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Tuesday, Aug. 24, 2010
A new push for nuclear fusion
ITER (International Thermonuclear Experimental Reactor) Council approved the Overall Project Schedule (OPS) and the Overall Project Cost (OPC) in an extraordinary meeting in late July. This means that the world's largest experimental nuclear fusion project, which is being undertaken by the Eropean Union, the United States, Japan, Russia, China, South Korea and India, will receive full thrust for the construction of the reactor in Cadarache in southern France. If everything goes well, a process similar to the nuclear forces that power the sun and the stars will be enacted in the reactor. The project participants' ultimate goal is to harness nuclear fusion to produce electricity.
The origin of the ITER project dates back to a 1985 summit of the U.S. and Soviet leaders. The original participants included the U.S., the Soviet Union, the EU and Japan. A detailed conceptual and engineering design was accepted in 2001. It was decided in 2005 that the ITER reactor would be built in France. In 2007, the ITER Agreement went into effect. Japan provides 20 percent of the research staff and a Japanese scientist serves as director general of the ITER Organization. In Latin, "iter" means "way" or "journey."
ITER will use deuterium and tritium as fuels. When they fuse, the two nuclei join and produce a helium nucleus, a high-energy neutron and a much larger amount of energy than was needed to fuse the two nuclei. For the fusion to occur, deuterium and tritium must be turned into plasma — an electrically neutral, ionized gas composed of electrons and positive ions — and the plasma must be confined for a duration of time. To create plasma, a temperature of more than 100 million C is needed. The key to success is to develop technology that can confine and control plasma in such a high temperature.
According to the OPS, the first plasma is to be created in November 2019, and deuterium-tritium fusion is scheduled to start in March 2027. The ITER Organization will also explore the possibility of moving up the start date of the fusion to 2026.
The cost to build ITER was originally estimated at ¥800 billion. But this figure has climbed to ¥1 trillion. The OPC is calling for a cap on any possible increases in the construction cost. It was agreed that if the cost rises, the increase should be less than ¥20 billion. The agreement to contain the cost is reasonable in light of the fact that the project participants are suffering from financial difficulties. The EU will shoulder 45.4 percent of the construction cost while the six other participants will each contribute 9.1 percent. Japan also has the International Nuclear Fusion Energy Research Center in Rokkasho, Aomori Prefecture, to carry out ITER-related research.
The participants will build and transport components, which will be assembled in Caradache. This will not be an easy task. The governments, manufacturing companies, researchers and engineers must closely cooperate to build components that meet the quality standards within the budget and on schedule.
The ITER reactor will be about 30 meters in both diameter and height but will not generate electricity. Since it will integrate advanced technologies, innovation spinoffs for more practical purposes can be expected. Apparently, to take advantage of this opportunity, China, South Korea and India joined the project.
It is expected that a prototype electricity-generating plant using nuclear fusion will be built by the mid-21st century and that a commercial plant will come into existence around 2100. A nearly limitless supply of deuterium can be obtained from sea water and tritium will be produced from lithium placed in a reactor. North and South America have lithium resources. Since fusion-based power generation does not release greenhouse gases, it is being touted as a dream energy source.
But it faces criticism such as: the technologies needed for the ITER project are extremely challenging, especially the technology to sustain plasma; the money should be used to develop renewable energy; high-energy neutrons produced by the fusion reaction will damage the reactor and make it radioactive. Tritium itself is radioactive. The ITER researchers must provide full explanations and make steady efforts to attain scientifically convincing achievements.
In the July meeting, Mr. Osamu Motojima, director general of Japan's National Institute for Fusion Science in Toki, Gifu Prefecture, succeeded Mr. Kaname Ikeda as director general of the ITER Organization. Mr. Motojima has strong experience not only in theoretical studies but also in constructing the nuclear fusion-related equipment and managing organizational work. The hope is that he will give full play to his ability so that the ITER project will become a safe and practical endeavor.