Abstract For the last 15 to 20 years, substantial advancement has been achieved globally in the field of pellet injector technology (PIT). Nuclear fusion is a method for producing high-energy neutrons, alpha particles, and an enormous amount of energy with the help of thermonuclear reaction of hydrogen isotopes. The way of producing this huge energy source is similar to that of the sun’s generated energy. This type of energy does not produce greenhouse gases or a high-level radioactive surplus. Solid hydrogen is used as a fuel in a fusion reactor in the form of pellets of different diameters and lengths. These pellets are produced by a pellet injector. In the sophisticated fueling system, these pellets are continuously produced with the help of a twin-screw extruder (TSE) and cooled by more than one cryocooler or liquid helium. Each pellet injection system has its pros and cons. We have identified different injection criteria for different types of injectors. Higher-density, continuous injection with high reliability is the major constraint of a future pellet injection system such as the Gifford-McMahon cryocooler-based TSE. In the past, limited innovative applications for PIT were established and used effectively in fusion experiments. At the present time, an innovative cryogenic-based extrusion system is being designed to meet the different injection criteria. This technical note presents the progress of eminent activities, discusses some of the best models as developed by Fisher and Arumugam et al., and highlights recent progress. Gray areas such as non-Newtonian behavior of solid H2 with thermodynamics analysis are also discussed as well as associated challenges with recent key developments in the field of PIT.

中文翻译：

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颗粒注射器技术回顾：简史和近期主要发展

摘要 在过去的 15 到 20 年中，全球在颗粒喷射器技术（PIT）领域取得了长足的进步。核聚变是一种借助氢同位素的热核反应产生高能中子、α粒子和大量能量的方法。产生这种巨大能源的方式类似于太阳产生的能量。这种类型的能源不会产生温室气体或高水平的放射性过剩。固体氢以不同直径和长度的颗粒形式用作聚变反应堆中的燃料。这些颗粒由颗粒注射器生产。在复杂的燃料系统中，这些颗粒在双螺杆挤出机 (TSE) 的帮助下连续生产，并由一个以上的低温冷却器或液氦冷却。每个颗粒注射系统都有其优点和缺点。我们为不同类型的喷油器确定了不同的喷油标准。更高密度、高可靠性的连续注射是未来颗粒注射系统的主要限制因素，例如基于 Gifford-McMahon 低温冷却器的 TSE。过去，在聚变实验中建立并有效地使用了 PIT 的有限创新应用。目前，正在设计一种创新的基于低温的挤出系统，以满足不同的注射标准。本技术说明介绍了著名活动的进展，讨论了 Fisher 和 Arumugam 等人开发的一些最佳模型，并重点介绍了最近的进展。