摘要:
A cask, comprising a shell body (101) having, therein, a basket (130) formed of square pipes (132) or plate-like members forming cells (131) for storing spent fuel assemblies and a neutron shielding body formed by filling a composition (106) for the neutron shielding body containing a neutron shielding material formed mainly of macro-molecules, a refractory material, and a density increasing agent between the shell body (101) and an outer tube (105) installed on the outer periphery of the shell body.