Abstract: Nuclear power plants include vertical shafts housing a reactor and plant equipment connected between the shafts. Shafts may be formed with VSM to nuclear standards, and a basemat may be poured at the bottom, which is compatible with reactor designs such as a simplified boiling water reactors, small modular reactors, advanced reactors and sodium cooled fast reactors. Additional plant systems may be placed in further shafts and connected through side-travelling tunnels that pass through the shafts. The plant may be segregated by safety class among different shafts. Floors, which may be modular and prefabricated with full equipment for delivery at the shaft, may be vertically lowered into appropriate shafts and seated to walls of the shaft. Equipment can be connected between floors by running connections along shaft walls.

Abstract: A nozzle adapted for use in a high excess air burner. The nozzle includes three combustion chambers and an outer flame retention ring for supporting combustion of gaseous fuel over a range of volumetric flow rates. Combustion air is staged to each of the combustion chambers and to the outer flame retention ring for mixing with the fuel to form a combustible fuel-air mixture. Combustion occurs in the first combustion chamber at relatively low flow rates of fuel. Combustion occurs in the second and third combustion chambers and the outer flame retention ring with increasingly higher fuel flow rates. The second combustion chamber is configured with a radially inwardly converging sidewall to provide for a smooth transition of the flame between the second and third combustion chambers.

Abstract: A shield for restricting molten corium from flowing into a water sump disposed in a floor of a containment vessel includes upper and lower walls which extend vertically upwardly and downwardly from the floor for laterally bounding the sump. The upper wall includes a plurality of laterally spaced apart flow channels extending horizontally therethrough, with each channel having a bottom disposed coextensively with the floor for channeling water therefrom into the sump. Each channel has a height and a length predeterminedly selected for allowing heat from the molten corium to dissipate through the upper and lower walls as it flows therethrough for solidifying the molten corium therein to prevent accumulation thereof in the sump.