Breakthrough advances in vacuum freezing

This paper reports that breakthrough advances in vacuum freezing now make this approach attractive for treating low-level liquid radioactive waste (LLW). The authors discuss the development of equipment that solves two key problems: the need for an effective and reliable way of liquefying the sub-triple-point vapor (vapor at a pressure below the triple point pressure) generated in the vacuum freezing operation, and the need for an efficient and reliable way of generating a super-triple-point vapor (vapor at a pressure above the triple point pressure) to melt purified ice. These problems previously prevented the commercialization of vacuum freezing. The two vacuum freezing processes are: the vacuum freezing multiple phase transformation (VFMPT) process, that can handle solutions up to a eutectic composition, and the primary refrigerant eutectic freezing (PREUF) process, an extension of VFMPT that can accomplish a complete separation of the eutectic mixture and, if desired, bring components to dry masses