The present invention relates generally to electric power and process heat generation using a modular, compact, transportable, hardened nuclear generator rapidly deployable and retrievable, comprising power conversion and electric generation equipment fully integrated within a single pressure vessel housing a nuclear core. The resulting transportable nuclear generator does not require costly site-preparation, and can be transported fully operational. The transportable nuclear generator requires an emergency evacuation area substantially reduced with respect to other nuclear generators as it may be configured for operation with a melt-proof conductive ceramic core which allows decay heat removal even under total loss of coolant scenarios.

Various embodiments of a transportable nuclear power generator having a plurality of subcritical power modules are disclosed. Each of the plurality of subcritical power modules includes a fuel cartridge, a power conversion unit, and a housing substantially enclosing the fuel cartridge and the power conversion unit. The fuel cartridge contains a nuclear fuel and has a proximal end and a distal end. The power conversion unit includes a compressor turbine disposed at the proximal end of the fuel cartridge and a power turbine disposed at the distal end of the fuel cartridge. At least one of the plurality of subcritical power modules is movable with respect to the other of the plurality of subcritical power modules between a first position and a second position to control criticality of the nuclear fuel contained in the fuel cartridges of the plurality of subcritical power modules.

A nuclear reactor includes a nuclear core comprising a fissile material, and a pressure vessel containing the nuclear core immersed in primary coolant water. Turbo pumps disposed in the pressure vessel provide active circulation of primary coolant water in the pressure vessel. Each turbo pump includes a turbine driving an impeller. A manifold plenum chamber is disposed in the pressure vessel, and is in fluid communication with inlets of the turbines of the turbo pumps. An electrically driven pump operatively connected with the manifold plenum chamber to pressurize the manifold plenum chamber with primary coolant water. The turbo pumps may be disposed in openings passing through the manifold plenum chamber. The pressure vessel may be vertically oriented and cylindrical, with a cylindrical riser oriented coaxially inside, and the manifold plenum chamber may be annular and disposed in a downcomer annulus defined between the cylindrical riser and the cylindrical pressure vessel.