Nuclear fuel assembly

Purpose: To prevent reduction in the excess reaction suppression effect thereby increase the stability upon reactor shutdown in nuclear fuel assemblies charged in a BWR type reactor. Constitution: Burnable poisons such as Gd, B-10, Hf, Eu, Dy or the compound thereof are incorporated into a Zr-alloy fuel can, or an inner liner layer made of Zr alloy containing burnable poisons is disposed to the inner surface of the Zr alloy fuel can. In a nuclear fuel assembly having burnable poisons and using Zr hydride as neutron moderators, since the Zr hydride and Gd, B-10, Hf, Eu, Dy or the compound thereof as the burnable poisons are separated from each other, the burnable poisons do not intrude into the Zr hydride and, accordingly, the molding property is not degraded and the problem of the reduction of the hydrogen content is not caused. Thus, it is possible to provide a nuclear fuel assembly of an efficient and novel structure containing solid moderator rods of high moderating performance. (Kamimura, M.)