Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||Tohoku University |
UCHIDA Shunsuke TOHOKU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, PROFESSOR, 大学院・工学研究科, 教授 (60321973)
SATOH Yoshiyuki TOHOKU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, ASSISTANT PROFESSOR, 大学院・工学研究科, 助手 (00005480)
IINUMA Koichi TOHOKU UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, ASSOCIATE PROFESSOR, 大学院・工学研究科, 助教授 (40005484)
|Project Period (FY)
2001 – 2003
Completed (Fiscal Year 2003)
|Budget Amount *help
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥8,100,000 (Direct Cost: ¥8,100,000)
|Keywords||ACCELERATOR / COOLING SYSTEM / STRESS CORROSION CRACKING / HYDROGEN PEROXIDE / ELELCTRO CHEMICAL CORROSION POTENTIAL / WATER RADIOLYSIS / CRACK PROGRESS SPEED / NUCLEAR FUSION REACTOR|
Stress corrosion cracking (SCC) of structural materials in cooling systems of high power accelerator targets, nuclear fission reactors and fusion reactors reactor are determined mainly by local concentrations of rodiolytic species around crock tips. Major purposes of the studies are to confirm the corrosion determining species, to determine the effects of local water chemistry on SCC crack growth rate and then so propose suitable water chemistry control, e.g.,weak alkali control for mitigation of SCC.
1.Determination of local water chemistry of crack tips under irradiation.
Energy deposition rate was measured in a simulated crack tip. Water chemistry in a crack tip could be theoretically estimated with the crevice radiolysis model.
2.Design and construction of high temperature high pressure hydrogen peroxide (H_2O_2) water loop
The concentration of H_2O_2 could be controlled at any desired concentration. Crack growth rate (CGR) could be measured.
3.Determination of CGR under irradiation
was measured under simulated irradiation conditions (controlled by H_20O_2 concentration). Difference in CGR under H_2O_2 and O_2conditions was discussed. It was confirmed that the major parameter to determine CGR was corrosion current rather than electrochemical corrosion potential.
4.Determination of CGR under irradiation and weak alkali water chemistry
(1)CGR was measured under simulated irradiation condition and under pH less than 8.5.
(2)The effects of crack tip pH on CGR was evaluated.
5.Feed back of measured date to crevice radiolysis model and corrosion condition evaluation procedures for operation plants
(1)Suitable sets far G values and reaction rate constants was proposed.
(2)Theoretical model containing the suitable constant sets was proposed.
(3)SCC CGR evaluation model which consisted of the crevice radiolysis model and the crack growth model, was proposed not only for fission reactor cooling systems but also cooling systems of accelerators and fusion reactors.
(4)Weak alkali water chemistry was proposed to prevent SCC not only for fission reactor cooling systems but also cooling systems of accelerators and fusion reactors. Less