Dynamic characteristics of nuclear fuel cycle

Using the dynamic characteristic models of nuclear fuel cycle, the effect of plutonium utilization in converters upon the change in the constitution of reactor types has been studied, i.e. the difference between the effects of its use in LWRs (light water reactors) and in ATRs (heavy water moderated reactors). In ATRs, the high conversion ratio is utilized effectively, while the effective conversion ratio (the quantity ratio of fissile material in taken out fuel and charged fuel) is lowered. Consequently, for the same amount of fissile plutonium, the capacity of ATRs becomes over twice as large as that of LWRs. Then, using the Pu in the fuel taken out from ATRs, and combining with FBRs, the maintainable capacity becomes larger in LWRs. Therefore, assuming the employment of many FBRs in future in a long-range view, the utilization of plutonium in LWRs is advantageous. (J.P.N.)