Nuclear reactor control rod

摘要

A control rod for a fast nuclear reactor comprises a tubular metal casing (10) enclosing a stack of neutron-absorbing cylinders, the cylinders (12a) in the upper part of the casing having a higher neutron-absorbing ability than those (12b) in the lower part. This is achieved by making cylinders (12a) of higher density and possibly by increasing the concentration of a more absorbent isotope therein.