Reactor Core Simulation Using Modal Perturbation Theory
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Solution Overview
Problem
Current reactor core modeling techniques face a trade-off between accuracy and computational efficiency, often requiring lower-fidelity models to achieve reasonable run times, which limits the precision of 3D power distribution simulations and introduces uncertainties due to heuristic adaptations that may not accurately represent real-world conditions.
Innovation Solution
A computer-implemented method that determines an initial state of the reactor core, calculates target power and neutron flux distributions, identifies differences with actual distributions, and applies Modal Generalized Perturbation Theory to determine a 3D cross-section distribution perturbation, enabling goal-oriented adaptation and improvement of the model to match observed discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-fidelity modeling standards are applied to reactor core simulations, then accuracy of 3D power distribution is improved, but computational run time becomes prohibitive (lasting days to weeks)
Solution Approach 1:
The patent transforms the high-fidelity continuous model into a low-fidelity discrete model by changing the spatial representation parameters. The continuous 3D power distribution is approximated using discrete nodal parameters with polynomial expansions, reducing the number of degrees of freedom while maintaining essential accuracy for engineering applications.
Solution Approach 2:
The reactor core is segmented into discrete nodes arranged in a grid structure. Each node represents a volumetric region with averaged properties, dividing the continuous domain into manageable discrete elements. This segmentation enables efficient computation while capturing the essential 3D power distribution characteristics through nodal expansion methods.
2Productivity
If lower-fidelity models are used to achieve reasonable run times, then computational efficiency is improved, but accuracy and sophistication of system modeling deteriorates
Solution Approach 1:
The patent introduces adjustable polynomial expansion orders (e.g., linear, quadratic, cubic) that allow users to tune the fidelity of the nodal representation. By changing the expansion parameters, the model can adapt between computational efficiency and accuracy requirements for different application scenarios.
Solution Approach 2:
The model employs dynamic adaptation mechanisms where the nodal expansion parameters can be adjusted based on the specific computational requirements. The system can dynamically select appropriate polynomial orders and nodal configurations to balance accuracy and computational cost for different simulation scenarios.
3Ease of operation
If fixed heuristic adaptation approaches are applied to tune 3D power distribution, then ease of operation is improved, but manufacturing precision (model accuracy) deteriorates due to restricted degrees of freedom
Solution Approach 1:
The patent replaces fixed heuristic adaptation with a dynamic systematic methodology. The nodal expansion parameters can be systematically adjusted based on measured deviations between calculated and observed power distributions, providing flexible degrees of freedom while maintaining model physical consistency through the expansion framework.
Solution Approach 2:
The systematic approach enables controlled parameter changes in the nodal expansion coefficients based on observed discrepancies. By adjusting the expansion parameters systematically rather than through fixed heuristics, the model achieves better accuracy in correcting 3D power distribution while maintaining ease of operation through automated parameter optimization.
Data Source
AI summary
A computer implemented method for simulating an operation of a reactor core includes determining an initial state of the reactor core; calculating a nodal target power distribution and/or the target 3D neutron flux distribution; obtaining an actual power distribution and/or the actual 3D neutron flux distribution of the nuclear reactor core; determining a difference between the target power distribution and the actual power distribution of the nuclear reactor core and/or determining a difference between the target 3D neutron flux distribution and the actual 3D neutron flux distribution of the nuclear reactor core; determining modal expansion coefficients using a Fourier modal decomposition based on the determined difference and applying a Modal Generalized Perturbation Theory to the modal expansion coefficients for determining a 3D cross-section distribution perturbation causing the determined difference; and determining a 3D adaptation distribution for the determined difference based on the determined 3D cross-section distribution perturbation.