Thermo-hydraulic test of the moderator cell of LH2 cold neutron source at BNC

Thermo-hydraulic experiment was carried out in order to test the performance of the direct cooled liquid hydrogen moderator cell to be installed at the research reactor of the Budapest Neutron Center (BNC). Two electric heaters up to 300 W each imitated the nuclear heat release in the liquid hydrogen as well as in the construction material. The test moderator cell was also equipped with temperature gauges to measure the hydrogen temperature at different positions as well as the inlet and outlet temperatures of cooling He gas. The hydrogen pressure in the connected buffer volume was also controlled. At 140 W expected total heat load the moderator cell was filled with liquid hydrogen within 4 h. The heat load and hydrogen pressure characteristics of the moderator cell are also presented. (C) 2000 Elsevier Science B.V. All rights reserved.