Nuclear Reactor DBNR Calculation Using Deep Neural Networks

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Solution Overview

Problem

The existing low DBNR algorithm in nuclear reactors is not precise and requires large safety margins due to simplified thermo-hydraulic modeling, leading to costly and complex calculations, which affects reactor control efficiency.

Innovation Solution

A method using a deep neural network with at least two hidden layers of five neurons each to calculate Departure from Nuclear Boiling, incorporating neutron flux measurements and other reactor operation parameters, to generate precise control signals for reactor shutdown or alarm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If simplified thermo-hydraulic modeling is used to calculate DBNR, then calculation speed is improved, but calculation precision deteriorates requiring large safety margins

Engineering Contradiction:
Improvecalculation speedVSAvoidDBNR calculation precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional simplified thermo-hydraulic modeling approach with a neural network-based computational system. The neural network is trained offline using detailed 3D thermo-hydraulic reference code data, then deployed for rapid online DBNR calculations. This substitution maintains calculation speed while achieving precision comparable to the complex reference code, eliminating the need for large safety margins that were previously required due to simplified model inaccuracies.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex 3D thermo-hydraulic reference code is used to calculate DBNR, then calculation precision is improved, but calculation complexity and cost increase

Engineering Contradiction:
ImproveDBNR calculation precisionVSAvoidcalculation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs the complex computational work in advance by training a neural network offline using extensive 3D thermo-hydraulic reference code simulations. During actual reactor operation, the pre-trained neural network provides rapid DBNR calculations without requiring access to the complex reference code. This preliminary action transfers the computational burden from online operation to offline preparation, achieving high precision while maintaining simple real-time operations.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If large safety margins are used to compensate for calculation imprecision, then reactor safety is improved, but reactor control efficiency deteriorates

Engineering Contradiction:
Improvereactor safetyVSAvoidreactor control efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the neural network continuously monitors actual reactor conditions and adjusts DBNR calculations in real-time based on measured parameters such as neutron flux, coolant flow rate, and power distribution. This feedback loop enables precise determination of actual safety margins, allowing operators to optimize reactor control by avoiding excessive conservative margins while maintaining adequate safety levels through accurate, condition-specific calculations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS12400767B2Method for operating a nuclear reactor using calculation of the departure from nucleate boiling ratio
Publication Date: 2025.08.26 FRAMATOME SA
  • US12400767B2 patent drawing
  • US12400767B2 patent drawing
  • US12400767B2 patent drawing

AI summary

A method for operating a nuclear reactor comprises acquiring a plurality of quantities characterizing the operation of the nuclear reactor; and calculating at least one Departure from Nucleate Boiling Ratio using a deep neural network. The entries of the deep neural network are determined by using the acquired quantities. The deep neural network includes at least two hidden layers of at least five neurons each. The method further includes calculating the deviations between the at least one calculated Departure from Nucleate Boiling Ratio and a plurality of predetermined reference threshold values and formulating a control signal for a reactor control system by using the calculated deviations. The control signal is an automatic reactor shutdown or alarm. The method also includes emergency shutdown of the nuclear reactor or emission of an alarm signal if relevant.