Dec 5 2018
With scientists demonstrating that the reliability and safety of parts utilized in a fusion energy device can be evaluated through two types of imaging, harnessing nuclear fusion to meet the earth’s energy requirements could soon become a reality. Nuclear fusion is known to power the stars and the sun.
Researchers have moved a step closer to harnessing fusion energy by showing how imaging enables better testing of components for devices. (Image credit: Swansea University)
Researchers from Swansea University, the Max-Planck Institute of Plasma Physics in Germany, Culham Centre for Fusion Energy, and ITER in France tested the sturdiness of parts by combining neutron imaging and X-ray. They discovered that valuable data, which can be used for designing components, was produced by both techniques.
One excellent example of fusion in action is the sun. During extreme temperature and pressure at the core of the sun, atoms move sufficiently fast to combine together, and as they do so, they discharge huge amounts of energy. For years, researchers have been exploring ways on how to harness this carbon-free, safe, and almost limitless source of energy.
However, one significant barrier is the extreme temperatures that have to be tolerated by components in fusion devices: around 10 times the heat of the sun’s core.
One of the key methods to fusion, magnetic confinement, needs reactors that contain some of the highest temperature gradients on the planet, and possibly in the universe: the cryopump, which is just meters away, as low as –269 °C, and plasmas that reach as high as 150 million degrees Celsius.
Scientists should be able to non-destructively test the sturdiness of engineering components that must work in such extreme conditions. In this regard, the researchers concentrated on one major component, known as a monoblock, which is actually a pipe carrying coolant. For the first time, the novel tungsten monoblock design was imaged by computerized tomography. The researchers utilized ISIS Neutron and Muon Source’s neutron imaging instrument called IMAT.
Each technique had its own benefits and drawbacks. The advantage of neutron imaging over x-ray imaging is that neutrons are significantly more penetrating through tungsten. Thus, it is feasible to image samples containing larger volumes of tungsten. Neutron tomography also allows us to investigate the full monoblock non-destructively, removing the need to produce ‘region of interest’ samples.
Dr Triestino Minniti, Science and Technology Facilities Council
This work is a proof of concept that both these tomography methods can produce valuable data. In future these complementary techniques can be used either for the research and development cycle of fusion component design or in quality assurance of manufacturing.
Dr Llion Evans, College of Engineering, Swansea University.
The next step for the researchers is to change the 3D images created by this robust method into engineering simulations with micro-scale resolution. Termed image-based finite element method (IBFEM), this technique makes it possible to assess the performance of each component separately and account for any slight deviations from design induced by production processes.
The study has been published in Fusion Engineering and Design.