In this paper, a comparative study of the pipe-wall thinning prediction with existing experimental data is carried out for some typical cases of flow accelerated corrosion of carbon steel. The numerical model tested in this study is the pipe-wall thinning model based on the standard k-εmodel of turbulence with the modification of high-Schmidt-number effect. The comparative study is carried out for the straight pipe flow, the pipe flow behind an orifice and the pipe flow behind a long elbow combined wit...
英字タイトル:
Investigation on Pipe-wall Thinning Prediction by Flow Accelerated Corrosion

In the seawater system of nuclear power plants (NPPs), piping with polymer lining material is used to prevent corrosion. In recent years, however, seawater leakages due to aging deterioration of lining material have occurred, and improvement of reliability is needed. In response to the development of a polyethylene lining material with high durability that greatly exceeds the performance of conventional products and the start of its application to NPPs in operation ,this paper introduces the current of effo...
英字タイトル:
Maintenance and Inspection Efforts to Improve the Reliability of Seawater System Piping

At Fukushima Daiichi Nuclear Power Station Unit 3, the Spent Fuel Pool(SFP) was buried in rubble due to the hydrogen explosion. In order to keep the Spent Fuel stored in the SFP safe, we removed them to the Common Spent Fuel Pool, which is not damaged by the explosion. This paper describes rubble removal, installation of Spent Fuel Removal System and Spent Fuel Removal at Fukushima Daiichi Nuclear Power Station Unit 3....
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Completion of Spent Fuel Removal from Fukushima Daiichi NPS Unit 3

Experimental and analytical study was carried out with notched specimens which simulated multiaxial stress state in structural discontinuity, in order to reveal the mechanism and dominant parameters of “local failure”. Both the tensile test and finite element analyses (FEA) exhibited, notch strengthening. Furthermore, in the tensile test, failures of notched specimens were progressed from inside, where hydrostatic stress showed the maximum value in the FEM, whereas Mises stress did not show the maximum valu...
英字タイトル:
Experimental and Analytical Study on Dominant Parameters of Local Failure of Structures

An irradiation hardening behavior in a SUS316 steel was investigated from the ultra-micro hardness test after hydrogen ion irradiation as parameters of irradiation dose and indentation depth systematically. Based on the crystal orientation of the sample surface specified using EBSD, comparative evaluation of ultra-micro hardness in the same crystal orientation relationship was performed. Cross-sectional TEM observation of ion-irradiated microstructure under the indentation after deformation was performed to...
英字タイトル:
Effect for irradiation hardening due to interaction between deformation process and microstructural evolution during nano-indenter examination

It is necessary to conduct development to measure the thickness of the inner wall for each vessel from the outer wall, because there are double-walled vessel with a heating jacket in reprocessing plant Therefore, we have developed sensors based on electromagnetic induction test (EMIT). In this paper, we report on the development results of the device for transporting the sensors....
英字タイトル:
Development of Measuring Techniques of Thick Wall Samples by Electro-Magnetic Induction - An Application for Vessels with Heating Jacket-

The water of Suppression pool at severe accident has become a hot, high chloride ion concentration and strong alkaline because of exhaust of the reactor heat, the melted cable, and pH controller. The equipment using the water has wetted part made stainless, therefore there is a possibility that SCC because of chloride ion occurs this wetted part. However, alkaline environment may reduce a possibility the SCC although poor knowledge. As such we examined the effect of structural material in a hot, high chlori...
英字タイトル:
Effect assessment of structural material in a hot, high chloride ion concentration, and strong alkaline environment

The experimental fast reactor Joyo is the first sodium cooled fast reactor (SFR) that was constructed in Japan. In 2007, it was confirmed that the top of the irradiation test sub-assembly (S/A) of “MARICO-2” (material testing rig with temperature control) had been broken and bent as an obstacle inside of the Joyo reactor vessel and had damaged the upper core structure (UCS). This incident necessitated the replacement of the UCS and the retrieval of the MARICO-2 sub-assembly for Joyo restoration. This p...