Abstract: A nuclear power system comprises a plurality of modules disposed in below-grade pits to provide a compact, self-contained nuclear power supply. The modules are preferably individually transportable so that they may be substantially preassembled prior to installation. The system operates at relatively low temperatures and pressures, and includes various safety features which would prevent radioactive contamination of the surrounding environment in the event of a disturbance causing rupture of one or more of the odules or the pipes interconnecting the modules. The system also provides a low resistance flow path for vapor discharged from the turbine to improve efficiency.

Abstract: A nuclear reactor includes a core submerged in a pool of liquid. Under normal conditions, coolant flows through the core without intermixing with the liquid in the pool. In the event of failure of the primary coolant circulation system, liquid from the pool flows through openings in the primary circulation system so as to cool the core by natural convection. Flow through the openings during normal operating conditions may be controlled regardless of the flow rate.

Abstract: A system is disclosed for supporting and protecting the coaxially disposed helical coils of a heat exchanger arranged with its axis in the vertical direction. The system includes saddle-shaped vertical spacers secured on selected adjacent convolutions of each coil at selected angular positions about the axis of the coils. The vertical spacers are selectively axially aligned to axially support the convolutions of the respective coils, and are cooperable with axially disposed spacer bars between the radially spaced coaxial coils to transfer horizontal and tangential loads between the coils. The tube support system provides vibration damping and facilitates subassembly of different diameter helical coils prior to coaxial assembly thereof into a coil bundle.