A detector signal-processing circuit comprises the following: a current/voltage conversion part that converts the current value of a neutron detector to a voltage value; a variable gain amplification part that performs amplification by a first-step variable gain using a D/A converter; a current level response-use resistance circuit that selects the measurement range in accordance with the voltage value; temperature measurement units for measuring the temperature of the resistance circuit for current level response; a temperature compensation part for commanding gain compensation by the D/A converter on the basis of the measured temperature; and a selective adjustment control part for selective control of the measurement range and adjustment of the variable gain of the variable gain amplification part. Due to this configuration, neutron flux can be measured with high precision while maintaining a constant output precision, before and after switching of the measurement range.

A method comprising measuring a number of gamma-ray counts in a gamma-ray sensitive detector (60) that is placed outside a biological shield (10) near a primary cooling circuit (30) of a nuclear power plant, and determining the thermal power of the nuclear power plant based on the number of gamma-ray counts measured in the gamma-ray sensitive detector (60).

A method comprising measuring a number of gamma-ray counts in a gamma-ray sensitive detector (60) that is placed outside a biological shield (10) near a primary cooling circuit (30) of a nuclear power plant, and determining the thermal power of the nuclear power plant based on the number of gamma-ray counts measured in the gamma-ray sensitive detector (60).

A method for determining at least one threshold value of at least one operating parameter of a nuclear reactor is implemented by an electronic determination system and includes the steps of determining a first threshold value of a respective operating parameter for an operation of the reactor at a first power; and determining a second threshold value of said parameter for an operation of the reactor at a second power. The operation at the lower power of the first and second powers is an operation continued for a duration of at least 8 hours over a 24-hour sliding window. The method also includes determining a third threshold value of said parameter for an operation of the reactor at a third power between the first power and the second power.

A method for determining at least one threshold value of at least one operating parameter of a nuclear reactor is implemented by an electronic determination system and includes the steps of determining a first threshold value of a respective operating parameter for an operation of the reactor at a first power; and determining a second threshold value of said parameter for an operation of the reactor at a second power. The operation at the lower power of the first and second powers is an operation continued for a duration of at least 8 hours over a 24-hour sliding window. The method also includes determining a third threshold value of said parameter for an operation of the reactor at a third power between the first power and the second power.

The invention relates to a device for controlling a plurality of nuclear reactors in clusters, comprising, for each reactor, a plurality of sensors for measuring operating parameters as well as a system for controlling the nuclear reactor, the nuclear reactors being grouped into clusters having a cluster head.

The invention relates to a device for controlling a plurality of nuclear reactors in clusters, comprising, for each reactor, a plurality of sensors for measuring operating parameters as well as a system for controlling the nuclear reactor, the nuclear reactors being grouped into clusters having a cluster head.

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 (U.sub.S) 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.

The method estimates the damaging dose of fast neutrons (dpa) which results in unacceptable degradation of paste-forming properties of steel. Upon achievement of the reactor energy yield, the direction of the coolant flow is changed from the standard direction to the reverse direction. Then an acceptable period of time is set for the annealing of reactor core elements. The temperature of the annealing mode is set and maintained by controlling the power level sufficiently to restore paste-forming properties of steel of the lower core section within the set period of time. At the end of the pre-set annealing period, the direction of the coolant flow is changed from reverse to the standard one.

The method estimates the damaging dose of fast neutrons (dpa) which results in unacceptable degradation of paste-forming properties of steel. Upon achievement of the reactor energy yield, the direction of the coolant flow is changed from the standard direction to the reverse direction. Then an acceptable period of time is set for the annealing of reactor core elements. The temperature of the annealing mode is set and maintained by controlling the power level sufficiently to restore paste-forming properties of steel of the lower core section within the set period of time. At the end of the pre-set annealing period, the direction of the coolant flow is changed from reverse to the standard one.