COMBINED PELLET OF NUCLEAR FUEL Russian patent published in 2011 - IPC G21C3/00 

FIELD: power engineering.

SUBSTANCE: pellet is made of several concentric layers each consisting of fissile and breeder material. An external concentric layer containing less fissile nuclear material per a unit of volume in comparison with an internal cylinder core additionally contains burnable absorber in form of perovskite phase ABO₃, where A=Gd, Er; B=Al, Mg, Ti, for example GdAlO₃. Also, average size of grain in the internal cylinder core is over 20 mcm, while average size of grain in external concentric layer of a combined pellet is less, than 5 mcm. The internal cylinder core of the combined pellet can have an axial orifice.

EFFECT: increased degree of fuel combustion, reduced expenditure of nucleus fuel per unit of output power, reduced volume of spent fuel, decreased value of coefficient of initial reactivity, and increased duration of operating period at nominal heat load onto fuel elements.

5 cl, 1 dwg