Determination of Temperature of Structural Material Specimens in an Irradiation Capsule by an Analytical and Simulation Techniques

Abstract

The main aim of this work is to determine the temperature of structural material specimens kept in an irradiation capsule during their irradiation in a nuclear reactor to find out the changes in mechanical properties. In the irradiation capsule, the specimens are kept in four to five separate leak-tight compartments located one over the other. Helium/Argon gas or mixtures of these gases are filled around the specimens in the compartments. The coolant of reactor, liquid sodium, flows around the irradiation capsule. During irradiation, due to attenuation of gamma rays and neutrons on the specimens, heat is generated in the specimens. Due to this generation of heat, the temperature of the specimens is more than the temperature of the sodium flowing over the capsule/compartment and we can obtain an irradiation temperature in the specimens which is much higher than the sodium temperature. In the present analysis, the temperature of specimens has been determined with various types of gases (helium/argon/helium-argon mixture) filled in the compartments around the specimens. Variable properties of gases have been used and an iterative method has been employed to calculate the temperatures. Using the results obtained, we can select the type of gas mixture required to attain a specific higher temperature in the specimens during irradiation. The results have been compared with the results obtained using a computer code COMSOL.