REMARKS ON REACTIVITY CONTROL IN LIGHT WATER MODERATED REACTORS

摘要

In light water moderated reactors the thermal diffusion length is quite small and, consequently, a non-moderating, poison containing, control rod draws the thermal neutrons that it absorbs from only a small surrounding region. Thus, a neutron which becomes thermalized in a region not in the immediate vicinity of the control rod’s surface has a high probability of being absorbed by other materials before it can reach the control rod by diffusion.