The use of ionising radiation to image nuclear fuel:a review

Imaging of nuclear fuel using radiation has been carried out for decades for a variety of reasons. Two important reasons are Physical Inventory Verification (PIV) and Quality Assurance (QA). The work covered in this review focuses on the imaging of nuclear fuel using ionising radiation. The fuels investigated are both fresh and spent, composed of assorted materials, and in various physical forms. The radiations used to characterise the nuclear fuel include γ, α, β, muons, neutrons and X-rays. The research covered in this review, spans the past four decades and show how the technology has developed over that time. The advancement of computing technology has greatly helped with the progression of the images that are produced. The field began with 2D images in black and white showing the density profiles of rays from within an object, culminating in 2013 when a pebble bed fuel element was reproduced in 3D showing each 0.5 mm UO2 globule within it. With the ever increasing computing technology available to the industry, this can only mean an increase in the rate of development of imaging technologies like those covered in this review

Investigation of the hydrodynamics and scale-up of advanced TRISO nuclear fuel manufacturing using sophisticated measurement techniques

The successful performance and safety of the Very-High-Temperature Nuclear Reactors (VHTR) extremely depend on the quality of the TRISO nuclear fuel coated particles. However, the coating of the TRISO particles is delicate process and impacted by the hydrodynamics of spouted beds. Therefore, in this work, we applied advanced non-invasive measurement techniques which are gamma-ray computed tomography (CT) and radioactive particle tracking (RPT), to investigate foremost the local parameters to advance the fundamental understanding of the hydrodynamics and scale-up of gas-solid spouted beds. The CT technique has been applied to study the effects of particle density, particle size, bed size, and superficial gas velocity on the gas-solid cross-sectional distributions of spouted beds. The CT results demonstrated that the summation that operating spouted beds at stable spouting state would lead to achieving proper coating layers of the particles in the TRISO fuel coating process is not adequate. On the other hand, the RPT technique has been applied to evaluate the hydrodynamics, and mixing and segregation behavior of binary solids mixture spouted beds with particles of same size but different densities encountered in the TRISO nuclear fuel particles manufacturing process. The RPT results demonstrated that for the hydrodynamics of binary solids mixture spouted beds having particles of similar size but different densities, particle collisions by the particle-particle interaction plays an important role. At last, we evaluated the new mechanistic scale-up methodology that has been developed in our laboratory based on matching the radial profile of gas holdup at the region of the developed flow since the gas dynamics dictate the hydrodynamics of the gas-solid spouted beds. The measured local parameters obtained in this part confirm the validation of our new methodology of scale-up of gas-solid spouted beds --Abstract, page iii

University of Nevada, Las Vegas Transmutation Research Program Annual Report Academic Year 2006-2007

It is my pleasure to present the UNLV Transmutation Research Program’s sixth annual report that highlights the academic year 2006-2007. Supporting this document are the many technical reports and theses that have been generated over the past five years. In the sixth year of our program, we continued to see growth in the Radiochemistry Ph.D. program with a total of 13 students in the third year of the program (we anticipated eight in the program proposal). Since our inception, the program has sponsored to their conclusion 42 M.S. and 4 Ph.D. degrees. The program supported 39 graduate students, 17 undergraduates, and seven post-doctoral scholars in six academic departments across the UNLV scientific and engineering communities in the academic year 2006-2007. Our research tasks span the range of technology areas for transmutation, including separation of actinides from spent nuclear fuel, methods of fuel fabrication, reactoraccelerator coupled experiments, corrosion of materials exposed to lead-bismuth eutectic, and special nuclear materials protection and accountability. We continued our emphasis on molten metal technology and actinide chemistry in our enhancements to UNLV this year to build a foundation in areas that are in line with UNLV’s strategic growth and our ability to address student-appropriate research in the transmutation program

Marshall Space Flight Center Research and Technology Report 2019

Today, our calling to explore is greater than ever before, and here at Marshall Space Flight Centerwe make human deep space exploration possible. A key goal for Artemis is demonstrating and perfecting capabilities on the Moon for technologies needed for humans to get to Mars. This years report features 10 of the Agencys 16 Technology Areas, and I am proud of Marshalls role in creating solutions for so many of these daunting technical challenges. Many of these projects will lead to sustainable in-space architecture for human space exploration that will allow us to travel to the Moon, on to Mars, and beyond. Others are developing new scientific instruments capable of providing an unprecedented glimpse into our universe. NASA has led the charge in space exploration for more than six decades, and through the Artemis program we will help build on our work in low Earth orbit and pave the way to the Moon and Mars. At Marshall, we leverage the skills and interest of the international community to conduct scientific research, develop and demonstrate technology, and train international crews to operate further from Earth for longer periods of time than ever before first at the lunar surface, then on to our next giant leap, human exploration of Mars. While each project in this report seeks to advance new technology and challenge conventions, it is important to recognize the diversity of activities and people supporting our mission. This report not only showcases the Centers capabilities and our partnerships, it also highlights the progress our people have achieved in the past year. These scientists, researchers and innovators are why Marshall and NASA will continue to be a leader in innovation, exploration, and discovery for years to come

CFD-DEM Modeling of Spouted Beds With Internal Devices Using PTV

195 p.Esta tesis se centra en la extracción de perfiles de velocidad de sólidos, tanto esféricos como irregulares, en un spouted bed y el análisis de estos valores bajo la influencia de diferentes dispositivos internos en el contactor y caudales. El análisis se ha centrado en un contactor cónico mientras que un contactor de perfil prismático también ha sido utilizado para analizar el efecto de esta geometría en la dinámica del sistema. Estos valores experimentales de sólidos regulares e irregulares han sido modelados y simulados a través de un modelo CFD-DEM en el que la fase continua y discreta se han acoplado, a fin de garantizar simulaciones realistas y capaces de predecir parámetros difíciles de obtener de manera experimental y cruciales para el diseño y escalado de estos tipos de lechos; como son los tiempos de ciclo de los sólidos y la distribución de tiempos de residencia del gas bajo diferentes condiciones. Estos parámetros determinan la capacidad de un sistema y la eficacia a la hora de utilizar el volumen del reactor