Present state of analysis of dynamic characteristics of fast reactors

In the dynamic characteristic analysis laboratory, the simulators for fast reactor plants such as the testing facility of 50 MW steam generator for the experimental reactor ''Joyo'' and the prototype reactor ''Monju'' have been developed, using a hybrid computer system, and the dynamic characteristic models developed have been proved with the experimental data on various dynamic characteristics obtained in these facilities. This paper describes the method of analyzing the dynamic characteristics of fast reactors and the method of verification developed so far, and also the outline of the problems. At present, it is required to simulate the conditions of plants exactly, such as the input data for transient thermal analysis in the structural design of equipments and the procedure of operation at the time of an accident in a plant. Hybrid computer means the hybrid of analog and digital computers, and has the functions of both computers. The hybrid computer system installed in the laboratory comprises four digital and two analog computers. The method of computation is explained. The one-loop simulator HYST 50, the two-loop simulator JOPHYS, the one-loop simulator for the prototype reactor DYAMON-1 and so on have been developed so far. The verification of the dynamic characteristic models is described. (J.P.N.)