Materials for future nuclear energy systems must operate under more extreme conditions than those in current Gen II or Gen III systems. These conditions include higher temperature, higher dpa, and ...more corrosive environments. This paper reviews some of the fuels and structural materials used in advanced nuclear energy systems and identifies promising candidates for these systems. Fuel systems includes metallic fuels for the sodium cooled reactor, TRISO-coated particle fuel for the high temperature gas reactor, molten salt reactor fuels, and accident tolerant fuels for light water reactors. Structural materials applications include the sodium fast reactor, lead fast reactor, high temperature gas reactor, molten salt reactor and extended life light water reactors. A final section focuses on plasma-facing and blanket materials for deuterium-tritium fusion reactors.
The yield of gamma-quanta from nuclear fusion reactions proceeding from various spin states of muonic molecules ptmu and pdmu has been measured. The work was performed on the "Triton" facility at ...DLNP JINR using a specially designed liquid-tritium target. For the first time, channels of the fusion reaction with the yield of double gamma-quanta were observed: ptmu right arrow .sup.4Hemu + gamma + gamma, pdmu right arrow .sup.3Hemu + gamma + gamma. The data obtained for the yield of single gamma-quanta in the channel of the fusion reaction ptmu right arrow .sup.4Hemu + gamma is consistent with earlier research. The partial coefficient of sticking of a muon to a helium nucleus was determined experimentally in a channel of pt- and pd-fusion reactions with the yield of single gamma-quantum.
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.
Molten salt reactors (MSRs) are being considered as one of the potential nuclear options to meet future energy demands. While the MSR designs are drastically different from the more traditional light ...water reactor, many of the waste streams are similar between the concepts. The purpose of this paper is to outline strategies for the treatment and processing of MSR-type wastes from concepts of reconditioning and recycle of certain components to partitioning and direct immobilization of other waste components. To help bridge science and technology gaps, knowledge gained from similar efforts such as pyroprocessing of Experimental Breeder Reactor II salt wastes can be leveraged to develop concept-to-disposition pathways.
VERA, the Virtual Environment for Reactor Applications, is the system of physics capabilities being developed and deployed by the Consortium for Advanced Simulation of Light Water Reactors (CASL), ...the first DOE Hub, which was established in July 2010 for the modeling and simulation of commercial nuclear reactors. VERA consists of integrating and interfacing software together with a suite of physics components adapted and/or refactored to simulate relevant physical phenomena in a coupled manner. VERA also includes the software development environment and computational infrastructure needed for these components to be effectively used. We describe the architecture of VERA from both a software and a numerical perspective, along with the goals and constraints that drove the major design decisions and their implications. As a result, we explain why VERA is an environment rather than a framework or toolkit, why these distinctions are relevant (particularly for coupled physics applications), and provide an overview of results that demonstrate the application of VERA tools for a variety of challenging problems within the nuclear industry.
Next-generation nuclear reactor concepts and advanced techniques for reprocessing spent nuclear fuel (SNF) are drawing great attention in the nuclear field. Molten halide salts have been proposed as ...the fuel solvent and coolants for many molten salt reactor (MSR) concepts, and the electrolyte for the electrochemical separation of the SNF. The major concern of using molten salts is the corrosion of the structural materials imposed by these extreme environments. Materials corrosion is more challenging in the molten salt nuclear systems than in the traditional water reactors as the formation of the passivating oxide layer on the corrosion resistant alloys becomes thermodynamically unfavorable in molten salts and the use of many corrosion resistant alloys is restricted. This review takes a comprehensive approach covering all relevant work in the field: corrosion data accumulated since the 1950s to date, major corrosion problems and corresponding mechanisms, metallurgical factors, historical development of corrosion resistant alloys and recent attempts. The key environmental factors influencing corrosion in various nuclear systems, electrode kinetics, thermodynamic properties, and corrosion prevention techniques are also reviewed. Finally, current progress and challenges are summarized with an attempt at identifying knowledge gaps and future research directions.
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![The Yield of [gamma]-Quanta...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1063-7761/small "The Yield of [gamma]-Quanta from the Reactions of Nuclear Fusion in Muonic Molecules pt[mu] and pd[mu]")
