In the course of research on materials for pressurized components for gascooled reactors, a fundamental study was begun upon two kinds of materials: (1) manganese-molybdenum weldable steel similar to that used in the pressure vessels of the French gas-cooled graphite reactor projects, and (2) Zircaloy-2, chosen for the pressurized tubes of the French gas-cooled heavy water projects. Preliminary results are reported. Both impact tests and tension tests were performed in order to correlate brittleness and hardening after irradiation. Other tests were also made to study the recovery of steel following irradiation damage.
Irradiation temperatures were 180 C for steel and less than 100 C for Zircaloy-2.
In addition to tests on the original material, cold-worked materials and several heat treatments have been studied in order to obtain different grain sizes and microstructures, with resulting increase in yield strength and change in transition temperature. Some attempts were made to correlate results with radiation damage theory. Conclusions agree well with those reported in the literature.