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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Fusion Science and Technology
October 2025
Latest News
DOE awards $134M for fusion research and development
The Department of Energy announced on Wednesday that it has awarded $134 million in funding for two programs designed to secure U.S. leadership in emerging fusion technologies and innovation. The funding was awarded through the DOE’s Fusion Energy Sciences (FES) program in the Office of Science and will support the next round of Fusion Innovation Research Engine (FIRE) collaboratives and the Innovation Network for Fusion Energy (INFUSE) awards.
S. K. Combs, J. R. Reed, M. S. Lyttle, L. R. Baylor, J. R. Carmichael, T. E. Gebhart, S. J. Meitner, D. A. Rasmussen
Fusion Science and Technology | Volume 72 | Number 3 | October 2017 | Pages 404-415
Technical Paper | doi.org/10.1080/15361055.2017.1333824
Articles are hosted by Taylor and Francis Online.
Injection of multiple large (~10 to 30 mm diameter) shattered pellets into ITER plasmas is presently part of the scheme planned to mitigate the deleterious effects of disruptions on the vessel components. To help in the design and optimize performance of the pellet injectors for this application, a model referred to as “the gas gun simulator” has been developed and benchmarked against experimental data. The computer code simulator is a Java program that models the gas-dynamics characteristics of a single-stage gas gun. Following a stepwise approach, the code utilizes a variety of input parameters to incrementally simulate and analyze the dynamics of the gun as the projectile is launched down the barrel. Using input data, the model can calculate gun performance based on physical characteristics, such as propellant-gas and fast-valve properties, barrel geometry, and pellet mass. Although the model is fundamentally generic, the present version is configured to accommodate cryogenic pellets composed of H2, D2, Ne, Ar, and mixtures of them and light propellant gases (H2, D2, and He). The pellets are solidified in situ in pipe guns that consist of stainless steel tubes and fast-acting valves that provide the propellant gas for pellet acceleration (to speeds ~200 to 700 m/s). The pellet speed is the key parameter in determining the response time of a shattered pellet system to a plasma disruption event. The calculated speeds from the code simulations of experiments were typically in excellent agreement with the measured values. With the gas gun simulator validated for many test shots and over a wide range of physical and operating parameters, it is a valuable tool for optimization of the injector design, including the fast valve design (orifice size and volume) for any operating pressure (~40 bar expected for the ITER application) and barrel length for any pellet size (mass, diameter, and length). Key design parameters and proposed values for the pellet injectors for the ITER disruption mitigation systems are discussed.