Potassium and sodium vapor diffusion pump development for fusion system

Abstract

An alkali metal diffusion pump, which can meet many requirements for DT fusion system, was developed based on a commercial oil diffusion pump. Using sodium, potassium, and oil each as a vapor source, their evacuation behaviors were compared. The evacuation rate using potassium was comparable to that by original oil, and operation using sodium was found to require higher temperature. The compression ratio and evacuation of deuterium were also investigated. The diffusion pumping system was operated successfully, making this type of evacuation system a potential candidate for the fusion system.