The purification system of JUNO liquid scintillator

JUNO liquid scintillator should be high transparency and low radiation background, liquid scintillator purification system is needed. JUNO liquid scintillator purification system consists of six sub purification systems: alumina filtration system, distillation system, LS mixing system, water extraction, nitrogen stripping system and high pure nitrogen system. The alumina filtration system, high pure nitrogen system, stripping system and distillation system has been  have been installed in JUNO site. The water extraction system and mixing system is under cleaning.  All of them will be installed and commissioned in JUNO site in this year.