Method of controlling the power up by fluid poisons in heavy water moderated reactors

Purpose: To increase power by the gradual decrease in the amount of fluid poisons mixed in moderators or coolants of heavy water moderated reactors. Method: Power fluctuation rate for the period of time in multiple integer of one cycle period in the main loop of moderators (coolants) is determined by the detection signals for the reactor power and the deviation between it and the power fluctuation rate required for the operation is determined. Pulse signals of different series are generated depending on the polarities of the deviation by the number corresponding to the magnitude of the deviation, and the power control in the reactor power up is conducted by these pulses while operating the fluid supply device which issues a certain amount of fluid per one pulse and mixing the moderators (coolants) containing no substantial poisons or moderators (coolants) having poison density higher than that in the moderators (coolants) in the main loop. (Horiuchi, T.)