Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

Scheele, R.D.; Casella, Andrew M.

doi:10.2172/1017120

Cited by 7 publications

(7 citation statements)

References 44 publications

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“…The length of the connections provided good thermal equilibration of emitted gases from the center of the furnace (400-500C) to the deposition chamber, which maintained an internal temperature of ~20C. The deposition chamber and connections to the furnace were not corroded by room temperature exposure to the fluorinating gas [3,7] and were inexpensive to replace, as they eventually became contaminated with U. The gases were routed out of the deposition chamber to a water bubbler to control U emissions and then were routed to the plenum of the fume hood.…”

Section: Apparatus and Methodsmentioning

confidence: 99%

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

McNamara

O’Hara

Casella

et al. 2016

Talanta

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We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other U compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within a fixed reactor geometry to a highly predictable degree. We demonstrate the preparation of U deposits that range between approximately 0.01 and 500ngcm(-2). The data suggest the method can be extended to creating depositions at the sub-picogramcm(-2) level. The isotopic composition of the deposits can be customized by selection of the U source materials and we demonstrate a layering technique whereby two U solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit that bears an isotopic signature that is a composite of the two U sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics. Further, the method allows access to very low atomic or molecular coverages of surfaces.

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Section: Apparatus and Methodsmentioning

confidence: 99%

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

McNamara

O’Hara

Casella

et al. 2016

Talanta

Self Cite

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“…Just as in the MSRE, the fluorine would be extremely corrosive to the purification vessel. Adding hydrogen to control fluorine's oxidizing nature exothermically produces hydrogen fluoride, which brings the chemistry back to hydrofluorination [13,14]. The price of nitrogen trifluoride, nearly five times that of hydrogen fluoride, and its chemistry prevents its immediate implementation.…”

Section: Purification Theorymentioning

confidence: 99%

Batch-Scale Hydrofluorination of Li27BeF4 to Support Molten Salt Reactor Development

Kelleher

Dolan

Brooks

et al. 2015

Journal of Nuclear Engineering and Radiation Science

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Li 2 BeF 4 , or flibe, is the primary candidate coolant for the fluoride-salt-cooled high-temperature nuclear reactor (FHR). Kilogram quantities of pure flibe are required for repeatable corrosion tests of modern reactor materials. This paper details fluoride salt purification by the hydrofluorination–hydrogen process, which was used to regenerate 57.4 kg of flibe originating from the secondary loop of the molten salt reactor experiment (MSRE) at Oak Ridge National Laboratory (ORNL). Additionally, it expounds upon necessary handling precautions required to produce high-quality flibe and includes technological advancements which ease the purification and analysis process. Flibe batches produced at the University of Wisconsin are the largest since the MSRE program, enabling new corrosion, radiation, and thermal hydraulic testing around the United States.

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“…A new chemical purification process for fluoride salts that makes use of a less dangerous cleaning gas, nitrogen trifluoride (NF 3 ), has been evaluated as an alternative to the HF/H 2 system [53,54]. Compared to HF, NF 3 is only mildly toxic, noncorrosive, and nonreactive at room temperature.…”

Section: Salt Chemistry Controlmentioning

confidence: 99%

Strategic need for a multi-purpose thermal hydraulic loop for support of advanced reactor technologies

O’Brien¹,

Sabharwall²,

Yoon³

et al. 2014

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This report presents a conceptual design for a new high-temperature, multi-fluid, multi-loop test facility for Idaho National Laboratory (INL) to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications. In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs) at prototypical operating conditions, flow and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for light water reactors (LWRs) at prototypical conditions. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. Research performed in this facility will advance the state of the art and technology readiness level of high-temperature IHXs for nuclear applications, while establishing INL as a center of excellence for development and certification of this technology. The thermal energy storage capability will support research and demonstration activities related to process heat delivery for a variety of hybrid energy systems and grid stabilization strategies. Experimental results obtained from this research will assist in development of reliable predictive models for thermal-hydraulic design and safety codes over the range of expected advanced reactor operating conditions. Proposed/existing IHX heat transfer and friction correlations and criteria will be assessed with information on materials compatibility and instrumentation needs. The experimental database will guide development of appropriate predictive methods and be available for code verification and validation (V&V) related to these systems. viii ix ACKNOWLEDGMENTS The authors would like to acknowledge the Laboratory Directed Research and Development Program of the Nuclear System Design and Analysis Division for supporting the development of the advanced reactor technology multipurpose thermal hydraulic loop.

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Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

Cited by 7 publications

References 44 publications

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

Batch-Scale Hydrofluorination of Li27BeF4 to Support Molten Salt Reactor Development

Strategic need for a multi-purpose thermal hydraulic loop for support of advanced reactor technologies

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