Start-up thaw concept for the SP-100 space reactor power system

Piping and component arrangements for typical SP-100 configurations are described, and appropriate methods for accomplishing thaw during startup procedures are identified. Of particular interest are methods for achieving thaw within the reactor vessel, means for thawing progressively along piping and within components, and assuring fluid communication of molten zones with free expansion spaces to avoid structural damage. The results of analytical studies are presented and an overall assessment of thaw concept feasibility is discussed from the energy delivery, control, thaw time, and structural points of view