HEAT TRANSFER IN CIRCULAR TUBES WITH SUPERCRITICAL FLUID USING THE STAR – CCM + CFD CODE

Abstract

Nuclear generation began about 70 years ago and today generates 16% global electricity. This percentage is still growing rapidly. About two-thirds of world population lives in nations where nuclear power plants are an integral part of electricity production and industrial infrastructures. Half the people in the world live in countries where new nuclear power plants are in planning or under construction. In 2007, the International Atomic Energy Agency (IAEA) reported that there were over 400 nuclear power reactors in operation in the world, operating in 31 countries, and 29 more are under construction. After the a long depression period due to the TMI and the Chernobyl accidents, the nuclear industry right now is undergoing a revival. Recent concerns over the emission of nitrous oxides and carbon dioxide is increasingly getting people‟s attention on the continued use of fossil fuels as a source of energy. The Kyoto Protocol, developed in 1997 and signed by 187 states, requires a reduction in emissions below current values. The Copenhagen Summit, held in 2009 and with 192 countries in attendance, also aims at reducing the carbon dioxide emissions. These targets can be reached very likely by continuing use of nuclear power for the generation of electricity. A typical 1,000-megawatt fossil fired power plant may emit yearly as much as 100,000 tons of sulfur dioxide, 75,000 tons of nitrogen oxides, and 5,000 tons of fly ash. 

Nuclear power plants produce none of these air pollutants and emit only little amounts of radioactive gases. Compromising between the rapidly increasing energy demand and the target of a reduction in emissions, nuclear power plant has been naturally highlighted in the energy market.
Nuclear reactor generations have been differentiated from each other in the nuclear energy market. Generation I reactors were developed in 1950-60s, which was the early prototype of the power plant. Generation II reactors typified by the commercial reactors were built up to the end of the 1990‟s and are the most in operation worldwide.