Development of a compact, passive helium purification system for the advanced high temperature reactor

Abstract

In this study the possibility of a compact, passive membrane system to separate helium from the impurities that may be present in the AHTR primary system was investigated. The current helium purification systems that are used in the HTTR, HTR-10, and the old PBMR system are discussed and a more efficient alternative is sought in membrane technology. The Memcal software was identified and is validated as an accurate method of designing preliminary systems to prove the idea. Five different designs were decided upon each with their own specific setup and reasoning. Design 1 features as many membranes as possible and a stage cut of 90%. Design 2 features a changing stage cut and a minimum limit of what the retentate flow can be for each last membrane in a row. Design 3 was similar to design 1 in that it had a set stage cut at 90% but it also had a minimum limit for permeate and retentate flows. Design 4 featured a different transmembrane pressure, 5 bar, which allowed separation of certain species to happen much faster. Design 5 is just a shortened version of design 1, such that it has the same membrane system as design 4 and so that they can be compared. The designs are simulated and the results compared with each other, as each has a different setup and configuration, in an attempt to find the best solution. With the results for each of the different designs, displayed in Table 0-1, it is shown that a passive helium purification system, while compact, may be designed successfully through the use of gas separation membranes.