Charging procedures: effects on high temperature sodium thermosyphon performance

Abstract

In this work, the influence of the charging procedures on the performance of two-phase thermosyphons operating with sodium as working fluid is studied experimentally. Solid charging and liquid charging, both in controlled and uncontrolled environments, with a non-condensable gases purge process after the thermosyphon closing were the methods employed. A charging apparatus for liquid sodium was designed and constructed, taking into consideration the operator safety, industrial applicability, cost of implementation, minimization of sodium contamination and, most importantly, the thermosyphon performance. Before charging, all thermosyphons experimentally studied were subjected to standard fabrication processes: cleaning, preparation, leak checking, tube vacuuming, sodium handling and case closure. The results show that the thermosyphon charged with sodium in liquid state under controlled environment and with non-condensable gases purging after closing presented the best performance among all. Therefore, the developed charging apparatus, in spite of its low cost of implementation, showed to be adequate for the manufacturing of sodium thermosyphons, as the sodium handling is quite safe and the resulting devices present excellent performance.