Irradiation swelling, creep, thermal shock and thermal cycling fatigue analysis of cylindrical controlled thermonuclear reactor first wall

Abstract

Abstract The irradiation swelling, irradiation creep, and thermal shock and thermal cycling fatigue developed in the first wall of the cylindrical controlled thermonuclear reactor (CTR) are analyzed theoretically on the basis of experimental results. The first wall will suffer heavy radiation damage from fast neutrons, primary γ- (or X-) rays, and high energy charged particles produced in the thermonuclear reactions. The void formation, void density, mean void diameter, and volume change due to nuclear irradiation in the first wall will increase or vary with the neutron fluence, irradiation temperature, helium production, and atom displacement damage of the wall material. Irradiation swelling can greatly enhance the irradiation creep rate. The relationships between the irradiation creep strain, neutron fluence, and radiation-induced creep stress are introduced on the basis of experimental data. Computed results of the principal stresses and strain rates obtained from the radiation, thermal, and creep analysis are depicted by graphs. Correlation equations for thermal shock and thermal cycling fatigue are derived on the basis of analytical and experimental results. From experimental data analysis the effects of hold time and crack initiation, propagation, and growth on cyclic fatigue life of the first wall can be predicted. It is postulated that the shearing stress can nucleate cracks and that the maximum principal stress can propagate and extend cracks along the failure plane normal to the principal stress. The damage resistance criterion for irradiation swelling, irradiation creep, and thermal shock and thermal cycling fatigue is proposed. The theoretical analysis and experimental results can be correlated, compared, and verified in the development of a CTR first wall when equivalent uniaxial tests (instead of multiaxial complicated experiments) of the first wall material are conducted.