NUCLEAR REACTOR PRESSURE CONTROLLER

PURPOSE:To prevent the contingent nuclear reactor scram by providing a bypass valve control circuit which makes control by the difference between the output signal f a circuit for calculating the steam flow of governar valves and the signal corresponding to the steam flow of the reactor. CONSTITUTION:The opening degree signals 3a, 3a' of the plural governar valves 3, 3' are respectively inputted to respective circuits 17, 17' for calculating the flow of the governar valves, by which the correction of the flow characteristics of the valves 3, 3' by the number of the operating units of the valves 3, 3' is executed and from which steam flow signals 17a, 17a' are respectively outputted. These signals 17a, 17a' are inputted to an adder 18 and are added. A turbine total steam flow signal 18a is outputted from the adder 18. This signal 18a is computed together with a steam flow request signal 12a and a bias signal 20 in an adder 19. A bypass valve is controlled by an opening degree request signal 13b outputted from this adder 19. The scram occurring in a change in the nuclear reactor pressure is effectively averted in this way.