A peep into the future

Last week, 16-20 September, the fusion community convened in Barcelona, Spain for the International Symposium on Fusion Nuclear Technology (ISFNT). More than 750 participants gathered at the Palau de Congressos to be brought up to date on developments in the field of fusion technology and materials and on the construction of ITER—the „symbol and example of global cooperation to tackle a global energy problem,” according to Pere Torres, Secretary of Enterprise and Competitiveness of the Generalitat de Catalunya, as he opened the symposium.

The ISFNT is recognized as one of the main international gatherings on fusion energy with a clear focus on reactor-relevant technology. In its 11th edition last week, the symposium took a close look not only on the current state-of-the-art technology related to ITER, but also dared to look forward to the possible design, requirements and safety aspects of future DEMO reactors and power plants.

The road forward, it seems, is not yet clearly delineated. Different concepts were presented; some countries, like China, seem to even have more than one iron in the fire. Complementing these discussions, a special fusion Roadmap Panel—moderated by prominent fusion representatives—tried to narrow down the key issues on the way to a fusion reactor.

Dedicated workshops addressed future reactor-relevant technologies such as ceramic breeder blankets or the treatment of beryllium; a half-day industrial workshop was set up to provide companies with updated information on the current procurement status of ITER and forthcoming opportunities; no less than 161 posters gave lots of opportunity to exchange and connect. And this is what the ISFNT is all about. In the words of Pere Torres, „This event contributes to the collaboration amongst researchers and allows for the sharing of knowledge.” 

The conference closed with a presentation by South Korea as host to the next ISFNT from 14-18 September 2015 on the island of Jeju.

Fusion draws on Japanese traditions

The Japanese people have a long history of creating ceramics of great beauty and elegance. Now they are putting their skills towards the search for materials for future fusion plants — in this case not crafting elegant forms, but elegant solutions: ceramics are nearly impervious to tritium.

In a colloquium delivered at JET last week, Assistant Professor Takumi Chikada from the University of Tokyo outlined promising progress in research into the ceramic coating, erbium oxide, which may prove to be a vital coating for use in tritium-carrying pipework. „Without solving this problem it will be impossible to operate a fusion reactor,” he stated.

Because of its very small size, tritium tends to permeate through materials readily — an undesirable characteristic in a tritium processing plant, where tritium would be exposed to a large surface area as it passes through cooling, ducting and processing pipework.
Assistant Professor Chikada’s results showed that a layer of erbium oxide only tens of microns thick on a steel surface could reduce permeation of tritium by 100 000 times.

Erbium oxide was originally chosen as an insulation coating because it has a high thermodynamic stability and is resistant to liquid lithium-lead — a proposed blanket material for fusion plants, which is corrosive to many materials.

Read more on the EFDA website.

A GÉANT on the fusion data highway

Since the ninth of April, GÉANT, the world’s leading high-speed research and education network managed and operated by DANTE in Cambridge, UK, has been providing data links to the International Fusion Energy Research Centre (IFERC) in Rokkasho, Japan.

IFERC hosts the Helios supercomputer, a system with a compute power exceeding 1 PFlops attached to a storage capacity of 50 PB. The Helios supercomputer is provided and operated by the French Alternative Energies and Atomic Energy Commission (CEA) and is a European Domestic Agency resource.

GÉANT is supplying a 10 Gbps (10 Gigabits per second) link to connect Helios with scientists involved in ITER and DEMO, the demonstration fusion reactor considered as the follow-up to ITER.

It is hoped that, after the first fusion plasmas of ITER planned for 2020 and beyond, DEMO, an industrial demonstration fusion reactor, will lead to full-scale fusion energy reaching the commercial market in the second half of this century.

Read more on the European Domestic Agency website.

633 vacuum vessel forgings shipped to Korea

In the early hours of Monday, 29 October 2012, the last of 633 massive stainless steel forgings for the ITER vacuum vessel left the KIND premises in rural Gummersbach, Germany. Their destination: Hyundai Heavy Industries in Ulsan, South Korea.

The forgings, made from highly refined F316L(N) IG steel, will be used for the construction of the first two sectors of the ITER vacuum vessel. The vacuum vessel is a hermetically-sealed steel container that contains the fusion plasma and acts as a first safety containment barrier. The manufacturing of the vessel is divided between Europe, which will supply seven sectors, and Korea, which will supply two sectors.

"We are very proud of being able to deliver these very special and tailor-made components for ITER on time,” said Markus Kind, commercial managing director of the family-run company that is well-known for its experience in custom-made forgings (whether the 2,000 pieces manufactured for the Large Hadron Collider at CERN or the 15-ton propeller shaft of a super yacht).

It took two full days to load the precious goods weighing 360 tons into 20 shipping containers.

The cargo Don Giovanni is now headed for Ulsan, South Korea, where the fabrication of the first two vacuum vessel sectors is in full swing. 

"The start of vacuum vessel sector welding is a historical moment for the ITER project as it marks the manufacturing of the first fully licensed vacuum vessel for a fusion reactor in the word,” said Alexander Alekseev, director of the ITER Tokamak Directorate during a recent visit to the Hyundai facility. „The Korean Domestic Agency and Hyundai Heavy Industries have done a great job. I know that it was not easy … I appreciate very much the work done. This is a good start; we are quite confident that Korea will deliver all the sectors according to schedule.”

Dancing DT retention in tungsten!

What is your research about? It’s not often that you see a scientist break out in dance when you ask that question. Yet this is exactly what the international contest Dance your PhD challenges young researchers to do: explain their work in the form of a dance performance. The winner gets featured in Science and at TEDxBrussels, and wins a $ 1000 prize.

At the Dutch Institute for Fundamental Energy Research DIFFER, PhD candidate Rianne 't Hoen took up the gauntlet with the great escape, a performance about hydrogen retention in the wall materials of future fusion reactors.

As a researcher, Rianne 't Hoen works on the physics behind retention of deuterium and tritium in tungsten, the candidate material for the ITER divertor. She started her four year PhD research at DIFFER in 2009, the same year that saw the first edition of Dance your PhD.

"My PhD dance is performed around and on the experiment I’m using for my research, Magnum-PSI. It is capable of reproducing the conditions that we expect in the wall of a fusion reactor so that we can test materials on their capabilities of withstanding such a harsh environment."

Rianne 't Hoen’s performance is one of the entries in the physics category of Dance your PhD. A jury consisting of scientists and artists rate each entry on the creativity and on how it manages to bring across the key scientific concept in the research.

Participants can win one of four $ 500 prizes in the categories of biology, chemistry, physics and social science, with the best of these four receiving another $ 500 prize and the chance to present their movie at the TEDxBrussels event. The winners will be announced in the coming weeks.

Click here to watch a video of Rianne 't Hoen’s performance

Pneumatic Shutter for Nuclear Fusion

From 2020 onwards, the ITER fusion reactor will demonstrate how nuclear fusion can be used as an energy source. However, inside the reactor, the plasma at a temperature of 100 million degrees presents scientists with huge challenges. Direct contact would destroy important optical instruments within a short period of time.

At the 27th Symposium on Fusion Technology (SOFT), from 24 to 28 September 2012 in Liège (Belgium), Jülich researchers are showing how the delicate instruments can be protected by means of new shutter and cooling systems. Among other options, they will present a patented shutter controlled by a pneumatic cylinder which was developed specifically for ultra-high vacuum.

For the first time, ITER will generate excess energy of 500 million watts for a duration of about ten minutes in order to provide us with experience for the construction of subsequent fusion power plants. Not only the burn chamber but the entire measuring technology has to be developed from scratch for this fusion experiment, which is being monitored by scientists all over the world.

Optical monitoring methods are indispensable for assessing the plasma properties and composition. However, optical elements in the vicinity of the plasma are exposed to extremely high loads. The plasma, largely composed of hydrogen and helium nuclei, erodes part of the surface material but also deposits contaminants. Thermal energy must be continuously removed in order to keep the temperature constant.

„The greatest technological challenge is to find suitable materials and designs to protect and cool the optical elements that can also be cleaned when they are installed in the machine” explains Dr. Olaf Neubauer from the Jülich Institute of Energy and Climate Research, Plasma Physics (IEK-4). Together with colleagues from Forschungszentrum Jülich and partner institutions, Neubauer organized the SOFT conference with more than 800 participants this year.

All the components in ITER’s burn chamber can essentially only be serviced by remote-controlled tools or robots. At the conference, Jülich plasma researchers are presenting a new fast shutter for a spectrometer that protects the optical instruments when they are not in use for measurements, in particular during ignition when most of the contaminating particles are mobile.

„In designing the structure, the main problem was that the shutter is exposed to even higher loads than the optical instruments themselves. Furthermore, a movement mechanism had to be invented that could cope with the extreme plasma conditions and the ultra-high vacuum," says David Castaño Bardawil. Conventional bearings cannot be used because of their abrasion and the Jülich solution therefore makes use of flexible arms. They are operated by an actuator that was specially developed and patented, into which helium is fed under pressure.

Electric drives cannot be used in the burn chamber due to the strong disturbing magnetic fields.  „The shutter is additionally protected by a molybdenum screen, which reflects the thermal radiation. Together with a sophisticated combination of thermally conducting and insulating materials this maintains an acceptable temperature,” says Castaño Bardawil, an engineer in Neubauer’s working group.

At SOFT 2012, other Jülich scientists are presenting new concepts for uniformly cooling the instrument mirrors under extreme conditions. „Large temperature differences arise on the mirror surface close to the cooling channels. With the aid of simulations, we optimized the cooling channels in order to minimize divergences,” explains Andreas Krimmer, who also works in the field of fusion technology. The temperature-related high pressure of the coolant causes other deformations. At the moment, researchers are testing various elastic materials in order to even out the deformations thus ensuring that in 2020 the fusion plasma can be ignited in Cadarache.
Source: Forschungszentrum Jülich

Click here to read the Press Release.

Imagine the unimaginable

Following the nuclear accident at the Fukushima Daiichi Power Plant in Japan in March 2011, the European Union declared „that the safety of all 143 nuclear power plants [in Europe] should be reviewed on the basis of a comprehensive and transparent risk assessment.” These assessments are known as stress tests.
As the first fusion reactor to undergo full nuclear licensing, ITER will also have to pass this complementary safety assessment, In the words of Licensing Officer Joëlle Elbez-Uzan, the stress tests are „a targeted reassessment of ITER’s safety margins in the light of the events that occurred at Fukushima.”

„What this means, is that we will look into the resistance of the facility in the face of a set of extreme situations leading to the sequential loss of the ITER lines of defence—irrespective of the probability of this loss. In other words, we are imagining the unimaginable.”
The type of extreme situation under examination: very severe flooding, a severe beyond that postulated in the ITER safety case, or a combination of both. „Special focus will be given to our crisis management plan describing how to react in such an extreme situation,” explains Joëlle.
As a first step, the French regulator (Autorité de Sûreté Nucléaire, ASN) asked the ITER Organization to draft a report describing the methodology by which the stress tests will be performed. This report was sent to Paris on 15 January and the methodology has been approved.

Currently the Safety, Quality & Security Department is carrying out its stress test evaluation and the outcome will be submitted to the authorities mid-September.