Design and development of LN2 cooled cryopump for application in high heat flux test facility

Abstract

• A liquid nitrogen cooled sorption cryopump is developed for the High Heat Flux Test Facility at IPR. • Design details, fabrication details, operational concept and thermo-structural analysis results are described. • The pump geometrical concept is novel because it provides ease of assembly, integration and trouble free operation in horizontal and vertical direction mounting. • The pump has 250 mm opening and offers pumping speed of ∼5106.6 l/s for water vapour and ∼1197 l/s for nitrogen using liquid nitrogen as coolant. • The pump integration and operation with High Heat Flux Test Facility is discussed. High Heat Flux Test Facility (HHFTF) at Institute for Plasma Research is established for testing thermal performance of Plasma Facing Components (PFC) and Plasma Facing Materials (PFM) that are expected to withstand steady-state and transient heat flux of the order of 10 MW/m 2 and 20 MW/m 2 , respectively, expected in plasma fusion devices. During high heat flux testing of PFCs and PFMs, water vapour and other trapped gases are released. For the pumping need, a cryocooler based commercial cryopump and a turbo-pump is used. In addition to that, an indigenously developed liquid nitrogen cooled cryopump is mounted to the High Heat Flux (HHF) test facility. The developed cryopump has 250CF inlet flange and mounted vertically downward to an angle port (50°) to the D-shaped vacuum chamber of the HHF facility. The pump has integrated liquid nitrogen bath to provide stable cooling to the cryopanels and radiation shield. Cryopanels are made of copper and coated with micro-porous activated charcoal. The pump's geometrical concept is novel because it provides ease of assembly, integration and trouble free operation in horizontal and vertical direction mounting. The pump offers pumping speed of ∼5106.6 l/s for water vapour and ∼1197 l/s for nitrogen using liquid nitrogen as coolant. The pump geometry, thermal and structural analysis, fabrication and experimental details are discussed in this paper. After integrating the cryopump to the HHF test facility, performance studies were carried out and initial test results are also discussed.