NUCLEAR REACTOR FUEL ELEMENT Russian patent published in 2002 - IPC

FIELD: nuclear power engineering; pressure-tube uranium-graphite reactors. SUBSTANCE: fuel assembly has column of bushing slugs mounted on support in process tube. Neutron absorbing rod is placed in central space of bushing- slug column. Rod is made of material based on boron, lithium, or thorium. Bushing-slug body has vertical channels equally spaced from external and internal surfaces of bushing slug. Channels accommodate fuel pellets with fissionable material including burning-out absorber. Ratio of width of bushing-slug ring to pellet diameter is 1.01-5.45. Bushing slug also has gas-collection channels communicating with fuel channels. Pellets are enclosed in aluminum, zirconium, or stainless-steel cans. EFFECT: enhanced lifetime at same steam void reactivity effect throughout entire life of reactor and desired subcriticality when shutting off the reactor. 6 cl, 4 dwg