Capsule-Type and Loop-Type Experimental Rigs for Irradiation Testing of Molten Salt Reactor Materials

Nowadays, such countries as Russia, China, USA and others perform calculations and experiments focused on the molten salt reactor (MSR) concept. This project requires, first of all, the justification of structural materials to have the appropriate corrosion and radiation resistance under the MSR operating conditions. The MSR materials should undergo both out- and in-reactor testing under the relevant condition. Capsule-type irradiation rigs (IR) have been developed to test candidate MSR materials in the SM-3 reactor in the environment LiF-BeF2 and LiF-NaF-KF. The IR allows testing flat and cylindrical (small dog-bone) samples in molten salts. The samples are placed into the capsules filled with molten salt and sealed. Each capsule is made of the same material as the sample. Up to thirty capsules are inserted into the IR that also has tellurium-containing capsules and samples to be tested in the helium environment. In total, one IR may contain up to fifty samples to be tested in the molten salt, up to fifty samples to be tested in the tellurium vapors and up to hundred samples to be tested in the helium environment. The IR design provides for maintaining the test temperature from 500℃ to 750℃ depending on the requirements to the material and type of molten salt. A loop design has been developed for the SM-3 reactor with a natural molten salt circulation to test structural materials under the simulated operating conditions of both MSR vessel and internals. (author)