Advancing Radiative Heat Transfer Modeling in High-Temperature Liquid Salts

Coyle, Carolyn; Baglietto, Emilio; Forsberg, Charles W.

doi:10.1080/00295639.2020.1723993

Cited by 11 publications

(7 citation statements)

References 12 publications

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“…From our previous study, including an RHT model for the high-temperature fuel salt does not impact the temperature distribution significantly, while RHT marginally decreased the maximum temperature of the fuel salt by 3.0 K as expected. 9,30 As such, RHT modeling is not considered in the transient analysis for this work. This motivates the use of distributed temperature monitoring of the reflector wall for validation of the multiphysics codes to support the LFMSR licensing basis.…”

Section: Iiib Steady-state Analysismentioning

confidence: 99%

Informing Performance Metrics of Advanced I&C Systems for Liquid Fueled Fast Molten Salt Reactors

Jeong

Shirvan

Buric

2022

Nuclear Science and Engineering

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This work establishes a generic multiphysics tool for liquid-fueled molten salt reactors (LFMSRs) to select key installation locations and specify the expected operating temperature range for the development of advanced instrumentation and control systems, particularly distributed temperature sensors using fiber optics. A commercial computation fluid dynamics package (STAR-CCM+) is used to formulate a neutronics and thermal-hydraulic coupled solver, showing good agreement with a recent benchmark problem developed for evaluating the coupling methodology of neutronics and thermal hydraulics. The multiphysics model is then applied to the reference molten chloride salt fast reactor (MCFR) design under development by TerraPower based on publicly available information. The available twodimensional axisymmetric model for the reactor core is used for coupling calculations, and system component details are leveraged using the lumped method to complete the energy balance. The dynamic responses of the MCFR model are investigated during operational transients, such as unprotected loss-offlow and uniform perturbation scenarios. Maximum temperature and local temperature distributions are characterized during unprotected loss of flow and unprotected loss of heat sink events. The thermal responses of the fuel salt and core components are analyzed from induced perturbation of the system parameters, such as the flow rate and the heat sink capacity. The results motivate the use of continuous monitoring of the temperature variation in real time along the reflector region with the use of fiber optics to validate the multiphysics code to support a reactor's licensing basis, as well as to support the structural longevity and improve safety in LFMSRs.

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Section: Iiib Steady-state Analysismentioning

confidence: 99%

Informing Performance Metrics of Advanced I&C Systems for Liquid Fueled Fast Molten Salt Reactors

Jeong

Shirvan

Buric

2022

Nuclear Science and Engineering

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“…Flibe is semitransparent and at 700°C radiative heat transfer begins to become important. 30 Radiative heat transfer reduces temperature differences in the system. This is significant in an FHR, particularly in accident scenarios.…”

Section: Radiative Heat Transfermentioning

confidence: 99%

Fusion Blankets and Fluoride-Salt-Cooled High-Temperature Reactors with Flibe Salt Coolant: Common Challenges, Tritium Control, and Opportunities for Synergistic Development Strategies Between Fission, Fusion, and Solar Salt Technologies

et al. 2019

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Recent developments in high-magnetic-field fusion systems have created large incentives to develop flibe (Li 2 BeF 4) salt fusion blankets that have four functions: (1) convert the high energy of fusion neutrons into heat for the power system, (2) convert lithium into tritium-the fusion fuel, (3) shield the magnets against radiation, and (4) cool the first wall that separates the plasma from the salt blanket. Flibe is the same coolant proposed for fluoride-salt-cooled high-temperature reactors that use clean flibe coolant and graphite-matrix coated-particle fuel. Flibe is also the coolant proposed for some molten salt reactors (MSRs) where the fuel is dissolved in the coolant. The multiple applications for flibe as a coolant create large incentives for cooperative fusion-fission programs for development of the underlying science, design tools, technology (pumps, instrumentation, salt purification, materials, tritium removal, etc.), and supply chains. Other high-temperature molten salts are being developed for alternative MSR systems and for advanced Gen-III concentrated solar power (CSP) systems. The overlapping characteristics of flibe salt with these other salt systems create significant incentives for cooperative fusion-fission-solar programs in multiple areas. We describe the fission and fusion flibe-cooled systems, what has created this synergism, what is different and the same between fission and fusion in terms of using flibe, and the common challenges. We review (1) the characteristics of flibe salts, (2) the status of the technology, (3) the options for tritium capture and control in the salt, heat exchangers, and secondary heat transfer loops, and (4) the coupling to power cycles with heat storage. The technology overlap between flibe systems and other high-temperature MSR and CSP salt systems is described. This defines where there are opportunities for cooperative programs across fission, fusion, and CSP salt programs.

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“…Furthermore, liquid salts are semitransparent and can be a participating medium for radiative heat transfer. 34,35 This is a system that bleeds heat as temperatures increase. In real systems this will become a significant factor in limiting temperature rises under any over-temperature transients.…”

Section: Iiie Radiation Heat Transfermentioning

confidence: 99%

“…For the first three heat transfer steps, the temperatures are high enough that there is an additional radiative heat transfer through the salt where the salt is a participating medium and heat transfer goes up as the fourth power of the absolute temperature. 35 These BDBA options exist only because of the combination of a fuel that fails at very high temperatures (above 1650°C) and salt coolants with very high boiling points that approach the melting point of iron. These characteristics enable BDBA decay heat removal by brute-force high-temperature heat conduction, with a temperature drop of more than 1200°C through many materials with high conductivity from the fuel to the environment before fuel failure.…”

mentioning

confidence: 99%

Fluoride-Salt-Cooled High-Temperature Reactor (FHR) Using British Advanced Gas-Cooled Reactor (AGR) Refueling Technology and Decay Heat Removal Systems That Prevent Salt Freezing

et al. 2019

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The flouride-salt-cooled high-temperature reactor (FHR) uses graphite-matrix coated-particle fuel [the same as high-temperature gas-cooled reactors (HTGRs)] and a clean liquid salt coolant. It delivers heat to the industrial process or the power cycle at temperatures between 600°C and 700°C with average heat delivery temperatures higher than for other reactors. The melting point of the liquid salt coolant is above 450°C. The high minimum temperatures present refueling challenges and require special features to control temperatures, avoiding excessively high temperatures and freezing of the coolant that could impact decay heat cooling systems. This paper describes a preconceptual FHR design that addresses many of these challenges by adopting features from the British advanced gas-cooled reactor (AGR) and alternative decay heat cooling systems. The bases for specific design choices are described.The AGRs are carbon dioxide-cooled and graphite-moderated reactors that use cylindrical fuel subassemblies with vertical refueling at 650°C, which meets the FHR high-temperature refueling requirements. Fourteen AGRs have operated for many decades. The AGR uses eight cylindrical fuel subassemblies, each 1 m tall coupled axially together by a metal stringer to create a long fuel assembly. The stringer assemblies are in vertical channels in a graphite core that provides neutron moderation. This geometric core design is compatible with an FHR using graphite-matrix coatedparticle fuel. The FHR uses a once-through fuel cycle. The design minimizes used nuclear fuel volumes relative to other FHR and HTGR designs. The primary system is inside a secondary liquid salt-filled tank that (1) provides an added heat sink for decay heat, (2) helps to ensure no freezing of primary system salt, and (3) helps to ensure no major fuel failures in a beyond-design-basis accident. The refueling standpipes above each stringer fuel assembly in the AGR core with modifications can be used in an FHR for refueling and can provide efficient heat transfer between the primary system and the secondary liquid salt-filled tank. The passive decay heat removal system uses heat pipes that turn on and off at a preset temperature to avoid overheating the core in a reactor accident and to avoid freezing the salt coolant as decay heat decreases after reactor shutdown.

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Advancing Radiative Heat Transfer Modeling in High-Temperature Liquid Salts

Cited by 11 publications

References 12 publications

Informing Performance Metrics of Advanced I&C Systems for Liquid Fueled Fast Molten Salt Reactors

Informing Performance Metrics of Advanced I&C Systems for Liquid Fueled Fast Molten Salt Reactors

Fusion Blankets and Fluoride-Salt-Cooled High-Temperature Reactors with Flibe Salt Coolant: Common Challenges, Tritium Control, and Opportunities for Synergistic Development Strategies Between Fission, Fusion, and Solar Salt Technologies

Fluoride-Salt-Cooled High-Temperature Reactor (FHR) Using British Advanced Gas-Cooled Reactor (AGR) Refueling Technology and Decay Heat Removal Systems That Prevent Salt Freezing

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