Briggs Research Site

The Molten Salt Load Frame (MSLF) mates a dual-chamber autoclave and an Interactive Instruments Model 5K Servo to enable mechanical testing of materials with simultaneous exposure to molten salt environments. the MSLF is capable of achieving temperatures of up to 700°C through the use of an external, three heat zone clamshell furnace. Salt circulation between upper and lower chambers, which can be held at different temperatures, is achieved through the use of a bubble pump, allowing for simulation of thermal-gradient driven mass transport behavior expected in full-scale molten salt reactor designs.

FLiNaK is stored in its frozen state in the lower chamber of the autoclave while not in use. Test specimens are positioned between a clevis and a load-bearing tube. The tube has three heat shield fins to better insulate the salt with feedthroughs to accommodate wiring from additional instrumentation. Thermocouple probes are fed into the body of the MSLF to monitor lower chamber temperature. The lid has multiple feedthroughs that are used for upper chamber thermocouples and additional feedthroughs for future instrumentation. The servo can be actuated in load, strain, or stroke-controlled modes, giving flexibility to the type of testing that can be performed. The same software can be configured with DCPD instrumentation to measure and record crack length and stress intensity factor in operando for K-controlled fatigue crack growth rate testing.