METHOD FOR NUCLEAR FUEL CYCLING IN GRAPHITE-MODERATED PRESSURIZED-TUBE REACTOR Russian patent published in 2004 - IPC

FIELD: nuclear power engineering; pressurized-tube power reactors.

SUBSTANCE: proposed method that ensures cycling of nuclear fuel by producing reactor core in the coarse of loading fuel assemblies with distributed neutron absorber, programmable movements of fuel assemblies, and programmable changing of absorbing-rod positions in control and protection system includes replacement of burnt-out fuel assembly in periodicity subchannels with neutron spectrum hardened to energy of neutron resonant absorption by plutonium as soon as it attains mean energy output of 1500 - 1600 MW-day per fuel assembly by fuel assembly having residual content of uranium-235 between 0.5 and 0.6 kg. Neutron spectrum is hardened by charging uranium-erbium fuel initially enriched to 2.8 + 3.6% of uranium-235; zonal coolant flowrate is reduced in process channels with fuel assemblies of power output between 2300 and 3500 MW-day per fuel assembly in the course of programmable displacement of fuel assemblies in reactor core. Moderator temperature is controlled by blowing down reactor space with nitrogen-helium mixture having 10 - 40% content of nitrogen in basic mode of operation of reactor and 10 -100%, at reduced power levels.

EFFECT: enhanced fuel burnout percentage and power output of fuel assemblies.

4 cl, 1 dwg