“Star in a jar” project will create the largest fusion reactor in history.
The International Thermonuclear Experimental Reactor (ITER) project, one of the most ambitious energy projects in the world, boasting 35 participating nations, is teaming up with Ansys to deliver cutting-edge simulation technologies in the pursuit of fusion energy.
ITER is in the process of constructing the world’s largest tokamak: a magnetic fusion device that could, in theory, prove fusion energy to be not only feasible but also commercially viable as a carbon-free way of keeping the lights on around the world. The organization will work with Ansys to create simulations that help optimize the design of the electromagnetic (EM) structures used to generate power. Ansys simulations will also be used to improve project risk management, make system development more efficient, and ensure that critical safety requirements are met.
A tokamak produces fusion energy by replicating—on a much smaller scale—the way stars make energy. In the massive heat and gravity of a star’s core, hydrogen nuclei smash into each other and fuse into heavier helium atoms, releasing an astonishing amount of energy as they do so.
The ITER tokamak uses two hydrogen isotopes in particular: deuterium and tritium, which produce the highest energy gain at relatively low temperatures—though in this case, “low” is still millions of degrees Celsius!
In fact, the tokamak will generate this fusion at 150 million degrees Celsius: at this level of heat, electrons become separated from nuclei, converting gas into plasma. The tokamak also requires that the mass of plasma particles be dense enough to ensure that subatomic collisions take place—and the tokamak also needs to be strong enough to contain the plasma as it expands.
The plasma is contained inside the tokamak’s donut-shaped vacuum chamber, where the heat and pressure are applied to create fusion energy. The energy produced is absorbed as heat by the plasma containment vessel walls. And just like in conventional power plants, that heat is used to produce steam, which is channeled through turbines and generators to create electricity.
The vacuum chamber is surrounded by massive magnetic coils, which scientists use to shape and control the charged particles of the plasma and confine it away from the chamber walls.
This process requires that the tokamak’s EM structure be incredibly sophisticated, precise and error-free—and simulation and prototyping tools such as those provided by Ansys can prove to be invaluable in making the record-breaking tokamak a reality.
Simulation gives ITER’s engineers insight into how their designs will work in millions of real-world scenarios, allowing them to adjust and validate their design before it is even given physical form.
Fly-through of the ITER tokamak.
“Ansys simulation solutions will continue to help our team to satisfy the required safety and accuracy levels for this first-of-a-kind initiative,” said Bernard Bigot, ITER’s director general. “For ITER to achieve hydrogen fusion at industrial scale requires unprecedented levels of engineering precision, so it is incredibly important that our simulation software is highly reliable and efficient. Ansys has consistently delivered that capability to us for many years, enabling our team to safely push boundaries, dream bigger and deliver Earth’s biggest fusion reactor.”
ITER is using Ansys Fluent fluid simulation software to test and validate the cooling water system used to manage heat during the tokamak’s operation. The system is tasked with bringing the internal surfaces of the vacuum chamber down to 240 degrees Celsius, mere meters away from the 150-million-degree plasma. Ansys Fluent can create advanced physics models and accurately solve large complex models—including models that incorporate hydrogen plasma. ITER engineers used Fluent to create simulations of EM current flows and the forces they generate, as well as to create the structural models of the cooling water system and other components that need to handle the immense EM currents the tokamak will produce. And as an additional challenge, plasma EM currents can fluctuate over time—and ITER’s systems will need to cope with that.
Fluent is also being used to develop a set of key touchstone documents that engineers will consult to make sure the system design is robust and that the system meets rigorous project and industry safety requirements.
ITER is also turning to Ansys Mechanical to design vital structural supports called outer intercoil structures (OISs), which are positioned around the tokamak’s fusion chamber to help it withstand the immense force it generates—which can reach 77,000 tons of electromagnetic stress.
The design of the OISs were optimized to make best use of construction materials—and save weight and costs. The original OIS design was uniform in shape and the component could weigh 367 tons. Engineers used Ansys Mechanical to define the mechanical loads the OISs would need to deal with, and in conjunction with other Ansys platforms, designers were able to reduce the original design’s weight by 38 percent.
“To power the sun and the stars, light atoms fuse at very high pressures and temperatures. Replicating this process on Earth with ITER will help solve the world’s energy demands; however, engineers must overcome extremely difficult design challenges,” said Prith Banerjee, chief technology officer at Ansys. “Using Ansys simulations, ITER engineers are rapidly building a structurally sound fusion power reactor, drastically reducing the EM structures’ material content and substantially decreasing the plant’s development cost—driving the delivery of clean, sustainable energy for our planet.”
The ITER tokamak is set to go online in 2025—after decades of research and design work. It will conduct experiments for a 15-year period to test the viability of fusion power. There is high confidence that the facility will perform at its optimized best—thanks in part to the simulation work done with Ansys.
For more on the quest for fusion power, read Chinese “Artificial Sun” Reactor Could Unlock Limitless Clean Energy.
