Speaker
HIDEKI TATSUMOTO
(Japan Atomic Energy Agency)
Description
At the J-PARC spallation neutron source, high-energy MeV-order neutrons generated from a mercury target are reduced to the appropriate energy level (meV order) in three types of hydrogen moderators (coupled, decoupled, and poisoned).The J-PARC cryogenic hydrogen system provides supercritical cryogenic hydrogen to the moderators at a pressure of 1.5 MPa and temperature of 18 K and removes 3.8 kW of the nuclear heating for the 1 MW proton beam operation, when the nuclear heating is estimated to be 3.8 kW. The temperature rise is estimated to be 2.4 K at a circulation flow rate of 0.19 kg/s. 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 below the allowable pressure of 0.1 MPa because the slight temperature rise leads to a large pressure increase in the supercritical hydrogen loop because of its incompressibility. In this study, an 1-D simulation code has been developed to understand pressure and temperature propagation through the hydrogen loop when the proton beam is turned on and off. Pressure drop through each component was estimated using a CFD code, STAR-CD. Heat transfer of supercritical hydrogen was calculated using authour’s correlation. It was confirmed that the simulation results agreed with the experimental data under the same condition.
Author
HIDEKI TATSUMOTO
(Japan Atomic Energy Agency)
Co-authors
Mr
Kiichi Ohtsu
(Japan Atomic Energy Agency)
Dr
Tomokazu Aso
(Japan Atomic Energy Agency)
Mr
Yoshihiko Kawakami
(Japan Atomic Energy Agency)
