Laboratory and Engineering Studies of Sol--Gel Processes at Oak Ridge National Laboratory.

Wymer, R.G.

doi:10.2172/4539651

“…For smaller scale, µg reactions, calcination of ion-exchange resins is also possible [179]. Synthesis of polycrystalline samples of actinide oxides have also been reported through sol-gel [53] and aqueous routes [72,124,130]. Many of the actinide oxides can be hypo-or hyperstoichiometric, i.e.…”

Section: Crystal Growthmentioning

confidence: 99%

Crystal structure and magnetism of actinide oxides: a review

Rai,

Bretaña,

Morrison

et al. 2024

Rep. Prog. Phys.

3

0

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In actinide systems, the 5f electrons experience a uniquely delicate balance of effects and interactionshaving similar energy scales, which are often difficult to properly disentangle. The interplayof factors such as the dual character of 5f-states, competing interactions, and strong spin-orbit couplingresults in magnetically unusual and intriguing behavior: multi-k antiferromagnetic ordering,multipolar ordering, mixed valence configurations, and more. Despite the inherent allure of theirexotic properties, the exploratory science of even the more basic, binary systems like the actinideoxides has been extremely limited due to their toxicity, radioactivity, and reactivity. In this article,we provide an overview of the available synthesis techniques for selected binary actinide oxides,including the actinide dioxides, sesquioxides, and a selection of the higher oxides. For these oxides,we review and evaluate the current state of knowledge on their crystal structures and magneticproperties. In many aspects, substantial knowledge gaps exist in the current body of research onactinide oxides related to understanding their magnetic ground states. Bridging these gaps is vitalfor improving not only a fundamental understanding of these systems but also of future nucleartechnologies. To this end, we note the experimental techniques and necessary future investigationswhich may aid in better elucidating the nature of these fascinating systems.

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“…Over an extended period V of use, it has been found that the catalyst activity decreases because of blockage of the surface by a small amount of black precipitate (probably uranous hydroxide). 14 The catalyst can be regenerated by washing with 1 to 2 M HN0 3 and then H z O followed by air drying at 100 C. 15 However, in early sol-gel development work at B&W, it was found that this treatment was not always sufficient for complete regeneration. Therefore, during these runs the catalyst was rejected after each reduction.…”

Section: 2 Catalyst Separationmentioning

confidence: 99%

Preparation of Plutonia--Urania Fuels by a Sol-Gel Process.

Carlson¹

1969

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Coated Particle Fuels for High‐Temperature Reactors

Kania

¹

,

Nabielek

²

,

Nickel

³

2015

Materials Science and Technology

8

0

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The article contains sections titled: Introduction History of HTGRs and Coated Particle Fuel Development HTGRs Built and Operated HTGRs Designed but Not Built Modular Reactors (1980 s Design) Current Modular Reactor Designs Coated Particle Fuel Development Development in the UK Development in G ermany Development in the US Recent Directions Fuel Manufacturing Processes Fuel K ernel Manufacture Powder Metallurgical Process Sol–Gel Process Gel‐Precipitation Process for UO 2 Kernels Gel‐Precipitation Process for UCO Kernels Fabrication of PuO 2 Kernels Ceramic Coatings by CVD Pyrolytic Carbon ( PyC ) Coatings Silicon Carbide ( SiC ) Coatings Fuel Element Manufacture Spherical Fuel Elements for Pebble‐Bed Cores Hexagonal‐Block Fuel Elements for Prismatic Cores HTGR Fuel Materials Properties Properties of UO 2 Fuel Kernels Thermal Properties of UO 2 Mechanical Properties of UO 2 Swelling Rate of UO 2 Properties of Pyrolytic Carbon ( PyC ) Coatings Thermal Properties of PyC Theoretical Density of PyC Mechanical Properties of PyC Irradiation‐Induced Dimensional Change of PyC Properties of Silicon Carbide ( SiC ) Coatings Thermal Properties of SiC Mechanical Properties of SiC Swelling Rate of SiC Fuel Quality Control and Performance Evaluation Quality Control of UO 2 Kernels Quality Control of Coated Particles Quality Control of Spherical Fuel Elements Failure Statistics and Performance Requirements The Mathematics of Failure Statistics Statistical Analysis of Fuel Element Manufacture Statistical Analysis of Irradiation Performance Statistical Analysis of Accident Condition Performance Comparison to Performance Requirements Fuel Performance under Normal Operating Conditions Irradiation Testing of Modern UO 2 TRISO‐Coated Particles Accelerated Irradiations in Material Test Reactors HFR ‐ P 4 Test SL ‐ P 1 Test HFR ‐ K 3 Test FRJ 2‐ K 13 Test FRJ 2‐ K 15 Test FRJ 2‐ P 27 Test Conduct of the Accelerated Tests HTR MODUL Proof Tests HFR ‐ K 5 and HFR‐K 6 AVR Real‐Time Irradiation Testing Performance Assessment for Normal Operating Conditions Fuel Performance under Accident Conditions Simulation of Core Heat‐Up after Depressurization under Dry Conditions Analysis of Accident Simulation Testing Behavior after Water and Air Ingress Simulation of Water Ingress Simulation of Air Ingress HTGR Fission Product Generation and Transport Fission Product Generation Fission Product Transport Equivalent Sphere Model for Gas Release Recoil Release from Fuel Kernel Release from Post‐Irradiation Heating Tests Release of Short‐Lived Xe and Kr Isotopes Retention by a Single Coating Layer Release for a Single Shell Diffusion Data for Coating Layers Applicability and Uncertainties of Transport Data Transport and Release from Fuel Elements in Reactor Tests and HTGRs Fission Product Chemistry and CO Generation in UO 2 Coated Particle Failure Mechanisms Pressure‐Induced Failure Internal Gas Pressure Buildup Predicting Pressure‐Induced Particle Failure STRESS Modeling The R edlich– K wong Equation for Internal Gas Pressure Cracking of PyC Coatings due to Fast Fluence iPyC Failure iPyC – SiC Interface Debonding oPyC Failure Fast Neutron‐Induced PyC Cracking Kernel Migration (Amoeba Effect) Kernel Migration in UO 2 ‐Coated Particle Fuel Kernel Migration in Uranium Carbide Coated‐Particle Fuel Kernel Migration in Thorium Oxide Coated‐Particle Fuel Corrosion of the SiC Layer CO Attack of SiC Palladium– SiC Interactions Silver Migration through SiC Layer Rare Earth Fission Product Attack SiC Decomposition As‐Manufactured Defective Particles Contamination during Manufacture Irradiation‐Induced Failures Summary of Coated Particle Failure Mechanisms

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Laboratory and Engineering Studies of Sol--Gel Processes at Oak Ridge National Laboratory.

Cited by 6 publications

References 3 publications

Crystal structure and magnetism of actinide oxides: a review

Crystal structure and magnetism of actinide oxides: a review

Preparation of Plutonia--Urania Fuels by a Sol-Gel Process.

Coated Particle Fuels for High‐Temperature Reactors

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