PDF Basket
Fusion power is seen as a clean and sustainable energy source of the future. Scientists around the world are currently tackling technical challenges holding it back and working on ways to ready it for widespread use.
The European Commission's SOFT Innovation Prize – which honours excellence in fusion research – was recently awarded to two such scientists, Jens Reiser of the Karlsruhe Institute of Technology and Simon Kirk of the United Kingdom Atomic Energy Authority.
Stress-resistant reactor material
Reiser, who heads a group focused on high-temperature materials, won first place for developing a high-performance metal as well as a novel technique to manufacture it.
The extremely crack-resistant tungsten can be used to build a crucial part of a nuclear fusion reactor known as the divertor which, among other things, has to withstand very high temperatures and removes heat and ash produced by a fusion reaction.
'The divertor is a key component of a nuclear reactor that causes a lot of trouble because currently it gets destroyed after being in operation a certain time,' Reiser says. 'To produce a more long-lasting version, the nuclear fusion community is looking for novel ideas for novel materials – and we presented them with such a novel material.'
The material is already on the market and being made using a rolling process Reiser and his team tailored and then tested together with an industry partner.
To start off, however, they began with fundamental science, developing multi-scale simulation models to understand the fracture behaviour – or resistance to temperature and pressure – of metals.
Their findings enabled them to harmonise previous contradictory research in this area that dates back to the 1930s.
'Fracture behaviour is very important because every machine made of metal will fail due to crack initiation, crack growth and crack propagation,' says Reiser.
'These findings will now help us to tailor a material's properties so it will not fail due to cracking.'
After an experimentation phase to verify their models, Reiser then joined forces with the Austria-based Plansee Group, a tungsten metals manufacturer which agreed to modify its production process.
'They produced a metal together with us with world record values,' Reiser says of the outcome, noting that a patent has been filed. 'The materials community is really astonished that we were able to produce a metal with such properties.'
Within nuclear fusion reactors, it could help avert calamity. 'The temperatures are very high and the loads are very high and so fracture would be a very bad situation,' Reiser says.
Robots to service reactors
Simon Kirk, an EU-funded EUROfusion engineering fellow at the UK Atomic Energy Authority, won second place for creating robots that could slash the time it takes to maintain future nuclear fusion reactors.
While one of Kirk's robots can slice steel pipes, the other can fuse them back together thanks to tiny, specially designed laser-cutting and laser-welding heads.
The idea is that the robots would be used to first cut through and then reconnect cooling pipes during the replacement of reactor components – a maintenance requirement that will have to be done every three to five years in extremely difficult conditions.
'Because there are hundreds of pipes, we want to be able to do this quickly and reliably,' says Kirk. 'By speeding up the maintenance, we can hopefully make fusion reactors more efficient and more economical.'
Trials Kirk carried out showed that his laser heads could cut a pipe in about 34 seconds, with the same for welding. That is significantly faster than the half an hour it would take with older techniques involving the mechanical cutting of pipes and torch welding to fuse them back together. 'We went from 30 minutes to 30 seconds,' Kirk says.
The laser heads on both robots ¬– one blue and one yellow – are small enough to fit inside a 90 mm-pipe. 'The real challenge with these was miniaturising them,' says Kirk, who is a laser specialist. 'We had to go back to basics and redesign everything ourselves to fit into these tight space constraints.'
The result: laser heads that are about 10 times smaller than standard ones.
Kirk says his technology could also be used for nuclear decommissioning and could come in handy in the oil and gas industry, as well as in chemical processing plants where pipes are difficult to reach or contain hazardous materials.
Rewarding pioneering research
The SOFT Innovation Prize has existed since 2014 and honours researchers who come up with groundbreaking solutions to the challenges of fusion. It is awarded at the biennial Symposium on Fusion Technology (SOFT), with the winners chosen by an independent jury from both industry and academia. This year's ceremony took place in Sicily in September.
Reiser plans to use his EUR 50 000 prize money to buy microscopy equipment, while Kirk says his EUR 25 000 award will go toward improving his robots to make them more ergonomic and easier to use.