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C waterIto, Yuzuru; Saito, Masahiro*; Abe, Katsunori*; Wakai, Eiichi
Journal of Plasma and Fusion Research SERIES, Vol.11, p.73 - 78, 2015/03
Crack growth is a one of the key mechanical properties for the design evaluation in fusion materials to be tested at the High Flux Test Module (HFTM) in IFMIF. In this study, crack growth rate of the F82H steel in the 288C water was investigated by using an almost standard size specimen in order to avoid the specimen size effect on the crack growth. It was found that the typical intergranular fracture surface could be obtained during the crack propagation even at room temperature. Chromium carbide, Cr
C
, precipitation along the grain boundaries in F82H steel may influence the intergranular fracture under the fatigue crack propagation at room temperature in air. The possible evidence of crack growth in the 288C water was also observed. The crack growth rate at 30 MPa ![$$sqrt[]{m}$$](/search/images/EROHG2LSORNV041NPUSA.gif)
in the 288C water was conservatively estimated to about 7
10
m/s. Further systematic study of crack growth, and the improvement of surface finishing against crack propagation are necessary for the design evaluation in fusion materials.
Nakajima, Motoki; Hirose, Takanori; Tanigawa, Hisashi; Enoeda, Mikio
Journal of Plasma and Fusion Research SERIES, Vol.11, p.69 - 72, 2015/03
Water-cooled blanket is an attractive concept for its compactness and its compatibility with the conventional technologies for PWR. For blanket application, the structural material is required to be as thin as possible for tritium breeding. On the other hand, it is also required the pressure tightness to withstand 15 MPa of internal pressure. Therefore it is necessary to understand the corrosion mechanism in high temperature pressurized water. The effects of water flow and DO in the test water on corrosion properties were investigated using rotating disk specimen in autoclave. In summary, the weight loss by flowing was occurred except for test with DO 8 ppm, and it was more pronounced at lower DO concentration. Since Fe
O
was observed on the specimen of small weight change, and the iron-poor layer thickness increased with decreasing the specimen weight, it seemed that the formation of FeO was effective for the suppression of weight loss.
Wakai, Eiichi; Ando, Masami; Okubo, Nariaki
Journal of Plasma and Fusion Research SERIES, Vol.11, p.104 - 112, 2015/03
The reduced-activation ferritic/martensitic (RAFM) steels for the fusion DEMO reactor have been developing from around the 1980s. RAFM steels are the first candidate materials for the first wall and blanket structure of fusion DEMO reactors, the target back-plate and the target assembly of IFMIF. In this study, two subjects had been examined and are summarized as below: (1) Effect of initial heat treatment on the microstructures and mechanical properties of RAFM steels, including irradiation damage, is very important to design the fusion DEMO reactors and also control the changes of mechanical properties after the irradiation. (2) Effects of He and H production on the microstructures and mechanical properties of RAFM steels, including irradiation damage, are essential in the evaluation of design of fusion DEMO reactor, and we have to check and evaluate them in Fusion irradiation environment like IFMIF.
Ohira, Shigeru
no journal, ,
Under the Broader Approach (BA) activities, which are research and development activities jointly implemented by Japan and EURATOM in support of the ITER Project and an early realization of fusion energy for peaceful purpose, projects of the Engineering Validation and Engineering Design Activities for International Fusion Materials Irradiation Facility (IFMIF/EVEDA) and the International Fusion Energy Research Centre (IFERC) are being carried out in Rokkasho, Aomori, Japan. In this presentation, Status of research & development for DEMO under the Broader Approach Activities are introduced.
