Multiple Restart Testing of a Stainless Steel Sodium Heat Pipe Module

Abstract

A heat pipe cooled reactor is one of several candidate reactor cores being considered for space power and propulsion systems to support firture space exploration activities. Long life heat pipe modules. with designs verified through a combination of theoretical analysis and experimental evaluations. would be necessary to establish the viability of this option. A hardware-based program was initiated to begin experimental testing of components to verify c.omp:iao~e ofproposed ies;gtlj. TG this snd. a n u m b of stairlie55 a'b&'w&unl fr& pipe modules haw 'ken designed and fabrat& to support experimental testing of a Safe Affordable Fission Engine (SAFE) project, a 100-kWt a r e design pursued jointly by the Marshall Space Flight Center and the Los Alamos National Laboratory. One of the SAFE heat pipe modules was successllly subjected to over 200 restarts. examining the behavior of multiple passive 5eeze'thiw opesations Typical operation included a I-hour startup to an average evaporator temperature of IO00 K followed by a 15minute hold at tempaature. Nominal maximum input power during the hold period was 1.9 kW. Between heating cycles the module was cooled to less than 325 K, returning the sodium to a frozen state in preparation fop the next stiutup cycle.