| 摘要 |
In an atomic reactor, gaps are defined between fuel assemblies so that moderators can be inserted. Hence, the nuclear characteristics vary between the central portion and periphery of the fuel assembly so that the local output peaking becomes greater on the periphery of the fuel assembly. The present invention contemplates to make this local output peaking flat by reducing the loading quantity of a nuclear fuel material per fuel rod on the outermost layer of the fuel assembly to be smaller than the loading quantity of the fuel material per fuel rod at the central portion of the fuel assembly. Anyone of the following three constructions can be used for accomplishing this object:
(1) The theoretical density of the nuclear fuel material pellets to be inserted into the fuel rod is reduced.
(2) The nuclear fuel material pellets to be inserted into the fuel rod is made hollow.
(3) The diameter of the fuel rod is reduced. |
