Liquid metal-cooled fast reactor instrumentation technology development - CFD model development and validation
Lead Research Organisation:
University of Sheffield
Department Name: Mechanical Engineering
Abstract
The UK government considers nuclear energy to play an important role in the country's energy mix to establish a secure, environmentally friendly and diverse energy portfolio and meet the future energy demand. There are currently two reactors being built in the southwest of the UK and a number of others currently under development. In order to ensure nuclear energy safer and economically competitive, the Generation IV International Forum (GIF) has been formed, which has selected six advanced nuclear reactor designs to be the focus of the development by its member countries. Two of them use liquid metal as primary-circuit coolant, i.e., the sodium-cooled fast reactor (SFR) and the lead-cooled fast reactor (LFR). In the UK, BEIS has recently supported feasibility studies for eight advanced modular reactors (AMRs), three of which are Liquid Metal-cooled Fast Reactor (LMFRs).
The knowledge gaps and modelling challenges in LMFR are broadly speaking related to two facts. Firstly, the heat transfer characteristic of liquid metal is markedly different from that of the conventional fluids (air and water) due to the extremely low Prandtl number, which makes the conventional turbulence models invalid under most conditions. Secondly, the special pool-type design gives rise to thermal hydraulic phenomena including natural circulation and stratification, which are unique for such reactors. Additionally, there is a lack of benchmarking data due to the difficulties associated with the measure of the flow and thermal fields in liquid metal.
This proposal, developed in response to the EPSRC's collaborative research call on 'UK/US NEUP 2019', is aimed at addressing the above challenges. This joint research project will focus on developing instrumentation technology and associated modelling for liquid metal cooled fast reactor. The US partners will carry out experimental investigations, while the UK partners will develop computational tools for high fidelity modelling and conjugate heat transfer analysis.
High fidelity large eddy simulation (LES) of stagnation and stratification flow of liquid metal will be carried out to complement physical experiment to provide valuable detailed data for turbulence and engineering model development, as well as to help in advancing the knowledge in such complex flow phenomena. This will be followed by refinement and validation of the 'conventional' CFD models using experimental and numerical data to develop new understanding of turbulent models and numerical methods for the simulation of liquid metal flows. Finally, a highly innovative conjugate heat transfer model of the sodium-to-supercritical-CO2 compact printed circuit heat exchanger (PCHE) will be developed based on the novel coarse-grid CFD recently developed and the immerse boundary method. If successful, they represent a major advancement in modelling of heat exchangers with highly complex geometry and physics and can be used to assist the design and optimisation of such systems effectively.
The knowledge gaps and modelling challenges in LMFR are broadly speaking related to two facts. Firstly, the heat transfer characteristic of liquid metal is markedly different from that of the conventional fluids (air and water) due to the extremely low Prandtl number, which makes the conventional turbulence models invalid under most conditions. Secondly, the special pool-type design gives rise to thermal hydraulic phenomena including natural circulation and stratification, which are unique for such reactors. Additionally, there is a lack of benchmarking data due to the difficulties associated with the measure of the flow and thermal fields in liquid metal.
This proposal, developed in response to the EPSRC's collaborative research call on 'UK/US NEUP 2019', is aimed at addressing the above challenges. This joint research project will focus on developing instrumentation technology and associated modelling for liquid metal cooled fast reactor. The US partners will carry out experimental investigations, while the UK partners will develop computational tools for high fidelity modelling and conjugate heat transfer analysis.
High fidelity large eddy simulation (LES) of stagnation and stratification flow of liquid metal will be carried out to complement physical experiment to provide valuable detailed data for turbulence and engineering model development, as well as to help in advancing the knowledge in such complex flow phenomena. This will be followed by refinement and validation of the 'conventional' CFD models using experimental and numerical data to develop new understanding of turbulent models and numerical methods for the simulation of liquid metal flows. Finally, a highly innovative conjugate heat transfer model of the sodium-to-supercritical-CO2 compact printed circuit heat exchanger (PCHE) will be developed based on the novel coarse-grid CFD recently developed and the immerse boundary method. If successful, they represent a major advancement in modelling of heat exchangers with highly complex geometry and physics and can be used to assist the design and optimisation of such systems effectively.
Planned Impact
The beneficiaries include engineers in R&D of liquid metal fast reactors (LMFRs), modellers for liquid metal heat transfer in any industry including nuclear energy and engineers who are interested in modelling complex heat exchangers in an efficient detail-efficiency balanced manner.
The knowledge gaps and modelling challenges in LMFR are broadly speaking related to two facts. Firstly, the heat transfer characteristic of liquid metal is markedly different from that of the conventional fluids (air and water) due to the extremely low Prandtl number, which makes the conventional turbulence models invalid under most conditions. Secondly, the special pool-type design gives rise to thermal hydraulic phenomena including natural circulation and stratification, which are unique for such reactors. Additionally, there is a lack of benchmarking data due to the difficulties associated with the measure of the flow and thermal fields in liquid metal. The proposed research will contribute to addressing the above challenges.
The high-fidelity LES of natural circulation of liquid metal will complement physical experiment to provide valuable detailed data for turbulence and engineering model development, as well as help in advancing the knowledge in such complex flow phenomena. The RANS model will result in new understanding of turbulent models and numerical methods for the simulation of liquid metal flows following refinement and validation using experimental and numerical data. The new knowledge and improved turbulence modelling will consequently help the R&D engineers to optimise the advanced nuclear reactors for both safety and economics.
The conjugate heat transfer model of the PCHE is highly innovative and is exploratory in nature using the novel coarse-grid CFD recently developed and the immerse boundary method. If successful, they represent a major advancement in modelling of heat exchangers with highly complex geometry and physics and can be used to assist the design and optimisation of such systems effectively. This will ultimately reduce cost of heat exchangers and improve thermal efficiency and consequently save energy.
The knowledge gaps and modelling challenges in LMFR are broadly speaking related to two facts. Firstly, the heat transfer characteristic of liquid metal is markedly different from that of the conventional fluids (air and water) due to the extremely low Prandtl number, which makes the conventional turbulence models invalid under most conditions. Secondly, the special pool-type design gives rise to thermal hydraulic phenomena including natural circulation and stratification, which are unique for such reactors. Additionally, there is a lack of benchmarking data due to the difficulties associated with the measure of the flow and thermal fields in liquid metal. The proposed research will contribute to addressing the above challenges.
The high-fidelity LES of natural circulation of liquid metal will complement physical experiment to provide valuable detailed data for turbulence and engineering model development, as well as help in advancing the knowledge in such complex flow phenomena. The RANS model will result in new understanding of turbulent models and numerical methods for the simulation of liquid metal flows following refinement and validation using experimental and numerical data. The new knowledge and improved turbulence modelling will consequently help the R&D engineers to optimise the advanced nuclear reactors for both safety and economics.
The conjugate heat transfer model of the PCHE is highly innovative and is exploratory in nature using the novel coarse-grid CFD recently developed and the immerse boundary method. If successful, they represent a major advancement in modelling of heat exchangers with highly complex geometry and physics and can be used to assist the design and optimisation of such systems effectively. This will ultimately reduce cost of heat exchangers and improve thermal efficiency and consequently save energy.
Publications
He S
(2023)
NEW INSIGHT INTO HEAT TRANSFER DETERIORATION
Huang X
(2022)
Study of a Lead-Bismuth Eutectic Jet Issued into a Heated Cavity Using Large Eddy Simulation
in SSRN Electronic Journal
Huang X
(2022)
Study of a lead-bismuth eutectic jet issued into a heated cavity using large eddy simulation
in International Journal of Heat and Mass Transfer
Huang X
(2022)
Study of a negatively buoyant jet of liquid metal in a density-stratified ambient
in International Communications in Heat and Mass Transfer
McDermott M
(2024)
An open-source porous media modelling approach to investigate thermohydraulic features of compact printed circuit heat exchangers
in Nuclear Engineering and Design
Wang W
(2024)
Numerical simulation of thermal mixing of liquid sodium in a Y-junction
in Nuclear Engineering and Design
| Description | A high fidelity computer model has been developed to simulate a research facility at Belgium to study advanced nuclear reactor design. The model has been validated against experiments. A paper has been submitted, which is currently under review. A multi-scale model has been developed for an experimental air-foil printed circuit heat exchanger (PCHE) with CO2 as a working fluid at Wisconsin-Madison within the OpenFOAM environment as a freely available package. A paper has been published in Nuclear Engineering and Design reporting the open-source code. |
| Exploitation Route | The results will be presented at conferences and published in journals. The model for the PCHE is open sourced. |
| Sectors | Energy |
| Description | We have been running up to 2 Final Year Projects each year during the project period, which contributed to the education of future engineers. While the open-sourced software package for PCHE is available to industrial users, its uptake is unknown. |
| Sector | Education,Energy |
| Impact Types | Societal |
| Description | Talk given to Nuclear Innovation and Research office (NIRO) |
| Geographic Reach | National |
| Policy Influence Type | Contribution to a national consultation/review |
| Description | Liquid metal - collaboration with Wisconsin Madison |
| Organisation | University of Wisconsin-Madison |
| Department | Department of Engineering |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Developed a model which enable us to simulate experiments carried out in partner university. |
| Collaborator Contribution | Partner university provided experimental data to be used by us to validate by model. |
| Impact | Development of computer model |
| Start Year | 2021 |