ITER to adopt Ratio toolset

ITER is driven to prove the world how fusion, the nuclear reaction that powers the Sun and the stars, is a potential source of safe, non-carbon emitting, and virtually limitless energy. The Ratio team is delighted to announce that Torben Beernaert, a dedicated TU/e Ph.D. candidate is using the Ratio toolset to analyze parts of the fusion reactor.

Tomorrow’s fusion power plants

ITER is an international collaboration project that started in 2007. Current partners in the ITER project are the European Union, Japan, South Korea, China, India, the United States, and the Russian Federation. Harnessing fusion’s power is the goal of ITER, which has been designed as the key experimental step between today’s fusion research machines and tomorrow’s fusion power plants. ITER is facing many challenges in realizing its ambition. However, as can be read on their website, many breakthroughs are already listed. For example, the company recently started assembling the 1,250-tonne‘ cryostat base’, by an overhead crane. This is going to be the heaviest of all planned crane lifts. The cryostat is the vacuum-tight container that will surround the ITER vacuum vessel and superconducting magnets.

Torben’s Ph.D. project

In January Torben moved to France and has been using the Ratio toolset for a while now. In this article, we reflect on how the Ratio ESL Toolbox is supporting system development in his project from a systems engineering perspective. His Ph.D. project is mostly focused on the Visual Spectroscopy Reference System. This reference system measures the characteristics of the plasma used in the fusion process.

In our conversation Torben has nicely outlined the fundamentals of Ratio tools and methods: “The Ratio software package is founded on a strong academic basis, combining elements from functional modeling, requirements engineering, and system architecture. In the context of Model-Based Systems Engineering (MBSE), it aims to model the specification of a system’s structure, functionality, and requirements, rather than writing this down. Creating a system model 1) allows the direct identification of dependencies between components, functions, and requirements, 2) improves traceability and prevents human mistakes (e.g. misinterpretation and conflicting statements) and 3) enables the automatic visualization of different views of the system (e.g. to identify functional chains/blocks and change propagation). Generally, the Ratio toolbox provides two services: 1) The analysis of graphs (networks) of systems engineering elements, such as components, functions, variables, requirements, etc., and 2) the automatic generation of such graphs based on user-specified statements in the ESL-format (Elephant Specification Language).”

Visualizations and system specification elements

Now, exactly how does Ratio fit in the bigger ‘ITER’ picture? Torben summarizes; “In its simplest form, we can use the software as syntax and database for system specification elements. If everyone understands and uses the ESL format, communication about functions, requirements, and dependencies will become unambiguous. Furthermore, the software provides an integrated environment that can automatically validate these statements and ensure consistency throughout multiple aspects of the system. For example, the optomechanical designers working on mirrors will be able to use the same language as the control engineers working on instrumentation and control. Furthermore, this enables us to fully trace and visualize the dependencies from front- to back-end.

Currently, we are gathering requirements for the instrumentation and control subsystem. This requires following the dataflow from optical instruments, and specifying the transformations and validations it is subjected to. The Ratio toolbox can help us to automatically visualize the relevant parts of the specification, displaying, for example, the dependencies between components and functions. These visualizations make it easy to assess the impact of potential changes to components or functions.”

The ITER journey towards a cleaner future

Did you know Iter is Latin for ‘journey’? How is this journey going to continue and what will the future bring? Torben: “I did not know that, how interesting! In my opinion, comparing the design and construction of ITER to a journey is very applicable. ITER will travel for a long time and will follow paths that no one has ever taken. From a systems engineering perspective, this poses unique challenges. Because the lifetime of ITER will stretch over multiple decades, today we have to think about how its subsystems will be used in 2030 or 2035. For example, we plan to conduct some upgrades in the future, but of course, we don’t know the possibilities of state-of-the-art imaging systems 15 years from now. Another challenge in ITER’s journey is that we are moving into unknown territories. Due to the conditions within the tokamak, ITER incurs extreme requirements and design questions that have never been asked before. So in parallel to the design of ITER, there is actually a lot of R&D going on that aims to bring together physics, engineering, and material science in unique ways, to provide new techniques that deal with these specific requirements. For these reasons, it is key to design our system in such a way that it can perform properly under extreme and uncertain circumstances, and that new technologies can still be incorporated flexibly in the future. Needless to say, using state-of-the-art system architecture techniques is vital if we want to push the boundaries of the current status quo and develop towards a cleaner future.”