scholarly journals Microstructural Changes and Chemical Analysis of Fission Products in Irradiated Uranium-7 wt.% Molybdenum Metallic Fuel Using Atom Probe Tomography

2021 ◽  
Vol 11 (15) ◽  
pp. 6905
Author(s):  
Mukesh Bachhav ◽  
Brandon Miller ◽  
Jian Gan ◽  
Dennis Keiser ◽  
Ann Leenaers ◽  
...  

Understanding the microstructural and phase changes occurring during irradiation and their impact on metallic fuel behavior is integral to research and development of nuclear fuel programs. This paper reports systematic analysis of as-fabricated and irradiated low-enriched U-Mo (uranium-molybdenum metal alloy) fuel using atom probe tomography (APT). This study is carried out on U-7 wt.% Mo fuel particles coated with a ZrN layer contained within an Al matrix during irradiation. The dispersion fuel plates from which the fuel samples were extracted are irradiated at Belgian Nuclear Research Centre (SCK CEN) with burn-up of 52% and 66% in the framework of the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) project. The APT studies on U-Mo particles from as-fabricated fuel plates enriched to 19.8% revealed predominantly γ-phase U-Mo, along with a network of the cell boundary decorated with α-U, γ’-U2Mo, and UC precipitates along the grain boundaries. The corresponding APT characterization of irradiated fuel samples showed formation of fission gas bubbles enriched with solid fission products. The intermediate burnup sample showed a uniform distribution of the typical bubble superlattice with a radius of 2 nm arranged in a regular lattice, while the high burnup sample showed a non-uniform distribution of bubbles in grain-refined regions. There was no evidence of remnant α-U, γ’-U2Mo, and UC phases in the irradiated U-7 wt.% Mo samples.

2018 ◽  
Vol 25 (2) ◽  
pp. 425-437 ◽  
Author(s):  
Ty J. Prosa ◽  
Savanna Strennen ◽  
David Olson ◽  
Dan Lawrence ◽  
David J. Larson

AbstractSpecimen survivability is a primary concern to those who utilize atom probe tomography (APT) for materials analysis. The state-of-the-art in understanding survivability might best be described as common-sense application of basic physics principles to describe failure mechanisms. For example, APT samples are placed under near-failure mechanical-stress conditions, so reduction in the force required to initiate field evaporation must provide for higher survivability—a common sense explanation of survivability. However, the interplay of various analytical conditions (or instrumentation) and how they influence survivability (e.g., decreasing the applied evaporation field improves survivability), and which factors have more impact than others has not been studied. In this paper, we report on the systematic analysis of a material composed of a silicon-dioxide layer surrounded on two sides by silicon. In total, 261 specimens were fabricated and analyzed under a variety of conditions to correlate statistically significant survivability trends with analysis conditions and other specimen characteristics. The primary result suggests that, while applied field/force plays an obvious role in survivability for this material, the applied field alone does not predict survivability trends for silicon/silicon-dioxide interfaces. The rate at which ions are extracted from the specimen (both in terms of ions-per-pulse and pulse-frequency) has similar importance.


Separations ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 104
Author(s):  
Leah M. Arrigo ◽  
Jun Jiang ◽  
Zachary S. Finch ◽  
James M. Bowen ◽  
Staci M. Herman ◽  
...  

The measurement of radioactive fission products from nuclear events has important implications for nuclear data production, environmental monitoring, and nuclear forensics. In a previous paper, the authors reported the optimization of an intra-group lanthanide separation using LN extraction resin from Eichrom Technologies®, Inc. and a nitric acid gradient. In this work, the method was demonstrated for the separation and quantification of multiple short-lived fission product lanthanide isotopes from a fission product sample produced from the thermal irradiation of highly enriched uranium. The separations were performed in parallel in quadruplicate with reproducible results and high decontamination factors for 153Sm, 156Eu, and 161Tb. Based on the results obtained here, the fission yields for 144Ce, 153Sm, 156Eu, and 161Tb are consistent with published fission yields. This work demonstrates the effectiveness of the separations for the intended application of short-lived lanthanide fission product analysis requiring high decontamination factors.


The Analyst ◽  
2021 ◽  
Vol 146 (1) ◽  
pp. 69-74
Author(s):  
Elizabeth Kautz ◽  
John Cliff ◽  
Timothy Lach ◽  
Dallas Reilly ◽  
Arun Devaraj

235U enrichment in a metallic nuclear fuel was measured via NanoSIMS and APT, allowing for a direct comparison of enrichment across length scales and resolutions.


Small Methods ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 2170004
Author(s):  
Daniel S. Mosiman ◽  
Yi‐Sheng Chen ◽  
Limei Yang ◽  
Brian Hawkett ◽  
Simon P. Ringer ◽  
...  

2021 ◽  
pp. 150193
Author(s):  
D. Kuczyńska-Zemła ◽  
G. Sundell ◽  
M. Zemła ◽  
M. Andersson ◽  
H. Garbacz

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. M. Schwarz ◽  
C. A. Dietrich ◽  
J. Ott ◽  
E. M. Weikum ◽  
R. Lawitzki ◽  
...  

AbstractAtom Probe Tomography (APT) is currently a well-established technique to analyse the composition of solid materials including metals, semiconductors and ceramics with up to near-atomic resolution. Using an aqueous glucose solution, we now extended the technique to frozen solutions. While the mass signals of the common glucose fragments CxHy and CxOyHz overlap with (H2O)nH from water, we achieved stoichiometrically correct values via signal deconvolution. Density functional theory (DFT) calculations were performed to investigate the stability of the detected pyranose fragments. This paper demonstrates APT’s capabilities to achieve sub-nanometre resolution in tracing whole glucose molecules in a frozen solution by using cryogenic workflows. We use a solution of defined concentration to investigate the chemical resolution capabilities as a step toward the measurement of biological molecules. Due to the evaporation of nearly intact glucose molecules, their position within the measured 3D volume of the solution can be determined with sub-nanometre resolution. Our analyses take analytical techniques to a new level, since chemical characterization methods for cryogenically-frozen solutions or biological materials are limited.


2021 ◽  
pp. 113334
Author(s):  
Katja Eder ◽  
Vijay Bhatia ◽  
Jiangtao Qu ◽  
Brandon Van Leer ◽  
Mikhail Dutka ◽  
...  

Author(s):  
Luke Daly ◽  
Martin R. Lee ◽  
James R. Darling ◽  
Ingrid McCarrol ◽  
Limei Yang ◽  
...  

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