Future fusion reactors will require fuelling by cryogenic pellets made from a mixture of deuterium and tritium. Nowadays fusion experiments are running with protium or deuterium plasmas in order to reduce radiological licensing issues but the hydrogen safety has to be addressed as well.

The ASDEX Upgrade pellet centrifuge is serving for experiments to fuel the plasma or to pace Edge Localized Modes (ELMs) since 1991 and was continuously adapted to new tasks. The hydrogen safety was based on a limited hydrogen inventory, preventing the system from explosive atmosphere in case of incidents: loss of vacuum or loss of power.

In order to get the system licensed, both failure scenarios must be considered at once. The actual system did not meet these requirements. Furthermore, part of the present equipment was not licensed to be operated in hazardous zones according to explosion protection regulations. Many of these components could not be replaced by classified ones, in particular components of the cryostat and the centrifuge itself.

The goal of the new concept is to minimize the part of the system classified as hazardous zones. Such classification can be avoided in case the following two conditions apply at the same time: a pressure level below 50 mbar under normal operating conditions and a hydrogen concentration below 1 % (25 % of the lower explosion limit) under disturbed conditions. A new setup was developed in order to reduce the complexity of the existing vacuum system, introducing buffer volumes and implementing proper safety routines to withstand the presence of two incidents at once. Doing so, the classifications of hazardous zones could be reduced to areas, where appropriate licenced components were available (e.g. rough vacuum gauges and dry pumps). The system was successfully licensed and commissioned, first experimental results show enhanced system performance.

未来的聚变反应堆将需要使用由氘和tri的混合物制成的低温粒料作为燃料。如今，为了减少放射许可问题，正在使用pro或氘等离子体进行聚变实验，但是氢安全性也必须得到解决。

自1991年以来，ASDEX升级颗粒离心机一直用于为血浆提供燃料或加速Edge Localized Modes（ELM）的实验，并不断适应新任务。氢气安全性基于有限的氢气存量，可防止发生真空或动力中断等事故时使系统免受爆炸性气体的影响。

为了获得系统许可，必须同时考虑两种故障情况。实际系统不满足这些要求。此外，根据防爆规定，本设备的一部分未经许可可在危险区域中使用。这些组件中的许多组件无法用分类组件代替，尤其是低温恒温器和离心机本身的组件。

新概念的目标是最大程度地减少分类为危险区域的系统部分。如果同时满足以下两个条件，则可以避免这种分类：在正常操作条件下压力水平低于50 mbar，在受干扰条件下氢浓度低于1％（爆炸下限的25％）。为了降低现有真空系统的复杂性，引入缓冲液量并实施适当的安全程序以一次承受两次事故的存在，开发了一种新的装置。这样做可以将危险区域的分类减少到可以使用适当许可组件的区域（例如，粗真空计和干式泵）。该系统已成功获得许可和调试，第一个实验结果表明该系统具有增强的性能。