A method regulates operating parameters comprising at least the mean temperature of the core (T.sub.m), and the axial power (AO) imbalance.The method includes development of a vector (Us) of control values of the nuclear reactor by a supervisor (31) implementing a predictive control algorithm; development of a vector (u.sub.K) of corrective values of the nuclear reactor controls by a regulator (33) implementing a sequenced gain control algorithm; development of a vector (U) of corrected values of the commands of the nuclear reactor, by using the vector (U.sub.S) of the values of the commands produced by the supervisor (31) and the vector (U.sub.K) of the corrective values of the commands produced by the regulator (33); and regulation of the operating parameters of the nuclear reactor, by controlling actuators using the vector (U) of the corrected values of the controls.

Chemical control system for a power plant including at least one coolant electrochemical indication sensor of a flow type electrically connected to the measurement data processing and transmission unit with its outlet connected to a central computer (CPC) controlling the actuator for injection of hydrogen and chemical reagents. The hydraulic inlet of the electrochemical sensor in use of the system is connected by a sampling tube to the power plant process circuit and its hydraulic outlet is hydraulically connected to the first heat exchanger and the first throttling device with a coolant supply circuit in series. The sampling tube is configured to pass a coolant sample to the coolant electromechanical sensor and the coolant supply circuit contains tubes and valves configured to reverse the flow of the coolant sample through the first throttling device.

Chemical control system for a power plant including at least one coolant electrochemical indication sensor of a flow type electrically connected to the measurement data processing and transmission unit with its outlet connected to a central computer (CPC) controlling the actuator for injection of hydrogen and chemical reagents. The hydraulic inlet of the electrochemical sensor in use of the system is connected by a sampling tube to the power plant process circuit and its hydraulic outlet is hydraulically connected to the first heat exchanger and the first throttling device with a coolant supply circuit in series. The sampling tube is configured to pass a coolant sample to the coolant electromechanical sensor and the coolant supply circuit contains tubes and valves configured to reverse the flow of the coolant sample through the first throttling device.

A reactor water radioactivity concentration of a nuclear power plant can be predicted with high accuracy. First, a plant state quantity prediction value is calculated by using a physical model that describes plant state quantities of the power plant including a flow rate of feedwater and a metal corrosion product concentration in feedwater of the reactor water is calculated. Next, data for supervised learning is created, and the data for supervised learning includes the previously calculated plant state quantity prediction value and a plant state quantity such as the flow rate of feedwater, the metal corrosion product concentration in feedwater, a metal corrosion product concentration in reactor water, and a radioactive metal corrosion concentration of the reactor water in the reactor as input data and includes a radioactive metal corrosion concentration in the reactor water which is an actual measured value as output data, and a predictive model is trained.

A method whereby signals that are output by replacement SPNDs are converted into equivalent signals that would have been detected by legacy SPNDs for input to the legacy software. The replacement SPNDs have a different geometry than the legacy SPNDs and also have a different neutron sensitivity than the legacy SPNDs. The replacement SPNDs are subjected to a neutron flux in a core of a reactor and responsively output a set of signals. The set of signals and the geometry of the replacement SPNDs are employed to create a characterization of the neutron flux in the form of a curve that represents flux as a function of location along the core of the reactor. The legacy geometry of the legacy SPNDs is then employed to find the values on the curve that correspond with the positions where the legacy SPNDs had been located to create inputs for the legacy software.

A method whereby signals that are output by replacement SPNDs are converted into equivalent signals that would have been detected by legacy SPNDs for input to the legacy software. The replacement SPNDs have a different geometry than the legacy SPNDs and also have a different neutron sensitivity than the legacy SPNDs. The replacement SPNDs are subjected to a neutron flux in a core of a reactor and responsively output a set of signals. The set of signals and the geometry of the replacement SPNDs are employed to create a characterization of the neutron flux in the form of a curve that represents flux as a function of location along the core of the reactor. The legacy geometry of the legacy SPNDs is then employed to find the values on the curve that correspond with the positions where the legacy SPNDs had been located to create inputs for the legacy software.

The power plant chemical control system includes at least one coolant electrochemical indication sensor electrically connected to the measurement data processing and transmission unit with its outlet connected to a central computer controlling the actuation devices and for injection of hydrogen and chemical reagents. The sensor is of a flow type with its hydraulic inlet connected by a sampling tube to the power plant process circuit and its hydraulic outlet hydraulically connected to the first heat exchanger and to the first throttling device with a reversible coolant supply circuit in series.

The power plant chemical control system includes at least one coolant electrochemical indication sensor electrically connected to the measurement data processing and transmission unit with its outlet connected to a central computer controlling the actuation devices and for injection of hydrogen and chemical reagents. The sensor is of a flow type with its hydraulic inlet connected by a sampling tube to the power plant process circuit and its hydraulic outlet hydraulically connected to the first heat exchanger and to the first throttling device with a reversible coolant supply circuit in series.

A method for controlling a pressurized water nuclear reactor is provided, including core producing thermal power, sensors for acquiring the mean temperature of the primary coolant and for calculating the thermal power, actuators for controlling the axial distribution of power, the control method including: a first control phase for controlling the reactor during normal operation by controlling the mean temperature of the primary coolant so as to make it correspond to a reference temperature profile (P.sub.ref) dependent on the thermal power of the reactor; and a second control phase, referred to as stretchout, that occurs after normal operation of the reactor in order to control the reactor in stretchout by controlling the axial distribution of power, the mean temperature varying freely in a temperature range delimited by an upper limit and a lower limit.

A method for controlling a pressurized water nuclear reactor is provided, including core producing thermal power, sensors for acquiring the mean temperature of the primary coolant and for calculating the thermal power, actuators for controlling the axial distribution of power, the control method including: a first control phase for controlling the reactor during normal operation by controlling the mean temperature of the primary coolant so as to make it correspond to a reference temperature profile (P.sub.ref) dependent on the thermal power of the reactor; and a second control phase, referred to as stretchout, that occurs after normal operation of the reactor in order to control the reactor in stretchout by controlling the axial distribution of power, the mean temperature varying freely in a temperature range delimited by an upper limit and a lower limit.