PURPOSE: To prevent the clogging within a fuel pin bundle due to impurities in coolant, by means of setting up a collector of mesh shape having smaller cross section of flow path than the cross section of unit cells within the fuel pin bundle at the flow path of the coolant in the lower part of the fuel pin bundle.
CONSTITUTION: An impurity collector 10 is constituted by means of forming a mesh 16 by arranging a large number of lattice plates 14,15 of length and breadth in a zigzag shape. The largeness of the mesh is specified as smaller than the flow path cross section of unit cells formed between the fuel pins 11. The clogging of the space between the fuel pins is prevented by the impurities in the coolant, by means of arranging this device 10 at the interval between the lower shielding body and the fuel pin bundle.
TEZUKA MASAHARU
KASAHARA FUMIO
IIDA TAKEHIKO
TOKYO SHIBAURA ELECTRIC CO