Patent Number: 047042486
Section: claims

1. A pair of generally vertically stacked prismatic fuel elements disposed in a nuclear reactor, each of said elements being substantially identical and comprising: a block of refractory material, such as graphite, having substantially parallel spaced first and second end surfaces,  said first end surface having a peripheral sealing flange formed thereon extending away from said second surface, and said second end surface having a peripheral sealing recess sized to receive said flange,  said block having a plurality of longitudinal first coolant passages therethrough disposed inwardly of said flange and said recess coolant,  said block further including a plurality of peripheral longitudinal second coolant passages extending intermediate said end surface and in general alignment with said flange and recess, each of said second coolant passages having a first end and a second end with each end of each of said second coolant passages being blocked,  said block further comprising two bypasses for each of said second passages, one bypass intersecting the second passage adjacent but spaced from said first end surface and intersecting a first passage, and the other bypass intersecting the second passage adjacent but spaced from said second end surface and intersecting a first passage,  the extent of said flange being greater than the depth of said recess so that a plenum is defined by facing first and second end surfaces, said plenum being uninterrupted within the flange of the first end surface defining the plenum.