The Tore Supra, flexible and electrically insulating, cryogenic connection line

Abstract This paper describes the “Junction JC3” inserted between the cryogenic connection lines and the cold box of the helium refrigerator: each component of the JC3 is flexible and electrical breaks insulate the refrigerator from the Tokamak. Two concentric pipes, carrying the superfluid helium supply are located on the axis of the line. These are surrounded by two concentric thermal shields, each connected to four cooling tubes, the inner set working at 4.5K, the outer at 80K. Each of these ten pipes, surrounded by vacuum, operate with internal helium pressures of between 1.2 kPa and 1.8 MPa.