Cryogenic thermal analysis of the HANARO cold neutron moderator cell

Accurate prediction of a temperature distribution is very important for investigating the heat transfer characteristics in a cryogenic system such as a cold neutron moderator cell. The cold neutron moderator cell is a 13.2-cm-diameter cylinder with the liquid hydrogen in it contained by an aluminum alloy cell. It will be placed in a cold neutron hole that is inside the heavy water reflector tank of HANARO. The liquid hydrogen serves both as a neutron moderator and a single-phase cryogenic coolant for the cold neutron moderator cell. For the cold neutron moderator cell, its interactions with neutrons and gamma-rays produce a heat load of 629 W on the aluminum alloy cell and liquid hydrogen itself. A half of the cold neutron moderator cell was modeled with a three-dimensional axisymmetric cylinder geometry by using the HEATING 7.3 code. A numerical analysis was performed to determine the temperature distribution over the entire inner surface of the moderator cell, whose moderator and cell walls are heated differently, under a steady-state operating condition. This paper presents the steady-state temperature distribution for providing the cryogenic thermal analysis and for supporting the thermal stress analysis of the moderator cell walls.