To precisely and inexpensively create the nuclear constant of a MOX fuel assembly with reduced time and labor.

A nuclear constant creating method comprises the nuclear constant creating step for a representative specification of creating the nuclear constant of a nuclear fuel having a nuclear constant related item of a value specified in a representative specification, the correction data creating step of creating correction data by investigating an influence of deviation of the value of the nuclear constant related item from the value specified in the representative specification when the value of the nuclear constant related item deviates from the value specified in the representative specification, the inspection step of inspecting an actual fuel assembly for the nuclear constant related item to detect the deviation from the representative specification and the correction step of correcting the nuclear constant of representative specification on the basis of the correction data and the deviation from the representative specification to acquire the nuclear constant of the actual fuel assembly. The fuel assembly comprises the MOX fuel.

COPYRIGHT: (C)2009,JPO&INPIT