12 T Insulated REBCO Magnet Used as 1 MJ SMES: Protection Strategies and Preliminary Assembly Tests

In the framework of BOSSE project, a 12 T insulated REBCO solenoid is being manufactured. This magnet will be used as SMES with objective to reach 1 MJ and specific energy 20 kJ/kg for winding. To manufacture this such performances, 21 Double Pancakes (DPs) assembled cooled in liquid helium bath at 4.2 K. validate solenoid's electromagnetic design, prototype DP tested self-field up its critical current (972 A), thanks sensitive protection system, was presented previous work. Here we present background magnetic field test which allowed coil's mechanical design. order performances DPs, each them rated current. The 17 DPs already validated also presented. Finally, tests results 2 preliminary assemblies 3 5 DPs. These were two different philosophies. these show that an individual preferred obtain better sensitivity on signal.