FUEL CYCLE CONTROL METHOD FOR PRESSURE-TUBE REACTOR Russian patent published in 2003 - IPC

FIELD: nuclear power engineering; controlling fuel burn-up during any moment of reactor life. SUBSTANCE: method includes organization of reactor core by charging fuel assemblies with distributed neutron absorber in the course of program- controlled displacement and extraction of fuel assemblies, program-controlled displacement of control and protection system rods, and replacement of additional absorbers by partially burned out fuel assemblies. When reactor is running upon extraction of all additional absorbers part of fully immersed rods of control and protection system are replaced by rods of cluster design. Uranium- erbium fuel having original enrichment of U²³⁵ higher than that of uranium-erbium fuel charged before extraction of control and protection system rods by 0.2-0.5% is used as distributed-neutron- absorber fuel. EFFECT: maximized fuel burn-up, reduced number of refueling operations, enhanced self-protection ability of reactor and economic efficiency of fuel cycle. 1 cl