Nuclear reactor

The core catcher for the gas-cooled fast breeder reactor operating with a ceramic mixture of PuO2/UO2 fuel contains a great number of inserts. Each insert consists of a pile of superimposed, spaced loss plates ( ) from cast iron, copper, or uranium essentially depleted with regard to the isotope 235U. The loss plates have got hexagonal shape and, at their corners, are provided with cutouts so that they form elongated, tapered passages in the assembled state. The plates themselves are fastened to hollow graphite columns containing a tube coil through which a coolant is flowing. By means of the core catcher it is possible to absorb the heat of a core melt, a great number of interconnected subcritical masses being formed. (DG)