Critical experiments on a liquid poison tube study of nuclear characteristics

not registered; not registered; not registered; not registered

Nuclear characteristics on a liquid poison tube have been studied by use of DCA. Reactivity worthes of the poison tube were measured as functions of 10B content in liquid and liquid poison level. Also, radial flux distributions around the poison tube and axial flux distribution in a fuel channel, DO moderator and poison tube were measured. The results of present experiment are summarized as follows. (1)Excess content of B beyond 800 ppm makes no increase in reactivity change. (2)Reactivity change in reference to poison level change in poison tube shows the S curve like the characteristics of control rod. (3)Change of liquid poison level gives a small change for the axial flux distribution in the center of fuel cluster. (4)The depression of thermal neutron flux around the poison tube with black poison remarkedly increases at about 2 cm distant from surface of poison tube. On the other hand, poison tube with gray poison makes small change in gross flux distribution at DO region.