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Nuclear Fusion 179 - Japanese Team Discovers That Turbulence Moves Much Faster Than Heat In A Fusion Reactor

     In order to construct a fusion power plant, it is necessary to generate a stable plasma at a temperature of more than two hundred million degrees Fahrenheit in a magnetic field and maintain it as long as necessary to generate excess energy. A research group led by Assistant Professor Naoki Kenmochi, Professor Katsumi Ida, and Associate Professor Tokihiko Tokuzawa of the National Institute for Fusion Science (NIFS), National Institutes of Natural Sciences (NINS), Japan, used measuring instruments developed independently and with the cooperation of Professor Daniel J. den Hartog of the University of Wisconsin, USA, in plasma experiments. They discovered for the first time that turbulence moves faster than heat when heat escapes in plasmas in the Large Helical Device (LHD). One characteristic of this plasma turbulence makes it possible to predict changes in plasma temperature. It is expected that observation of turbulence will lead to the development of a method for real-time control of plasma temperatures in the future.
     When high-temperature plasma is confined by a magnetic field, “turbulence” is generated. This means that there is a flow with vortexes of various sizes. This turbulence causes the plasma to be disturbed. The heat from the confined plasma flows outward which results in a drop in plasma temperature. In order to solve this problem, it is necessary to understand the characteristics of heat and turbulence in plasma. However, the turbulence in plasmas is so complex that scientists have not yet achieved a full understanding of it. One important question is how the generated turbulence moves in the plasma. This is not well understood. It requires instruments that can measure the time evolution of minute turbulence with extremely high sensitivity and extremely high spaciotemporal resolution.
     A “barrier” can form in the plasma. This acts to block the transport of heat from the center outward. The barrier causes a strong pressure gradient in the plasma and that generates turbulence. Assistant Professor Kenmochi and his research group have developed a method to break down this barrier by devising a magnetic field structure. It allows researchers to focus on the heat and turbulence that flows vigorously as the barrier breaks to study their relationship in detail. Using electromagnetic waves of various wavelengths, the researchers measured the changing temperature and heat flow of electrons and millimeter-sized fine turbulence with the highest levels of accuracy in the world. Previously, heat and turbulence had been known to both move at a speed of about three thousand miles per hour which is about the speed of a passenger aircraft. The new research led to the world’s first discovery of turbulence moving at speeds of twenty-five thousand miles per hour.
     Assistant Professor Naoki Kenmochi said that “this research has dramatically advanced our understanding of turbulence in fusion plasmas. The new characteristic of turbulence, that it moves much faster than heat in a plasma, indicates that we may be able to predict plasma temperature changes by observing predictive turbulence. In the future, based on this, we expect to develop methods to control plasma temperatures in real-time.”

Geiger Readings for May 24, 2022

Latitude 47.704656 Longitude -122.318745

Ambient office = 91 nanosieverts per hour

Ambient outside = 107 nanosieverts per hour

Soil exposed to rain water = 108 nanosieverts per hour

Ginger root from Central Market = 97 nanosieverts per hour

Tap water = 90 nanosieverts per hour

Filter water = 72 nanosieverts per hour

Radioactive Waste 857 - Lawrence Livermore National Laboratory and Penn State University Are Collaborating On The Development Of Synthetic Versions Of Lanmodulin

     Scientists at Lawrence Livermore National Laboratory (LLNL) and Penn State University are modifying and improving natural molecules that would help target specific radioactive elements that are found in nuclear waste or used in nuclear medicine.
     Even the most effective molecules for such tasks which evolved over billions of years can still be improved for non-natural applications. Lanthanides are natural elements used in numerous items like computer hard drives and magnets. The team bioengineered nature’s most potent protein for attaching to lanthanides which is called lanmodulin in order to make it even more selective for actinide elements. Actinides are radioactive metals that a present in nuclear waste such as uranium, plutonium and americium.
     The research by the team of scientists was published in the journal Chemical Science. Their results improve our understanding of how natural compounds can interact with nuclear waste in the environment. They could lead to new molecules for scavenging and detection of specific radioactive metals.
     The team designed, synthesized and characterized five variants of lanmodulin (LanM) to decipher and eventually improve its actinide-binding properties. They found that the presence of water molecules that bridge the metal and protein molecule is particularly important for controlling the stability and metal preferences of the metal-protein complexes. This design principle permitted the scientists to improve the protein’s ability to discriminate between actinide and lanthanide elements.
     Molecules that are selective for actinides over lanthanides are among the most preferred. This is because these two families of elements are found in nuclear waste. Separating them would allow for a more efficient management of radioactive materials. The team’s discovery could lead to new separation systems for applications in nuclear waste disposal and radiochemistry fields. LanM was discovered by the Penn State University members of the team in 2018. The LLNL-Penn State collaboration has been exploring applications of this important molecule in the field of nuclear sciences.
     LLNL scientist Gauthier Deblonde is co-lead author of the study. He said, “This is the first study where someone made changes to lanmodulin to dissect and improve its metal binding properties. As we were tuning the protein’s properties to target radioactive elements, we also learned a lot about the mechanisms by which it binds the metals.”
     Classic molecules have a limited set of chemical interactions. The new research showed that macromolecules, such as proteins, have an extended repertoire of chemical interactions that scientists can fine-tune to target specific metals.
     Joseph Cotruvo, Jr. is a Penn State assistant professor of chemistry and a co-lead author of the study. He said, “This study uncovers yet another tool that this remarkable protein has at its disposal to discriminate between metals that differ from one another in only very subtle ways. This realization is an important step toward high-performance LanM-based separation methods and molecules custom-designed to bind specific medical isotopes.”
     Joseph Mattocks of Penn State also contributed to this work. The work is being funded by the National Nuclear Security Administration’s Office of Defense Nuclear Nonproliferation Research and Development and the U.S. Department of Energy’s Basic Energy Sciences program.