A Study on the Profile Change Measurement of Steam Generator Tubes with Tube Expansion Methods

Young Kyu Kim,Myung Ho Song,Myung Sik Choi 한국비파괴검사학회 2011 한국비파괴검사학회지 Vol.31 No.5

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry.

Analysis of the Magnetic Effect on the Tube Infrastructure for a Super Speed Tube Train

Hyung-Woo Lee,Su-Yeon Cho,Woo Yeon Cho,Ju Lee,Hyeok-Bin Kwon 한국철도학회 2009 International Journal of Railway Vol.2 No.4

Super speed tube train is introduced to increase the speed of ground transportation. The super speed tube train levitates magnetically and runs in a partial vacuum tube, which can reduce the air resistance significantly. However, the strong magnetic force enough to propel the massive train can affect to the tube infrastructure. In this paper, authors have analyzed the leakage flux patterns and induced eddy current on the tube by using 3-dimensional Finite Element Method. These effects are investigated, especially by varying the materials and diameters of the tube. From the simulation results, the aluminum tube with the diameter of 3[m] is needed to be concerned because the induced eddy current produces joule heat, raises the inside temperature of the tube, and might be able to lead to electro-chemical corrosion on the tube, consequently reduce the durability.

Relationship between Circular Hole Depth and Eddy Current Signal in CFRP Tube Applied to the Quasi-passive Leg Exoskeleton (LeSATA) Frame

Cheon-Woong Park(박천웅),Yong-Beom Seo(서용범),Un-Shob Shim(심은섭),Cheol-Woong Kim(김철웅) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

The possibilities and limitations of eddy current methods for the inspection of carbon fiber-reinforced plastics have been investigated. The present investigation was undertaken to gain a better understanding of the possibilities and the limitations of eddy current methods for the inspection of CFRP tube. The main objective of this study is to evaluate the investigation of ECT for the inspection of defects containing saw-cut and circular hole in CFRP tube using the LeSATA<SUP>TM</SUP>. This research was carried out to characterize the ECT effect on the defect-shapes such as the saw-cut and the hole ones of CFRP tube and on the ratio of the defect-depth (20%, 40%, 60%, 80%, and 100% depth to the thickness of CFRP tube) and conclusions were obtained. 1) For the self-manufactured CFRP tube, the inspection of the defect between 100Hz and 1kHz was not possible and it had nothing to do with the defect-shape. The high frequency such as 100kHz~500 kHz made the inspection of defects possible. 2) The different 3-D pictures was obtained by the direction of axial and circumferential saw-cuts that have the same shape. The fact that both the sum of magnetic vector potential and the interference components were considered for the circumferential one, made them exaggerated. 3) While the depth of the defect was increasing, the phase angle was lowering and the amplitude of EC was gradually increasing. Therefore, while the lower amplitude of EC made the permeable depth of the signal deeper, it made the sensitivity of the defect lower.

Analysis of the Magnetic Effect on the Tube Infrastructure for a Super Speed Tube Train

Lee, Hyung-Woo,Cho, Su-Yeon,Cho, Woo-Yeon,Lee, Ju,Kwon, Hyeok-Bin The Korean Society for Railway 2009 International Journal of Railway Vol.2 No.4

Super speed tube train is introduced to increase the speed of ground transportation. The super speed tube train levitates magnetically and runs in a partial vacuum tube, which can reduce the air resistance significantly. However, the strong magnetic force enough to propel the massive train can affect to the tube infrastructure. In this paper, authors have analyzed the leakage flux patterns and induced eddy current on the tube by using 3-dimensional Finite Element Method. These effects are investigated, especially by varying the materials and diameters of the tube. From the simulation results, the aluminum tube with the diameter of 3[m] is needed to be concerned because the induced eddy current produces joule heat, raises the inside temperature of the tube, and might be able to lead to electro-chemical corrosion on the tube, consequently reduce the durability.

A Study on the Profile Change Measurement of Steam Generator Tubes with Tube Expansion Methods

김용규,송명호,최명식 한국비파괴검사학회 2011 한국비파괴검사학회지 Vol.31 No.5

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry.

A Study on the Profile Change Measurement of Steam Generator Tubes with Tube Expansion Methods

Kim, Young-Kyu,Song, Myung-Ho,Choi, Myung-Sik The Korean Society for Nondestructive Testing 2011 한국비파괴검사학회지 Vol.31 No.5

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry.

Fin 높이가 다른 Fin Tube의 와전류탐상에 관한 연구

이동진 한국공작기계학회 2003 한국공작기계학회 추계학술대회논문집 Vol.2003 No.-

응축기, 증발기, 전열관에 사용되는 Fin Tube는 열전달효율 향상을 위하여 Fin의 높이를 증가시키고, Tube의 최소두께를 얇게 가공하는 경향으로 발전하고 있다. 따라서, Fin Tube의 와전류탐상(ECT; Eddy Current Testing)에 의한 결함검출에 더욱 어려움이 예상된다. 본 연구에서는 Fin Tube의 Fin 높이를 3단계로 변화시켜 Tube를 제작하고, Tube에 축방향결함, 원주방향결함, 원형결함을 각각 Fin Tube의 안쪽에 최소두께의 20%, 40%,60%의 동일결함율을 갖는 인공결함 시험편을 제작하였다. 제작한 원형결함시험편에 와전류탐상을 수행하여 Fin 높이를 따른 최적주파수의 변화를 연구하였다. Fin높이가 다른 원형결함 시험편에 1~2㎑ 주파수를 적용한 결과 최적주파수는 12㎑로 Fin높이에 크게 영향을 받지 않음을 밝혔다. 또한 Fin높이에 따른 최적주파수변화는 크지 않으나 Fin 높이가 높을수록 100%관통결함을 위상각(40′)에 근접하여 나타났다. 축방향결함, 원주방향결함, 원형결함을 갖는 시험편에 와전류탐상을 수행한 결과 원형결함을 갖는 시험편의 신호 감도가 축방향결함, 원주방향결함보다 좋게 나타나다.

Effect of Physical Factors on Electromagnetic Radiation Therapy Planning Dose Calculation in Computed Tomography

Jae-Uk Jang,Man-Seok Han,Min-Cheol Jeon,Se-Jong Yoo,Gab-Jung Kim,Hyun-Soo Kang,Seoul-Hee Nam 한국자기학회 2018 Journal of Magnetics Vol.23 No.3

The tube voltage in computed tomography (CT) changes the Hounsfield Unit (HU) and affects the electromagnetic radiation therapy planning (RTP) dose calculation. In this study, physical factors (tube voltage, tube current) of CT were analyzed for their RTP effects. A CT density phantom (CTDP) was exposed to measure the HU with an RTP system while we controlled the physical factors. The human body phantom was exposed with different CT tube voltages (70 kVp, 80 kVp, 100 kVp, 120 kVp, and 140 kVp) and electromagnetic radiation dose calculations were performed with the RTP system. The HU decreased when tube voltage was increased, in particular, the largest gap was found in bone, which has a high density (1792 ± 54 at 70 kVp, 1065 ± 13 at 140 kVp). However, a remarkable HU gap was not observed with the changes in tube current. In RTP the calculated dose increased when the tube voltage was raised, in particular, we observed a 3 % gap in brain tissue and bone, a remarkable HU gap. The chest had a small HU gap because of its relatively low density. The RTP dose calculation with changes in tube voltage had a 3 % error, which is acceptable. However, it can be eliminated of because daily QA/QC was performed and a CT density curve with rational exposure condition can be applied to brain or spine patients who experience large errors. This method enables reduction of the error caused by the physical factors in CT.

The study of exposure dose measurements on practitioner in specific area with C-arm by angle change

( Byung Sam Kang ),( Hoon Hee Park ),( Kyung Rae Dong ),( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2013 공학기술논문지 Vol.6 No.4

C-arm have used a lot to accuracy of the surgery and to observe the progress and the elapsed, but it become a problem to practitioners and radiation`s considerably higher increase of radiation dose by first and even the scattering rays. In this paper, we learn exposure dose measurements by type of phantoms and change in the angle of C-arm and studied exposure dose reduction method. Each type of phantoms had illuminated to practitioner on constant tube current, tube voltage and time. In each angles exposure dose value had measured three times and average values were calculated. Experiment results with under tube method, low dose and when decreasing angle are going to decreasing and more closer C-arm and tube at 140cm have less dose than 100cm. however when high-dose pelvis phantom measure with over tube leakage dose was increase and at 140cm more closer from X-ray tube are have higher value. Pelvis phantom have More Scattering ray from Entrance dose because higher and thicker than skull phantom and leakage dose increase from X-ray tube. Case in high voltage used, angle of the C-arm relative to increase from 90degree, it seems to be helpful in reducing the exposure dose to practitioner that position move away from the X-ray tube.

A prediction method for the general corrosion behavior of Alloy 690 steam generator tube using eddy current testing

Shim, H.S.,Choi, M.S.,Lee, D.H.,Hur, D.H. North-Holland Pub. Co 2016 Nuclear engineering and design Vol.297 No.-

The purpose of this work is to develop an eddy current testing method to predict the general corrosion behavior of Alloy 690 steam generator tubes. A corrosion test was conducted for tubes with different levels of eddy current noise in simulated primary water at 330<SUP>o</SUP>C, and their corrosion behavior was correlated with the tube noise measured using bobbin and rotating probes. The corrosion behavior was closely correlated with the tube noise measured using a rotating probe. However, there was no correlation between the corrosion behavior and the tube noise measured using a bobbin probe. The tube noise value measured using a rotating pancake coil probe is suggested to be a significant parameter in estimating the general corrosion behavior of tubes.