NDE Inspections of the NRU Calandria Vessel Part 1: NRU and ET Inspections

Transcription

1 NDE Inspections of the NRU Calandria Vessel Part 1: NRU and Inspections 3 rd International CANDU In-Service Inspection and NDT in Canada 2010 June Presenters: R. Lakhan & R.H. Lumsden UNRESTRICTED/ILLIMITÉ

2 Overview First Presentation Overview of NRU Low-Resolution for Corrosion Assessment Hi-Resolution Scanning of Inside Vessel Surface Marking of Repair Locations Repair Inspection Technique Second Presentation Mk. I and II Inspection Tools Inspection Techniques Summary UNRESTRICTED/ILLIMITÉ 2

3 Inspection Progression May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Heavy water leak discovered in May 2009 Visual inspection in the annulus confirmed the leak Leak located 10 meters below the reactor deck Above bottom flange, which is welded to the vessel wall Access through 120 mm diameter reactor positions Reactor shutdown, de-fuelled, and partially drained in mid. June Seven inspection campaigns required to determine the vessel condition and provide information for a repair strategy Combination of and UNRESTRICTED/ILLIMITÉ 3

4 What is NRU? FUELING MACHINE DECK PLATE CONCRE SHELDING SHELDING BLOCKS FUEL RODS THERMAL SHIELDS NERON BEAM HOLES BOTTOM RING THERMAL SHIELDS ALUMINUM TANK NERON BEAM HOLES WARM HEAVY WATER COOLED HEAVY WATER HEAT EXCHANGER HEAVY WATER PUMP PUMP MOTOR A.C. STANDBY MOTOR D.C. PROCESS WATER UNRESTRICTED/ILLIMITÉ 4

5 Plan View of the NRU Reactor Vessel Fuel Rods Control Rods Adjuster Rod Flux Detectors Isotope Production Sites Experimental Test Loops Experimental Irradiation Sites Blocked Sites Dummy Rods Vacant Sites UNRESTRICTED/ILLIMITÉ 5

6 Vessel Overview Material: Aluminum 5052, 8 mm Thick Top-of-Reactor (TOR) Re-entrant Cans Reactor Vessel 10 m Annulus Leak Site Through Tubes 3.5 m UNRESTRICTED/ILLIMITÉ 6

7 Leak of the NRU Calandria Vessel Vessel(D20) Inner Wall Lower Weld Tapered Flange Heat Baffle Annulus Water Reflector Leak Site UNRESTRICTED/ILLIMITÉ 7

8 Probe Design Approach All probes developed and manufactured in-house Transmit-Receive type probes used in all designs FEM Modelling used to design probes, optimize parameters, and simulate signals of possible flaw types Two coil configurations used: G3 and G4 G3 mode Scan Direction T R + + G4 mode Scan Direction T R + + UNRESTRICTED/ILLIMITÉ 8

9 Combined - May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Vessel partially drained of heavy water Measurement of wall thickness and detection and sizing of corrosion Combined 3 T/R array and conventional head Far Surface/ Near Surface Large Diameter Coils with Large Spacing Maximize Penetration (6-7 mm) monitored Lift-off for data quality (1 mm or less) probes from AFCIS 10 MHz, 9.5 mm Diameter Minimum thickness can reliably measure - 3 mm UNRESTRICTED/ILLIMITÉ 9

10 Combined - May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Two methods chosen due to Aluminum Oxide/ Hydroxide layer on vessel wall Data acquisition and preliminary data analysis on TOR Very complementary confirming and vice versa Camera on separate tool inside the vessel for guidance Limited visibility due to water in vessel and turbidity Required very close liaison with procurement, manufacturing, designers, transportation, inspectors, quality assurance, and operations. UNRESTRICTED/ILLIMITÉ 10

11 Probe and Corrosion Signal Frequencies: 500 Hz, 2000 Hz, 4000 Hz, Hz Sizing curves developed for sizing wall thickness Ch. 1 Ch. 2 Ch. 3 Ch.2 Ch. 1 Ch mm Corrosion No Corrosion UNRESTRICTED/ILLIMITÉ 11

12 High Resolution Probe May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Re-inspects areas with external corrosion Inspection of near surface Accurately locate the leak site Frequencies: 2500, 5000, 7500, Hz Measuring wall thickness 4 mm or less T05 R04 T06 R05 T07 R06 T08 R07 T01 R01 T02 R02 T03 R03 T04 Scan Direction UNRESTRICTED/ILLIMITÉ 56 mm 12

13 Hi-Resolution Signal of Leak Site Leak Site UNRESTRICTED/ILLIMITÉ 13

14 May Comparison of Results: Wall Thickness Map June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Conventional High Resolution Leak Site UNRESTRICTED/ILLIMITÉ 14

15 Marking Phase May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair Inspect corroded areas and accurately mark flaw locations Complete 360 scanning of near surface Scanning direction: horizontal Frequencies: 2500, 5000, 7500, Hz Sizing curves for wall thickness 4 mm or less Using a mixture of amplitude and phase curves for sizing High frequency phase curves best for localized flaws 32-Coil Transmit-Receive Array Probe UNRESTRICTED/ILLIMITÉ 15

16 120 mm 32-Coil High Resolution Array Probe G3 and G4 modes operate separately by changing adapters G3 mode G4 mode CFN30 CFN28 CFN26 CFN24 CFN22 CFN20 CFN18 CFN16 CFN14 CFN12 CFN10 CFN08 CFN06 CFN04 CFN02 1-R7 2-T8 3-R6 4-T7 5-R4 6-T6 7-R3 8-T5 9-R7 10-T8 11-R6 12-T7 13-R5 14-T6 15-R4 16-T5 1-T4 2-R8 3-T3 4-R5 5-T2 6-R2 7-T1 8-R1 9-T4 10-R3 11-T3 12-R2 13-T2 14-R1 15-T1 1R-R8 CFP29 CFP27 CFP25 CFP23 CFP21 CFP19 CFP17 CFP15 CFP13 CFP11 CFP09 CFP07 CFP05 CFP03 CFP01 Scan Direction 1-T16 2-T15 3-T14 4-T13 5-T12 6-T11 7-T10 8-T9 9-T8 10-T7 11-T6 12-T5 13-T4 14-T3 15-T2 16-T1 1-R16 2-R15 3-R14 4-R13 5-R12 6-R11 7-R10 8-R9 9-R8 10-R7 11-R6 12-R5 13-R4 14-R3 15-R2 16-R1 The Brick UNRESTRICTED/ILLIMITÉ 16

17 Inspection Planning UNRESTRICTED/ILLIMITÉ 17

18 Position Verification Encoder: Vertical Position Baffle Bolt LASER Resolver: Horizontal Position UNRESTRICTED/ILLIMITÉ 18

19 Marking of Repair Locations Inspect region in a single pass Position probe and hold at the deepest flaw location Deploy tool to mark location Mark wings for visual clarity Marks used to position the welding electrode Elevation Above Taper Transition Mark Directly Above T min Distance to T min Taper Transition UNRESTRICTED/ILLIMITÉ 19

20 Marking In Vessel Mark Nuclear Grade Marker Tool Arm Pneumatic Cylinder UNRESTRICTED/ILLIMITÉ 20

21 Post Repair Probes May June July Aug. Sept. Oct. Nov. Dec. Leak Detected Combined - High Resolution PA- Wall Thickness Vertical Strips Below Weld Marking / Repair for detection of surface-breaking flaws in repair Used as an alternative to liquid penetrant testing Based on X-Probe coil layout and operation Simultaneous operation of G3 and G4 modes Provides detectability to linear flaws in the transverse and longitudinal directions, and volumetric flaws Smaller coils spacing to achieve higher resolution Higher frequencies to inspect surface only UNRESTRICTED/ILLIMITÉ 21

22 Post Repair Probes Frequencies: 7.5, 15, 25, 50 khz External multiplexer located on the reactor deck Two probe variants: horizontal and vertical orientation depending on weld bead direction Scan Direction Scan Direction 48 mm UNRESTRICTED/ILLIMITÉ 22

23 Example Signals EDM Notch Plate Signals obtained on Flat Plate EDM notches 1.5, 2, 3 and 5 mm deep 1.5, 3, and 10 mm long UNRESTRICTED/ILLIMITÉ 23

24 Performance Demonstration Samples Weld overlay test sample EDM notches 0.5 to 3 mm deep, 3 to10 mm long All notches mm wide Flaws on crown, in valleys and in heat affected zones technique for detecting flaws in crown and valleys UNRESTRICTED/ILLIMITÉ 24

25 Example Signal Qualification Sample Signals obtained with Post Repair Probe UNRESTRICTED/ILLIMITÉ 25

26 Fatigue Crack Samples Three fatigue crack specimens manufactured Only detectable with florescent PT, and Each sample contained 14 cracks Two specimens destructively analysed 6 to 16 mm long 2 to 5 mm deep UNRESTRICTED/ILLIMITÉ 26

27 Example Data Mock-up Sample G4 Mode G3 Mode UNRESTRICTED/ILLIMITÉ 27

28 PROTECTED UNRESTRICTED/ILLIMITÉ - SENSITIVE / PROTÉGÉ - DÉLICAT 28