Assessment on the Practicality of Off-the-Shelf Valves for Use in Molten Salt

Abstract

From the mid to late 1960s, the Molten Salt Reactor Experiment (MSRE) was operated at Oak Ridge National Laboratory (ORNL). The MSRE design is unique: instead of standard valves, freeze valves were used to isolate the fluid salt as needed. While standard valves were considered for use in the MSRE, key design challenges (leaking, corrosion, valve alignment, and cold-welding, etc.) were all avoided by choosing a freeze type valve. While the freeze valves were integral to the MSRE’s success, they do not respond quickly, and they are not capable of throttling flow: two key features important to commercial operation and test facilities. More than half a century after the MSRE’s inception, design and manufacturing capabilities have changed. There is a renewed interest in molten salts for energy storage in nuclear and concentrated solar power. Therefore, there is a strong desire to have a functioning valve that can be obtained off the shelf or with minimal modification to a custom valve. This research addresses the known challenges associated with valve selection in fluoride salts, provides guidelines as to potential options for selection of a valve, and uses these guidelines to select a valve for testing in ORNL’s Liquid Salt Test Loop (LSTL).