as a safety related component andcontinued operation of the NPP for an additional fuel cycle is contingent upon the NuclearRegulator approving the NPP owner’s ISI documentation before and on completion of the ISIactivities.

The Bulgarian Nuclear Regulator (CUAEPP - Committee on the Use of Atomic Energyfor Peaceful Purposes) requires compliance with these requirements, accordingly it is theresponsibility of the NPP owner to obtain the necessary approvals of the Nuclear Regulator touse this document as part of the in-service inspection program.

3. COMPONENT

The component is weld number 3 of the Kozloduy Nuclear Power Plant (NPP) Unit 5Reactor Pressure Vessel (RPV). This is part of a WWER-1000 system. A typical layout of theWWER-1000 plant illustrating the RPV and other primary components is shown in figure 2.

Kozloduy NPP Unit 5 was first commercially operational in September 1988 and sincethat time there have been no unusual operating events recorded which influence the scope ofthis specification.

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Component Dimensions & Weld Geometry

A general arrangement drawing of the Kozloduy Unit 5, RPV, is illustrated in Figure 3[2].

Weld number 3, is a shell to shell circumferential weld in the core region. The insidediameter of the RPV at weld number 3 is 4,137 mm. The two RPV shell sections forming theweld are made from a low alloy, high strength steel with a nominal thickness of 192.5 mm.The RPV design specification requires the base material to be overlaid with a minimum of 7mm stainless steel cladding. Material thickness measurements from Kozloduy Unit 5 Weld 3show the RPV shell to be 190-191 mm with a cladding thickness ranging from 9-12 mm [2].

The profile of Weld 3 is a double grove profile illustrated in figure 4. The weld root areastarts at 55 mm from the inside surface (approximately at 1/3 of the base material thickness)and the root face is approximately 10 mm. The maximum fusion face angle is 13°. Forconstruction of the weld up to 250 mm of the base material are left unclad on either side of theweld profile [2].

Component Material and Welding Procedures

Table 1 provides a list of known materials provided by Kozloduy [2,3].

Table 1COMPONENT MATERIALS

(Kozloduy Nuclear Power Plant Unit 5, Reactor Pressure Vessel, Weld 3)

Area of Component Material CommentsUpper and lower shellsection forming weld 3

Low Alloy SteelType 15Ch2NMFA

Stainless steel overlay onthe upper and lower shellsection forming weld 3

Stainless Steel Exact composition underinvestigation.

Weld deposited material –Weld 3

Low Alloy (Cr.Ni-Mo)Steel

Stainless steel overlay onweld 3 and immediate areaon the Upper and lowershell section forming weld 3

Stainless Steel Exact composition underinvestigation.

Construction of the component requires the weld to be filled using a submerged arctechnique. On completion of the weld the exposed base material is overlaid using a three layerprocess with an anti-corrosion stainless steel cladding.

Except for the stainless steel cladding that is recorded as being up to 5mm thicker thanspecified by design the RPV materials are considered typical and do not require any specialconsideration for ISI.

Component Weld Repairs

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During construction the weld was subject to 100% surface and volumetric NDE usingvisual inspection, magnetic particle ultrasonic and radiographic methods. The designspecification required any unacceptable fabrication defects to be repaired by welding to thesame specifications as the original welds.

No weld repairs to weld number 3 or the adjacent cladding have been recorded duringconstruction or in-service, consequently no special considerations apply to the ISI.

Component Surface Conditions

The clad surface (RPV inside surface) of weld 3 and the adjacent examination volumesurface area has been ground smooth to a surface condition of RMS 3.2 [4]. There is thepossibility that in some isolated areas the local surface condition may be irregular. (The designspecifications required that during construction the clad surface be examined for surfacedefects using a liquid dye penetrant NDT method. Any defect may be removed and the defectarea should be ground to provide a smooth transition of the local provided that the minimumclad thickness is maintained).

NDE experts reviewed a video from an earlier ISI of the RPV and determined that thetypical areas of localized grinding on the inside surface observed would provide an efficientultrasonic coupling capability for ultrasonic transducers of the type typically used for RPV ISI.Consequently no special surface conditions need to be considered for the ISI.

4. NON-DESTRUCTIVE EXAMINATION (NDE) METHOD

An ultrasonic NDE method shall be used to examine 100% of the examination volumespecified.

Any ultrasonic procedure will be considered, however based on published internationalreports it is expected that NDE procedures using a combination of traditional amplitude basedtechniques for detection and more advanced tip diffraction techniques for defectcharacterization and sizing are most suited to meet the ISI requirements. In this case it isforeseen that practical trials combined with a technical justification of the NDE procedure,will establish a technically strong case to meet the qualification objectives agreed upon.

5. INSERVICE INSPECTION CONDITIONS

The NDE method shall be applied from the inside surface of the RPV during the routinere-fueling outages planned by the NPP. The following conditions should be considered whendeveloping the NDE procedure

Inspection Area (Examination Volume)

The inspection area (examination volume) for the component shall be the entire volumeof the weld and adjacent base material up to a distance half of the shell thickness on each sideof the weld, as illustrated by ASME Section XI, Figure IWB-2500-2 [5]. The stainless steelcladding is not considered part of the inspection volume.

Access and Restrictions for ISI

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Access to the inside of the RPV will be by removal of the RPV cover head, the fuelassemblies and all reactor internals allowing a central mast manipulator or other roboticdevice unrestricted access to the component.

When developing the NDE procedure the core barrel support lugs on the lower side ofthe weld 3 shall be duly considered to ensure full volumetric coverage of the examinationvolume. The scan plans to obtain 100% examination coverage and particulars to overcomelimitations (if any) shall be described both in the technical justification for the NDE procedureand the NDE procedure.

Environmental Factors for ISI

The equipment used to deploy the NDE method shall be capable of operating in a highradiation environment and is capable of deploying the NDE method so that the demonstratedinspection reliability of the NDE procedure is maintained. The qualification dossier shouldassess to if the mechanical equipment parameters influence the ISI reliability requirements.

6. EXPECTED OR POSTULATED FLAWS

For the purpose of controlling the performance of the NDE method a target flaw sizeshall be specified separately from this technical specification. The target flaw size shall becalculated through a plant specific structural integrity analysis of the component. In thiscontext the target flaw size means that a flaw of this size, if present, shall not be cause forconcern for the continued safe operation of the component.

To establish the target flaw size the following general principles are applied during thestructural integrity analysis.

�� Substantial safety factors are used in the calculations. - Consistent with regulatoryrequirements.

�� It considers that reasonable NDE sizing tolerances will be applied.�� The probability of correct rejection or sentencing, of detected flaws, shall be high and

improves with flaw size.�� The NDE method is capable of characterizing and resolving if the flaw is connected to the

inside surface.�� Flaw growth, if present, to the next inspection is considered

Additionally the following plant specific information shall be considered during thestructural integrity analysis.

�� Use of the IAEA-EBP-WWER-08 document on Guidelines on Pressurized Thermal ShockAnalysis for WWER NPP’s, April 1997 [6].

�� Substitution of design neutron fluence values with the actual neutron fluencemeasurements of the Kozloduy Unit 5 RPV

�� Improvements to the operating conditions of the NPP are included in the calculations –Effect of heating the emergency core cooling water.

�� Cladding effects are considered in the analysis�� Calculations shall be based on the 30 year design life of the NPP

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The NPP main designer, OKB Gidropress, have prepared a detailed structural integrityanalysis report of the component (weld 3). This report has been delivered to IAEA and will beindependently reviewed by experts for conformity with recognized practices and accuracy.

Table 2 provides a summary of the most consequential defect characteristics from theviewpoint of integrity to the RPV which the NDE system shall be capable of determining.

Table 2Summary of the most consequential defect characteristics for the integrity to the

RPV which the NDE system shall be capable of determiningDefect Type Crack, elliptical or semi-ellipticalLocation of defect in the RPV Welds and base material (cylindrical shells)

in the zone of irradiationLocation of defect within the pressureboundary

Inside Surface or Near Inside surface

Orientation of the defect to pressureretaining boundary surface (Tilt)

Perpendicular to vessel surface

Orientation relative to the component /weld(Skew)

Circumferential - Longitudinal and Axial –Transverse.

7. INSPECTION EFFECTIVENESS (ISI PERFORMANCE AND RELIABILITY) & FLAWPARAMETERS TO BE MEASURED

The effectiveness of the NDE system for ISI of the component shall be determined. Inthis case the effectiveness will be described as a measurement of the reliability of the ISIresults so that with due consideration the results can be used with confidence to assurecontinued safe operation of the component.

The required inspection effectiveness is a matter to be agreed upon, in written form,between the NPP operator and the regulatory body having jurisdiction at the plant site takinginto account the safety significance of the component. As a general rule the followingprinciples shall be applied when designating the inspection effectiveness.

a) A very high level of ISI reliability should be established through the combination ofTechnical justification and practical trials to show the NDT system is capable of detection,characterization and size estimation of flaws equal to or greater than the target flaw size.

b) A reasonable level of ISI reliability should also be established through the combination ofTechnical justification and practical trials which shows the NDT system is capable ofdetection, characterization and size estimation for defect sizes less than the target flawsize.

The inspection effectiveness criteria agreed upon shall then measure the NDE systemscapability through the following parameters.

�� To inspect the examination volume.�� To determine the location and characterization with dimension of flaws at or greater than

the target flaw size in the examination volume which meet the following descriptions.

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�� Start on the inside clad surface of the RPV and that have propagated through the cladmaterial into the base metal/weld examination volume.

�� Start at the clad to base metal surface and propagate into the base metal/weldexamination volume.

�� Wholly contained within the base metal/weld examination volume, including defects,which may be connected to the outside surface.

�� To establish if the NDE system and processes incorrectly identify flaw conditions (Falsecall rate).

�� To establish the sizing accuracy of flaws for both height and length of flaw.�� To establish the resolution of remaining ligament and measurement accuracy.

Table 3, provides a classification of the flaw dimensions required.

Table 3Flaw Dimensions Required by NDE method

Dimension DescribedLength of flaw 2cHeight of flaw 2aLigament of flaw to the cladding interface H

8. QA REQUIREMENTS

As a minimum and for the purpose of the pilot study typical nuclear practices shall befollowed, and any specific QA requirements shall be agreed between the NPP and theregulatory body having jurisdiction at the plant site.

Cladding

Weld /BaseMaterial a

c

H

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REFERENCES

1. IAEA-EBP-WWER-11 Methodology for Qualification of In-service Inspection Systemsfor WWER Nuclear Power Plants. March 1998.

2. Technical Justification RPV WWER-1000, Mr. Vasil Nichev3. E-Mail from V. Nichev, Kozloduy NPP to P. Ashwin, EPRI January 5, 20004. E-Mail from V. Nichev, Kozloduy NPP to P. Ashwin, EPRI November 23, 19985. ASME Section XI, Division1, 1995 Edition.6. IAEA-EBP-WWER-08 Guidelines on Pressurized Thermal Shock Analysis for WWER

Nuclear Power Plants. April 1997.

BIBLIOGRAPHY

1. IAEA Regional Workshop, Performance Demonstration for UT and ET Systems 25-28November 1997, Zagreb, Croatia

2. IAEA Regional Workshop, RER/4/020, Qualification of NDT Systems - A PracticalApproach, 18 - 22 January 1999, Zagreb, Croatia

3. IAEA Technical Meeting on Pilot Study Implementation, 26-28 May 1999 Sofia, Bulgaria.4. International Nuclear Safety Center Database, http://www.insc.anl.gov5. Progress report by EPRI on IAEA Project RER4020-0020002G, task 1.2 – Assess

Inspection Procedure. November 23, 19986. Technical document on WWER-1000 design criteria. 320-EKO2.09-0001 V. Piminov,

OKB Gidropress, October 1998.7. Letter to Mr. V. Nichev, Kozloduy NPP from P. Ashwin, EPRI January 7,1999.8. E-mail from V.Piminov, OKB Gidropress to P. Trampus, IAEA December 7, 1998.

Subject: RFP Number: RER4020-001-001G (Technical document on WWER-1000 designcriteria).

9. EPRI Accuracy of Ultrasonic Flaw Sizing Techniques for Reactor Pressure Vessels,March 1989. NP-6273.

10. E-mail from Rositza Miteva to Frank Ammirato July 01, 1998. Subject: Qualification ofUT system of WWER-1000 RPV shell weld

11. E-mail from V.Piminov, OKB Gidropress to P.Ashwin, September 13, 1999. Subject:Target Flaw Size for the Pilot Study.

12. E-Mail from V. Nichev, Kozloduy NPP to P. Trampus, IAEA October 5,199913. E-mail from V.Piminov, OKB Gidropress to P.Ashwin, November 22, 1999. Subject:

RER/4/020, Pilot Study.

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BULGARIAN NUCLEAR SAFETY AUTHORITY

DRAFT

REGULATORY REQUIREMENTS

FOR ISI QUALIFICATION

1. The ISI qualification is required for the ISI of the NPP components, important to safety,for example: RPV, pipe lines DN500 and DN200 on the basis of the requirements of theexisting analysis and for pre-service inspection of new components and for repairs toexisting ones.

2. The non-destructive testing is carried out with testing systems which have been qualified

to reliably detect, characterize and accurately size the flaws which can occur in the typesof components in question.

3. The plant operator is responsible for ensuring that the ISI for NPP is performed according

to the specified requirements and that inspections are qualified at the appropriate level. 4. The proper qualification is carried out by the inspection vendor. 5. The qualification is relevant to the inspection to be carried out. 6. Each part of inspection system (procedure, equipment and personnel) can be qualified

separately or qualified together as a complete system. 7. The inspection personnel is qualified for both detection and sizing through blind trials

using fully representative test specimens. 8. It is possible to use different NDT qualification levels depending on the importance of the

inspection in demonstrating structural integrity and the nuclear safety significance of theplant item being inspecting. Risk-informed approach can be used for the qualificationlevels estimation. Where inspection is the primary method for establishing structuralintegrity of a safety critical component the highest level of qualification is needed.

9. The qualification should be based on an appropriate combination of practical

demonstration and technical justification. 10. Qualification process includes:�� technical specification�� inspection procedure�� practical trials (open and/or blind), evaluation of the qualification results�� certification and approval 11. Qualification procedure contains the description of:�� technical justification

69

�� practical trials�� evaluation of the qualification results 12. The objectives of the technical justifications are:�� to show that the inspection system (procedures, equipment and personnel) will be� capable of detecting and sizing all defects contained within the defect descriptions�

�� to include physical reasoning, theoretical modeling and experimental evidence,� supported by the results of other qualifications or round-robin trails�

�� to suggest test pieces used for qualification purposes. 13. The Qualification defects are only well known defects with well defined positions and

characteristics can be subject to real qualification. 14. The practical trials pieces include inspection worst case defects (for detection and for

sizing). 15. The acceptance criteria are consistent with the safety relevance of the component,

potential defect and their structural significance. 16. The practical demonstration is performed under conditions as close as possible to real

conditions (work environment, duration and other possible access problems). 17. The parties involved in the qualification process are: the licensees, the qualification body,

the inspection organizations and testing laboratories. 18. The qualification is invigilated, reviewed and assessed by a special body (Qualification

Body) approved for the purpose by the regulator (with ref. to the document Regulatoryrequirements for Qualification body). The regulatory body has to assess the quality systemof the QB before granting permission to act as a QB.

19. The qualification body and testing laboratories are accredited according to the Bulgarian

accreditation law. 20. All qualifications are thoroughly documented in qualification dossier. 21. Qualification dossier is completed upon completion of a specific qualification and

includes:�� the input information for the qualification�� the Qualification Procedure�� he Technical Justification�� results of practical trials�� outcome of the qualification�� the restrictions for which the qualification is valid�� copies of the Qualification Certificates.

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����The qualification is valid as long as the essential variables remain within the tolerance ofthe qualified procedure, as long as practical experience does not reveal any failure todetect correctly sentence those defects for which it has been qualified.

23. NDT system qualified in another country has to be endorsed by the regulatory body.

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B������������������ ���� ���� �

�����

REGULATORY REQUIREMENTS

FOR QUALIFICATION BODY

1. The Qualification body must be approved by the Regulatory body. 2. The Regulatory body has to assess the structure and quality system of Qualification body

before granting permission to act as a Qualification body. 3. The main task of the Qualification body is to supervise and assess qualifications of non-

destructive testing systems. 4. The Qualification body has to continuously evaluate and reconsider the effectiveness and

appropriateness of applied qualification procedures. 5. The responsibility of the Qualification body has to be define in accordance with the

recommendations of IAEA-EBP-WWER-11 “Methodology for qualification of in-serviceinspection systems or WWER NPPs”;

�� to develop qualification protocols;�� to review and comment qualification procedures;�� to identify and/or design the required test specimens for supplementary and personnel�� qualification practical trials;�� to manage the procurement of test specimens according to its quality system;�� to conduct and supervise the qualification process, including:• initial review and preliminary approval of the proposed inspection procedure;• invigilation of practical trials;• evaluation of results;• assembly of the qualification dossier;• issuance and withdrawal of certificates. 6. The quality system has to fulfill the general requirements as specified in the standard BDS

EN 45004. 7. The quality system must include all technical instructions and all necessary personnel. 8. The quality system has to be reviewed on an annual basis to ensure the suitability and

effectiveness and the results of such reviews have to be documented. 9. The Qualification body shall have independent and impartial status and an appropriate

organization with necessary technical competence for the tasks in question.

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10. The chairman and the personnel who supervise and assess the qualification process cannot simultaneously be employed by any inspection company which they can be calledupon to qualify.

11. The Qualification body, apart from the qualification role, may not perform such

inspections and consultancy that are not compatible with the qualification role from theaspect of integrity.

12. The Qualification body must has good competence and long experience of the NDT

methods on which the NDT system which can come in question for qualification arebased.

13. The Qualification body must also have competence in other areas which can be important

when assessing the detection, characterization and sizing capabilities of an inspectionsystem (degradation mechanisms, crack characteristics, statistical methods, signaldetection theory and mathematical-physical inspection modeling).

14. The Qualification body monitors and assesses the inspection companies qualification of

their inspection system. The inspection procedure is qualified on open test specimen andthe personnel on blind test specimen.

15. The Qualification body issues a qualification certificate specifying the system, personnel

and validation of certificate, if the qualification of equipment, procedure and personnelfulfill the different requirements set up by the Qualification body in the qualificationprocedure.

16. The Inspection Company starts the actual inspection in the NPP with the qualification

certificate.