There are two categories of valve specified in the system; Manual Drain Valves and Automatic Gate Valves in two configurations, fail open and fail closed. Gate valves were selected based on the learnings of many pioneering molten salt facilities including Solar One and Solar Two. Ball Valves were avoided for this reason due to many reports of leakage past the valve and overboard.
    The gate valves selected utilized a 304L stainless steel body with zirconia ceramic wetted interiors. They are compatible with the 60 to 40% Sodium nitrate and Potassium nitrate molten salt and are rated for use up to 1085°F (585 °C). They have 3/4 inch NPD weld fittings and are rated to 20psi at max operating temperature. The maximum inline leakage at 20psi is 20ml/hr. The valves selected utilize electric actuators and are switchable between fail-open and fail-closed operation.