Abstract:
A water-cooled metal basin is located under a nuclear reactor vessel to catch, cool, solidify and retain molten core material dropped from the vessel upon a burn-through of the vessel. A plurality of horizontally disposed water-filled tubes in the basin have a common inlet connected with an elevated storage tank and have discharge outlets positioned at a height at least equal to the water level in the storage tank. The basin provides a level floor on which the molten core material may spread out in a thin layer and be solidified and maintained solid by transfer of heat to water passing through the tubes. The tubes may also extend vertically above the basin to absorb heat radiated from the upper surface of the layer and radiating fins may be provided in the basin. A second material may also be provided to absorb heat from the molten reactor material by melting of the second material thereby solidifying the molten core material. Waterflow is started automatically by convention and gravity.