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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 …