GB992021A - Improvements in nuclear reactors - Google Patents

Abstract

992, 021. Reactors. BABCOCK & WILCOX Ltd. Nov. 7, 1961 [Nov. 8, 1960], No. 39775/61. Heading G6C. A nuclear reactor includes magazines containing bundles of fuel pins spaced from one another and the magazine wall by spacing means, and each magazine wall, which forms externally part of a pressure compartment, is constructed of thin metallic sheeting made flexible by flutes or corrugations so that a fluid pressure differential maintained between the compartment and a coolant flowing through the magazine serves to pack the spacing means tightly between and around the fuel pins. The flutes or corrugations 23 are also used to space the magazines apart. The spacers 28A, 28B and 28C (Fig. 3) which space the fuel pins 25 from one another and from the magazine walls 22, comprise short annular cylindrical rollers of identical length but different diameters, and are arranged in vertically spaced horizontal layers throughout the magazine 13. Each fuel pin is shouldered at its ends 26 for the rollers to rest on. The coolant is heated in the magazine 13, passed through a turbine, heat exchanger and pump respectively, and then recirculated through the magazine. The pressure compartment, which is contained in a pressure vessel, is pressurized by coolant fed through an opening in the pressure vessel from a point downstream of the pump. In Fig. 4 the coolant is not fed into the compartment 20 through the vessel, but is fed through a conduit 31. The conduit 31 has a flared mouth 32 adjacent a nozzle restriction 33 which causes high velocity coolant to enter the mouth 32 resulting in a pressure build-up within the conduit 31 which is transmitted to the coolant within the compartment 20. The pressurising conduits need not be supplied from the reactor coolant supply, but from special booster pumps which normally supply new coolant to the circuit. The new coolant can be fed to the compartment from which an overflow can open into the main coolant circuit.