A Review of the Eddy Current Loose Part Signals and STD Tubes for the SG Tubes

Transcription

1 A Review of the Eddy Current Loose Part Signals and STD Tubes for the SG Tubes Kyong-Mahn MIN 1 *, Jung-Am PARK 1, Se-Gon CHO 1, Dong-Jun GO 1, Ki-Dong PARK 1 1. UMI Inc., Daejeon, South Korea * kmmhin@hanmail.net

2 Contents Abstracts Overview Variables to the LP EC Signals LP Spacing to the SG Tubes Material Property of LP Size of the LP SG Tubing Material LP STD Tubes & ETSS Conclusion & Remarks

3 Abstracts The structural integrity of the SG tubes has been challenged by numerous factors such as flaws, operation, atmosphere, inherently degraded materials, loose parts and even human errors. Of the factors, loose parts on the secondary side of the tubes can bring about volumetric defects and even leakage from the primary to the secondary side in a short period of time. Therefore it is imperative to detect and characterize the foreign materials and the defects. A variety of variables affecting the detectability and characterization of the LP s must be considered and those variables are assumed to be LP spacing to the SG tubes, the size and material property of LP s, and even the material of the SG tubes, etc. In this study, the factors affecting LP s signals were reviewed and the LP standard tube and ETSS was presented as a way to accurately detect and characterize LP signals. The information derived from this study can be applicable to the engineering assessment of the structural integrity of SG tubes. Keywords: SG, ECT, Loose Part, ETSS

4 Overview Related Research Activities Sang-Yoon, Kim, Jung-Am, Park, Kyong-Mahn, Min, Ho-Sung, Han, Ki-Seok, Shin, EC Signal Analysis and Review of Foreign Materials on Inconel Alloy Tubes, 2008 KSNT Fall Conference Min Kyong Mahn, Park Jung Am, Go Dong Jun, EC Signal Characteristics of Materials and Spacing of Loose Parts Contacted on the SG Tube Secondary Side, 2008KPVP Annual Seminar Min Kyong Mahn, Park Jung Am, Han Ho Sung, Fabrication of Ref. STD Specimen & EC Signal Analysis Technique Development for the Detection of the Foreign Objects on the Secondary Side of the SG Tubes, 2009 KHNP NPP Tech. Workshop Kim Hyun Hee, Park Jung Am, Min Kyong Mahn, Ji Chun Hee, Soft and Hard Sludge Reproduction of SG Tubes and EC Signal Analysis, 2010 KSNT Spring Conference Shin Ki Seok, Moon Yong Sig, Min Kyong Mahn, Development of ETSS for the SG Secondary Side Loose Part Signal Detection and Characterization, Transactions of KPVP, Vol.07, No.03, (2011.9) J. A. Park, D. J. Go, K. M. Min, H. H. Kim, H. S. Han, Eddy Current Signal Analysis of the Loose Parts on the SG Tubes, 2012 NDT in Canada Conference & 4th Int l CANDU ISI Workshop

5 Overview Q. What is Foreign Object? Piece of material located within the SG where it does not belong. The material could have originated from outside of the SG or from within the SG and could be metallic or non-metallic ERPI G/L Rev. 7 Any object in an undesirable location that has the po tential of damaging components John Gay of R. Br ooks Inc. Any object not part of a system or component per d esign. Including loose items that have the potential t o cause damage to systems and components John Gay of R. Brooks Inc.

6 Loose Parts in EPRI G/L Rev. 7 Overview

7 Variables to the LP EC Signals 1. LP Spacing to the SG Tubes(1) Contacted on the secondary side of tubing w/o spacing Contacted on the secondary side of tubing w/ spacing Tube Test Inconel 690 TT (0.750 x in) STD EDM notch combo Loose Parts Cu, Ti, CS Equipment & procedure Procedure UMI-NDT-800-1,2,3,5 (R0) Software Eddynet 11i_1.14 Oscillator MIZ30 RDAU Data Acquisition Test Freq.(kHz) 400, 300, 100, 20, 700 Probe +PT-610-MRPC/3C

8 Variables to the LP EC Signals 1. LP Spacing to the SG Tubes(2) CS Cu

9 Cs_02_15_010_000 Cs_02_15_015_000 Cu_02_15_005_000 Cu_02_15_005_005 Cu_02_15_005_010 Cu_02_15_005_015 Cu_02_15_010_000 Cu_02_15_015_000 Cu_02_15_020_000 Ti_02_15_005_000 Ti_02_15_005_005 Ti_02_15_005_010 Ti_02_15_005_015 Ti_02_15_010_000 Ti_02_15_015_000 Ti_02_15_020_000 Cs_02_15_005_000 Cs_02_15_005_005 Cs_02_15_005_010 Cs_02_15_005_015 Volt. Cs_02_15_020_000 Variables to the LP EC Signals 1. LP Spacing to the SG Tubes(3) S: Spacing T: Thickness Average amplitude of specimens T T T S S S Specimen No.

10 Cu_02_15_005_000 Cu_02_15_005_005 Cu_02_15_005_010 Cu_02_15_005_015 Cu_02_15_010_000 Cu_02_15_015_000 Cu_02_15_020_000 Ti_02_15_005_000 Ti_02_15_005_005 Ti_02_15_005_010 Ti_02_15_005_015 Ti_02_15_010_000 Ti_02_15_015_000 Ti_02_15_020_000 Cs_02_15_005_000 Cs_02_15_005_005 Cs_02_15_005_010 Cs_02_15_005_015 Cs_02_15_010_000 Cs_02_15_015_000 Deg. Cs_02_15_020_000 Variables to the LP EC Signals 1. LP Spacing to the SG Tubes(4) Average phase angle of specimens S: Spacing T: Thickness T S T S S T Specimen No.

11 Variables to the LP EC Signals 1. LP Spacing to the SG Tubes(5)

12 Variables to the LP EC Signals 2. LP Size & Tube Material(1) Cu SS304 CS SS420

13 Variables to the LP EC Signals 2. LP Size & Tube Material(2) LP Size (mm, Dia) SG Tube Mat'l SS CS A600 Cu SS SS CS A690 Cu SS

14 Variables to the LP EC Signals 2. LP Size & Tube Material(3)

15 Variables to the LP EC Signals 2. LP Size & Tube Material(4)

16 Variables to the LP EC Signals 2. LP Size & Tube Material(5)

17 Variables to the LP EC Signals 2. LP Size & Tube Material(6)

18 Variables to the LP EC Signals 2. LP Size & Tube Material(7)

19 Why LP Standard Tube? LP STD Tubes & ETSS Reference standard tubes are needed for detection and characterization of the multiple variations of the specimens : Cracking Surface Roughness Conductivity & Permeability Variations Other materials Conditions How about LP? In the absence of LP STD tubes : Experience based LP data analysis Trigger human errors

20 LP Types LP STD Tubes & ETSS

21 Sludge Simulation(1) LP STD Tubes & ETSS Hard Sludge

22 Sludge Simulation(2) LP STD Tubes & ETSS Soft Sludge

23 LP STD Tubes & ETSS

24 LP STD Tubes & ETSS 1. The screening area includes the support structure and the free span area. 2. Screen the long strip chat in the lower freq. differential channel(usu. Ch. 7, 20kHz) 3. If needed, make process channel, P7 with 90 to 120 deg. for screening both mag. & non-mag. LP materials. (Currently the deg. of TSP is 90. in Ch. 7) 4. Verify the distorted signal in the 300 khz(mid. range freq.) diff. Ch., whether it s flaw or not. If defects, review the analysis history 5. If not defects, resolve the PLP, deposit or non-relevant signal after the additional RPC retest 6. Additionally, 150kHz diff. Ch. can be applicable in the case of nonferromagnetic.

25 LP STD Tubes & ETSS

26 Conclusions & Remarks Variables to the LP EC Signals LP Spacing to the SG Tubes Preceding signals encountered in the sizing process of LP s are more prevalent in the case of ferrite materials. The amplitude of LP EC signals decreases as the spacing between tube and LP increases and the phase angle variation of LP EC signals is similar to that of the liftoff loci. as the spacing between tube and LP increases. The thickness of the LP has not crucial affect to the variation of phase angle and amplitude of EC signals.

27 Conclusions & Remarks Variables to the LP EC Signals LP Spacing to the SG Tubes Preceding signals encountered in the sizing process of LP s are more prevalent in the case of ferrite materials. The amplitude of LP EC signals decreases as the spacing between tube and LP increases and the phase angle variation of LP EC signals is similar to that of the liftoff loci. as the spacing between tube and LP increases. The thickness of the LP has not crucial affect to the variation of phase angle and amplitude of EC signals. LP Size and tube material As the size of the LP contacted SG tubes increases, the phase angle of the each signal increases in the clockwise direction and the amplitude also showed a tendency to increase as expected. Comparing with the phase angle of alloy600 and 690, the variation patterns did not show a clear distinction in accordance with the materials and the LP size. However, as a whole, the phase angle of the alloy690 was lower than that of alloy600. It should be noted that the LP EC signals of SG tubing materials show different phase angle variation tendency. LP STD Tubes & ETSS For the detection and characterization of the loose part material, it is necessary to apply loose part standard tubes in site steam generator inspection. Furthermore, it is urgent to develop loose part indication detection and characterization technique for the improvement of the SG tube eddy current confidence level.

28 Thanks!