Effects of reflector parameters on neutronic performance of coupled hydrogen moderator with extended premoderator

摘要

Extensive neutronic optimization studies on the reflector for a coupled hydrogen moderator with extended premoderator have been performed with various parameters such as reflector material, size, cooling water and the existence of decoupled moderators located at the opposite side of the target. Time-integrated and peak intensities, pulse widths and decay times from a coupled hydrogen moderator (12 x 12 x 5 cm~3) with optimized premoderator in a lead (Pb) and a beryllium (Be) reflectors have been studied as a function of reflector dimensions with and without an iron outer reflector-shield. The effects of cooling water (H_2O or D_2O) fraction were also studied A larger inner reflector (Pb or Be) and a larger outer reflector-shield give a higher neutron intensity for both reflector systems.