REACTOR SYSTEM PRESSURE CONTROL METHOD THROUGH CORE POWER CONTROL

摘要

PROBLEM TO BE SOLVED: To provide an operation method for a boiling water reactor plant in a state which maintains electric power at maximum and the reactor system pressure within a limit. SOLUTION: A power generation system 8 has a turbine generator 24 and a boiling water reactor 10 for controlling the thermal power of core 12 which maintains a main turbine control valve 22 at a steady position. The core thermal power control is made possible by controlling the control rod density in the core or controlling the flow rate through the reactor. The flow control is attained by controlling the speed of a variable frequency recirculation pump 40 or controlling a recirculation flow control valve 44. The pressure control method includes switching the power generation system from normal turbine flow control valve for controlling pressure control to core thermal power controlling pressure control. It also includes changing of a bypass valve 54 closing bias and an output control bias, so as to correspond to the variation from the core power controlling pressure control exceeding the normal pressure control. When the pressure transient value is out of a specific safety range, this method can return the system pressure control to normal turbine control valve controlling pressure control.