Intermediate storage assembly for spent nuclear fuel elements

摘要

The storage rack proposed has a baseplate (2) on which are mounted several structural-support shafts (4) with an essentially square cross-section. The shafts (4) stand vertically on the baseplate (2) and are disposed in a chess-board pattern essentially diagonally with respect to each other, each pair of facing shafts (4) having an empty space (3) between them. Located in the space (3) and/or in the shafts (4) is a neutron-absorbing structure (1) including boron-treated steel, this structure being movable with respect to the structural shafts (4) and having sheets (7) of boron-treated steel. These sheets (7) form an essentially square neutron-absorbing shaft (15) which has no role in supporting the storage rack. The neutron-absorbing shaft (15) is kept in position against the steel sheets (7) using spacer elements, in particular lateral corrugations (13).