CANDU nuclear power reactor

All over the world, 432 nuclear power reactors are under operation and more than 36 GW of electricity could be produced as of December 31, 2001. There are several types of reactors such as boiling water reactor (BWR), pressurized water reactor (PWR), Canada deuterium uranium (CANDU), and others. In these reactors, light water is normally used not only as a coolant, but also as a moderator. On the contrary, in CANDU reactors, heavy water is taken. It is widely known that the quality control of coolant water, the so-called water chemistry, is inevitably important for keeping the integrity of the plant. 

The CANDU nuclear power system has evolved over a 40-year period, and has accumulated over 105 reactor-years of operating experience. Standardization and modularization has always been a key thrust of CANDU designs. 

Lambert, I., Brunet, S., Roy, M., Gerlinger, Ph. Chemical decontamination process for PWR primary circuits. Proc. 5. BNES Conf Water Chemistry of Nuclear Reactor Systems, Bournemouth, UK, 1989, Vol. 1, p. 321—322 LeSurf J. E. Control of radiation exposures at CANDU nuclear power stations. J. British Nucl. Energy Soc. 16, (1), 53—61 (1977)... 

To produce power, a fission nuclear reactor requires fissile material. Generation II or in reactors (pressurized water reactor [PWR], CANDU, evolutionary power reactor [EPR], etc.), being imder-breeder systems (ie, using more fissile material than they... 

Furthermore the target nuclear cross section is good, and the product cross section is lower than the target s by a factor of ten. Another factor in cobalt-60 s long list of advantages is the Canadian CANDU family of nuclear power reactors. They are heavy watermoderated and readily adapted to Co-60 production, and 16 are committed to that use. In 1990, 50 megacuries was produced with a catalog price of 1.20/curie. 

Because early Canadian reactors used heavy water, and because it is also fundamentally the most efficient moderator, Canada naturally adopted the heavy water reactor for the development of a nuclear power system. By using heavy water both as moderator and as coolant, and by refuelling with the reactor at power, it was possible to develop the CANDU system to operate efficiently and economically with natural uranium fuel. This in turn resulted in the simplest possible fuel cycle. 

Fig. 25. Series of towers comprising part of the heavy water production plant at Ontario Hydro s Bruce nuclear power complex near Tiverton on the shores of Lake Huron. Heavy water is a clear, colorless liquid that looks and tastes like ordinary water. It occurs naturally in ordinary water in the proportion of approximately one part heavy water to 7000 parts of ordinary water. While ordinary water is a combination of hydrogen and oxygen (H20), heavy water (D.-1.0) is made of up of deuterium—a form, or isotope, of hydrogen—and oxygen. Deuterium is heavier than hydrogen in that it has an extra neutron in its atomic nucleus, so heavy water weighs about 10% more than ordinary water. It also has different freezing and boiling points. It is the extra neutron that makes heavy water more suitable than ordinary water for use in CANDU nuclear reactors as both a moderator and a heat transport medium. (Ontario Hydro, Toronto, Ontario, Canada)...

Beamer, N.V. et. ah, Conditioning CANDU reactor wastes for disposal management of radioactive waste from nuclear power plants. In Proceedings of a Seminar, Karlsruhe, 1981, International Atomic Energy Agency, lAEA-TECDOC 276, Vienna, 1983. 

The capital cost of nuclear fission will have dropped significantly— especially compared with that of the then-dinosaur-technology coal-fired generation. (As one example, today the capital costs of Advanced Candu Reactors are in the range of 1000 per kilowatt [kW]—about the same as coal-fired plants.) But since the operating cost of a nuclear power plant will always be a small fraction of that for a coal-fired power plant, the energy currencies from nuclear plants will be lower. 

In the CANDU heavy-water reactor the dominant source of tritium is the deuterium activation reaction of Eq. (8.53). The data given in Prob. 3.3 for the Douglas Point Nuclear Power Station provide a basis for estimating the rate of production of tritium in the heavy-water moderator and coolant ... 

The general arrangement of the CANDU 3 nuclear power plant is shown in Figure 5.8.3 A The principal structures included the Reactor Building, two separate Service Buildings and the Turbine Building. Other structures include the Administration Building, two separate Pump houses and the Main Control Area. 

Most of the discussions are presented here in the context of radionuclide behaviour during accidents at existing pressurised water reactors (PWRs) and boiling water reactors (BWRs). The basic principles in these discussions are applicable to all nuclear power plants. Readers may need to make some mental modifications of the specific details of the discussions to accommodate the imique features of other types of plants such as gas-cooled reactors, CANDU t5q)c reactors and RBMK reactors. 

This section includes a brief early history of the development of nuclear power, primarily in the United States. Individual chapters cover the pressurized water reactor (PVVR), boiling water reactor (BWR), and the CANDU Reactor. These three reactor types are used in nuclear power stations in North America, and represent more than 90% of reactors worldwide. Further, this section includes a chapter describing the gas cooled reactor, liquid metal cooled fast reactor, the molten salt reactor, and small modular reactors, and concludes with a discussion of the next generation of reactors, known as "Gen IV."... 

The pressure in the PHTS of a CANDU 6 reactor is controlled by a pressurizer connected to the outlet headers at one end of the reactor. Pressure in the pressurizer is controlled by heaters in the pressurizer and by steam bleed. Heavy water in the pressurizer is heated electrically to pressurize the vapor space above the liquid. The volume of the vapor space is designed to cushion pressure transients, without allowing excessively high or low pressures to be generated in the HTS. (Nuclear power plants that do not allow the coolant to boil in the channels, do not use a pressurizer, and rely on the feed-and-bleed system for control.)... 

As a member of the CANDU family, the CANDU 300 design closely follows that of the larger CANDU 600 and CANDU 950 nuclear power plants and is is illustrated in Figure A key CANDU features include a pressure tube reactor, heavy water (D2O) moderator, natural uranium fuel, and on-power refuelling. 

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