Abstract: An induced current heating probe is of thimble form and has an outer conducting sheath (30) and a water flooded flux-generating unit formed from a stack of ferrite rings (10) coaxially disposed in the sheath. The energizing coil (14) is made of solid wire which connects at one end (16) with a coaxial water current tube (15) and at the other end (17) with the sheath. The stack of ferrite rings (10) may include non-magnetic insulating rings (11) which help to shape the flux.

Abstract: Failed fuel detection apparatus for nuclear reactors cooled by liquid metal has a pump (11) for impelling coolant metal along sampling pipes (10) to outlet points (10a) in the pipes. A rotary collector (15) is provided to scan the outlet points with a gap between the outlet points and the collector across which coolant in the sampling pipes can be impelled. The pump (11) is preferably of the helical annular linear induction type with the pipes passing through the annulus of the pump while being wetted internally and externally by liquid metal.

Abstract: An electromagnetic pump of the helical annular linear induction type has pumped flow along paths which lie both inside and outside pipes (21) passing through the pump annulus (14). The pipes may be sampling pipes of failed fuel element detection apparatus. A number of pumps according to the invention may be arranged in cascade with selected pipes passing in series through selected combinations of pumps in the cascade so that, with an appropriate energization of selected pumps, flow along one pipe can be created while flow along other pipes is prevented.

Abstract: A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods.

Abstract: A liquid metal cooled fast breeder nuclear reactor of the pool kind has an intermediate heat exchange module comprising a tube-in-shell heat exchanger and an electromagnetic flow coupler in the base region of the module. Primary coolant is flowed through the heat exchanger being driven by electromagnetic interaction with secondary liquid metal coolant flow effected by a mechanical pump.

Abstract: A liquid metal cooled fast breeder nuclear reactor of the kind wherein the fuel assembly is submerged in a pool of liquid metal coolant in a primary vessel which is housed in a concrete vault. The fuel assembly, which comprises a multiplicity of elongate fuel pins, is sub-divided into a plurality of elongate sub-assembly constructions which upstand side-by-side. The fuel assembly has an inner zone comprised mainly of fissile material and a surrounding outer zone comprised mainly of breeder material. The sub-assemblies in the outer zone include electro-magnetic braking devices for regulating the flow of coolant through the sub-assemblies and the magnetic fields of the electro-magnetic braking devices are temperature sensitive being arranged so that as the power output of the breeder sub-assemblies increases the electro-magnetic resistance to coolant flow is reduced thereby maintaining the temperature of the coolant outlets from the sub-assemblies substantially constant.