For the commercialization of fast breeder reactors (FBR), it is essential to enhance the economic competitiveness by reduction of total cost by elongation of plant service period. In this point of view, it is important to establish the assessment method of integrity of aged weld joint and repair welding for the components of future long life FBR. In the present study, evolution of microstructure is evaluated for the 304SS-304SS weld joint which was used for 88,000h at 526-545°C in the French proto-typ...
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Influence of FBR plant service and repair welding on microstructure and residual stress of austenitic stainless steel weld joint

In nuclear power plants, surface treatment including the shot peening is carried out after welding for the prevention of stress corrosion cracking. In this research, the authors developed evaluation systems of the persistence of compressive residual stresses due to shot peening based on the Idealized Explicit FEM which can conduct large-scale non-linear structure analyses in realistic computing time. The developed evaluation system was applied to the analysis of the compressive residual stress due to sho...
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Study of behaver to relieve residual stress at the time of the shot peening

For the commercialization of fast breeder reactors (FBR), it is essential to enhance the economic competitiveness by reduction of total cost by elongation of plant service period. For this reason, it is needed to establish the aged weld joint integrity assessment method for future FBR compon ents. Additionally, since it is expected to employ the repair weld for aged structural components, it is essential to investigate the effect of repair weld. To investigate the influence of high temperature-long service...
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Basic investigation of aging weld joint and repair weld joint integrity assessmentusing neutron residual stress measurement method

To validate the FEM simulation technique presented in the previous report, we made pipe butt welded joints between base metals of the same material SUS316L and between base metals of the dissimilar materials SUS316L and STPT370. Shot peening (SP) on the outer surface or the inner surface of these welded joints induces high compressive residual stresses on the surface. After heat treatment with the peak temperature of 623 K was applied to the welded joints, they retained high compressive residual stresses ...
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Evaluation of the sustainability of compressive residual stress by introduced a stress improvement method (the second report) ?Residual stress change of welded joint with shot peening by thermal cycle and stress loading.

When the steel structure is built such as nuclear power plant, residual stress occurs in or near the welding joint and it may cause the stress collision cracking(SCC). Therefore, as prediction of SCC, surface treatment such as the shot peening(following SP) is carried out in the weld, but the case analyzed about residual stress reforming by the SP does not exist. So, we developed the analysis method that can predict compressive residual stress relaxation behavior during shot peening by modelling dynami...
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Evaluation of the sustainability of compressive residual stress by introduced a stress improvement method (the first report) -Development of analysis method of the shot peening using idealized explicit FEM

The structural integrity of equipment and piping systems to a fault displacement depends on the damage state of a reactor building. When there is no damage in a reactor building, the supporting function of equipment and piping systems is maintained. In this case, FEM analysis can estimate the allowable state of the entire system of the important safety equipment. In this part, an example of the analysis evaluation for the equipment and piping systems, which are important for safety, in the case of loading a...
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Risk Evaluation Method for Faults Displacement by Engineering Approach (4)The Analysis Evaluation of Equipment and Piping System

Non-destructive examination (NDE) methods for joint interfaces between different materials in high heat flux components of ITER divertor should be urgently developed to assure qualit y and reliability of joining techniques. This paper reports the present R&Ds status of NDE for ITER divertor and its outlook. The detection ability of joint defect by using ultrasonic wave and thermography NDE are examined in the joint interface between armor tiles and a cooling tubes of divertor mock-ups. The results of both ...
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Development of Non-destructive technique for ITER divertor high heat flux component

An infrared thermography NDE facility which is utilized in the acceptance test of ITER d ivertor components has been developed in JAEA. This NDE facility can inspect the integri ty of the bonding interface of the divertor components based on its surface temperature response by means of switching of hot (95 deg C)/cold (5 deg C) water. The advantages of this facility are 1) to have active coolant purging system which enables rapid temperatu re change and 2) to inspect the surface and the both side walls of...
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Development of a non destructive evaluation system using infrared images for divertor on nuclearfusion experiment reactor