[en] Improve of resistivity against nuclear proliferation is one of the most important technology for the next generation FBR recycle. Any method which evaluates quantitatively the resistivity against nuclear proliferation, however, is not established yet. The necessary matters to establish some important evaluation factors and methods in connection with the resistivity are discussed as follows; (1) Investigation forms of all nuclear materials and characteristics of products at every nuclear fuel cycle process, (2) Investigation process for manufacturing metallic plutonium with each form of product and it's difficulty, (3) Examination of the evaluation factors for intermediate and final products, such as radioactivity, needed mass of raw nuclear materials, facility capacity, conversion time, safeguard, transparency, purity as a nuclear weapon, difficulty of diversion and concealment, easiness for stealing, and so on, (4) Discussion of a risk evaluation method on the resistivity. The report indicates that a value function method needs to be introduced in the future. (Suetake, M.)