GB1159807A - Improvements in or relating to Nuclear Reactors - Google Patents

Abstract

1,159,807. Reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 25 Nov., 1966 [26 Nov., 1965], No. 50475/65. Heading G6C. To reduce attrition between fuel pellets of a fluidized bed reactor the bed is fluidized by a coolant comprising an inert gas having dust particles entrained therein, the fluidized bed also containing granules of moderator material which are circulated in heat exchange with the coolant. As shown, helium gas coolant containing a suspension of carbon dust is driven by a circulator 5 into an inlet plenum 8 of the reactor and upwardly through a perforated plate 7 into a bed 15 of fuel pellets which is thereby fluidized, the bed 15 also containing carbon granules of a size intermediate between the carbon dust particles and the fuel pellets these granules serving as a moderator and reflector and being lifted by the gas stream so as to spill over the edge of a baffle 9 and descend through outer annular zone 11. Heat is removed from the granules in the zone 11 by the upward flowing of the coolant in that zone through the plate 7, the granules re-entering the bed 15 by passing through the plate 7. By altering the degree of fluidization the reactor may be controlled, greater changes being effected by absorber rods 12. Heat is removed from the coolant by circulating the latter through a manifold 2 to a heat exchanger 4. In a modification in which the reactor is used for the direct conversion of heat into electricity by magnetohydrodynamic principles the carbon dust particles are replaced by particles of thorium or thoria dust.