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Charles Forsberg - One of the best experts on this subject based on the ideXlab platform.
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heat pipe heat exchangers for Salt cooled fission and fusion reactors to avoid Salt freezing and control tritium a review
Nuclear Technology, 2020Co-Authors: Bahman Zohuri, Stephen T Lam, Charles ForsbergAbstract:The Fluoride-Salt-cooled high-temperature reactor and some proposed fusion reactors use clean Fluoride Salts as reactor coolants that have melting points above 450°C and generate tritium. Tritium d...
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fhr htgr and msr pebble bed reactors with multiple pebble sizes for fuel management and coolant cleanup
Nuclear Technology, 2019Co-Authors: Charles Forsberg, Per F. PetersonAbstract:Three reactor types can be designed with pebbles (carbon spheres) as the reactor core: the pebble-bed high-temperature gas-cooled reactor (PB-HTGR), the pebble-bed Fluoride-Salt-cooled high-tempera...
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redox potential control in molten Salt systems for corrosion mitigation
Corrosion Science, 2018Co-Authors: Jinsuo Zhang, Raluca O Scarlat, Francesco Carotti, Kevin J Chan, William Doniger, Charles Forsberg, Michael F. Simpson, Kumar Sridharan, Preet M. Singh, James R. KeiserAbstract:Abstract In a molten Salt nuclear reactor system, the redox potential must be controlled for mitigating corrosion of structural materials. The paper presented a critical review on the available knowledge of redox potential control in molten Fluoride Salt systems. The major phenomena that affect the redox potential and material corrosion are fission, TF production by transmutation, and Salt contamination with metal Fluorides or other oxidizing impurities. Redox potential control methodologies include gas sparging, contacting the Salt with a reducing metal, and adding soluble Salt redox buffers to the Salt. Redox potential measurement technologies include electrochemical sensors and optical spectroscopy. The paper also analyzed the current technology issues and recommended near future studies.
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neutronics feasibility of an mit reactor driven subcritical facility for the Fluoride Salt cooled high temperature reactor
International Journal of Energy Research, 2017Co-Authors: Kaichao Sun, Charles ForsbergAbstract:Summary The current study explores an innovative option for demonstrating the Fluoride-Salt–cooled High- temperature Reactor (FHR) technologies with a reactor-driven subcritical facility. The FHR uses clean Salt coolants, carbon-matrix coated-particle fuel similar to that used in High-temperature Gas-cooled Reactors and can be coupled to a nuclear air-Brayton combined cycle. Recent assessments indicate favorable economics and safety characteristics, but no FHR has been built. The question is what experimental facilities should be constructed to reduce technical uncertainties before a decision to build a test or demonstration reactor? The MIT Reactor design and license would allow the construction and operation of a subcritical facility with 700°C Salt circulating through multiple full-width partial-height fuel assemblies operating with a power density up to 60% of a commercial FHR. This option would allow hot systems testing as a major step toward building the test or demonstration reactor. Preliminary system design, power control options, testing capabilities, and key nuclear characteristics of such a reactor-driven subcritical facility are described. A method of deriving subcritical multiplicity using surface source has been proposed and verified in this study. Finally, the neutronic impacts on the driver facility, ie, the MIT Reactor, have been evaluated.
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tritium management and control using carbon in a Fluoride Salt cooled high temperature reactor
Fusion Science and Technology, 2017Co-Authors: John D Stempien, R G Ballinger, Charles ForsbergAbstract:AbstractResearch characterizing hydrogen behavior on carbon has been primarily focused on collecting data at near-ambient temperatures and pressures for storage or for high volume applications such as fusion. Transport models of a pre-conceptual 236 MWt pebble-bed Fluoride-Salt-cooled, high-temperature reactor (PB-FHR) estimate that the production of tritium is relatively low resulting in partial pressures ranging between 0 and 20 Pa. Operating temperatures in an FHR range from 600 to 700°C. Under these operating conditions, the interaction between hydrogen and carbon is currently undefined. Since an FHR contains large quantities of carbon (reflectors, fuel, structures), the tritium behavior in carbon must be investigated in order to develop methods to control tritium release rates to the environment and material corrosion. Preliminary modeling and experiments demonstrate high performance is achieved in a carbon adsorption tower, which can reduce system release rates by greater than 99%. This research aim...
Per F. Peterson - One of the best experts on this subject based on the ideXlab platform.
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fhr htgr and msr pebble bed reactors with multiple pebble sizes for fuel management and coolant cleanup
Nuclear Technology, 2019Co-Authors: Charles Forsberg, Per F. PetersonAbstract:Three reactor types can be designed with pebbles (carbon spheres) as the reactor core: the pebble-bed high-temperature gas-cooled reactor (PB-HTGR), the pebble-bed Fluoride-Salt-cooled high-tempera...
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a general approach for determination of acceptable flibe impurity concentrations in Fluoride Salt cooled high temperature reactors fhrs
Nuclear Engineering and Design, 2019Co-Authors: Jeffrey E Seifried, Per F. Peterson, Raluca O Scarlat, Ehud GreenspanAbstract:Abstract This work quantifies the reactivity impact of 53 impurities within the 7Li2BeF4 (FLiBe) primary coolant for thermal spectrum Fluoride-Salt Cooled High-Temperature Reactors (FHR). It does so not by assuming a mixture of impurities, but by individually assessing the impact of each impurity per amount present, and computing specific reactivity worths. Two approaches are taken to making these estimates, one using the KSEN tool in MCNP6.1 and a more traditional one using spectrum-collapsed absorption cross-sections. The KSEN tool is shown to be quite effective at this procedure. The utility of these specific reactivity worths is demonstrated by estimating the impact of FLiBe impurities upon the coolant temperature coefficient of reactivity, the system excess reactivity, and the achievable discharge burnup for an example FHR. The impurities considered in this analysis are based on an impurity vector that is considered representative for FHR FLiBe. A discussion is provided on the likely sources of impurities in the FHR coolant and the available detection and removal techniques for impurities from FLiBe.
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basis for Fluoride Salt cooled high temperature reactors with nuclear air brayton combined cycles and firebrick resistance heated energy storage
Nuclear Technology, 2016Co-Authors: Charles Forsberg, Per F. PetersonAbstract:AbstractThe Fluoride Salt–cooled high-temperature reactor (FHR) with a nuclear air-Brayton combined cycle (NACC) and firebrick resistance-heated energy storage (FIRES) is a new reactor and plant concept. The development of a new reactor is a large undertaking that requires a strong commercial case and a strong basis for government support to enable commercialization. The goals are (1) increase plant revenue by 50% to 100% relative to base-load nuclear plants with capital costs similar to light water reactors, (2) enable a zero-carbon nuclear renewable electricity grid, (3) no potential for major fuel failure and thus no potential for major radionuclide off-site releases in a beyond-design-basis accident, and (4) offer a pathway to more advanced energy systems. The approaches to achieve those goals are described herein.The FHR uses liquid-Salt coolants originally developed for molten Salt reactors (MSRs) where the fuel is dissolved in the coolant. However, in the FHR the fuel is not dissolved in the coolan...
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design and licensing strategies for the Fluoride Salt cooled high temperature reactor fhr technology
Progress in Nuclear Energy, 2014Co-Authors: Raluca O Scarlat, Charles Forsberg, Anselmo T Cisneros, Edward D Blandford, Michael R Laufer, Nicolas Zweibaum, Ehud Greenspan, Charalampos Andreades, D L Krumwiede, Per F. PetersonAbstract:Abstract Fluoride-Salt-cooled, high-temperature reactor (FHR) technology combines the robust coated-particle fuel of high-temperature, gas-cooled reactors with the single phase, high volumetric heat capacity coolant of molten Salt reactors and the low-pressure pool-type reactor configuration of sodium fast reactors. FHRs have the capacity to deliver heat at high average temperature, and thus to achieve higher thermal efficiency than light water reactors. Licensing of the passive safety systems used in FHRs can use the same framework applied successfully to passive advanced light water reactors, and earlier work by the NGNP and PBMR projects provide an appropriate framework to guide the design of safety-relevant FHR systems. This paper provides a historical review of the development of FHR technology, describes ongoing development efforts, and presents design and licensing strategies for FHRs. A companion review article describes the phenomenology, methods and experimental program in support of FHR.
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the current status of Fluoride Salt cooled high temperature reactor fhr technology and its overlap with hif target chamber concepts
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2014Co-Authors: Raluca O Scarlat, Per F. PetersonAbstract:Abstract The Fluoride Salt cooled high temperature reactor (FHR) is a class of fission reactor designs that use liquid Fluoride Salt coolant, TRISO coated particle fuel, and graphite moderator. Heavy ion fusion (HIF) can likewise make use of liquid Fluoride Salts, to create thick or thin liquid layers to protect structures in the target chamber from ablation by target X-rays and damage from fusion neutron irradiation. This presentation summarizes ongoing work in support of design development and safety analysis of FHR systems. Development work for Fluoride Salt systems with application to both FHR and HIF includes thermal-hydraulic modeling and experimentation, Salt chemistry control, tritium management, Salt corrosion of metallic alloys, and development of major components (e.g., pumps, heat exchangers) and gas-Brayton cycle power conversion systems. In support of FHR development, a thermal-hydraulic experimental test bay for separate effects (SETs) and integral effect tests (IETs) was built at UC Berkeley, and a second IET facility is under design. The experiments investigate heat transfer and fluid dynamics and they make use of oils as simulant fluids at reduced scale, temperature, and power of the prototypical Salt-cooled system. With direct application to HIF, vortex tube flow was investigated in scaled experiments with mineral oil. Liquid jets response to impulse loading was likewise studied using water as a simulant fluid. A set of four workshops engaging industry and national laboratory experts were completed in 2012, with the goal of developing a technology pathway to the design and licensing of a commercial FHR. The pathway will include experimental and modeling efforts at universities and national laboratories, requirements for a component test facility for reliability testing of Fluoride Salt equipment at prototypical conditions, requirements for an FHR test reactor, and development of a pre-conceptual design for a commercial reactor.
Raluca O Scarlat - One of the best experts on this subject based on the ideXlab platform.
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kinetic study of hydrogen transport in graphite under molten Fluoride Salt environment
Electrochimica Acta, 2020Co-Authors: Jie Qiu, Raluca O Scarlat, Jizheng Yao, Digby D MacdonaldAbstract:Abstract In this work, a kinetic model, which describes the reactions occurring during the hydrogen charging process on a graphite surface, was optimized on Electrochemical Impedance Spectroscopic (EIS) to study the entry of hydrogen into graphite in high temperature molten FLiNaK Salt. The results show that the rate constants of k1 increases with decreasing applied potential (becoming more negative), and k2 and k3 are independent of the applied potential. At the same charging potential, all the three rate constants are independent of the water concentration in the FLiNaK Salt. The surface coverage of absorbed hydrogen increases with decreasing the charging potential and increasing the moisture content in the Salt. The adsorption efficiency of hydrogen increases with increasingly charging potential and decreases with increasing moisture content of the FLiNaK Salt. These results demonstrate that EIS is a promising technique for measuring the kinetic parameters for hydrogen transport in graphite under molten Fluoride Salt environment.
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galvanic corrosion of type 316l stainless steel and graphite in molten Fluoride Salt
Corrosion Science, 2020Co-Authors: Angjian Wu, Raluca O Scarlat, Yanhui Li, Yi Xu, Digby D MacdonaldAbstract:Abstract The effect of Graphite on the corrosion of Type 316L stainless steel (SS) was investigated in molten FLiNaK (LiF-NaF-KF: 46.5−11.5−42 mol.%) Salt using electrochemical methods. Results show that Type 316L SS and Graphite, when ohmically-coupled, are susceptible to galvanic corrosion in molten Fluoride Salts. The Graphite, with the more positive electromotive potential, acts as the cathode in the Type 316L SS/Graphite galvanic couple and accelerates the corrosion of the steel. The galvanic effect of Graphite on Type 316L SS in molten FLiNaK Salt increase linearly with increasing Graphite/Type 316L SS surface area ratio, temperature, and moisture impurities of the Salt.
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a general approach for determination of acceptable flibe impurity concentrations in Fluoride Salt cooled high temperature reactors fhrs
Nuclear Engineering and Design, 2019Co-Authors: Jeffrey E Seifried, Per F. Peterson, Raluca O Scarlat, Ehud GreenspanAbstract:Abstract This work quantifies the reactivity impact of 53 impurities within the 7Li2BeF4 (FLiBe) primary coolant for thermal spectrum Fluoride-Salt Cooled High-Temperature Reactors (FHR). It does so not by assuming a mixture of impurities, but by individually assessing the impact of each impurity per amount present, and computing specific reactivity worths. Two approaches are taken to making these estimates, one using the KSEN tool in MCNP6.1 and a more traditional one using spectrum-collapsed absorption cross-sections. The KSEN tool is shown to be quite effective at this procedure. The utility of these specific reactivity worths is demonstrated by estimating the impact of FLiBe impurities upon the coolant temperature coefficient of reactivity, the system excess reactivity, and the achievable discharge burnup for an example FHR. The impurities considered in this analysis are based on an impurity vector that is considered representative for FHR FLiBe. A discussion is provided on the likely sources of impurities in the FHR coolant and the available detection and removal techniques for impurities from FLiBe.
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redox potential control in molten Salt systems for corrosion mitigation
Corrosion Science, 2018Co-Authors: Jinsuo Zhang, Raluca O Scarlat, Francesco Carotti, Kevin J Chan, William Doniger, Charles Forsberg, Michael F. Simpson, Kumar Sridharan, Preet M. Singh, James R. KeiserAbstract:Abstract In a molten Salt nuclear reactor system, the redox potential must be controlled for mitigating corrosion of structural materials. The paper presented a critical review on the available knowledge of redox potential control in molten Fluoride Salt systems. The major phenomena that affect the redox potential and material corrosion are fission, TF production by transmutation, and Salt contamination with metal Fluorides or other oxidizing impurities. Redox potential control methodologies include gas sparging, contacting the Salt with a reducing metal, and adding soluble Salt redox buffers to the Salt. Redox potential measurement technologies include electrochemical sensors and optical spectroscopy. The paper also analyzed the current technology issues and recommended near future studies.
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tritium control and capture in Salt cooled fission and fusion reactors
Fusion Science and Technology, 2017Co-Authors: Charles Forsberg, Raluca O Scarlat, David Carpenter, Dennis G Whyte, Liu WeiAbstract:AbstractThree advanced power systems use liquid Salt coolants that generate tritium and thus face common challenges to prevent release of the tritium to the environment. The Fluoride-Salt-cooled High-temperature Reactor (FHR) uses the same graphite-matrix coated-particle fuel as High-Temperature Gas-cooled Reactors (HTGRs) and clean Fluoride Salt coolants. Molten Salt reactors (MSRs) dissolve the fuel in a Fluoride or chloride Salt and release the fission product tritium to the Salt. High-magnetic-field fusion machines may use liquid Salt cooling and blankets because of the very high power densities of this new class of fusion machine. The three technologies can be coupled to a Nuclear Air-Brayton Combined Cycle (NACC) enabling variable electricity with base-load reactor operation.Converging requirements for tritium control in 700°C liquid Salts are leading to cooperative programs across technologies; tritium models that combined generation, chemistry, metal corrosion and transport; and new tritium contro...
Digby D Macdonald - One of the best experts on this subject based on the ideXlab platform.
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kinetic study of hydrogen transport in graphite under molten Fluoride Salt environment
Electrochimica Acta, 2020Co-Authors: Jie Qiu, Raluca O Scarlat, Jizheng Yao, Digby D MacdonaldAbstract:Abstract In this work, a kinetic model, which describes the reactions occurring during the hydrogen charging process on a graphite surface, was optimized on Electrochemical Impedance Spectroscopic (EIS) to study the entry of hydrogen into graphite in high temperature molten FLiNaK Salt. The results show that the rate constants of k1 increases with decreasing applied potential (becoming more negative), and k2 and k3 are independent of the applied potential. At the same charging potential, all the three rate constants are independent of the water concentration in the FLiNaK Salt. The surface coverage of absorbed hydrogen increases with decreasing the charging potential and increasing the moisture content in the Salt. The adsorption efficiency of hydrogen increases with increasingly charging potential and decreases with increasing moisture content of the FLiNaK Salt. These results demonstrate that EIS is a promising technique for measuring the kinetic parameters for hydrogen transport in graphite under molten Fluoride Salt environment.
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galvanic corrosion of type 316l stainless steel and graphite in molten Fluoride Salt
Corrosion Science, 2020Co-Authors: Angjian Wu, Raluca O Scarlat, Yanhui Li, Yi Xu, Digby D MacdonaldAbstract:Abstract The effect of Graphite on the corrosion of Type 316L stainless steel (SS) was investigated in molten FLiNaK (LiF-NaF-KF: 46.5−11.5−42 mol.%) Salt using electrochemical methods. Results show that Type 316L SS and Graphite, when ohmically-coupled, are susceptible to galvanic corrosion in molten Fluoride Salts. The Graphite, with the more positive electromotive potential, acts as the cathode in the Type 316L SS/Graphite galvanic couple and accelerates the corrosion of the steel. The galvanic effect of Graphite on Type 316L SS in molten FLiNaK Salt increase linearly with increasing Graphite/Type 316L SS surface area ratio, temperature, and moisture impurities of the Salt.
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effect of so42 on the corrosion of 316l stainless steel in molten flinak Salt
Corrosion Science, 2018Co-Authors: Jie Qiu, Digby D Macdonald, Bin Leng, Huajian Liu, Yanyan Jia, Wandong Xue, Xingtai ZhouAbstract:Abstract The effect of SO42− on the corrosion behavior of 316 L stainless steel (SS) in molten FLiNaK (LiF-NaF-KF: 46.5–11.5–42 mol.%) Salt was studied. Results reveal that the SO42− in the Salt remarkably accelerates the corrosion of 316 L SS by promoting the dissolution of Cr, leading to increasing intergranular corrosion of the alloy. On the other hand, the results of structural characterization indicate that the SO42− can react with Mn to form MnS at the grain boundaries of the alloy. The galvanic couple between MnS and steel matrix could further accelerate the intergranular corrosion of 316 L SS in molten Fluoride Salt environments.
Anselmo T Cisneros - One of the best experts on this subject based on the ideXlab platform.
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design summary of the mark i pebble bed Fluoride Salt cooled high temperature reactor commercial power plant
Nuclear Technology, 2016Co-Authors: Charalampos Andreades, Anselmo T Cisneros, Massimiliano Fratoni, Jae Keun Choi, Alexandre Y K Chong, Sea Hong, Lakshana Huddar, Kathryn D Huff, James Kendrick, D L KrumwiedeAbstract:The University of California, Berkeley (UCB), has developed a preconceptual design for a commercial pebble-bed (PB), Fluoride Salt–cooled, high-temperature reactor (FHR) (PB-FHR). The baseline desi...
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phenomenology methods and experimental program for Fluoride Salt cooled high temperature reactors fhrs
Progress in Nuclear Energy, 2014Co-Authors: Nicolas Zweibaum, Raluca O Scarlat, Charles Forsberg, Mark H. Anderson, Anselmo T Cisneros, Michael R Laufer, G Cao, Brian C Kelleher, Jeffrey E Seifried, Ehud GreenspanAbstract:Abstract Due to their combination of high-temperature coated-particle fuel, molten Salt coolant and related materials requirements, Fluoride-Salt-cooled, high-temperature reactors (FHRs) exhibit different thermal hydraulic, neutronic and structural mechanics phenomena compared to conventional and more extensively studied other advanced nuclear reactor concepts. This paper highlights key phenomena unique to FHRs, and reviews general issues for developing, verifying, and validating evaluation models for FHR technology that may apply to other advanced reactors. System response codes that are appropriate to predict the behavior of FHRs under steady-state operation and licensing basis events are identified, along with experimental data needs to validate these codes. FHR materials requirements are highlighted, and the missions and licensing program for an FHR test reactor, providing ultimate validation data and proof of concept before a commercial prototype is built, are presented. This review draws upon information compiled in a series of four white papers based on FHR experts workshops held in 2012 in the U.S.
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design and licensing strategies for the Fluoride Salt cooled high temperature reactor fhr technology
Progress in Nuclear Energy, 2014Co-Authors: Raluca O Scarlat, Charles Forsberg, Anselmo T Cisneros, Edward D Blandford, Michael R Laufer, Nicolas Zweibaum, Ehud Greenspan, Charalampos Andreades, D L Krumwiede, Per F. PetersonAbstract:Abstract Fluoride-Salt-cooled, high-temperature reactor (FHR) technology combines the robust coated-particle fuel of high-temperature, gas-cooled reactors with the single phase, high volumetric heat capacity coolant of molten Salt reactors and the low-pressure pool-type reactor configuration of sodium fast reactors. FHRs have the capacity to deliver heat at high average temperature, and thus to achieve higher thermal efficiency than light water reactors. Licensing of the passive safety systems used in FHRs can use the same framework applied successfully to passive advanced light water reactors, and earlier work by the NGNP and PBMR projects provide an appropriate framework to guide the design of safety-relevant FHR systems. This paper provides a historical review of the development of FHR technology, describes ongoing development efforts, and presents design and licensing strategies for FHRs. A companion review article describes the phenomenology, methods and experimental program in support of FHR.
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pre conceptual design of a Fluoride Salt cooled small modular advanced high temperature reactor smahtr
2011Co-Authors: S R Greene, Jess C Gehin, David Eugene Holcomb, Juan J Carbajo, Dan Ilas, Anselmo T Cisneros, Venugopal Koikal Varma, W R Corwin, Dane F Wilson, Graydon L. YoderAbstract:This document presents the results of a study conducted at Oak Ridge National Laboratory during 2010 to explore the feasibility of small modular Fluoride Salt-cooled high temperature reactors (FHRs). A preliminary reactor system concept, SmATHR (for Small modular Advanced High Temperature Reactor) is described, along with an integrated high-temperature thermal energy storage or Salt vault system. The SmAHTR is a 125 MWt, integral primary, liquid Salt cooled, coated particle-graphite fueled, low-pressure system operating at 700 C. The system employs passive decay heat removal and two-out-of-three , 50% capacity, subsystem redundancy for critical functions. The reactor vessel is sufficiently small to be transportable on standard commercial tractor-trailer transport vehicles. Initial transient analyses indicated the transition from normal reactor operations to passive decay heat removal is accomplished in a manner that preserves robust safety margins at all times during the transient. Numerous trade studies and trade-space considerations are discussed, along with the resultant initial system concept. The current concept is not optimized. Work remains to more completely define the overall system with particular emphasis on refining the final fuel/core configuration, Salt vault configuration, and integrated system dynamics and safety behavior.