Abstract:
A nuclear reactor is disclosed wherein hydraulic drive mechanisms are provided to vary the location of a plurality of neutron-absorbing control elements associated with selected fuel assemblies. Each fuel assembly comprises a fixed array of commingled and spaced fuel pins and guide tubes. Each selected assembly has a plurality of individually movable two-position control elements which are coupled to drive mechanisms which operate to telescope the control elements within their associated guide tubes.
Abstract:
A metallic clad sealed fuel element for a nuclear reactor which may be initially pressurized to resist creep collapse in the early stages of burnup and which has one or more normally sealed plenum chambers which are automatically punctured when predetermined increased pressures are reached during burnup to provide void space for fission gases. In one example, the plenum chambers each comprise an elongated bellows-like structure which when compressed by the increasing pressures within the fuel element cause a wall thereof to be punctured by an internally mounted pin.
Abstract:
A NECULEAR REACTOR IS DISCLOSED WHEREIN A PORTION OF ITS FUEL ASSEMBLIES HAVE PRIMARY OR SHUTDOWN NEUTRON ABSORBING CONTROL ELEMENTS COUPLED TO INCREMENTAL DRIVE MECHANISMS, AND A PORTION OF ITS FUEL ASEMBLIES HAVE ONE OR MORE INDIVIDUALLY MOVABLE AUXILIARY FINE FLUX TRIM RODS (FFT) COUPLED TO NEW AND IMPROVED TWO-POSITION MECHANISMS. THE TWO-POSITION MECHANISMS ARE ASSOCIATED WITH CURVED GUIDE CHANNELS IN SUCH A MANNER AS TO CONTROL THE POSITION OF INDIVIDUAL FFTG RODS ASSOCIATED WITH A PLURALITY OF FUEL ASSEMBLIES.