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2020 Transactions of the American nuclear Society, ANS 2020

作者： Ghiglieri, Cliff H. King, Jeffrey C. Nuclear Science and Engineering Program Colorado School of Mines 1500 Illinois St. GoldenCO80401 United States

This summary describes an evaluation of the predicted dose rates from the operating and storage conditions of the proposed Mines Neutron science Laboratory. The laboratory should result in dose rates which are safe and manageable. Dose rates from the operating subcritical assembly, the storage of the neutron source, and the storage of the fuel are less than 5 mrem/hr. Combined doses for the expected storage conditions should be below the public dose limit of 100 mrem/yr in all adjacent rooms. The several operating cases where the dose rate could exceed the public dose rate limit of 100 mrem/yr in adjacent rooms could be mitigated with shielding and/or operating time limits. © 2020 American nuclear Society. All rights reserved.

关键词： Neutron sources

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Gamma-Ray Spectra of Post-Irradiated Uranium Salt for Total Mass Accounting with a Sodium-22 Tracer

SSRN

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SSRN 2023年

作者： Van Zile, Matthew Herminghuysen, Kevin Kauffman, Andrew White, Susan Kandlakunta, Praneeth Li, Shelly Simpson, Michael Cao, Lei R. Nuclear Engineering Program Department of Mechanical and Aerospace Engineering The Ohio State University 201 W. 19th Avenue ColumbusOH43210 United States Nuclear Reactor Laboratory College of Engineering The Ohio State University 1298 Kinnear Rd. ColumbusOH43212 United States Department of Materials Science & Engineering University of Utah 122 S. Central Campus Drive #304 Salt Lake CityUT84112-0056 United States

In order to meet the safeguard requirements for nuclear Material Control and Accountability (MC&A) in liquid- fueled molten salt reactors, fuel salt transportation, and fuel cycle processes, it is important to develop effective methods for measuring and monitoring the mass of molten fuel salt or coolant salt. This paper seeks to validate the radioactive tracer dilution (RTD) method used for determining the mass of irradiated uranium-bearing molten salt. Small scale testing was conducted for this method by irradiating 6.065 g of MgCl-KCl-UCl3 salt mixture with 1.21 mg of 235 U at The Ohio State University, resulting in a neutron fluence of 4.0x1016 cm2 . Gamma spectra were acquired over the course of a 42-day period to assess fission products and activity levels of the 22 Na tracer that was added before irradiation. No additional interference peaks were observed to overlap with the 1274.54 keV energy peak from 22 Na, aside from the known 154 Eu peaks, which can be corrected based on prior studies. By placing a thin piece of lead between the source and detector, deadtime was effectively reduced while still allowing observation of the higher-energy peaks, most notably around the 154 Eu peak at 1004.73 keV used for interference correction. Overall, the uranium salt irradiation techniques applied in this experiment demonstrate the potential of the RTD method to effectively measure small irradiated samples for large scale molten fuel salt applications. © 2023, The Authors. All rights reserved.

关键词： Fission products

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Modeling Task Time Duration Using the Hunter Dynamic Human Reliability Analysis FrameworK

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Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2022年第1期66卷 1612 - 1616页

作者： Ronald L. Boring Thomas A. Ulrich Jooyoung Park Jeeyea Ahn Roger Lew Human Factors and Reliability Department Idaho National Laboratory Idaho Falls Idaho USA Nuclear Engineering Ulsan National Institute of Science and Technology Ulsan Republic of Korea Virtual Technology and Design Program University of Idaho Moscow Idaho USA

The Human Unimodel for nuclear Technology to Enhance Reliability (HUNTER) is simulation software for modeling the human portion of risk. HUNTER is built on a framework that separately models individual, task, and environmental factors. As a dynamic human reliability analysis (HRA) method, it affords advantages over traditional static or worksheet-based HRA approaches, such as the ability to model what-if scenarios and produce outputs beyond human error probabilities. In this paper, a validation was conducted of HUNTER task time estimates vs. empirical data collected for a steam generator tube rupture scenario. The HUNTER model produced using GOMS-HRA task-level primitives yielded timing results very closely aligned to empirical reference data for base and complex conditions, suggesting the tool holds promise for HRA requiring time estimation.

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Antibacterial evaluation of radiolytically synthesized silver nanoparticles with ι-carrageenan stabilizers

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Radiation Physics and Chemistry 2025年 236卷

作者： Gili, Mon Bryan Z. Manuel, Wendell A. Guillermo, Neil Raymund D. Shankaregowda, Rakshith Gowda H. Phan, Manh-Huong Conato, Marlon T. Vega, Marienette M. Department of Science and Technology Philippine Nuclear Research Institute Commonwealth Avenue Diliman Quezon City1101 Philippines Materials Science and Engineering Program College of Science University of the Philippines Diliman Diliman Quezon City1101 Philippines Department of Physics University of South Florida 4202 East Fowler Avenue TampaFL33620 United States Institute of Chemistry College of Science University of the Philippines Diliman Diliman Quezon City1101 Philippines

The synthesis of silver nanoparticles (AgNPs) using green, eco-friendly methods has garnered significant attention due to the potential advantages of using natural polymers, such as ι-carrageenan, as stabilizing agents. However, challenges remain in controlling the size, distribution, and stability of the nanoparticles, as well as optimizing their antimicrobial activity. In this study, gamma irradiation of ι-carrageenan solutions was investigated as a method for synthesizing AgNPs and exploring their antimicrobial properties. The primary objective was to assess how varying radiation doses and ι-carrageenan concentrations affect the formation, size distribution, and antimicrobial activity of the AgNPs. ι-Carrageenan solutions (0.1, 0.5, and 1.0 w/v %) were mixed with 0.2 M silver nitrate (AgNO3) solutions and irradiated at doses ranging from 0 to 20 kGy using Co-60. UV–vis spectroscopic analysis indicated the successful formation of AgNPs, with surface plasmon resonance (SPR) peaks appearing between 402 and 418 nm. These peaks shifted slightly towards shorter wavelengths as the irradiation rose, signaling a reduction in nanoparticle size. The optimal synthesis of AgNPs occurred at 0.5 % ι-carrageenan concentration and a dose of 15 kGy, where the SPR peak intensity and nanoparticle formation were most pronounced. XRD confirmed the presence of silver nanoparticles with face-centered cubic (FCC) structure. Particle size analysis, using dynamic light scattering (DLS), revealed that AgNPs ranged in size from 85 to 142 nm, with smaller particles forming at higher doses. At a 1 kGy dose, the nanoparticle size averaged 114 nm, but increased doses (15–20 kGy) led to a significant reduction in particle size to 85 nm. This size reduction was attributed to the fragmentation of larger particles as the irradiation dose increased. Fourier-transform infrared (FTIR) spectroscopy showed notable changes in the ι-carrageenan structure, with the formation of new functional groups, includ

关键词： Fourier transform infrared spectroscopy

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Coal Structure: Visualizing Micropore Distributions Through Hierarchical 3D Pore Modeling for a Bituminous Coal 38

Coal Structure: Visualizing Micropore Distributions Through ...

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38th Annual International Pittsburgh Coal Conference 2021: Clean Coal-based Energy/Fuels and the Environment, PCC 2021

作者： Lu, Guanwen Watson, Justin K. Mathews, Jonathan P. Leone Family Department of Energy and Mineral Engineering The EMS Energy Institute Pennsylvania State University University ParkPA16802 United States China University of Mining & Technology Xuzhou221008 China Department of Material Science and Engineeing Nuclear Engineering Program Florida University GainesvilleFL32661 United States

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A reduced kinetic method for investigating non-local ion heat transport in ideal multi-species plasmas

arXiv

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arXiv 2024年

作者： Mitchell, Nicholas T. Chapman, David A. McDevitt, Christopher J. Read, Martin P. Kagan, Grigory The Blackett Laboratory Imperial College LondonSW7 2AZ United Kingdom First Light Fusion Ltd. Unit 9/10 Oxford Pioneer Park Mead Road Yarnton Kidlington OX5 1QU United Kingdom Nuclear Engineering Program Department of Materials Science and Engineering University of Florida GainesvilleFL32611 United States

A reduced kinetic method (RKM) with a first-principle collision operator is introduced in a 1D2V planar geometry and implemented in a computationally inexpensive code to investigate non-local ion heat transport in multi-species plasmas. The RKM successfully reproduces local results for multi-species ion systems and the important features expected to arise due to non-local effects on the heat flux are captured. In addition to this, novel features associated with multi-species, as opposed to single species, case are found. Effects of non-locality on the heat flux are investigated in mass and charge symmetric and asymmetric ion mixtures with temperature, pressure, and concentration gradients. In particular, the enthalpy flux associated with diffusion is found to be insensitive to sharp pressure and concentration gradients, increasing its significance in comparison to the conductive heat flux driven by temperature gradients in non-local scenarios. The RKM code can be used for investigating other kinetic and non-local effects in a broader plasma physics context. Due to its relatively low computational cost it can also serve as a practical non-local ion heat flux closure in hydrodynamic simulations or as a training tool for machine learning surrogates. © 2024, CC BY.

关键词： Ions

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Internal dose assessment of lymphoma 18F-FDG Positron Emission Tomography (PET) scan

Internal dose assessment of lymphoma 18F-FDG Positron Emissi...

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2023 National Physics Seminar, SNF 2023

作者： Murat, H. Karim, M.K.A. Kechik, M.M.A. Amer, M.F. Razak, H.R.A. Kamal, I. Chew, M.T. Department of Physics Faculty of Science Universiti Putra Malaysia Selangor Serdang Malaysia Department of Nuclear Medicine Hospital Sultanah Aminah Johor Bahru Johor Malaysia Medical Imaging Program College of Medicine and Health St Luke's Campus University of Exeter DevonEX1 2LU United Kingdom Medical Imaging Department KPJ Healthcare University Nilai Negeri Sembilan Malaysia Research Centre for Applied Physics and Radiation Technologies School of Engineering and Technology Sunway University Petaling Jaya Malaysia

This study aimed to assess the internal radiation exposure of patients who have undergone a Positron Emission Tomography (PET) scan using 18F-FDG radiopharmaceutical. A total of 24 patients (8 men, 16 women, with an average age of 43.88 ± 18.57 years and weight of 57.54 ± 13.04 kg) who had been diagnosed with lymphoma were administered with 300.80 ± 23.09 MBq of 18F-FDG for a PET scan of the whole body. The IDAC-Dose 2.1 program, developed by the International Commission on Radiological Protection (ICRP), was used to measure absorbed and effective doses. The organs selected for absorbed dose analysis were the breast, kidneys, adrenals, liver, and brain, with the brain receiving the highest absorbed dose and the breast receiving the lowest absorbed dose. The effective dose for all patients was 4.85 ± 0.37 mSv, and the ratio of the effective dose to the administered activity was 1.611 × 10-2 mSv/MBq. The safety of the current practice using 18F-FDG PET scan was ascertained, given that the ratio of effective dose to administered activity was lower than 1.9 x 10-2 mSv/MBq. © Published under licence by IOP Publishing Ltd.

关键词： Positron emission tomography

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Verification of Nek4nuc (Nek5000 integrated in NEAMS Workbench) via turbulent pipe flow simulation

Verification of Nek4nuc (Nek5000 integrated in NEAMS Workben...

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2020 Transactions of the American nuclear Society Winter Meeting, ANS 2020

作者： Fan, Yuqiao Delchini, Marc-Olivier G. Lefebvre, Robert A. Nuclear Engineering Science Laboratory Synthesis Program Oak Ridge Institute for Science and Education Oak RidgeTN37831 United States Reactor and Nuclear Systems Division Oak Ridge National Laboratory Oak RidgeTN37830 United States

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Autonomous Electron Tomography Reconstruction with Machine Learning

arXiv

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arXiv 2023年

作者： Millsaps, William Schwartz, Jonathan Di, Zichao Wendy Jiang, Yi Hovden, Robert Department of Nuclear Engineering & Radiological Sciences University of Michigan Ann ArborMI United States Department of Materials Science and Engineering University of Michigan Ann ArborMI United States Mathematics and Computer Science Division Argonne National Laboratory LemontIL United States Advanced Photon Source Facility Argonne National Laboratory LemontIL United States Applied Physics Program University of Michigan Ann ArborMI United States

This manuscript is published in Microscopy and Microanalysis (DOI: 10.1093/micmic/ozad083). Modern electron tomography has progressed to higher resolution at lower doses by leveraging compressed sensing methods that minimize total variation (TV). However, these sparsity-emphasized reconstruction algorithms introduce tunable parameters that greatly influence the reconstruction quality. Here, Pareto front analysis shows that high-quality tomograms are reproducibly achieved when TV minimization is heavily weighted. However, in excess, compressed sensing tomography creates overly smoothed 3D reconstructions. Adding momentum to the gradient descent during reconstruction reduces the risk of over-smoothing and better ensures that compressed sensing is well behaved. For simulated data, the tedious process of tomography parameter selection is efficiently solved using Bayesian optimization with Gaussian processes. In combination, Bayesian optimization with momentum-based compressed sensing greatly reduces the required compute time-an 80% reduction was observed for the 3D reconstruction of SrTiO3 nanocubes. Automated parameter selection is necessary for large scale tomographic simulations that enable the 3D characterization of a wider range of inorganic and biological materials. © 2023, CC BY.

关键词： Compressed sensing

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Challenges in Developing Materials for Microreactors: A Case-Study of Yttrium Dihydride in Extreme Conditions

SSRN

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SSRN 2023年

作者： Tunes, Matheus Araujo Parkison, Darren Huang, Yuqing Chancey, M.R. Vogel, Sven C. Mehta, Vedant K. Torrez, Michael A. Luther, E.P. Valdez, James A. Wang, Yongqiang Yu, Jianguo Cinbiz, Mahmut Nedim Shivprasad, Aditya P. Kohnert, Cailtin A. Montanuniversität Leoben Austria Materials Science and Technology Division Los Alamos National Laboratory United States Department of Nuclear Engineering University of California Berkeley United States Department of Nuclear Engineering North Carolina State University United States Irradiated Fuels and Materials Idaho National Laboratory United States Program Project Interface Division Los Alamos National Laboratory United States Sigma Division Los Alamos National Laboratory United States Computational Mechanics and Materials Idaho National Laboratory United States Materials Science and Technology Division Oak Ridge National Laboratory United States

The development of microreactor technology presents an efficient solution for providing portable electricity, catering to both human space exploration needs within our solar system and supplying power to remote Earth-bound areas. The miniaturization of nuclear reactors poses immediate new challenges for materials science with respect to the capability for controlling nuclear reactions via thermalization of highly-energetic neutrons. In a microreactor, neutron moderation takes place in compact geometries, therefore new moderator materials are required to exhibit high moderating power per unit of volume. This challenge is currently being addressed through the advancement of hydrogen technology and materials science, particularly focusing on development of transition metal hydrides, but to date, research on their irradiation response, specifically regarding phase stability, hydrogen in-lattice retention, and their dependence on irradiation temperature and dose, is limited. Herein, we present a detailed investigation on the response of yttrium dihydride (\ce{YH2}) - the most suitable moderator candidate with respect to its high operational temperature - to heavy ion irradiation. A combination of multiple experimental techniques indicate that \ce{YH2} is stable up to an irradiation dose of 2 dpa and below 800$^{\circ}$C, identified as a critical temperature for \ce{YH2}. Our study unravels that voids emerge as the major form of radiation damage. Below the critical temperature no phase change, precipitation or amorphization was observed to occur. Experimental results from ion beam and neutron scattering techniques with concomitant density functional theory calculations have allowed us to elaborate and propose new strategies to enhance the metal hydride performance in extreme environments. © 2023, The Authors. All rights reserved.

关键词： Hydrides

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