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Title: Operational characteristics of the J-PARC cryogenic hydrogen system for a spallation neutron source

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. Furthermore, the temperature fluctuation of the feed hydrogen stream is required to be within ± 0.25 K. A stable 300-kW proton beam operation has been carried out since November 2012. The para-hydrogen concentrations were measured during the cool-down process. It is confirmed that para-hydrogen always exists in the equilibrium concentration because of the installation of an ortho-para hydrogen convertor. Propagation characteristics of temperature fluctuation were measured by temporarily changing the heater power under off-beam condition to clarify the effects of a heater control for thermal compensation on the feed temperature fluctuation. The experimental data gave an allowable temperature fluctuation of ± 1.05 K. It is clarified through a 286-kW and a 524-kW proton beam operations that the heater control would be applicable for the 1-MW proton beam operation by extrapolating from the experimental data.
Authors:
; ; ; ;  [1]
  1. J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195 (Japan)
Publication Date:
OSTI Identifier:
22263971
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1573; Journal Issue: 1; Conference: International cryogenic materials conference, Anchorage, AK (United States), 17-21 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 07 ISOTOPES AND RADIATION SOURCES; CONTROL; HYDROGEN; J-PARC; NEUTRON BEAMS; NEUTRON SOURCES; PROTON BEAMS; PULSES