Nuclear Fusion Doesn’t End with the Plasma

The day began with a warm welcome at the historic waterworks building of Stadtwerke Zittau. HSZG then presented its portfolio and its research and development activities. The presentation also highlighted the university's four research institutes, including the Institute of Process Engineering, Process Automation and Measurement Technology (IPM), which had taken the lead in organising and shaping the day's programme.

The day's programme then took participants through the seven stops described below, each contributing to the goal of making fusion energy available.

The Zittauer Kraftwerkslabor (ZKWL) was established under IPM's leadership between 2011 and 2015. It supports experimentally based development in three areas: measures to improve the energy efficiency of energy systems, the development of energy storage systems, and solutions for making better use of renewable energy sources. At the heart of the laboratory are large-scale experimental facilities designed and built as part of several research projects. This approach illustrates its relevance to fusion: expertise in experimentally investigating large-scale steam cycles provides precisely the knowledge needed to extract heat from a future fusion power plant.

The experimental facility of the AQVA HEAT III project implements and seasonally tests an innovative integrated concept for supplying heat from surface waters throughout the year, accompanied by ecological monitoring of the water body. This concept could become a building block for a future heat supply based on renewable energy. Particularly noteworthy is the ambition to bring innovative heat generation systems out of research and into practical use - at regional heat suppliers and beyond. The project receives funding under the Free State of Saxony's Energy and Climate Funding Guideline (FRL EuK 2023, SAB).

The next stop was the High-Voltage Hall in Building ZV, which is used for research, teaching and demonstrations. Its equipment generates and measures high voltages of up to 700 kV AC, 800 kV DC and 1.2 MV impulse voltage. It is used to test high-voltage materials and components, such as insulators, cables and cable joints, under various stresses. These tests are conducted in accordance with applicable standards for industrial services, as well as beyond those standards for fundamental research into polymeric insulating materials.

Staff introduced the “DC LabSaxony” project and the Saxon DC Campus as an innovation hub for direct-current technology in the tri-border region. Direct-current grids are regarded as a forward-looking solution for the energy transition, particularly for integrating storage systems, supporting electric mobility and supplying industrial facilities. Benefits include two to three times greater transmission capacity, 20 per cent lower losses, reduced material requirements, greater resilience through decentralised island grids, and improved scalability when integrating renewable energy.

The group then visited the Radiation Technology Laboratory of the Faculty of Mechanical Engineering. The laboratory is equipped for handling sealed radioactive sources and operating a neutron generator – a facility that produces ionising radiation – in accordance with radiation protection legislation.

The Lubricant-free Steam Turbine developed by IPM's Mechatronic Systems Department was also part of the programme. It clearly demonstrates how heavy rotors can be supported by magnetic bearings without lubricants, while withstanding high thermal and mechanical loads. This approach could be applied to the heat conversion chain of a fusion power plant and to operation involving substantial load changes.

The Thermal-Hydraulics Laboratory of IPM's Nuclear Engineering/Soft Computing Department houses experimental facilities such as the Zittau Flow Tank, which have been developed and used in numerous nuclear safety research projects. Modular components enable a wide range of flow circuits to be assembled for liquids or multiphase systems. These can incorporate heating and cooling components, complex sections of plant geometry, sedimentation sections, free jets, screens and filters. The laboratory also provides adaptive image-based measurement devices and flow measurement equipment.

A special interactive exhibit then generated considerable enthusiasm: the H²-Scooter. Designed and built in close collaboration with Fraunhofer IWU it brings together the traditional engineering disciplines of electrical engineering, mechanical engineering and computer science, alongside contemporary topics such as hydrogen technology, lightweight construction, additive manufacturing and autonomous driving. This is also where the fusion industry comes in: for many companies, engagement with fusion begins not with the reactor itself, but with materials, manufacturing processes, sensor technology and plant engineering – in other words, with expertise already available at HSZG.

Participants' feedback on the day was consistently positive, with some highlighting the HSZG laboratory tour as a particular highlight of the Summer School. Three comments illustrate this response:

> „High voltage show was really nice!! - also the Kraftwerkslabor :)"

> „Thermal pump, thermal energy, accumulation of thermal energy, hydrogen-fuel car, high voltage, nuclear reactors (challenges). I liked everything from this trip. The program was very informative and interesting. People were very nice and answered all questions. I could see that they like what they do."

> „I did enjoy the practical and labs tour part."

What stands out is how precisely participants describe what they learned. The Summer School programme works because, rather than teaching fusion physics itself, it demonstrates the full range of tools used to build fusion facilities.