Spent fuel storage improvement

An apparatus is described which permits the compact storge of fissionable masses without creating the possibility of producing a critical geometry while at the same time minimizing construction costs. The design incorporates discrete neutron absorbing shields adapted to parametrically encircle each of the fissionable masses. It is assumed that the fissionable masses have lateral cross-sections which fit within the confines of a polygon. The apparatus comprises a first series of structural members, such as bands, alinged in spaced parallel rows, a second series of structural members, such as bands, alinged in spaced parallel rows which cross the first series of bands at an angle equal to the angle between two non-parallel sides of the polygon. With this arrangement the first and the second series of spaced crossed bands form a plurality of passages transverse to the first and second series of bands. A plurality of discrete neutron absorbing shields are then positioned in the passages formed by the first and second series of bands and are rigidly fastened to one band of each of the first and second series of bands. (auth)