Galeria

The Korean Superconducting Tokamak Advanced Research (KSTAR) tokamak-type nuclear fusion reactor has achieved a world record of 70 seconds in high-performance plasma operation, South Korea's National Fusion Research Institute (NFRI) has announced. The institute, based at Daejeon, 160 km south of Seoul, said a fully non-inductive operation mode - called a "high poloidal beta scenario" - has been used to achieve this long and steady state of operation using high-power neutral beam. It said various techniques, including a rotating 3D field, have been applied to alleviate the accumulated heat fluxes on the plasma-facing components.

"The world record for high-performance plasma for more than a minute demonstrated that the KSTAR is the forefront in steady-state plasma operation technology in a superconducting device," NFRI said in a statement today. "This is a huge step forward for realization of the fusion reactor."

In addition, the institute said, KSTAR researchers also succeeded in achieving an alternative advanced plasma operation mode with the internal transport barrier (ITB). This is a steep pressure gradient in the core of the plasmas due to the enhanced core plasma confinement. NFRI said this is the first ITB operation achieved in the superconducting device at the lowest heating power.

"With the progress of the Iter project, the KSTAR research will focus on the mission essential for the fusion reactor beyond Iter," the institute said. "They are new efficient mode of operation and a new divertor concept suitable for the Korean fusion demonstration reactor, the K-DEMO device, which will be the first runner in worldwide fusion energy development plan."

NFRI president Keeman Kim said, "We will exert efforts for KSTAR to continuously produce world-class results, and to promote international joint reearch among nuclear fusion researchers."

Construction of KSTAR, a tokamak-typed nuclear fusion reactor, began in December 1995 and it was completed in August 2007. The first experiment was conducted in KSTAR in 2009. It was the first in the world to feature a fully superconducting magnet system with a central solenoid, toroidal and poloidal field coils. It measures 8.6 m high, and 8.8 m in diameter.

Tokomak-design reactors like KSTAR use magnetism to contain a toroidal-shaped plasma at temperatures of up to 300 million °C. Despite this temperature it is necessary to cool superconducting magnets to -269°C. Inside the plasma, a few grams of deuterium and tritium atoms are stripped to the nuclei, which fuse to release energy. It is hoped that this form of nuclear energy could one day be used to generate electricity, but maintaining a steady plasma has proven very difficult.

Source: World Nuclear News

A recent article in the online journal Nature Communications confirms that the complex topology of the magnetic field of Wendelstein 7-X—the world's largest stellarator—is highly accurate, with deviations from design configuration measured at fewer than 1-in-100,000. 

In the complex shape of a stellarator, high engineering accuracy is needed because even the smallest magnetic field errors can have a large effect on the magnetic surfaces and the confinement of the plasma. 

After having completed the insulation of ITER’s first-ever winding pack, the inner core of the massive Toroidal Field coils which will magnetically confine the hot plasma, the stage of resin impregnation followed. Technically speaking this has been one of the most delicate operations to be performed on the most complex magnet to date. For Alessandro Bonito-Oliva, F4E’s Project Manager for Magnets, his team and their suppliers, this is an important achievement underpinned by the collective commitment to deliver on time, plan carefully and be sufficiently flexible to adapt to the engineering challenges along the way.

A team of ten technicians worked relentlessly to get the magnet ready for this important manufacturing milestone. First, they had to apply the impregnation mould all over the surface of the 14 m high, 9 m wide and 1 m thick magnet. It has taken an entire week to cover its surface with pads in order to make sure that the resin injected during impregnation would flow in an even and controlled manner. Next, the magnet was enclosed in a layer of stainless steel sheets and clamped by heating plates to create a solid shell. Approximately 100 clamps, tightened one by one, sandwiched the magnet to compact the electrical insulation at the right level. Welding of the stainless steel sheets came next, and after having completed this step, the leak and electrical tests were carried out.

The successful completion of the works paved the way for the impregnation process. What were the main elements of this step? First, the component needed to be heat-dried in vacuum at 110 ˚C to eliminate any vapor or humidity trapped in the insulation. Second, with the mould under vacuum, resin was injected from the bottom of the magnet to fill in any gap, and pressure of approximately 3,5 atmospheres was applied to ensure complete filling of the mould. Finally, the winding pack went through a curing cycle, at temperatures reaching 155 ˚C during five days, before extracting the impregnated magnet from the mould.

After having completed this step, dimensional checks were carried out together with laser scans to examine the state of the component. In order to protect the component in operation a special conductive paint was applied all over its surface. So what works are currently ongoing? Magnetic measurements, checking the geometrical compliance of the magnet, are being performed. The mechanical works for the electrical joints are advancing together with the external helium piping, which is going to channel the cold helium in the coil, and the high voltage wire connection.

And what will come next? Paschen tests, considered as the most demanding electrical conditions because even a tiny insulation defect would cause failure, and last but not least, leak tests to assess the vacuum tightness. When this cycle of activities is completed then the winding pack will be transported to SIMIC to go through a series of cold tests and be inserted in its coil case. 

Source: F4E

South Korea's state-run laboratory said Wednesday that it has successfully developed a technology for the mass production of tritium for nuclear fusion energy.

The technology allows the annual production of more than 50 kilograms of tritium, which is one of two core fuels used for nuclear fusion energy, according to the National Fusion Research Institute (NFRI). Another fuel, called deuterium, is naturally abundant while tritium can only be produced artificially.

This is the first time the mass production of the material will be possible. The NFRI said the technology would gradually decrease the cost needed to import tritium which costs about 30 million won (US$26,700) per one kilogram.

The tritium is needed for the International Thermonuclear Experimental Reactor (ITER) project under way in France, the NFRI said.

The US$20 billion project is an experimental reactor currently being built in Cadarache, France, to see if a super-hot plasma field can be used to create an artificial sun on Earth. If the experiment is successful, it could provide mankind with a limitless energy source. "South Korea can now produce the tritium needed for the ITER project instead of importing it," said Kim Ki-man, chief of the NFRI. The project is being participated by South Korea, the European Union, Japan and China, the NFRI said.

The NFRI also forecast that it can export tritium to countries conducting experiments on nuclear fusion energy.

The findings will be published in Fusion Engineering and Design, a monthly nuclear fusion journal, in November.

Source

Plasma—the hot ionized gas that fuels fusion reactions—can also create super-small particles used in everything from pharmaceuticals to tennis racquets. These nanoparticles, which measure billionths of a metre in size, can revolutionize fields from electronics to energy supply ... but scientists must first determine how best to produce them.

After more than two years of planning and construction, the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) has commissioned a major new facility to explore ways to optimize plasma for the production of such particles. The collaborative facility, called the Laboratory for Plasma Nanosynthesis, is nearly three times the size of the original nanolab, which remains in operation, and launches a new era in PPPL research on plasma nanosynthesis. Experiments and simulations that could lead to new methods for creating high-quality nanomaterials at relatively low cost can now proceed at an accelerated pace.

Nanomaterials exhibit remarkable strength, flexibility and electrical conductivity. Carbon nanotubes, found in sporting goods, body armor, transistors and countless other products, are tens of thousands of times thinner than a human hair and stronger than steel on an ounce-for-ounce basis.

Plasma could serve as an ideal substance for synthesizing, or producing, nanomaterial. The new laboratory will study so-called low-temperature plasmas that are tens of thousands degrees hot, compared with fusion plasmas that are hotter than the 15-million-degree core of the sun. These low-temperature plasmas contain atoms and free-floating electrons and atomic nuclei, or ions, that can be shaped by magnetic fields to provide reliable, predictable and low-cost synthesis of tailored nanoparticles.

Source: ITER/PPPL