In November 2022, the primary salt pump installed in the high-temperature FLUoride Salt Test FAcility (FLUSTFA) was successfully operated, including starting and stopping 20 times and running the pump at 0-928 RPM controlled by a variable frequency drive (VFD) for a total of about 20 hours. Subsequent attempts to operate the pump in May 2023 were unsuccessful. Steps taken to try to get the pump operational include adjusting the shaft position, increasing the heating power of the tape heaters on the pump volute, and manually rotating the pump shaft. None of these steps were successful to make the pump operational, and in September 2023 the pump was deemed inoperable.Root Cause Analysis (RCA) was performed. This RCA aims to determine root causes for two Events: the inoperability of the pump and the extreme corrosion of the volute. These two Events were assumed to be unrelated until proven otherwise. After considering probable scenarios, causes were assigned and corrective actions were developed to prevent those causes. Then, the RCA was presented to an advisory committee for review, the “Review Committee,” consisting of experts in large molten salt systems: Brandon Haugh, David Holcomb, Kevin Robb, and Vicente Rojas. The advisory committee provided comprehensive feedback, which have been incorporated into a revised RCA.
