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Japanese facility aimed at creating a sun on Earth

Plasma-burning device is major step in effort to supply clean and safe fuel

by Stephen Carr

Outside a small town in Gifu Prefecture is a little-known scientific research establishment engaged in a project to “create a sun on the Earth.” If successful, this venture will profoundly affect the lives of most people in the world.

The National Institute for Fusion Science (NIFS) is a collection of buildings on the tree-covered hillsides surrounding the town of Toki.

It houses the Large Helical Device (LHD), which cost ¥50 billion to make and is the only one of its kind in the world. The machine is designed to replicate fusion, the nuclear reaction that powers the sun. Once this is achieved, it will herald the end of humanity’s dependence on fossil fuels and begin an era of cheap and limitless energy.

The current Democratic Party of Japan administration is cutting back on big, expensive projects, and large-scale scientific organizations such as the LHD are under budgetary pressure. But it is worthwhile work according to Denis Humbert, an International Atomic Energy Agency (IAEA) scientist from France, who recently spent three months researching at the NIFS.

“The budget for this project is actually very small — $18 billion over the next 20 years. Fusion research has implications of great interest to many other fields such as research into new materials and the nanosciences. And most important, if it works, it will bring a solution to the planet’s energy problem.”

Hiroshi Yamada, executive director of research at the NIFS, gave The Japan Times a tour of the facility in July. We put on hard hats, climbed ladders and crossed metal gangways in a huge, cavernous building that measures 40 meters high, 75 meters long and 45 meters wide. The space houses the LHD — an enormous sprouting of pipes and coils all wrapped around a giant metal tube. Your reporter was invited to put on protective gear, crawl into a small space and stand upright to peer through a head-size hole, right into the silvery innards of the beast.

If I were to stand in the same spot a few months down the road, I thought, this thing would vaporize me in an instant.

Weighing 1,500 tons and measuring 13.5 meters long and 9.1 meters wide, the LHD is shaped somewhat like a vast twisted snake swallowing its own tail. It is the world’s largest superconductor and the only one of its type in the world. It costs the government ¥5 billion a year to run.

The technology started with secret military research in the Soviet Union and, separately, the United States and Great Britain, just after World War II. Until today, the most dramatic demonstration of fusion power the world has seen has been purely destructive: the testing of hydrogen bombs set off by atomic bombs and, of course, the nuclear weapons used against the cities of Hiroshima and Nagasaki in August 1945.

Nuclear fission splits nuclei to create energy and nuclear fusion joins them to do the same thing.

The first fusion device made for peaceful purposes was the Tokamak, which was invented by Leonid Zakharov in Russia in 1951.

Nuclear fission for peaceful use began in 1958 after a United Nations conference in Geneva on peaceful uses of atomic energy.

Since then, Japan, the European Union and the United States have made great efforts to modify and improve the machine. The Tokamak is still widely regarded as the most promising fusion device, but there are other similar devices in the world, including one in Naka, Ibaraki Prefecture, and at the Culham Centre for Fusion Energy near Oxford, England. The Tokamak has reached temperatures of 500 million degrees Celsius in experiments, more than 30 times hotter than the sun.

Nuclear power for peaceful use has developed rapidly and there are now 400 nuclear fission power plants around the world. By contrast, the aim of constructing fusion reactors to generate electricity is still in the research and development phase.

“Replicating the fusion of helium and hydrogen that powers the sun, in earthly conditions, means generating temperatures beyond 100 million degrees Celsius,” explains Yamada. “This creates plasma, the fourth state of matter after solids, liquids and gases.”

All stars, our sun included, are made of plasma. Flashes of lightning are natural plasma and so too are the spectacular Northern Lights. Artificial plasma, at much lower pressure, is present inside neon lights and plasma television screens.

“The extreme temperatures inside the LHD mean the plasma must not be allowed to touch the walls of the device. If it did, (the walls) would melt.”

Herein lies the main difficulty with the LHD. Researchers must create materials strong enough to withstand fusion at temperatures many times hotter than the sun. Plasma at extremely high temperatures creates wild, unstable reactions and would irreparably damage any machine made to contain it that uses existing materials.

Yamada demonstrates this process by heating a circular fluorescent tube inside a microwave oven in a NIFS display area. When he takes it out, it casts a purplish glow and is warm to the touch. He says, “The glass walls of the tube cool the plasma. When a similar reaction occurs inside the sun, its vast gravitational pull keeps the plasma from shooting in all directions.

“Once new materials have been invented, the way will be open to constructing fusion reactors able to generate electricity, using easily obtained resources that will never run out. The raw materials needed for creating plasma in fusion reactions, are lithium and deuterium, which can be extracted from seawater.”

One widespread modern use of lithium, is in mobile phones. The amount commonly used in each phone is about 0.3 grams. Together with the deuterium taken from 3 liters of seawater, a fusion reaction equivalent to 22,000 kilowatt-hours of electric power could be created. This amount of electricity would supply a typical family in a developed country for a couple of years. Or to put it another way, one liter of seawater contains enough deuterium to provide the energy content, when fused with tritium, of more than 500 liters of petroleum.

Fusion power plants of the future, producing a million kilowatts, would need about a tenth of a ton of deuterium and 10 tons of lithium a year as fuel. Seawater covers over 70 percent of our planet and rates of extraction for hundreds of fusion reactors around the globe would never exhaust supplies.

Plasma inside the LHD is prevented from touching the walls by a magnetic field created inside the sinuous innards of the machine. It is done by means of a twisting, orange-hued metal alloy, wound 450 times and coiling round the outer walls of the giant tube. The coil is exposed to an electromagnetic force reaching 1,000 tons per meter. Beforehand the coil and supporting structure are cooled to minus 270 C. When cooled the structure typically shrinks 2 mm. The machine is built to tolerate a shrinkage of 2 cm.

Hydrogen gas is heated and injected into the machine. After reaching 10,000 C, the hydrogen molecules disintegrate into atoms. Then the parts of the atoms, the positive nucleus and the tiny negative electrons spinning around it, are unbound and create plasma.

Yamada explains how the process works: “Atoms that have lost electrons become ions and are 2,000 times heavier than electrons. The ions are trapped and rotated along the magnetic field and the electrons are sent in an opposite motion. This is the means by which plasma many times the temperature of the sun is kept from destroying the LHD. The sun’s temperature is only 15 million degrees. Its vastness — it is 100 times the size of the Earth — allows fusion to occur at a much less fierce heat than inside the LHD.”

When being readied for experiments, the LHD is cooled for a month. Usually from October to February each year it makes plasma four days a week. Last year, however, the machine was switched on only between Oct. 11 and the end of December, due to budget cuts. When the experiment ends and the LHD is switched off, it takes another month to warm up again.

Although at the moment the Toki LHD is the only one of its type in the world, another device will be built in Germany in 2015. After that, the next big development in fusion science will be the ITER project (originally the International Thermonuclear Experimental Reactor), when a Tokamak 10 times bigger than Toki’s LHD will be built in Cadarache, France, in 2019. It is expected to be operational around 2027, when plasma will be ignited for the first time. Forty-five percent of the cost will be funded by the European Union, while Japan, China, India, Russia, the United States and South Korea will each contribute around 9 percent.

A demonstration reactor is expected to start producing electrical power from fusion energy in the 2030s. Then the next phase will be construction a new generation of fusion reactors. They are expected to start generating electric power, in place of current technologies, around the middle of this century.

Yamada defends the fusion process as a lot safer than conventional nuclear power.

“Radioactive materials used in fusion do not have to be moved off-site. Waste also does not have to be stored for thousands of years, as is the case with spent uranium at conventional nuclear power stations. Fusion waste could be reused after cooling off for 100 years.”

As regards local politics, the NIFS is seen by Toki’s municipal government as a valuable asset to the area. A couple of local politicians oppose it, however, fearing “industrial accidents.”

“But the LHD is for studying plasma at high temperatures,” says Yamada. “Not creating fusion. So the dangers of radioactive waste are not the same in Toki as they would be at the site of a real fusion reactor.”

As all the scientists analyzing the LHD experiments cannot be physically present in the control room, the results are studied by linking computer systems at eight universities around Japan. NIFS also attracts participating scientists from all over the world.

The Deputy Director General of NIFS, professor Osamu Kaneko, believes the educational function of the institute is very important.

“Since it will take 20 or more years to make fusion reactors a reality, it is necessary to educate young people as successors to our research. NIFS has a physical sciences department at the Graduate University of Advanced Studies in Kanagawa Prefecture. Thirty students from Japan and abroad study for their PhDs in Toki, at the forefront of nuclear fusion research,” says Kaneko.

This big science project is, in a sense, reaching for Utopia. It heralds the end of dependence on fossil fuels such as coal, petroleum and natural gas, along with all their attendant ills: environmental degradation, global warming and the unstable geopolitics of oil. The many unsolved problems associated with atomic fission power would also end.

Toki’s LHD is a project looking for results in the long term — extremely long term — explains Akio Komori, director general of the NIFS.

“Our era is the longest known period between ice ages,” Komori says. The occurrence of another ice age, despite the current fear of global warming, is an overwhelming likelihood. In that distant future, when the world is again covered in ice, fusion plants, creating ‘suns’ all over the globe, would allow life on Earth to flourish for another 5 billion years, until the sun in the sky finally burns out.”