The Experts below are selected from a list of 3615 Experts worldwide ranked by ideXlab platform

Suizheng Qiu - One of the best experts on this subject based on the ideXlab platform.

  • thermal hydraulic design and analysis of a small modular Molten Salt Reactor msr with solid fuel
    International Journal of Energy Research, 2018
    Co-Authors: Chenglong Wang, Dalin Zhang, Wenxi Tian, Kaichao Sun, Suizheng Qiu
    Abstract:

    Summary A 20 MWth, 540 EFPD once through fuel cycle small modular Molten Salt Reactor with solid fuel is proposed by Massachusetts Institute of Technology for off-grid applications. In this paper, various thermal-hydraulic analysis methods including computational fluid dynamics, Reactor Excursion Leak Analysis Program (RELAP5), and DAKOTA are adopted step-by-step for the Reactor design based on the neutronic analysis results. First, 1/12th full core thermal hydraulic analysis is performed by using STAR CCM+ with most conservative considerations. Second, the transient safety behaviors of Reactor system with risky assumptions are conducted by using REALP5. Finally, due to the unknown factors affecting Reactor thermal-hydraulic characteristics, the uncertainty quantification and sensitivity analysis for the designed Reactor is performed with DAKOTA code coupled with RELAP5. Numerical results show that a more uniform temperature distribution with reduced peak temperatures of fuel and coolant across the Reactor core has been achieved. Enough safety margin is maintained even under most severe transient accident. The uncertainties in the heat transfer coefficient and helium gap conductivity factor are the most remarkable contributors to the statistical results of peaking fuel temperature. All above results preliminarily indicate the feasibility of the current small modular Molten Salt Reactor design and provide the further optimization direction from Reactor thermal-hydraulic prospective.

  • Coupled Neutronics/Thermal-Hydraulics for Analysis of Molten Salt Reactor
    Volume 4: Thermal Hydraulics, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Khurrum Saleem Chaudri, Yao Xiao, Jianjun Zhou, Suizheng Qiu
    Abstract:

    The Generation IV international Forum (GIF) selected Molten Salt Reactor (MSR) among six advanced Reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of Molten Salt Reactor Experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. This work was helpful for further design analysis and operation of MSR.Copyright © 2013 by ASME

  • The effects of core zoning on optimization of design analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Chenglong Wang, Khurrum Saleem Chaudri, Suizheng Qiu
    Abstract:

    Abstract The Molten Salt Reactor (MSR) is one of six advanced Reactor types in the frame of the Generation 4 International Forum. In this study, a multiple-channel analysis code (MAC) is developed to analyze thermal-hydraulics behavior and MCNP4c is used to study the neutronics behavior of Molten Salt Reactor Experiment (MSRE). The MAC calculates thermal-hydraulic parameters, namely temperature distribution, flow distribution and pressure drop. The MCNP4c performs the analysis of effective multiplication factor, neutron flux, power distribution and conversion ratio. In this work, the modification of core configuration is achieved by different core zoning and various fuel channel diameters, contributing to flat flux distribution. Specifically, the core is divided into two regions and the effects of different core zoning on the both neutronics and thermal-hydraulic behavior of moderated Molten Salt Reactor are investigated. We conclude that the flat flux distribution cannot always guarantee better performance in thermal-hydraulic perspective and can decreases the graphite lifetime significantly.

  • Coupled neutronics/thermal-hydraulics for analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Khurrum Saleem Chaudri, Jianjun Zhou, Suizheng Qiu
    Abstract:

    Abstract The Generation IV International Forum (GIF) selected Molten Salt Reactor (MSR) among six advanced Reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of Molten Salt Reactor experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. For further design analysis, parametric studies are performed to provide valuable information for new design of MSR. The effect of inlet temperature, graphite to Molten Salt volume ratio (G/Ms) from varying channel diameter and different power levels on the effective multiplication factor, neutron flux, graphite lifetime and temperature distribution are discussed in detail.

  • Study on the Coupled Neutronic and Thermal-Hydraulic Characteristics of the New Concept Molten Salt Reactor
    Journal of Engineering for Gas Turbines and Power, 2010
    Co-Authors: Peng Wang, Libo Qian, Dalin Zhang, Wenxi Tian, Suizheng Qiu
    Abstract:

    The new concept Molten Salt Reactor is the only liquid-fuel Reactor of the six Generation IV advanced nuclear energy systems. The liquid Molten Salt serves as the fuel and coolant simultaneously and causes one important feature: the delayed neutron precursors are drifted by the fuel fiow, which leads the spread of delayed neutrons' distribution to noncore parts of the primary circuit, and it also results in reactivity variation depending on the flow condition of the fuel Salt. Therefore, the neutronic and thermal-hydraulic characteristics of the Molten Salt Reactor are quite different from the conventional nuclear Reactors using solid fzssile materials. Besides, there is no other Reactor design theory and safety analysis methodologies can be used for reference. The neutronic model is derived based on the conservation of particles considering the flow effect of the fuel Salt in the Molten Salt Reactor, while the thermal-hydraulic model applies the fundamental conservation laws: the mass, momentum, and energy conservation equations. Then, the neutronic and thermal-hydraulic calculations are coupled and the influences of inflow temperature and flow velocity on the Reactor physical properties are obtained. The calculated results show that the flow effect on the distributions of thermal and fast neutron fluxes is very weak, as well as on the effective multiplication factor k eff , while the flow effect on the distribution of delayed neutron precursors is much stronger. The inflow temperature influences the distribution of neutron fluxes and delayed neutron precursors slightly, and makes a significant negative reactivity. Coupled calculation also reveals that the flow velocity of Molten Salt has little effect on the distribution of neutron fluxes in the steady-state, but affects the delayed neutron precursors' distribution significantly.

Dalin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • thermal hydraulic design and analysis of a small modular Molten Salt Reactor msr with solid fuel
    International Journal of Energy Research, 2018
    Co-Authors: Chenglong Wang, Dalin Zhang, Wenxi Tian, Kaichao Sun, Suizheng Qiu
    Abstract:

    Summary A 20 MWth, 540 EFPD once through fuel cycle small modular Molten Salt Reactor with solid fuel is proposed by Massachusetts Institute of Technology for off-grid applications. In this paper, various thermal-hydraulic analysis methods including computational fluid dynamics, Reactor Excursion Leak Analysis Program (RELAP5), and DAKOTA are adopted step-by-step for the Reactor design based on the neutronic analysis results. First, 1/12th full core thermal hydraulic analysis is performed by using STAR CCM+ with most conservative considerations. Second, the transient safety behaviors of Reactor system with risky assumptions are conducted by using REALP5. Finally, due to the unknown factors affecting Reactor thermal-hydraulic characteristics, the uncertainty quantification and sensitivity analysis for the designed Reactor is performed with DAKOTA code coupled with RELAP5. Numerical results show that a more uniform temperature distribution with reduced peak temperatures of fuel and coolant across the Reactor core has been achieved. Enough safety margin is maintained even under most severe transient accident. The uncertainties in the heat transfer coefficient and helium gap conductivity factor are the most remarkable contributors to the statistical results of peaking fuel temperature. All above results preliminarily indicate the feasibility of the current small modular Molten Salt Reactor design and provide the further optimization direction from Reactor thermal-hydraulic prospective.

  • Coupled Neutronics/Thermal-Hydraulics for Analysis of Molten Salt Reactor
    Volume 4: Thermal Hydraulics, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Khurrum Saleem Chaudri, Yao Xiao, Jianjun Zhou, Suizheng Qiu
    Abstract:

    The Generation IV international Forum (GIF) selected Molten Salt Reactor (MSR) among six advanced Reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of Molten Salt Reactor Experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. This work was helpful for further design analysis and operation of MSR.Copyright © 2013 by ASME

  • The effects of core zoning on optimization of design analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Chenglong Wang, Khurrum Saleem Chaudri, Suizheng Qiu
    Abstract:

    Abstract The Molten Salt Reactor (MSR) is one of six advanced Reactor types in the frame of the Generation 4 International Forum. In this study, a multiple-channel analysis code (MAC) is developed to analyze thermal-hydraulics behavior and MCNP4c is used to study the neutronics behavior of Molten Salt Reactor Experiment (MSRE). The MAC calculates thermal-hydraulic parameters, namely temperature distribution, flow distribution and pressure drop. The MCNP4c performs the analysis of effective multiplication factor, neutron flux, power distribution and conversion ratio. In this work, the modification of core configuration is achieved by different core zoning and various fuel channel diameters, contributing to flat flux distribution. Specifically, the core is divided into two regions and the effects of different core zoning on the both neutronics and thermal-hydraulic behavior of moderated Molten Salt Reactor are investigated. We conclude that the flat flux distribution cannot always guarantee better performance in thermal-hydraulic perspective and can decreases the graphite lifetime significantly.

  • Coupled neutronics/thermal-hydraulics for analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Khurrum Saleem Chaudri, Jianjun Zhou, Suizheng Qiu
    Abstract:

    Abstract The Generation IV International Forum (GIF) selected Molten Salt Reactor (MSR) among six advanced Reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of Molten Salt Reactor experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. For further design analysis, parametric studies are performed to provide valuable information for new design of MSR. The effect of inlet temperature, graphite to Molten Salt volume ratio (G/Ms) from varying channel diameter and different power levels on the effective multiplication factor, neutron flux, graphite lifetime and temperature distribution are discussed in detail.

  • Study on the Coupled Neutronic and Thermal-Hydraulic Characteristics of the New Concept Molten Salt Reactor
    Journal of Engineering for Gas Turbines and Power, 2010
    Co-Authors: Peng Wang, Libo Qian, Dalin Zhang, Wenxi Tian, Suizheng Qiu
    Abstract:

    The new concept Molten Salt Reactor is the only liquid-fuel Reactor of the six Generation IV advanced nuclear energy systems. The liquid Molten Salt serves as the fuel and coolant simultaneously and causes one important feature: the delayed neutron precursors are drifted by the fuel fiow, which leads the spread of delayed neutrons' distribution to noncore parts of the primary circuit, and it also results in reactivity variation depending on the flow condition of the fuel Salt. Therefore, the neutronic and thermal-hydraulic characteristics of the Molten Salt Reactor are quite different from the conventional nuclear Reactors using solid fzssile materials. Besides, there is no other Reactor design theory and safety analysis methodologies can be used for reference. The neutronic model is derived based on the conservation of particles considering the flow effect of the fuel Salt in the Molten Salt Reactor, while the thermal-hydraulic model applies the fundamental conservation laws: the mass, momentum, and energy conservation equations. Then, the neutronic and thermal-hydraulic calculations are coupled and the influences of inflow temperature and flow velocity on the Reactor physical properties are obtained. The calculated results show that the flow effect on the distributions of thermal and fast neutron fluxes is very weak, as well as on the effective multiplication factor k eff , while the flow effect on the distribution of delayed neutron precursors is much stronger. The inflow temperature influences the distribution of neutron fluxes and delayed neutron precursors slightly, and makes a significant negative reactivity. Coupled calculation also reveals that the flow velocity of Molten Salt has little effect on the distribution of neutron fluxes in the steady-state, but affects the delayed neutron precursors' distribution significantly.

Xiangzhou Cai - One of the best experts on this subject based on the ideXlab platform.

  • Effect of FLiBe thermal neutron scattering on reactivity of Molten Salt Reactor
    EPJ Web of Conferences, 2020
    Co-Authors: Ya-fen Liu, Li Wenjiang, Rui Yan, Yang Zou, Yu Shihe, Bo Zhou, Xiangzhou Cai
    Abstract:

    Thermal neutron scattering data has an important influence on the calculation and design of Reactor with a thermal spectrum. However, as the only liquid fuel in the Gen-IV Reactor candidates, the research on the thermal neutron scattering effect of coolant and somewhat moderator FLiBe has not been carried out sufficiently either experimentally or theoretically. The effect of FLiBe thermal neutron scattering on reactivity of TMSR-LF (thorium Molten Salt Reactor - liquid fuel), TMSR-SF (thorium Molten Salt Reactor - solid fuel) and MSRE (Molten Salt Reactor experiment) were investigated and compared. Results show that the effect of FLiBe thermal neutron scattering on reactivity depends to some extent on the fuel-graphite volume ratio of core. Calculations indicate that FLiBe thermal neutron scattering of MSRE (with the hardest spectrum) has the minimum effect of 41 pcm on reactivity, and FLiBe thermal neutron scattering of TMSR-SF (with the softest spectrum) has the maximum effect of -94 pcm on reactivity, and FLiBe thermal neutron scattering of TMSR-LF has an effect of -61 pcm on reactivity at 900 K.

  • supply of i 131 in a 2 mw Molten Salt Reactor with different production methods
    Applied Radiation and Isotopes, 2020
    Co-Authors: Xiaohe Wang, Xiangzhou Cai, Chunyan Zou, Jingen Chen
    Abstract:

    Abstract Four I-131 production methods including irradiated TeO2 target and uranium target in the irradiation channel, batch-wise extracted iodine from the fuel Salt, and online extracted solid tellurium through the by-pass loop system have been assessed in a 2 MW Molten Salt Reactor. The latter method can produce a large annual yield of I-131 (about 155,000 Ci). The radioactivity shielding demand of the latter method is much smaller than the other I-131 production methods under the identical annual yield of I-131.

  • evaluation of 99mo production in a small modular thorium based Molten Salt Reactor
    Progress in Nuclear Energy, 2020
    Co-Authors: Xuzhong Kang, Ya-fen Liu, Rui Yan, Yang Zou, Ye Dai, Guifeng Zhu, Xiangzhou Cai
    Abstract:

    Abstract Producing medical radionuclide 99Mo in Molten Salt Reactors is a very attractive choice to solve its global shortage. In this study, we evaluated the yield of 99Mo in the small modular thorium based Molten Salt Reactor (SM-MSR). Firstly, the fuel burn-up analysis of SM-MSR was carried out by an in-house developed code (MOBAT), which takes the unique characteristics of Molten Salt Reactor into account, and the variation of fission yield of 99Mo with burn-up time was obtained. The minimum value of the fission yield of 99Mo is 1.13 × 10−3 (6-day TBq/MW/s) at approximately 600 equivalent full power day. Then, based on the behavior of noble metals in the fuel Salt and the experimental results of MSRE gas sample composition measurements, 99Mo migration probability from the primary loop to the off-gas module with the burn-up time was calculated, and the equilibrium value of the migration probability is obtained as 18.4%. When the load factor of SM-MSR is 0.75 (300 MWth), the annual 99Mo amount of migration to the off-gas module would be 1.96 × 106 (6-day TBq) under the most conservative calculation. Finally, a filter system was added in the off gas module, and 99Mo would be extracted from the off gas. As long as the utilization percentage of 99Mo in the off gas module can reach 0.94%, the global demand under current data could be met, which implies a huge additional economic value for the SM-MSR.

  • sustainable supply of 99mo source in a 2 mw Molten Salt Reactor using low enriched uranium
    Applied Radiation and Isotopes, 2020
    Co-Authors: Xiangzhou Cai, Chunyan Zou, Jingen Chen
    Abstract:

    Abstract The 99Mo production in a 2 MW Molten Salt Reactor using liquid low-enriched uranium (LEU) fuel has been evaluated. The batch-wise extraction period of 99Mo is optimized to be one day corresponding to 9415 6-day Ci/week of the 99Mo production rate. The required amount of uranium is only 4.77 kg annually. The required chemically reprocessed amount of FPs is about 58.4 g annually, accounting for only 4.9% of the solid LEU target method under the identical production capacity of 99Mo.

  • Dynamic analysis for a 2 MW liquid-fueled Molten Salt Reactor
    Progress in Nuclear Energy, 2020
    Co-Authors: Yong Cui, L. Cui, Shao-peng Xia, Jingen Chen, Xiangzhou Cai
    Abstract:

    Abstract In a liquid-fueled Molten Salt Reactor (MSR), the fuel Salt acts as both fuel and coolant, and the fission energy is released into the fuel Salt immediately. The delayed neutron precursors drift through the graphite channels in the core and the primary loop during operation. Therefore, the dynamics for a MSR is characterized by the strong interplay between the neutronics and thermal hydraulics, which is significantly different from that of a solid-fueled Reactor, such as PWR. In this study, a dynamic analysis for a graphite moderated, fluoride based, liquid-fueled Molten Salt Reactor with a power of 2 MWth (TMSR-LF) is carried out based on a coupled neutronics/thermal hydraulics code named TMSR-2D. The steady-state characteristics including the distributions of flow field, temperature and neutron fluxes, and effective delayed neutron fraction under different fuel flow rates, transients perturbed by fuel pump start-up and coast-down, overcooling and overheating of inlet fuel and reactivity insertion are simulated and analyzed. The numerical results indicate that the dynamic behavior of TMSR-LF is acceptable in the aspect of Reactor safety. Furthermore, the dynamic analysis offers valuable information for future construction and operation of this experimental Reactor.

Wenxi Tian - One of the best experts on this subject based on the ideXlab platform.

  • thermal hydraulic design and analysis of a small modular Molten Salt Reactor msr with solid fuel
    International Journal of Energy Research, 2018
    Co-Authors: Chenglong Wang, Dalin Zhang, Wenxi Tian, Kaichao Sun, Suizheng Qiu
    Abstract:

    Summary A 20 MWth, 540 EFPD once through fuel cycle small modular Molten Salt Reactor with solid fuel is proposed by Massachusetts Institute of Technology for off-grid applications. In this paper, various thermal-hydraulic analysis methods including computational fluid dynamics, Reactor Excursion Leak Analysis Program (RELAP5), and DAKOTA are adopted step-by-step for the Reactor design based on the neutronic analysis results. First, 1/12th full core thermal hydraulic analysis is performed by using STAR CCM+ with most conservative considerations. Second, the transient safety behaviors of Reactor system with risky assumptions are conducted by using REALP5. Finally, due to the unknown factors affecting Reactor thermal-hydraulic characteristics, the uncertainty quantification and sensitivity analysis for the designed Reactor is performed with DAKOTA code coupled with RELAP5. Numerical results show that a more uniform temperature distribution with reduced peak temperatures of fuel and coolant across the Reactor core has been achieved. Enough safety margin is maintained even under most severe transient accident. The uncertainties in the heat transfer coefficient and helium gap conductivity factor are the most remarkable contributors to the statistical results of peaking fuel temperature. All above results preliminarily indicate the feasibility of the current small modular Molten Salt Reactor design and provide the further optimization direction from Reactor thermal-hydraulic prospective.

  • Coupled neutronics/thermal-hydraulics for analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Khurrum Saleem Chaudri, Jianjun Zhou, Suizheng Qiu
    Abstract:

    Abstract The Generation IV International Forum (GIF) selected Molten Salt Reactor (MSR) among six advanced Reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of Molten Salt Reactor experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. For further design analysis, parametric studies are performed to provide valuable information for new design of MSR. The effect of inlet temperature, graphite to Molten Salt volume ratio (G/Ms) from varying channel diameter and different power levels on the effective multiplication factor, neutron flux, graphite lifetime and temperature distribution are discussed in detail.

  • The effects of core zoning on optimization of design analysis of Molten Salt Reactor
    Nuclear Engineering and Design, 2013
    Co-Authors: Zhangpeng Guo, Dalin Zhang, Wenxi Tian, Chenglong Wang, Khurrum Saleem Chaudri, Suizheng Qiu
    Abstract:

    Abstract The Molten Salt Reactor (MSR) is one of six advanced Reactor types in the frame of the Generation 4 International Forum. In this study, a multiple-channel analysis code (MAC) is developed to analyze thermal-hydraulics behavior and MCNP4c is used to study the neutronics behavior of Molten Salt Reactor Experiment (MSRE). The MAC calculates thermal-hydraulic parameters, namely temperature distribution, flow distribution and pressure drop. The MCNP4c performs the analysis of effective multiplication factor, neutron flux, power distribution and conversion ratio. In this work, the modification of core configuration is achieved by different core zoning and various fuel channel diameters, contributing to flat flux distribution. Specifically, the core is divided into two regions and the effects of different core zoning on the both neutronics and thermal-hydraulic behavior of moderated Molten Salt Reactor are investigated. We conclude that the flat flux distribution cannot always guarantee better performance in thermal-hydraulic perspective and can decreases the graphite lifetime significantly.

  • Study on the Coupled Neutronic and Thermal-Hydraulic Characteristics of the New Concept Molten Salt Reactor
    Journal of Engineering for Gas Turbines and Power, 2010
    Co-Authors: Peng Wang, Libo Qian, Dalin Zhang, Wenxi Tian, Suizheng Qiu
    Abstract:

    The new concept Molten Salt Reactor is the only liquid-fuel Reactor of the six Generation IV advanced nuclear energy systems. The liquid Molten Salt serves as the fuel and coolant simultaneously and causes one important feature: the delayed neutron precursors are drifted by the fuel fiow, which leads the spread of delayed neutrons' distribution to noncore parts of the primary circuit, and it also results in reactivity variation depending on the flow condition of the fuel Salt. Therefore, the neutronic and thermal-hydraulic characteristics of the Molten Salt Reactor are quite different from the conventional nuclear Reactors using solid fzssile materials. Besides, there is no other Reactor design theory and safety analysis methodologies can be used for reference. The neutronic model is derived based on the conservation of particles considering the flow effect of the fuel Salt in the Molten Salt Reactor, while the thermal-hydraulic model applies the fundamental conservation laws: the mass, momentum, and energy conservation equations. Then, the neutronic and thermal-hydraulic calculations are coupled and the influences of inflow temperature and flow velocity on the Reactor physical properties are obtained. The calculated results show that the flow effect on the distributions of thermal and fast neutron fluxes is very weak, as well as on the effective multiplication factor k eff , while the flow effect on the distribution of delayed neutron precursors is much stronger. The inflow temperature influences the distribution of neutron fluxes and delayed neutron precursors slightly, and makes a significant negative reactivity. Coupled calculation also reveals that the flow velocity of Molten Salt has little effect on the distribution of neutron fluxes in the steady-state, but affects the delayed neutron precursors' distribution significantly.

Ondrej Chvala - One of the best experts on this subject based on the ideXlab platform.

  • A Theory and Model of Molten Salt Reactor Xenon Behavior After the Solubility Limit
    Journal of Nuclear Engineering and Radiation Science, 2020
    Co-Authors: Terry J. Price, Ondrej Chvala
    Abstract:

    Abstract Due to the circulating nature of the fuel, there is a qualitative difference between xenon behavior in a Molten Salt Reactor (MSR) compared to a solid fuel Reactor. Therefore, the equations that describe 135Xe behavior in a Molten Salt Reactor must be formulated differently. Prior Molten Salt Reactor xenon models have focused on behavior below a solubility limit in which the 135Xe is partially dissolved in the fuel Salt. It is foreseeable that a Molten Salt Reactor may operate with a concentration of gas dissolved in the Salt sufficiently high such that no further gas may dissolve in the fuel Salt. This paper introduces a theory of Molten Salt Reactor xenon behavior for a Reactor operating above the solubility limit. A model was developed based on this theory and analyses performed are discussed. Results indicate: (1) steady-state xenon poisoning is not monotonic with respect to gas egress rate, (2) a increase in gas ingress rate leads to a characteristic increase which is followed by a new steady-state in xenon poisoning, and (3) given a sufficient rate of gas egress, it is possible to remove the iodine pit behavior.

  • Xenon Behavior in Molten Salt Reactor Graphite
    Journal of Nuclear Engineering and Radiation Science, 2020
    Co-Authors: Terry J. Price, Ondrej Chvala, Zack Taylor
    Abstract:

    Abstract This article discusses the aspects of 135Xe behavior in Molten Salt Reactor (MSR) graphite. Models of MSR graphite are described. The related mass transfer and mass diffusion coefficients are described and means by which they can be calculated are detailed. Xenon reactivity effects are explored. A method is presented to model the internal xenon distribution within the graphite stringers.

  • A dynamic model of xenon behavior in the Molten Salt Reactor Experiment
    Annals of Nuclear Energy, 2020
    Co-Authors: Terry J. Price, Ondrej Chvala, G.t. Bereznai
    Abstract:

    Abstract A dynamic model of xenon behavior in the Molten Salt Reactor Experiment (MSRE) has been developed. This model is the first to describe the behavior of both the start up and the shut down transients in the Molten Salt Reactor Experiment (MSRE) with a single parameter set.

  • A Review of Molten Salt Reactor Xenon Analysis Literature
    Journal of Nuclear Engineering and Radiation Science, 2019
    Co-Authors: Terry J. Price, Ondrej Chvala
    Abstract:

    Abstract This paper presents a review of xenon analyses literature related to Molten Salt Reactors (MSRs). A brief primer of Reactor xenon theory is presented for fluid fueled Reactors. A review of xenon analysis literature is presented for both the work done by the Oak Ridge National Laboratory, and the later work in academia. A review of experimental work is presented. The paper concludes with describing some of the difficulties in establishing a priori xenon models and includes a commentary on the sensitive dependence of the Molten Salt Reactor xenon behavior on the circulating void fraction.

  • Molten Salt Reactor Xenon Analysis: Review and Decomposition
    Journal of Nuclear Engineering and Radiation Science, 2019
    Co-Authors: Terry J. Price, Ondrej Chvala, Robert Z Taylor
    Abstract:

    Abstract This document analyzes Molten Salt Reactor (MSR) xenon theory and reviews the corpus of literature pertaining to it. A history of xenon behavior in MSRs is presented. Relevant literature is tabulated. Assumptions in MSR xenon theories are made explicit. The structure of graphite stringers is examined. The behavior of bubbles is investigated along with interfacial area perturbation in response to thermodynamic state perturbation. This document serves as an underpinning to further investigation into the MSR xenon theory.