Pool type LMFBR reactor

Nuclear reactor including a fuel assembly immersed in a coolant fluid, contained in a primary vessel, and a core blanket structure comprising a number of vertical tubes cross-linked by lower and intermediate perforated bedplates immersed in the coolant fluid. The nuclear reactor is characterized by the provision of a permeable shield on the upper side of the intermediate bedplate, so that the coolant fluid, which flows upward through intermediate bedplate perforations, must flow in a transverse direction on the upper surface of this bedplate, in order to reduce thermal stresses