Speaker
HIDEKI TATSUMOTO
(Japan Atomic Energy Agency)
Description
The J-PARC cryogenic hydrogen system provides supercritical hydrogen with the para-hydrogen concentration of more than 99 % and the temperature of less than 20 K to three moderators so as to provide cold pulsed neutron beams of a higher neutronic performance. The nuclear heating is estimated to be 3.75 kW at the moderators for a 1-MW proton beam operation. The temperature rise is estimated to be 2.4 K at a circulation flow rate of 0.19 kg/s. There was concerned that the slight temperature rise would lead to a large pressure increase in the hydrogen loop since the supercritical hydrogen behaves as an incompressible fluid. Furthermore, temperature fluctuation of the feed hydrogen stream should be also reduced below 0.25 K because the neutron performance is affected by a hydrogen density change. We prepared a heater for thermal compensation and an accumulator, with a bellows structure, for volume control, so as to mitigate the pressure fluctuation caused by the proton beam on and off. We have developed a compact orifice type high-power heater and perform its performance evaluation during off and on beam operation. It is clarified through the commissioning processes that the heater control would be applicable for the 1-MW proton beam operation by extrapolating from the experimental data.
Primary author
HIDEKI TATSUMOTO
(Japan Atomic Energy Agency)
Co-authors
Mr
Hideo Muto
(Japan Atomic Energy Agency)
Mr
Katsuhiro Aoyagi
(Japan Atomic Energy Agency)
Mr
Kiichi Ohtsu
(Japan Atomic Energy Agency)
Dr
Tomokazu Aso
(Japan Atomic Energy Agency)
Mr
Yoshihiko Kawakami
(Japan Atomic Energy Agency)
