Abstract: A load control system for a boiling water reactor power plant. A recirculating pump speed demand signal and a total steam flow demand signal are derived on the basis of combination of a first control signalproduced in accordance with a power difference signal representative of difference between an actual value of an output power of an electric generator and a set value for the generator output and a second control signal produced in accordance with a pressure difference signal representative of difference between an actually measured value of the reactor pressure and a set value therefor. Speed of a recirculating pump is controlled in dependence on the recirculating pump speed demand signal, while opening degrees of a governor valve and a bypass valve of a turbine are controlled in accordance with the total steam flow demand signal.

Abstract: A nuclear reactor is supplied with feed water through a feed water pump system. A primary steam flow produced from the reactor is controlled by regulating a recirculated flow of feed water. The feed water pump system comprises two main pumps each of 55%-capacity and two auxiliary pumps each of 27.5%-capacity. Normally, the two main pumps are operated. Upon occurrence of abnormal condition of at least one main pump, the auxiliary pumps are started to supply feed water. At that time, the recirculated flow is controlled for a predetermined time to a reduced rate which is smaller as compared with that of the primary steam flow decreased rapidly due to the shutdown of the main pump. Subsequently, the recirculated flow is so controlled that the primary steam flow rate is slightly smaller as compared with the feed water flow which is determined by the available capacity of the pumps.

Abstract: Excessive swing of the feedwater in power supply apparatus on the occurrence of a transient is suppressed by injecting an anticipatory compensating signal into the control for the feedwater. Typical overshoot occurs on removal of a large part of the load, the steam flow is reduced so that the conventional control system reduces the flow of feedwater. At the same time there is a reduction of feedwater level in the steam generator because of the collapse of the bubbles under increased steam pressure. By the time the control responds to the drop in level, the apparatus has begun to stabilize so that there is overshoot. The anticipatory signal is derived from the boiling power which is a function of the nuclear power developed, the enthalpy of saturated water and the enthalpy of the feedwater injected into the steam generator. From the boiling power and the increment in steam pressure resulting from the transient are anticipatory increment of feedwater flow is derived.