In nuclear power plants, the structural components that are in contact with coolant are susceptible to thermal loads due to the change in the fluid temperature. If the heating and cooling processes are cyclic, the structure will endure thermal fatigue that may lead to failure. Thermal stratification is one of the main loads that can lead to high cycle thermal fatigue damage. The Japan Society of Mechanical Engineers, (JSME) have published the evaluation guideline for high cycle thermal fatigue. It treat...
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Stress Generation Mechanism of Elbow Pipes Due to Thermal Stratification

A previously introduced two-dimensional EMAT (Electro-Magnetic Acoustic Transducer) simulation code developed in-house at JAEA, based on both coupling/uncoupling of eddy currents and wave displacement in a non-magnetic material is analyzed against 3D numerical simulations and experimental wave displacements performed by JAPEIC. The experimental setup visualizes wave propagations along the vertical surface of a stainless steel plate using a piezoelectric sensor, while the 3D simulations were performed u...
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A Two-Dimensional EMAT Code for Non-Magnetic Materials using a Coupled/Uncoupled Formulation

After the great earthquake and a tsunami as consequence March 11, 2011, a severe accident happened at nuclear power plant Fukushima Daiichi. The severe accident lead to core damage and containment failure and finally to large release of radioactive substances to the environment. As part of the severe accident management and to reinforce the mitigation concepts against a containment failure, the Filtered Containment Venting System (FCVS) will be introduced at Japanese nuclear power plants, to have a pos...
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AREVA?fs Filtered Containment Venting System (FCVS) Basic Design, Performance and Verification Test of FCVS for BWRs

Abstract: This paper is concerned with computational method in building database, called ECT data base, which is used in crack shape recovery arising in eddy current testing. Firstly, ECT simulat ion model with nodal-based FEM is introduced. Secondly, computational method using parallel virt ual machine in building ECT database is overviewed. Finally, usage of this database is discussed....
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Computational Method in Building Database for Crack shape Recovery Arising in Eddy Current Testing

Effects of thermal history and segregation on the susceptibility of stress corrosion cracking (SCC) in the heat-affected zone (HAZ) of an alloy 182-A533B dissimilar weld joint in high temperature, oxygenated water doped with SO4 2- and Cl- was evaluated by creviced bent beam test. Results indicate that step cooling and the addition of Cl- promoted SCC propagation and reactivation in HAZ. It is also suggested that compositional changes induced by welding and step cooling, especially the segregation of ph...
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Correlation between phosphorus segregation and stress corrosion cracking susceptibility in the heat affected zone of an A533B-A182 dissimilar weld joint

This paper describes detection of electro-discharged machine (EDM) defects in magnetic steam generator (SG ) tubes of Monju fast breeder reac tor (FBR). The EDM defects are located under support plate (SP), on the outer tube surface and they are detected by a remote field eddy curre nt probe. Using the experimental measurements and a multi frequency algorithm, the defect signal can be extracted from the SP signal. The pa rameters of the multi-frequency algorithm were calculated by comparing SP measurements...
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Detection of EDM Defects Under Monju Support Plate Using Experimental Data from Remote Field Eddy Current Probes and a Multi-frequency Algorithm

Grain boundary (GB) segregation of phosphorus and alloying elements in the heat-affected zone (HAZ) of an Alloy182- A533B dissimilar weld joint used in nuclear reactor pressure vessels was studied quantitatively by three-dimensional atom probe tomography. Non-equilibrium segregation occurred during welding and post-weld heat treatment, leading to remarkable enrichment of P, C, Mn and Mo at GBs, of which the levels were all microstructure- dependent. After step cooling, P and Mn showed further increase ...
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Effects of thermal history and microstructure on grain boundary segregation in the heat-affected zone of an Alloy182-A533B dissimilar weld joint

Eddy-current method is applied to evaluate electromagnetic properties of modified 9Cr-1 Mo steel used in power plants in order to investigate the material changes in heat affected zone (HAZ) and base metal in Type IV damage evaluation. A pancake-coil impedance model based on eddy current theory is proposed to evaluate conductivity and permeability of conducting mat erial. Further more a series of HAZ and base specimens of Modified 9Cr-1 Mo steel in different heat treatment conditions are experimentally mea...
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Electromagnetic Property Evaluation on HAZ and Base Metal of Modified 9Cr-1Mo steel by Eddy Current Method

Abstract: The use of portable and high-energy x-ray system can provide a very promising approach for the inspection of aged concrete structures. However, due to the effect of large scattering of low-energy x-ray in a thick concrete, the noise properties and contrast of the radiographic images need to be optimized to ensure reliable interpretation. Therefore, in order to improve the inspection ability, an image denoising method with the combination of wavelet and curvelet transform and image contrast e...
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Image Enhancement for Concrete Bridge Inspection with Portable 950 keV/ 3.95 MeV X-ray Source

A new technique to monitor SCC initiation event has been developed by using electrochemical potential transients which can be used to locate the position of natural occurring SCC initiation sites, in 3 dimensional space. 6 titanium wire used as reference electrode , were placed around the test piece, SUS 316, in a way to cover maximum space around the test piece in order to record the potential transients that would be coming out as a result of SCC initiation event during slow strain test carried out in Na...
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Multi- Electrode Monitoring of Transient Anodic Events in SCC Initiation Stage: Methodology Development