Energy dissipating resistors for the ITER switching network units

Abstract In ITER, before each plasma pulse the poloidal magnet system will be pre-charged with maximum energy up to 8GJ. Part of this energy will be used for the gas mixture breakdown and early plasma current ramp up. This will be provided with help of the switching network units (SNU) comprising of special hybrid (mechanical and semiconductor) DC circuit breakers and resistors, which, after being inserted into the coil circuits by opening of the circuit breakers, dissipate the energy extracted from the coils. The paper describes the design of the SNU resistor and reports on the results of the tests carried out with the aim to optimize the design, demonstrate its suitability and to confirm its compliance with ITER requirements.