Method and system for governing a pressurized water nuclear reactor

Patent metadata

Field	Value
Publication number	US-12437893-B2
Application number	US-201917608136-A
Country	US
Kind code	B2
Filing date	May 7, 2019
Priority date	May 7, 2019
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A method of governing a pressurized water nuclear reactor can simultaneously consider and balance a large number of control goals. The method includes iteratively considering a large number of randomly varied possible trajectories (Ta) of actuating variables for controlling reactor core reactivity for a future time interval. Each trajectory (Ta) of actuating variables is assigned a figure of merit (Σ) on the basis of a Value Table which contains weighting or penalty values for a number of events or adverse reactor core states which are characterized by preset conditions or values of the actuating variables, the process variables and/or variables derived from them. The trajectory (Ta) of actuating variables is chosen such that the figure of merit (Σ) has a local extremum, and corresponding actuators are moved accordingly.

First claim

What is claimed is:

1. A method for governing a pressurized water nuclear reactor, the pressurized water nuclear reactor comprising a reactor core and a cooling circuit for the reactor core holding a reactor coolant, a reactor state represented by measurable state variables, and a reactor core reactivity being controlled by actuating variables, the actuating variables including at least a first actuating variable and a second actuating variable, the first actuating variable being positions of control rods and the second actuating variable being a position or positions of at least one feed pump and/or at least one control valve for controlling a boron concentration in the cooling circuit, the method comprising:
measuring current values of the measurable state variables;
receiving, by a core governor, a load schedule giving a future electrical power demand as a function of time;
iteratively considering, by the core governor and for a future time interval of the future electrical power demand, a number of randomly varied possible trajectories of the first and second actuating variables under constraint of the received Load Schedule,
predicting, for each possible combination of the trajectories of the first and second actuating variables, trajectories for the measurable state variables on the basis of each of the possible combinations of the trajectories of the first and second actuating variables, the measured current values of the measurable state variables, calculated poisoning values and a reactivity balance equation of the reactor core reactivity,
wherein each of the possible combinations of the trajectories of the first and second actuating variables is assigned a figure of merit on the basis of a Value Table which contains weighting or penalty values for a number of events or adverse reactor core states of the reactor state, wherein the weighting or penalty values are based on:
preset conditions or values of the actuating variables,
the measurable state variables, and/or
variables derived from the preset conditions or values of the actuating variables, and/or the measurable state variables,

wherein a chosen combination of trajectories of the first and second actuating variables from amongst the possible combinations of the trajectories of the first and second actuating variables having a highest or lowest corresponding figure of merit is chosen by the core governor; and
moving actuators of the nuclear reactor to achieve the chosen combination of the trajectories of the first and second actuating variables to move the positions of the control rods with respect to the reactor core to change the reactivity of the core and/or to move the position or the positions of the at least one feed pump and/or the at least one control valve to change the boron concentration in the primary cooling circuit.

2. The method according to claim 1 , wherein the measurable state variables comprise one or several of: thermal reactor power, reactor coolant temperature, live steam pressure and/or axial offset of a reactor core power density.

3. The method according to claim 1 , wherein the control rods are consolidated into a plurality of control banks.

4. The method according to claim 1 , wherein the measured current values of the measurable state variables are updated in real-time.

5. The method according to claim 1 , wherein the randomly varied possible trajectories of the first and second actuating variables for the future time interval are varied using a random number generator.

6. The method according to claim 1 , wherein the future time interval is larger than one hour.

7. The method according to claim 6 , wherein the future time interval has an order of magnitude of 24 hours.

8. A governance system for governing a pressurized water nuclear reactor, the pressurized water nuclear reactor comprising a reactor core and a cooling circuit for the reactor core holding a reactor coolant, a reactor state represented by measurable state variables, and a reactor core reactivity being controlled by actuating variables, the actuating variables including at least a first actuating variable and a second actuating variable, the first actuating variable being positions of control rods and the second actuating variable being a position or positions of at least one feed pump and/or at least one control valve for controlling a boron concentration in the cooling circuit, the governance system including a computer programmed for executing the following steps:
receiving measured current values of the measurable state variables;
receiving a load schedule giving a future electrical power demand as a function of time;
iteratively considering, for a future time interval of the future electrical power demand, a number of randomly varied possible trajectories of the first and second actuating variables under constraint of the received Load Schedule,
predicting, for each possible combination of the trajectories of the first and second actuating variables, trajectories for the measurable state variables on the basis of each of the possible combinations of the trajectories of the first and second actuating variables, the measured current values of the measurable state variables, calculated poisoning values and a reactivity balance equation of the reactor core reactivity,
wherein each of the possible combinations of the trajectories of the first and second actuating variables is assigned a figure of merit on the basis of a Value Table which contains weighting or penalty values for a number of events or adverse reactor core states of the reactor state, wherein the weighting or penalty values are based on:
preset conditions or values of the actuating variables,
the measurable state variables, and/or
variables derived from the preset conditions or values of the actuating variables, and/or the measurable state variables,

wherein a chosen combination of trajectories of the first and second actuating variables from amongst the possible combinations of the trajectories of the first and second actuating variables having a highest or lowest corresponding figure of merit is chosen by the computer; and
instructing actuators of the nuclear reactor to achieve the chosen combination of the trajectories of the first and second actuating variables by moving the positions of the control rods with respect to the reactor core to change the reactivity of the core and/or moving the position or the positions of the at least one feed pump and/or the at least one control valve to change the boron concentration in the primary cooling circuit.

Assignees

• Framatome Gmbh

Inventors

• Morokhovskyi Victor

Classifications

• G21D3/001 Primary

  Computer implemented control · CPC title

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21D3/08 Primary

  Regulation of any parameters in the plant · CPC title

• Y02E30/00

  Energy generation of nuclear origin · CPC title