IIRC draining the fuel salt into the drain tanks was standard operating procedure for one of the early MSR experimental reactors. Next morning when they came i

IIRC draining the fuel salt into the drain tanks was standard operating procedure for one of the early MSR experimental reactors. Next morning when they came in to continue experiments, started the (electrical?) heaters to liquify the salt and pump it back into the reactor core. Wouldn't surprise me if the modern designs are similar.