Neutron moderator
MEDIUM THAT REDUCES THE SPEED OF FAST NEUTRONS, TURNING THEM INTO THERMAL NEUTRONS THAT CAN SUSTAIN NUCLEAR CHAIN REACTIONS; E.G. WATER, GRAPHITE, HEAVY WATER, BERYLLIUM
Neutron moderation; Neutron moderators; Neutron Moderator; Moderator (Nuclear Reactor); Thermalization of a neutron
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, ideally without capturing any, leaving them as thermal neutrons with only minimal (thermal) kinetic energy. These thermal neutrons are immensely more susceptible than fast neutrons to propagate a nuclear chain reaction of uranium-235 or other fissile isotope by colliding with their atomic nucleus.