プルトニウム,トリウムリサイクル系における原子炉動特性の解析, (III)

The analog reactor simulator is used to analyze the dynamic behavior of the plutonium recycled and non plutonium recycled reactor. The constant power removal model is used for this analysis from following two reasons. It is concluded from the analytical results of Part II of this serial report that the difference of the dynamic characteristics between the constant power removal and the Newton's law of cooling model is very small for this reference reactor which has small inverse time constants of temperature increase b1 and b2. Furthermore, the constant power removal model is easier to solve.The maximum power rise of the plutonium recycled reactor is always greater than that of the non plutonium recycled reactor due to the shorter effective neutron life time and the smaller effective delayed neutron fraction. From this result, it is likely to be mistaken that the plutonium recycled reactor has an unfavorable dynamic characteristics to the non plutonium recycled reactor. However, it should be recognized that the more important parameter of the reactor safety; as far as the reactor is stable; must be the total power release during the power excursion or the maximum temperature rise of the reactor materials to prevent the melting down of them. From this point of view, the dynamic charcteristics of the plutonium recycled reactor is no less favorable to that of the non plutonium recycled reactor.Another important conclusion is that the total power release or the maximum temprature rise of the plutonium recycled reactor differs from that of non plutonium recycled reactor due only to the change in the temperature coefficient of reactivity for the same input step reactivity. The effective delayed neutron has a significant meaning on the transient characteristics of the power rise and the temperature rise, but it has less weight on the maximum temperature rise which has an important meaning on the reactor safety.The authors extend their sincere thanks to Dr. Shigenori Hayashi and Dr. Akira Sakurai of the Engng. Res. Inst. of Kyoto Univ. for allowing us to use the analog reactor simulator.