Particle Method for Nuclear Reactor Thermal Safety Analysis
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Solution Overview
Problem
Traditional methods for analyzing thermal-hydraulic safety phenomena in nuclear reactors are inadequate due to their complexity, leading to low prediction accuracy and inability to capture multiphase, large-deformation processes, posing risks during severe accidents.
Innovation Solution
A high-precision analysis method based on a particle method using multi-resolution particles for fine geometric modeling, high-order discretization, and integrated thermal-hydraulic, mechanical deformation, chemical reaction, and neutron physics calculations, employing implicit and explicit hybrid solving techniques and asynchronous marching algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional system and sub-channel analysis models are used, then the analysis can be performed with simplified assumptions, but the prediction accuracy deteriorates due to dimensional reduction and numerous simplifications
Solution Approach 1:
The patent replaces traditional mesh-based numerical simulation methods with a particle method approach. This substitution allows the system to avoid mesh distortion issues while capturing multiphase, large-deformation, and complex-free-surface processes. The particle method uses discrete particles to represent the system state, enabling accurate tracking of thermal-hydraulic safety phenomena without requiring complex mesh generation and updating.
Solution Approach 2:
The patent implements multi-resolution particle methods that dynamically adjust particle resolution parameters based on local conditions. This allows high prediction accuracy in critical regions while maintaining computational efficiency in less critical areas. The method changes parameters such as particle spacing and refinement levels adaptively, resolving the contradiction between accuracy and computational cost.
2Adaptability or versatility
If mesh technology based numerical simulation methods are used, then the analysis can cover complex processes, but the ability to capture multiphase and large-deformation processes deteriorates due to mesh distortion
Solution Approach 1:
The patent replaces the mesh-based mechanical system with a particle-based system. This fundamental substitution eliminates the mesh distortion problem that plagues traditional numerical simulation methods when dealing with large deformations and multiphase flows. The particle method naturally handles free surfaces and phase interfaces without requiring mesh regeneration, thereby maintaining reliability in capturing complex thermal-hydraulic safety phenomena.
3Adaptability or versatility
If comprehensive physical models are integrated, then the analysis comprehensiveness is improved, but the computational complexity increases
Solution Approach 1:
The patent segments the comprehensive physical model into distinct modules: thermal-hydraulic module, mechanical deformation module, chemical reaction module, and neutron physics module. Each module is solved separately using appropriate numerical methods and time steps, then coupled through iterative information exchange. This segmentation reduces computational complexity by allowing specialized treatment of each physical process while maintaining overall comprehensiveness.
Solution Approach 2:
The patent implements dynamic coupling between different physical modules with adaptive time stepping. The implicit-explicit hybrid solving technique dynamically adjusts the coupling strength and time step sizes based on the relative timescales of different physical processes. This dynamic approach maintains computational efficiency while capturing the essential interactions between thermal-hydraulic, mechanical, chemical, and neutron physics phenomena.
Data Source
AI summary
A high-precision analysis method for key thermal safety phenomena in a nuclear reactor based on a particle method is provided. Fine complex geometric modeling is implemented based on a multi-resolution particle method. High-order discretization of control equations is implemented using a high-order particle discretization model. Key thermal-hydraulic, mechanical deformation, chemical reaction, and neutron physics phenomena can be analyzed. An implicit and explicit hybrid solving technique and an asynchronous marching algorithm are employed. The method of the present disclosure integrates the multi-resolution particle method, high-order discretization model, advanced solving and marching techniques, and comprehensive physical-mathematical model to achieve a comprehensive, fine, and efficient analysis of key thermal safety phenomena in a nuclear reactor, avoiding mesh distortion in the mesh approach, and significantly improving the precision, stability, calculation efficiency, and robustness of the particle method.