June 19th, 2008 11:00 EST
Sodium Can Make Nuclear Reactors Safer
The road to nuclear security leads through sodium-cooled reactors, say scientists. Although there are only three such facilities operating in the world, their number will have surely increased by 2030, when the IV Generation nuclear reactors are to be available for commercial construction.
Since the first civilian reactor was built in Russia in 1954, nuclear power plants have undergone several changes. The main technology, however, remained the same. The majority of 438 nuclear facilities that were in use in 30 countries last year were located near natural lakes and rivers. It is by far the easiest and cheapest method to maintain the low temperature of the reactor that, if overheated, could cause disastrous effects in the nearby area.
But water, insist experts, is a highly unstable substance. It is prone to atmospheric conditions and often does it happen that its shortages cause nuclear plants long hiatuses in production during warm seasons. There are also serious safety problems. A report published by a Swedish group warned that the long-term behavior of water-cooled plant is subject to a degradation in terms of the possible load factors achieved. " Stability is the center point of each nuclear power plant while the two-phase behavior of water prevents an easy determination of the consequences of a major accident. "
Sodium-cooled reactors are free of these deficiencies. To cut a long story short, sodium, which can be found in common salt, is not only more efficient than a cooling substance but also conserves the uranium so it can serve for much longer than when cooled by water. Moreover, some experts claim that the further mastering of the technology may substantially reduce the amount of waste produced by power plants. According to one Korean study, fuel from sodium-cooling power plants is safer to store since the radioactive half-life of such material is 400-500 years compared to thousands of years for conventional spent fuel. "
There are a number of scientists, however, who claim that investing into sodium-cooled reactors is a great mistake. A report prepared by French experts underlined that sodium is considered in itself as a hazardous chemical product and will be handled with cautions as long as it exists in its metallic form. " Sodium-cooled nuclear power plants are also more expensive to build and maintain and sodium technology requires a specific technology and know-how to handle it. " Of 59 nuclear facilities working in France, all but one depend on water. The second sodium-cooled reactor was closed in 1997 after only 12 years of exploitation. The remaining one is scheduled for decommissioning in 2009.
Two other active sodium-cooling reactors are in Russia and Japan. That this is the future of nuclear energy shows the fact that Japan, France, and the United States signed a deal in the first weeks of 2008 to share the research and cooperate in making the nuclear technology safer and more effective. As the Generation IV International Forum reported, the agreement relates to their collaboration in the Global Nuclear Energy Partnership, aimed at closing the nuclear fuel cycle through the use of advanced reprocessing and fast reactor technologies, and seeks to avoid duplication of effort. "
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