Sodium level control for 50MW steam generator

A sodium level control system for a 50 MW steam generator consisting of a superheater and an evaporator was developed. The response characteristics of the control system was analyzed both by experiment and by computer simulation. The purpose and the operational principles of the control system are described in the first part of this report. The second part describes the model and the assumptions employed in the simulation code. the third part explains the results of some experiment and the corresponding computer simulation. The experiment includes the variation of sodium level at normal operation, the variation of sodium level due to the ramp-wise increase and decrease of sodium flow at the rate of 2.5 %/min, the effect of the tripping of a sodium circulation pump, and the effect of disturbance in the feed water system. Agreement between the experiment and computation was generally excellent. The results of experiment indicated that the control system is applicable for actual operation and that the maximum rate of decreasing the sodium flow rate should be 3.5 %/min. The final part of this report briefly discusses the application of this control system to the prototype fast breeder reactor ''Monju'' together with some results of computer simulation. (Aoki, K.)