| | In May 2007 the Institute used US$30 million for a new heating system and other technology, India-Asian News Service reported."We want to set up new systems of six megawatts each for the central drive and the heating system. We expect to do this over the next three years,"
Institute deputy director Song Tao Wu told a group of visiting foreign journalists. This would double the energy produced to 10,000 KV. The Institute is not yet utilizing China's own Experimental Advanced Superconducting Tokomak (EAST), but the Russian-designed HT-7 tokomak."The EAST tokomak is functional and so is the H-7 one. But we have just one crew to run it. So, we are not using the EAST tokomak at this moment,"
Song explained. He said that the Indian fusion program "is very ambitious.""India is not using a fully superconducting technology. Its facility is smaller than ours. But the Indian government has spent a lot more money on it,"
Song said. India and China are participating in the international thermonuclear experimental reactor project, which also involves the European Union, the United States, Japan, Russia and South Korea.
ADVANTAGES OF FUSION (HISTORY)
Fuels commonly used in fusion reactors are deuterium and tritium, both isotopes of hydrogen, and both non-radioactive. Deuterium occurs naturally in sea water from which it is extracted, which is why all fusion reactors are located on coasts. Tritium does not occur naturally but can be made within the reactor itself from lithium, the lightest metallic element (but heavier than hydrogen or helium) which is used as a blanket to control the speed of the fusion reaction by slowing down the neutrons released from the fusion of deuterium and tritium to form helium. Lithium also is abundantly available on the earth's crust all over the world, thus promising an almost limitless availability of material for fusion reactors.
Fusion has several other advantages over fission.
Quantities of raw material used are very low, with grammes of material being used compared to kilogrammes in fission reactions. 1 gramme of fusion fuel could produce as much energy as 10,000 kg of fossil fuel. The fusion process has in-built safety features: fusion reactions require leak-tight confinement and if any leakage takes place, this results in extinguishing the plasma, like a candle getting blown out if the door is opened, and stopping the energy generation. There is no chain reaction in fusion unlike in fission where the danger is of the chain reaction going out of control.
In fusion, if excess plasma gets generated, temperatures will rise beyond the limit (close to which they are operating in reactors) after which the fusion reactions start winding down by themselves. Fusion processes are also limited by the quantum and rate of refueling without which the plasma gets rapidly extinguished: also, many conditions together must be satisfied and failure of any one leads to energy loss and plasma extinguishment. Further, reaction products from fusion are either absorbed by the surrounding lithium or are non radio-active like helium. There are no hazardous wastes produced, minimal exhaust releases into the environment and de-commissioning poses no long-term or other hazards, all making fusion power a highly attractive proposition.
The technologies involved have developed over several decades since the end of World War II. The basic problem confronting scientists was, although collision between nuclei released substantial energy, a large amount of energy was required to generate the plasma and therefore, could energy output be made greater than energy input. Soon ideas from nuclear physics, astrophysics and plasma physics came together to provide a realistic possibility. But there were huge engineering problems involved in designing and building a reactor, chief among which was how to contain and control the plasma in the absence of the massive gravity available in the sun and the mostly larger stars and the obvious difficulty of any containing material being able to withstanding the million-degree temperatures generated.
Among many approaches being pursued by American, British and Soviet experimental physicists and engineers, Soviet researches provided the crucial breakthroughs. Sakharov and Tamm first suggested that the plasma could be contained within a magnetic field. Soviet experimental successes with this approach were first revealed to an astonished world in 1956 by Kurchatov. By the time the "Atoms for Peace" conference was held in Geneva in 1958, the genie was out of the bottle, fusion was no longer a secret and information started getting shared in the global scientific community.
In the early '70s, the Soviets had built a reactor in the shape of a doughnut or vada i.e. a tube forming a circle with a hole in the middle. This design was called a "tokamak" after a Russian snack of that shape. Tokamak reactors soon came to be adopted worldwide and were further developed, the most advanced perhaps being the Joint European Torus (i.e. the toroidal doughnut shape) or JET reactor at Culham, UK, set up under the European Fusion Development Agreement, then becoming the flagship programme of the ITER Project and the world's largest and most powerful fusion reactor, which started operation in 1983. In 1981, JET demonstrated the generation of over 1 MW of power in a short burst. Other important experimental fusion reactors are in Japan, the second-largest after JET, France, Germany, Canada and Spain.
Despite the usual naysayers, who say nuclear power from fusion is unsafe or will not work, the last word on nuclear fusion energy are far from having been spoken. Research on nuclear energy must continue and, in this field, cannot be done at a small laboratory scale. Nuclear energy from fusion, is an option the world needs to keep open. |
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