Operation of the 8-T, 1-m-diameter test facility at Lawrence Livermore National Laboratory

Abstract

The High-Field Test Facility (HFTF) being built at Lawrence Livermore National Laboratory (LLNL) consists of a Set of four Nb-Ti coils, inside of which there is a oair of niultifilamentary NbjSn coils. The outer coils are designed lo generate 8 T in the l-m bore; the M>3Sn coils will boost this to 12 T in a 40-crn bore.This paper describes the first operation of the complete set of Nb-Ti coils and describ.es and gives results from the data acquisition and analysis sys tem that was used during the test.

Superconducting magnets for fusion

“…In the US fusion magnet development programme, in 1979, four teams began the tasks of designing 12-T TF coil conductor suitable for a tokamak reactor, manufacturing such conductor, and testing it in a 12-T background field. The High-Field Test Facility (HFTF) at Lawrence Livermore National Laboratory [39] will be used to test circular coils with a 0.4-m bore diameter and a 1.0-m outside diameter built of the 12-T conductor. One team, led by General Atomic Company, will use NbTiTa cooled to 2.5 or 1.8 K. Another, led by the Francis Bitter National Magnet Laboratory (FBNML), will use Nb 3 Sn conductor similar in configuration to the Westinghouse LCT conductor.…”

“…In the first step, 300 m of high-field conductor was wound into a solenoid and, in 1975, was operated at 2.55 kA and 10 T. (The nominal rating was 1.0 kA at 12 T.) Subsequent developments focused on improved fabricability in larger size conductors. This culminated in the design now being produced for use in the HFTF insert coils [39]. This conductor, having a nominal rating of 7.5 kA at 12 T, consists of a fully compacted cable inside a copper sheath to which extended-surface copper strips are soldered.…”