scholarly journals An Eulerian Single-Phase Transport Model for Solid Fission Products in the Molten Salt Fast Reactor: Development of an Analytical Solution for Verification Purposes

2021 ◽  
Vol 9 ◽  
Author(s):  
Andrea Di Ronco ◽  
Stefano Lorenzi ◽  
Francesca Giacobbo ◽  
Antonio Cammi
Keyword(s):  
Boundary Conditions ◽  
Molten Salt ◽  
Fast Reactor ◽  
Liquid Fuel ◽  
Mixed Type ◽  
Single Phase ◽  
Transport Model ◽  
Reactor Core ◽  
Fission Products ◽  
Phase Transport

Nuclear reactor modeling has been shifting, over the last decades, towards full-core multiphysics analysis due to the ever-increasing safety requirements and complexity of the designs of innovative systems. This is particularly true for liquid-fuel reactor concepts such as the Molten Salt Fast Reactor (MSFR), given their strong intrinsic coupling between thermal-hydraulics, neutronics and fuel chemistry. In the MSFR, fission products (FPs) are originated within the liquid fuel and are carried by the fuel flow all over the reactor core and through pumping and heat exchange systems. Some of FP species, in the form of solid precipitates, can represent a major design and safety challenge, e.g., due to deposition on solid boundaries, and their distribution in the core is relevant to the design and safety analysis of the reactor. In this regard it is essential, both for the design and the safety assessment of the reactor, the capability to model the transport of solid FPs and their deposition to the boundary (e.g., wall or heat exchanger structures). To this aim, in this study, models of transport of solid FPs in the MSFR are developed and verified. An Eulerian single-phase transport model is developed and integrated in a consolidated multiphysics model of the MSFR based on the open-source CFD library OpenFOAM. In particular, general mixed-type deposition boundary conditions are considered, to possibly describe different kinds of particle-wall interaction mechanisms. For verification purposes, analytical solutions for simple case studies are derived ad hoc based on the extension of the classic Graetz problem to linear decay, distributed source terms and mixed-type boundary conditions. The results show excellent agreement between the two models, and highlight the effects of decay and deposition phenomena of various intensity. The resulting approach constitutes a computationally efficient tool to extend the capabilities of CFD-based multiphysics MSFR calculations towards the simulation of solid fission products transport.

scholarly journals Pyrochemical reprocessing of molten salt fast reactor fuel: focus on the reductive extraction step

Nukleonika ◽  
2015 ◽  
Vol 60 (4) ◽  
pp. 907-914 ◽  
Author(s):  
Davide Rodrigues ◽  
Gabriela Durán-Klie ◽  
Sylvie Delpech
Keyword(s):  
Molten Salt ◽  
Fast Reactor ◽  
Liquid Fuel ◽  
Noble Metals ◽  
Fission Products ◽  
Selective Extraction ◽  
Fissile Material ◽  
Metallic Lithium ◽  
Fuel Salt ◽  
Static Conditions

Abstract The nuclear fuel reprocessing is a prerequisite for nuclear energy to be a clean and sustainable energy. In the case of the molten salt reactor containing a liquid fuel, pyrometallurgical way is an obvious way. The method for treatment of the liquid fuel is divided into two parts. In-situ injection of helium gas into the fuel leads to extract the gaseous fission products and a part of the noble metals. The second part of the reprocessing is performed by ‘batch’. It aims to recover the fissile material and to separate the minor actinides from fission products. The reprocessing involves several chemical steps based on redox and acido-basic properties of the various elements contained in the fuel salt. One challenge is to perform a selective extraction of actinides and lanthanides in spent liquid fuel. Extraction of actinides and lanthanides are successively performed by a reductive extraction in liquid bismuth pool containing metallic lithium as a reductive reagent. The objective of this paper is to give a description of the several steps of the reprocessing retained for the molten salt fast reactor (MSFR) concept and to present the initial results obtained for the reductive extraction experiments realized in static conditions by contacting LiF-ThF4-UF4-NdF3 with a lab-made Bi-Li pool and for which extraction efficiencies of 0.7% for neodymium and 14.0% for uranium were measured. It was concluded that in static conditions, the extraction is governed by a kinetic limitation and not by the thermodynamic equilibrium.

scholarly journals Molten Salt Reactors

2021 ◽  
Author(s):  
Thomas Dolan
Keyword(s):  
Molten Salt ◽  
Nuclear Power ◽  
Liquid Fuel ◽  
Fission Products ◽  
Processing Plant ◽  
Fast Reactors ◽  
Melting Temperatures ◽  
Load Following ◽  
Reactor Types ◽  
Reactor Accidents

<p><br></p> <div> <table> <tr> <td> <p>Molten Salt Reactors</p> </td> </tr> </table> </div> <br> <div> <table> <tr> <td> <p>© Thomas J. Dolan, Member, IEEE 2021</p> </td> </tr> </table> </div> <br> <p><i>Abstract</i>— Nuclear power is advancing slowly because of public concerns about nuclear accidents, radioactive waste, fuel supply, cost, and nuclear proliferation. The development of molten salt reactors could alleviate most of these concerns and prevent water-cooled reactor accidents like those at Three Mile Island, Chernobyl, and Fukushima. The purpose of this article is to provide information about the potential advantages and problems of molten salt reactors. The coolants could be either <i>fluorides</i> or <i>chlorides</i>, operated above their melting temperatures, to avoid solidification, and well below their boiling temperatures, to prevent evaporation losses. “Fast” reactors use energetic fission neutrons, while “thermal” reactors use graphite to slow the neutrons down to thermal energies. We describe four reactor types: solid fuel thermal, liquid fuel thermal, liquid fuel fast, and “stable salt” fast reactors (liquid fuel in tubes). We discuss load following, reactor design projects, and development problems. Liquid fuel reactors will require a chemical processing plant to adjust fissile fuel inventory, fission products, actinides, and corrosivity in a hot, highly-radioactive environment. </p>

Dynamic mode decomposition for the stability analysis of the Molten Salt Fast Reactor core

2020 ◽  
Vol 362 ◽  
pp. 110529 ◽  
Author(s):  
Andrea Di Ronco ◽  
Carolina Introini ◽  
Eric Cervi ◽  
Stefano Lorenzi ◽  
Yeong Shin Jeong ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Molten Salt ◽  
Fast Reactor ◽  
Reactor Core ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Mode Decomposition ◽  
The Stability

scholarly journals Molten Salt Reactors

2021 ◽  
Author(s):  
Thomas Dolan
Keyword(s):  
Molten Salt ◽  
Nuclear Power ◽  
Liquid Fuel ◽  
Fission Products ◽  
Processing Plant ◽  
Fast Reactors ◽  
Melting Temperatures ◽  
Load Following ◽  
Reactor Types ◽  
Reactor Accidents

<p><br></p> <div> <table> <tr> <td> <p>Molten Salt Reactors</p> </td> </tr> </table> </div> <br> <div> <table> <tr> <td> <p>© Thomas J. Dolan, Member, IEEE 2021</p> </td> </tr> </table> </div> <br> <p><i>Abstract</i>— Nuclear power is advancing slowly because of public concerns about nuclear accidents, radioactive waste, fuel supply, cost, and nuclear proliferation. The development of molten salt reactors could alleviate most of these concerns and prevent water-cooled reactor accidents like those at Three Mile Island, Chernobyl, and Fukushima. The purpose of this article is to provide information about the potential advantages and problems of molten salt reactors. The coolants could be either <i>fluorides</i> or <i>chlorides</i>, operated above their melting temperatures, to avoid solidification, and well below their boiling temperatures, to prevent evaporation losses. “Fast” reactors use energetic fission neutrons, while “thermal” reactors use graphite to slow the neutrons down to thermal energies. We describe four reactor types: solid fuel thermal, liquid fuel thermal, liquid fuel fast, and “stable salt” fast reactors (liquid fuel in tubes). We discuss load following, reactor design projects, and development problems. Liquid fuel reactors will require a chemical processing plant to adjust fissile fuel inventory, fission products, actinides, and corrosivity in a hot, highly-radioactive environment. </p>

Modelling Frozen Salt Films in a Molten Salt Fast Reactor

2018 ◽  
Author(s):  
Gregory M. Cartland-Glover ◽  
Stefano Rolfo ◽  
Alex Skillen ◽  
David R. Emerson ◽  
Charles Moulinec ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Molten Salt ◽  
Fast Reactor ◽  
Energy Production ◽  
Nuclear Energy ◽  
Numerical Models ◽  
Reactor Core ◽  
Separated Flow ◽  
Flow And Heat Transfer ◽  
Innovative Solutions

Molten salt reactors are a very promising option for the development of highly innovative solutions for the nuclear energy production of the future. The techniques used to model thermal hydraulics of a molten salt fast reactor when frozen salt wall technology is applied to the core vessel wall are presented here for 2D numerical models of a hyperboloid reactor core region with a heat exchanger was applied in Code_Saturne. A 3D simulation of the fluid flow and heat transfer with 16 recirculation loops containing the heat exchangers is also presented. It was found that there is strong cooling in separated flow regions in the external heat exchanger, which freezes where the porous model is applied.

Budget analysis of a pseudo-single-phase transport model for slurry flows

2020 ◽  
Vol 135 (3) ◽  
Author(s):  
Aurélien Bordet ◽  
Sébastien Poncet ◽  
Michel Poirier ◽  
Nicolas Galanis
Keyword(s):  
Single Phase ◽  
Transport Model ◽  
Budget Analysis ◽  
Slurry Flows ◽  
Phase Transport

Coupled study of the Molten Salt Fast Reactor core physics and its associated reprocessing unit

2014 ◽  
Vol 64 ◽  
pp. 430-440 ◽  
Author(s):  
X. Doligez ◽  
D. Heuer ◽  
E. Merle-Lucotte ◽  
M. Allibert ◽  
V. Ghetta
Keyword(s):  
Molten Salt ◽  
Fast Reactor ◽  
Reactor Core

An Experimental Study on Freeze Valve Performance in a Molten Salt Reactor

2018 ◽  
Author(s):  
Indarta Kuncoro Aji ◽  
Tokushima Tatsuya ◽  
Motoyasu Kinoshita ◽  
Tomio Okawa
Keyword(s):  
Molten Salt ◽  
Liquid Fuel ◽  
Reactor Core ◽  
Melting Process ◽  
Melting Time ◽  
Molten Salt Reactor ◽  
Liquid Temperature ◽  
Real Situation ◽  
Accident Condition ◽  
Experimental Process

Freeze valve technology is the main feature of safety system in the molten salt reactor. Freeze valve made from frozen salt located between reactor core and drain tank. The freeze valve will automatically melt and open on the accident condition, and respectively molten salt fuel will drain out from reactor core to the drain tanks. Melting time of frozen salt is important issues on this study, where draining process of the liquid fuel must be carried out immediately after the accident. Many factors affect to the opening time of freeze valve. On this experiment, describe a melting process of frozen salt which is affected by wall effect. HTS (high transfer salt) utilized as salt material, and a metal stick planted in the frozen HTS with a certain depth. The experimental process begins when the liquid HTS poured on the top of frozen HTS and ends when the metal stick detached from the frozen HTS. This experiments focus to analyze melting time of freeze valve which impacted by several parameters; material diameter which represent about material thickness in real situation, liquid temperature which represent about molten salt fuel, length of material which propose about the freeze valve thickness, and material difference which propose about thermal diffusivity effect. Results from the experiments will be utilized as a basic to developed mathematics and numerical analysis.

The Optimization Design of Lower Plenum and Distribution Plates in MSR

2013 ◽  
Author(s):  
Jianjun Zhou ◽  
Suizheng Qiu ◽  
Zhangpeng Guo ◽  
Guanghui Su
Keyword(s):  
Molten Salt ◽  
Optimization Design ◽  
Reactor Core ◽  
Fission Products ◽  
Physical Property ◽  
Maximum Temperature ◽  
Concept Design ◽  
Spent Fuel ◽  
Fuel Temperature ◽  
Cfd Method

Molten salt reactor was one of six Generation IV reactor types, which uses the liquid molten salt as the coolant and fuel solvent. In transmutation of actinides and long-lived fission products have marked advantages. As a liquid reactor the physical property and thermo-characteristic is different to solid fuel and water coolant reactors, which was influenced by many factors. MOSART was one of the advanced molten salt reactors concept design, which can burners TRU from LWR spent fuel. The reactor core does not contain graphite structure elements, so the flow pattern was potentially complex and may significantly affect the fuel temperature distributions. The optimizations of the salt flow may be needed, the present work designed three core models and three kinds of distribution plates to investigate the influence of lower plenum and distribution plates to thermohydraulics characteristics of the reactor core with CFD method use software FLUENT. Velocity field and maximum temperature of the core was simulated in each model at different mass flow rate.

Transport of organochlorine pesticides in soil columns enhanced by dissolved organic carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 139-145 ◽  
Author(s):  
Jiann-Yuan Ding ◽  
Shian-Chee Wu
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Organochlorine Pesticides ◽  
Transport Model ◽  
Phase Model ◽  
Soil Columns ◽  
Two Phase ◽  
Three Phase ◽  
Phase Transport ◽  
Remediation Of Soil

The objective of this study is to quantify the effects of humic acid solution infiltration on the transport of organochlorine pesticides (OCPs) in soil columns using a three-phase transport model. From experimental results, it is found that the dissolved organic carbon enhances the transport of OCPs in the soil columns. In the OCPs-only column, the concentration profiles of OCPs can be simulated well using a two-phase transport model with numerical method or analytical solution. In the OCPs-DOC column, the migrations of aldrin, DDT and its daughter compounds are faster than those in the OCPs-only column. The simulation with the three-phase model is more accurate than that with the two-phase model. In addition, significant decrease of the fluid pore velocities of the OCPs-DOC column was found. When DOC leachate is applied for remediation of soil or groundwater pollution, the decrease of mean pore velocities will be a crucial affecting factor.

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