| 3D printing Increasingly, it is used to make a variety of end-use products, but it can also help researchers achieve their ultimate goals. A good example is a recent project, ORNL, of Tennessee powered by American Energy. The Department (DOE) operates and has been responsible for many 3D printing innovations, assisting them by providing research and development work.  The parent radioactive isotope molybdenum-99 (Mo-99), a short-lived decay product made in the United States last time, was in the late 1980s... until now. The Tc-99m was tested for heart nuclear stress. Known for blood flow imaging, it is the most commonly used radioactive isotope in medical diagnostic imaging.  This winter, the FDA approved the first batch of domestic production of Mo-99 without using HEU. In the past decade, the US Department of Energy’s National Nuclear Safety Administration (NNSA) has been working hard to prevent Mo-99 from using high concentrations of uranium (HEU). uranium. 'We want to prepare for the commercial production of molybdenum-99 here in the US at full cost recovery. We are very pleased to be able to assist in the work without using highly enriched uranium.' said Chris Bryan, who is responsible for ORNL Mo-99 research. According to the National Nuclear Safety Administration, Mo-99 uses more than 40,000 medical procedures per day in the United States, but 100% is provided by foreign suppliers, most of which use HEU. To reduce the United States' dependence on other countries, it is Several US Department of Energy laboratories, including Argonne National Laboratory, ORNL, Los Alamos National Laboratory and Savannah River National Laboratory, provide non-proprietary national technical support funding.  Tc-99m failed within 6 hours, while Mo-99 remained slightly longer after 66 hours. For those who do not want to be exposed to radiation for a long time, this rapid decay is good, but Tc- cannot be stored. The 99m manufacturer was forced to provide it before it became too weak to produce high-contrast images. In this case, the radiopharmacist used a device that runs the solution through a resin loaded with Mo-99, and then Release Tc-99m, provided directly at clinics and hospitals. Both NorthStar Medical and SHINE Medical Technologies in Wisconsin have signed a cooperation agreement with the National Nuclear Safety Administration to increase domestic isotope yields. Researchers at ORNL have also participated in a number of programs designed to keep Mo-99 free of HEUs. research project.  'NorthStar and other cooperation agreement holders benefited from the technical development supported by the National Nuclear Safety Agency of the National Laboratory. ORNL's work reflects the value of cooperation and will enable our process to use molybdenum-rich targets. Material is more efficient. 'NorthStar senior vice president and chief science officer James T. Harvey said. NorthStar produces Mo-99 through a neutron capture process using a stable molybdenum target material. This is similar to the SHINE project because it uses an accelerator, but it is different because it does not involve uranium. On the contrary, an electron accelerator bombards a rich Mo. -100 targets six days, this will produce strong gamma rays, hit a neutron from the mixture, produce Mo-99. Helium flows in the system to remove heat, so the material used to make the target needs to be tough enough To withstand the stress, but still very light, so it can quickly dissolve to recover the isotopes. The only problem is that the concentrated Mo-100 is not cheap. ORNL set the initial goal, a raw material that is only half a dollar size still needs to spend thousands of dollars. In addition, the electron conversion rate in the crash accelerator is less than that of the Mo-100. 10%, which means NorthStar must recover and recycle the remaining electronics. ORNL's Rick Lowden, a metallurgist in charge of developing target materials and manufacturing techniques, explains: 'Every time the powder is processed, it is ground, screened, sprayed, etc. The goal is zero waste.'  First, ORNL researchers mixed molybdenum powder with a water-soluble polymer and used spray drying to combine small particles into larger spherical agglomerates. After pressing and heating the spray-dried powder, it produced a strong, fast-dissolving solution. Discs with tight dimensional tolerances. Unfortunately, when they heat the discs with lasers to simulate the conditions inside the NorthStar Accelerator, they are distorted due to uneven heating on the material. Working with ORNL materials scientists Jim Kiggans, Bryan, and Lowden, they decided to solve many problems with target assemblies on 3D printing discs, including the need to change the diameter and thickness of the disc due to the design of accelerator components. Bryan explained, 'This is an exciting goal.' ORNL teamed up with Los Alamos designers to run the accelerator system and use stainless steel 3D to print representative shapes and components. The materials were sent to chemists in Agung so that they could be dissolved in the process currently being developed. To recover unconverted Mo-100. This process is sustainable because the recycled precipitate is returned to the ORNL so it can be processed into a 3D print stock for the next assembly. Lowden said: 'The whole process is now only four steps, not dozens.' Since molybdenum has a high melting point of 2600°C, ORNL has installed a special 400 watt laser in the Renishaw laser melting system. Renishaw has also built a reduced-size disc that can accommodate a smaller amount of Mo-100 to save Cost. ORNL also installed a 15,000-watt plasma system that can recover materials that are laser melted by spray-drying molybdenum agglomerates to make dense, spherical particles into 3D printing materials. ORNL researchers will now focus on describing the material properties of the target component. '90% of 3D printing molybdenum does not have much data. We are basically opening up new roads, especially for such a unique application.' Lowden said. |
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