Array Coil EC Signal Analysis on the

SMART® Helical Type SG Tubes

K. M. MIN†1, H. K. JUNG2, J. S. PARK2

1. Universal Monitoring & Inspection Inc., KOREA

2. Korea Atomic Energy Research Institute, KOREA

Daejon, KOREA

kmmin@umi.co.kr

Contents

• Objective & Overview

• SMART System SG

• ECT by Multi-layered Array Coils

• Test Results & Review

• Conclusions

Objective & Overview

• SMART system SG tube ECT tech. development

• Detectability & characterization of the artificial defects fabricated on the ASME & notch STD tubes

• Applied testing probes : Multi-layered Array coils

• Multi-layered Array coils: Providing the improved inspection capability nearly equal to RPC + inspection speeds comparable to a bobbin coil

• Obtaining basic data and applicable testing technique (i.e. probe, STD tube, signal alignment, raster scan) ≫ determination of the optimal inspection condition ≫inspection probe (equipped with currently employed and developed) performance demonstration

SMART System SG

• SMART SG system currently being developed consists of helical structure tubes having high resistance properties to the FIV(Flow Induced Vibration) and crack defects. And the possibility to reach the re-critical condition accidents, resulted from the increased secondary heat removal has been dramatically decreased.

• A total of 8 SG’s is installed inside the reactor, and preserving a primary coolant flowing through the tube to the outside pressure. The modular concept also applies to each SG, thus installation as well as replacement of each SG unit is practically feasible.

SMART System SG

No. Parameter SMART SG SG Mock-Up

1 Tube Material Alloy 690 Alloy 690

2 # of Rows 17 6

3 SG Height 5,700mm 1,600mm

4 Tube ID 12mm 12mm

5 Tube OD 17mm 17mm

6 Effective Heat Transfer Height 3,800mm 1,000mm

7 Avg. Heat Transfer Area Length 2m 25m

8 Total Heat Transfer Length 500m2 -

9 Axial Tube Pitch 20mm 20mm

10 Radial Tube Pitch 22.5mm 22.5mm

11 Avg. Heat Transfer Angle 8.6° 1.75°

12 # of Tubes per SG 375 18

Design & Structure

ECT by Multi-layered Array Coils

ECT System

Curved STD Tubes Straight STD Tubes

ECT ML Array CoilsGeneral

Overview of

ECT System

ECT by Multi-layered Array Coils

EC Field Generation Mechanism

of Circ. & Axial Direction

Test Freq & Channel Configuration

of 12x2 Array Coils

ECT by Multi-layered Array Coils

EC Standard Tube for Array Cols

ECT by Multi-layered Array Coils

Spec. of the Straight STD Tubes

Sp. IDSpecifications

CommentsDepth(%) W, Ø (mm) L (mm) Dir.

1H OD 20,40,60,80,10020:4×4.840:4.8,60:2.880:2.0,100:1.3

N/A N/A ASME

1GOD 20,40,60,80,100 1.5 N/A Circ.

GrooveID 10,20 1.5 N/A Circ.

1C10 OD 20,40,60,80,100 0.2 10 Circ./Ax. Notch

1C08 OD 20,40,60,80,100 0.2 8 Circ./Ax. Notch

1C06 OD 20,40,60,80,100 0.2 6 Circ./Ax. Notch

1C04 OD 20,40,60,80,100 0.2 4 Circ./Ax. Notch

1C02 OD 20,40,60,80,100 0.2 2 Circ./Ax. Notch

ECT by Multi-layered Array Coils Spec. of the Curved STD Tubes

Sp. IDSpecifications

CommentsDepth(%) W, Ø (mm) L (mm) Dir.

2LH OD 20,40,60,80,10020:4×4.840:4.8,60:2.880:2.0,100:1.3

N/A N/A ASME(D:648.5)

2LC10 OD 20,40,60,80,100 0.2 10 Circ./Ax. Notch(D:648.5)

2LC06 OD 20,40,60,80,100 0.2 6 Circ./Ax. Notch(D:648.5)

2SH OD 20,40,60,80,10020:4×4.840:4.8,60:2.880:2.0,100:1.3

N/A N/A ASME(D:288.5)

2SC10 OD 20,40,60,80,100 0.2 10 Circ./Ax. Notch(D:288.5)

2SC6 OD 20,40,60,80,100 0.2 6 Circ./Ax. Notch(D:288.5)

2SSH OD 20,40,60,80,10020:4×4.840:4.8,60:2.880:2.0,100:1.3

N/A N/AASME(D:288.5,Sided Hole)

Test Results & Review

Signal Calibration by 10% ID GRV

3D Raster Scan of ASME Standard Tube

Test Results & Review

Test Results & Review

3D Raster Scan of EDM Notch Standard Tube

Test Results & Review

Signal Properties of the ASME STD Tubes wrt the Test Freq

(L:300,M:200,R:100kHz, U: Ax, L: Circ. Field)

Test Results & Review

Signal Properties of the EDM Notch(1C4) STD Tubes wrt the Test Freq

(L:300,M:200,R:100kHz, U: Ax, L: Circ. Field)

Test Results & Review

Signal Properties of the ASME STD Tubes wrt Tube Geometry

(L:Straight,M:650,R:290mm, Axial Field)

Test Results & Review

Signal Properties of the Notch STD Tubes wrt Tube Geometry

(L:Straight,M:650,R:290mm, U:Ax.,L:Circ. Field)

Test Results & Review

Differential Signal Absolute Signal

Bobbin Coil EC Signals

Test Results & Review

Detectability of the ASME STD Tubes (1)

4 * 20% FBH

Test Results & Review

Detectability of the ASME STD Tubes (2)

① 100% TWH (L: Ax. R: Circ. Field)

② 80% TWH (L: Ax. R: Circ. Field)

③ 60% TWH (L: Ax. R: Circ. Field)

④ 40% TWH (L: Ax. R: Circ. Field)

⑤ 20% TWH (L: Ax. R: Circ. Field)

1 2 3

4 5

Test Results & Review

Detectability of the Notch STD Tubes (1)

40% 2mm Ax. Notch

Test Results & Review

Detectability of the Notch STD Tubes (2)

20% 6mm Cir. Notch

STD Tubes

Defects

Notch STD Tubes(Length)

1C10(10㎜) 1C08(8㎜) 1C06(6㎜) 1C04(4㎜) 1C02(2㎜)

100%_OD_C O O O O O

80%_OD_C O O O O O

60%_OD_C O O O O O

40%_OD_C O O O O O

20%_OD_C O O O X X

100%_OD_A O O O O O

80%_OD_A O O O O O

60%_OD_A O O O O O

40%_OD_A O O O O O

20%_OD_A Ｘ Ｘ Ｘ Ｘ Ｘ

Test Results & ReviewSTD Tubes

Defects

ASME

100%_TWH O

80%_FBH O

60%_FBH O

40%_FBH O

20%_FBH O

Conclusions1. The eddy current testing of helical SMART SG tubes was successfully performed by

applying qualified 12X2 multi-layered array coils

2. In the case of straight ASME standard tubes, both of the axial and circumferential fields detected those flaws on the standard tubes, due to the non-directional flaw properties

3. In order to understand the effect of the curvature of the standard tubes, the straight 650mm and 290mm curved tubes of ASME and EDM notch were tested, they have not shown any significant difference with respect to the geometry difference.

4. After reviewing the detectability of the each defect,, at least ASME 20% FBH defects and 40% of circumferential and axial notch defects was detected in the optimum 100kHz

Acknowledgements:

On-going support from ---

Mr. Renato Gracin (INETEC)Dr. H. K. Jung (KAERI)Dr. J. S. Park (KAERI)