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DUAL Probe, an Imaginative Solution to Improve Inspection Times in SG with Denting at TTS
NaiaraRobles(Tecnatom)BelenRibes(Tecnatom)MiguelMéndez(Tecnatom)JordiTorrens(ANAV)
35th Annual EPRI Steam Generator NDE and Tube Integrity Workshop
35th EPRI SG NDE Workshop July 2016
INDEX
1. BACKGROUND
2. DENTING AT TTS
3. INSPECTION PLAN DUE TO DENTING
4. IMPROVEMENT: DUAL PROBE
5. INSPECTION PLAN USING DUAL PROBE
6. VALIDATION OF DUAL PROBE
7. CONCLUSIONS
35th EPRI SG NDE Workshop July 2016
BACKGROUND 1
35th EPRI SG NDE Workshop July 2016
BACKGROUND
4 PWR Nuclear Power Plants - Ascó 1 and 2 - Almaraz I and II - Vandellós 2 - Trillo
Ascó 1 & 2
Almaraz I & II SG replacement
1995-1996
1996-1997
NEW SG MODEL KWU 61W/D3 (Siemens)
ORIGINAL SG D3
(Westinghouse)
35th EPRI SG NDE Workshop July 2016
REPLACEMENT SG MODEL
61W/D3 MODEL Material: Incoloy 800 Modified Dimension: 0.075” OD x 0.043” N. of tubes: 5.130 tubes Pitch: Triangular Support plates: Lattice grid No pre-heater design
Lower Shell
Main Inlet
Main Outlet
Tube Bundle
Upper Shell
Feedwater Nozzle
Unexpected defectology
Denting at TTS and associated ODSCC
35th EPRI SG NDE Workshop July 2016
DENTING AT TTS 2
35th EPRI SG NDE Workshop July 2016
DENTING AT TTS
DENTING
Circumferential crack (ODSCC)
HARD SLUDGE
POSIBLE CORROSION OF THE TS
CONSTRICTION OF THE TUBE
RESIDUAL STRESSES DENTING
Hard Sludge DENTING
Mechanical Expansion
Hydraulic Expansion
35th EPRI SG NDE Workshop July 2016
EVOLUTION OF THE MECHANICAL AND HYDRAULIC EXPANSION DEFORMATION by denting
DENTING AT TTS DETECTION AND SIZING – BOBBIN PROBE
21
1: Hydraulic expansion 2: Mechanical expansion
2
35th EPRI SG NDE Workshop July 2016
ODSCC due to DENTING DETECTION AND SIZING – RPC PROBE
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN DUE TO DENTING 3
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN DUE TO DENTING
BOBBIN PROBE INSPECTION PLAN FULL LENGTH
COLD LEG
HOT LEG
Typical Scope: • 33% - 1.677 tubes
• Denting Cold Leg – about 781 tubes
• Denting Hot Leg – about 819 tubes
2.743 tubes F/L in total with Bobbin
1.066 additional tubes (HL+CL) due to denting
Denting Surrounding +2
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN DUE TO DENTING
MRPC INSPECTION PLAN
COLD LEG
HOT LEG
Typical Scope: • Denting Cold Leg - about 781 tubes
• Denting Hot Leg – about 819 tubes
1600 tubes in total with RPC
Denting Surrounding +2
35th EPRI SG NDE Workshop July 2016
Inspection Plan of Bobbin & MRPC Probe
≈ 2.743 tubes (Full Length) + ≈ 1.600 tubes (MRPC at the TS)
INSPECTION PLAN DUE TO DENTING
Denting inspection requires:
Bobbin Probe Denting detection (no circ. crack detection) MRPC probe (+Point) Crack detection and sizing (no denting detection)
Tubes with denting and surrounding are in both Bobbin and MRPC scope and must be inspected twice.
1.677 Tubes (33% of the SG) Denting: 1.380 tubes
BOBBIN PROBE
MRPC PROBE
Denting Hot leg: 819 tubes Denting Cold leg: 781 tubes
COLD LEG
HOT LEG
35th EPRI SG NDE Workshop July 2016
IMPROVEMENT: DUAL PROBE 5
35th EPRI SG NDE Workshop July 2016
IMPROVEMENT: DUAL PROBE
IMAGINATIVE SOLUTION: DUAL PROBE (MRPC and Bobbin in the same body) • MRPC (2 coils)
Coil 1 “ Cross Coil (+Point) ” Coil 2 “ 0.115" Pancake ” Detection and sizing of circumferential cracks.
• Bobbin (2 standard coils) Detection and sizing of superficial deformation as “denting” Detection and sizing of volumetric deformation
• Automatic acquisition process:
1. RPC data acquisition pushing 2. Bobbin data acquisition pulling Acquisition software provides two independent files (Bobbin and MRPC).
35th EPRI SG NDE Workshop July 2016
ADVANCED EDDY CURRENT TESTER
TECNATOM ETBOX8i
Independent probe configuration
ETBOX 8i Configuration
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN USING DUAL PROBE 6
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN USING DUAL PROBE
BOBBIN PROBE INSPECTION PLAN
Typical Scope: • 33% - 1.677 tubes F/L
35th EPRI SG NDE Workshop July 2016
INSPECTION PLAN USING DUAL PROBE
INSPECTION PLAN OF DENTING BY DUAL PROBE
DUAL Probe
Bobbin coil: Denting Detection (no crack detection)
MRPC: Crack Detection (no denting detection)
Inspection plan of dual Probe: Denting Hot Leg: 819 tubes Denting Cold Leg: 781 tubes
≈ 1600 tubes (Denting at TTS)
Denting Surrounding +2
35th EPRI SG NDE Workshop July 2016
COMPARISON – BOBBIN SCOPE
AFTER BEFORE
2.743 TUBES F/L 1.677 TUBES F/L
DIFFERENCES IN NUMBER OF TUBES CAN RESULT IN SOME SIGNIFICANT SAVINGS: • TIME (AROUND 24 HOURS) • PROBES • PERSONNEL DOSE
35th EPRI SG NDE Workshop July 2016
COMPARISON – MRPC SCOPE
SAME SCOPE BEFORE AND AFTER
COLD LEG
HOT LEG
35th EPRI SG NDE Workshop July 2016
VALIDATION OF DUAL PROBE 7
35th EPRI SG NDE Workshop July 2016
VALIDATION OF THE DUAL PROBE
VALIDATION WITH: CALIBRATION STANDARDS
Bobbin coil
MRPC coils +Point 0.115”
FIELD VALIDATION WITH REAL SIGNALS AND DEFECTS
Bobbin coil Tubes with denting
MRPC coils +Point 0.115”
Tubes with real circumferential cracks
35th EPRI SG NDE Workshop July 2016
VALIDATION OF THE DUAL PROBE BOBBIN
Conventional Bobbin Probe DUAL Probe
35th EPRI SG NDE Workshop July 2016
VALIDATION OF THE DUAL PROBE RPC
STANDARD RPC
DUAL RPC
35th EPRI SG NDE Workshop July 2016
CONCLUSIONS 8
35th EPRI SG NDE Workshop July 2016
CONCLUSIONS
DUAL PROBE
• Dual Probe is an imaginative solution aim to improve the SG with denting at TTS inspections. The following aspects improved:
• Inspection time depending on the number of tubes with denting
• Probes consuming and waste • Personnel Dose
• Combined techniques at the same time are possible thanks to advanced eddy current tester like Tecnatom ETbox8i
• Data acquisition process has been automated to be easy and fast.
• Regular data analysis of both techniques is possible since process provide independent files for each probe.
www.tecnatom.es
Thank you …