A nonintrusive adaptive reduced order modeling approach for a molten salt reactor system

Alsayyari, Fahad; Tiberga, Marco; Perkó, Zoltán; Lathouwers, D.; Kloosterman, Jan Leen

doi:10.1016/j.anucene.2020.107321

Cited by 19 publications

(7 citation statements)

References 17 publications

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“…In this case, Reduced Order Model (ROM) could be used as a catalyzer solution. ROM applications to support the assessment of NPP complex behavior using high-fidelity simulation have developed increasingly in the past few years [47][48][49][50][51]. Reduction in ROM means, using any computational tools to reduce simulation cost, especially for repeated executions in multi-query applications [51] like the BEPU process [52].…”

Section: Discussion and Final Remarksmentioning

confidence: 99%

Small Modular Reactors Licensing Process Based on BEPU Approach: Status and Perspective

et al. 2023

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The competitiveness of small modular reactors (SMRs) has been planned based on design simplification, short construction time, passive safety systems, and enabling self-financing by ramp-up construction. Due to the global energy challenges, SMRs have received pervasive attention from a wide range of researchers, designers, developers, stakeholders, and customers. Besides the many advantages related to the design of SMRs, there are challenges ahead of these reactors. SMR licensing is one of the most critical challenges in the front deployment of these reactors. This challenge stems from innovations in SMR designs and systems, such as modularity or deployment for desalination, energy storage, hydrogen production, process heat, and district heating. Due to the lack of experimental data and technical knowledge, the licensing challenges for non-water coolant SMRs are more complicated. Nearly all previous generation reactor licenses were based on conservative analysis while the decision-making methods based on best-estimate and realistic approaches have received more attention in recent years. Thus, the method known as the best estimate plus uncertainty (BEPU) approach is selected for licensing in some cases. At this time, using the BEPU approach in licensing for conventional NPPs is a mature technology and ready for industrial application. Nevertheless, because most previous reactors were licensed based on conservative methods, developers and even regulatory bodies resist re-assessments based on the BEPU approach, while using the choice of conventional conservative methods is a type of roll-back for next-generation SMRs. Thus, this work reviews the BEPU approach and clarifies the possibility of using this approach in the licensing process of SMRs. The lack of experimental data and tight coupling of phenomena along with uncertainty quantification are the main challenges ahead of using BEPU in the licensing process of SMRs.

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Section: Discussion and Final Remarksmentioning

confidence: 99%

Small Modular Reactors Licensing Process Based on BEPU Approach: Status and Perspective

et al. 2023

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“…Sensitivity analysis requires many repeated calculations that make it a suitable application for the low-cost calculation capabilities of ROM. For example, Alsayyari et al (2020) used ROM to perform sensitivity analysis on a simplified molten salt reactor reference model to successfully obtain the relationship between various neutronics and thermal parameters of the system.…”

Section: Introductionmentioning

confidence: 99%

POD-based reduced-order modeling study for thermal analysis of gas-cooled microreactor core

2023

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Small modular reactors require multi-physics coupling calculations to balance economy and stability, due to their compact structures. Traditional tools used for light water reactors are not effective in addressing the several modeling challenges posed by these calculations. The lumped parameter method is commonly used in the thermal analysis for its high computational speed, but it lacks accuracy due to the thermal model is one-dimensional. While computational fluid dynamics software (CFD) can provide high-precision and high-resolution thermal analysis, its low calculation efficiency making it challenging to be coupled with other programs. Proper Orthogonal Decomposition (POD) is one of the Reduced Order Model (ROM) methods employed in this study to reduce the dimensionality of sample data and to improve the thermal modelling of gas-cooled microreactors. In this work, a non-inclusive POD with neural network method is proposed and verified using a transient heat conduction model for a two-dimensional plate. The method is then applied to build a reduced order model of the gas-cooled micro-reactor core for rapid thermal analysis. The results show that the root mean square error of the reactor core temperature is less than 1.02% and the absolute error is less than 8.2°C while the computational cost is reduced by several orders of magnitude, shortening the calculation time from 1.5-hour to real-time display. These findings proved the feasibility of using POD and neural network in the development of ROMs for gas-cooled microreactor, providing a novel approach for achieving precise thermal calculation with minimized computational costs.

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“…With the recent advances in computational science, the focus of research is more towards the development of numerical methods and strategies for parametric problems involving PDEs 3 . Applications such as uncertainty/sensitivity analysis and design optimization require solving the equations repeatedly for different values of the PDE parameters 4,5 . The parameters can arise from the variations of material property, geometry, and non‐dimensional coefficients.…”

Section: Introductionmentioning

confidence: 99%

“…3 Applications such as uncertainty/sensitivity analysis and design optimization require solving the equations repeatedly for different values of the PDE parameters. 4,5 The parameters can arise from the variations of material property, geometry, and non-dimensional coefficients. The introduction of more parameters increases the dimensions of the problem space.…”

Section: Introductionmentioning

confidence: 99%

Nonintrusive reduced‐order modeling approach for parametrized unsteady flow and heat transfer problems

Hua

Sørheim

2022

Numerical Methods in Fluids

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A novel nonintrusive reduced-order modeling approach is proposed for parametrized unsteady flow and heat transfer problems. A set of reduced basis functions are extracted via a proper orthogonal decomposition (POD) method from a collection of high-fidelity numerical solutions (snapshots of spatial distribution at a series of time steps) that are computed for properly chosen parameters (e.g., material property, initial/boundary conditions) using a full-order model (finite-volume/finite-element methods). Here, the time dimension is treated separately from other parameters, reflecting the dynamic features of the flow problems. Dynamic mode decomposition is used to decompose the time-resolved data (POD coefficients) into dynamics modes and reconstruct/predict the dynamic evolution of the flow systems. The POD coefficients at every time step under the condition of a set of parameters are approximated through interpolation with the radial basis function method from those obtained from the snapshots of the chosen parameter space. Hence, the POD coefficients at a set of given time and parameters can be approximated, and the spatial distribution of the solution data can be reconstructed. The current reduced-order model has been applied to the problems governed by a set of parametrized unsteady Navier-Stokes and heat conduction equations. The model capability has been illustrated numerically by three numerical test cases: flow past a cylinder, melt solidification, and dam break. The model prediction capabilities have been evaluated by varying the material properties (viscosity and density) and the heat transfer conditions on some of the boundaries. An error analysis is also carried out to show the model prediction accuracy.

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A nonintrusive adaptive reduced order modeling approach for a molten salt reactor system

Cited by 19 publications

References 17 publications

Small Modular Reactors Licensing Process Based on BEPU Approach: Status and Perspective

Small Modular Reactors Licensing Process Based on BEPU Approach: Status and Perspective

POD-based reduced-order modeling study for thermal analysis of gas-cooled microreactor core

Nonintrusive reduced‐order modeling approach for parametrized unsteady flow and heat transfer problems

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