Nuclear Energy Essays - Nuclear Technology, Energy Conversion

Nuclear Energy From Theory to Practice The nuclear age began in Germany, in the 1930s in the lab of chemist Otto Hahn. Hahn was attempting to produce radium (In great need during the war) by bombarding uranium atoms with neutrons. To his surprise, he ended up with a much lighter element, barium. That was 1938, This started the race for the power of the atom. Just four years later Canada entered nuclear age in cooperation with the british. Wartime, 1942: The British wanted a safe place to conduct nuclear experiments; Since their country feared invasion by the nazi's or bombing attacks, Canada provided the haven the british needed in return for a opportunity to work in the project. The leader of the team that crossed the atlantic to Canada was Hans von Halban, who along with Dr. Lew Kowarski had escaped from the Institute Du Radium in Paris one step ahead of the invading german army. They took the world supply of 200 Kg of heavy water with them to Canada. Having pioneered the chain reaction using uranium and heavy water, the scientists applied their knowledge and their heavy water to the new Canadian nuclear industry. On September 5th, 1945 near Ottawa the team started up the first operating nuclear reactor outside the USA. Of course, the output was minuscule, but the significance was immense; the principal of getting energy from splitting atoms in a controlled chain reaction (fission) was established beyond doubt. It was now the job of the scientists and engineers to put it to a practical use. Nuclear Reactors A nuclear reactor is a device which produces heat. In a nuclear power station, the reactor performs the same function as a boiler in a conventional coal, gas or oil-fired station. Whether from a conventional boiler or a nuclear reactor, heat is required to turn water into steam. The steam is used to spin large turbines which in turn drive generators that produce electricity. A reactor creates heat by splitting uranium atoms. This is called 'Nuclear reaction' or 'Fission'. When the nucleus of an uranium atom is stuck by a neutron travelling at the right speed, it splits into fragments which separate rapidly and generate heat. It also gives off a few, new neutrons. In order to sustain a continuous nuclear reaction, the speed of these neutrons must be slowed down, or moderated. CANDU reactors use heavy water (Deuterium Oxide is called heavy water because it is heavier than normal water by about 10%), Thus the reactor is named CANDU, for (CAN)ada (D)euterium (U)ranium. During Fission (the process used in nuclear reactors) some of the atom breaks up, and energy is released. On average, 80% of the released energy is carried off by the fragments in the form of kinetic energy. The other 20% is collected by the heavy water in the form of heat. The core of a CANDU reactor The core of a reactor is contained in a large cylindrical tank called the 'Calandria'. The calandria contains a series of tubes that run from one end of the calandria to the other. Inside the calandria tubes are smaller tubes which house fuel bundles containing natural uranium in the form of ceramic pellets. Heavy water is also used as the reactor coolant and is pumped through the tubes containing the fuel pellets to pick up heat generated from the reaction. The heated, heavy water travels to heat exchangers to produce steam from ordinary water. This cooled heavy water is recycled back to the reactor. The steam is then piped to conventional turbines and generators that produce electricity. In this way the nuclear reactor is separate from the equipment used to produce electricity. Viable solutions for Energy needs Annually, the demand for energy in Ontario increases by 5%. In response to this increase, Hydro companies around Canada facing similar situations have the responsibility of meeting the increase, usually by adding to their arsenal of generators. The question which is brought up at this point is how to do this most effectively in terms of impact on the environment, cost, efficiency and several other aspects. In the case of Ontario Hydro, they have chosen to expand on the method which appears to be best: nuclear power. (Note: All of the following data on nuclear generating stations is based on information on Canada's CANDU plants.) There are four main competitors in the energy race, but only two of them are 'technically viable' Those right now are Nuclear and fossil fuels. Of the other two, Solar energy is