Design of a high power heater for the cryogenic hydrogen system at J-PARC

The cryogenic hydrogen system, which provides the supercritical hydrogen with the pressure of 1.5 MPa and the temperature of around 20 K, adopts to moderate and convert high-energy neutrons into cold neutrons for neutron scattering experiments in the J-PARC. Large pressure fluctuation caused by the intense pulsed-proton-beam injection and trip should be mitigated by both an active heater control and a passive accumulator control. A compact high power heater should be required to compensate the heat load corresponding to the nuclear heating while the proton beam stopping. In this study, the high power heater used in the cryogenic hydrogen was designed and a numerical analysis was performed. Then the results confirmed that the heater could apply kW-order heat powers to supercritical hydrogen without any disturbance.