The design working life of a properly maintained candu reactor is 60 years. Canada has exported candu reactors to argentina, china, india, pakistan, romania, and south korea. Candu 6 reactor building, including increased design. In the heavy water systems of the candu reactor, the proper equations describing the dissociation of heavy water. The containment is the fourth and final barrier to radioactive release part of a nuclear reactors defence. By the early 2000s, sales prospects for the original candu designs were dwindling due to the introduction of newer designs from other companies. The candu canada deuterium uranium reactor is a pressurized heavy water reactor phwr designed and built by canadian nuclear laboratories since the 1950s. Candu reactors are now in seven countries and provide approximately 15% of canadas electricity. Candu reactors were first developed in the late 1950s and 1960s by a partnership between atomic energy of canada limited aecl, the hydroelectric power. A short history of the candu nuclear power system 1 revision 2, december 2002 a short history of the candu nuclear power system by. The research and prototype reactors leading to the candu design are described with some of their principle technical parameters.
The candu 9 uses the same 37element fuel bundle design as the other operating candu. Pdf the behaviour of transuranic mixed oxide fuel in a. Currently, we are establishing the conceptual design for a nextgeneration mediumsized candu plant. The candu canada deuterium uranium is a canadian pressurized heavywater reactor design used to generate electric power. There are 31 candu reactors in operation globally, not including 16 reactors in india that are based on the candu design, but are not technically candus. Duffey and others published the future of candu find. Following this successful commercial sale, cge had hoped to. The fuel element design shall be such as to maintain internal gas pressure below that of the coolant under normal operating conditions.
Current candu reactors incorporate a mixture of passive and active design features to protect against a wide variety of accident scenarios. December 31, 1969 every nuclear reactor is a disaster waiting to happen and candu reactors are no exception. The latest, singleunit design of this type is the candu 9, a 935 mwe reactor based on the multiunit darlington and bruce b designs with additional enhancements from ongoing aecl engineering and research programs reference 3. The essential candu is brought to you by unene with administrative and sponsorship support from cog. Candu reactor is a type of nuclear reactor which was developed in canada, and is currently used in nuclear power plants for electrical generation in various countries around the world. The candu development program is aimed at enhancing these two reactor designs. This candu textbook is suitable for students, educators, trainers and working professionals at a target level of senior undergraduate year university engineering and science. A thumbnail description of the candu reactor design along with its unique safety features and control operations is provided, followed by identification of process and systemic cybersecurity several vulnerabilities prevalent in the design and operation of such plants. The first reactor in such a sequence consists of a candu phw operating on a low enriched uranium leu cycle 10. Modular horizontal fuel channel fuel bundle design low temperature, low pressure heavy water moderator onpower fueling passive shutdown systems in low pressure moderator. The candu canada deuterium uranium is a canadian pressurized heavy water reactor.
Reasons for the choice of key parameters are given. All canadian nuclear reactors are of the candu type but the. Table 1 shows the range in outputs available from these three types. Of particular significance is the presence of a large volume of cool heavywater moderator within the core. Some of the design features and unique characteristics of the candu reactor are. Candu reactors are also used in new brunswick and in numerous export markets. This chapter discusses the historical beginnings and evolution of the candu reactor. No need for special borated casks it has few 7 different components. The acronym refers tae its deuterium oxide hivy watter moderator and its use o originally, natural uranium fuel. Advanced technologies for candu reactors pdf free download. The moderator in light water reactors is ordinary water, but the candu heavy water reactor uses heavy water or deuterium oxide, which has a chemical formula of d 2 o.
Atomic energy of canada limited aecl developed the candu reactor technology starting in the 1950s. Candu 9 design, where extensive modularization of components. Identifying vulnerabilities in candu nuclear power plants to. A containment building, in its most common usage, is a reinforced steel or lead structure enclosing a nuclear reactor.
The fuelling operations for these stations begin with the semimanual loading of new fuel. In the case of the candu reactor, where the only initial heavy element in the fuel is uranium, the initial mass of heavy element is the mass of uranium in the bundle. The current design optimized version of the candu reactor is the candu e6 which is available from candu energy inc. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of 275 to 550 kpa 40 to 80 psi citation needed. The results indicated that the dry storage costs for the candu system were about 30% lower than the lwr system. The book will emphasize theory over other aspects of nuclear science. The ca1idu 9 reactor uses the 37elementfuel bundle design ofthe candu 6. Candu reactors achieve these performance objectives through the use of oxide fuel, pressure tubes, moderator tubes and heavy water as both a moderator and as a primary. Candu reactor core design candu is the most efficient of all reactors in using uranium. The candu reactor consists of the horizontal cylinder called the calandria. May 02, 2017 candu, which stands for canada deuterium uranium, is a pressurized heavy water reactor.
Since there is a smaller fraction of fissile material in natural uranium, a somewhat larger reactor core was needed. Introduction this is a descriptive course on the physics of candu reactors. Candu reactors that have, or are still producing cobalt60, include pickering a, pickering b, gentilly 2, embalse in argentina, and bruce b. This distinguishes it from comparable textbooks based on pwr reactors. The candu nuclear reactor got its name because this heavy water reactor design was developed in canadait stands for canada deuterium uranium. The candu canada deuterium uranium is a canadian pressurized heavywater reactor. R9 requirements for emergency core cooling systems for. By the early 2000s, sales prospects for the original candu designs were dwindling due tae the introduction o newer designs from other companies. Chapter 2 genealogy of candu reactors prepared by dr. Heavy water cooled and moderated the only design of heavy water moderated reactor in commercial use is the candu, designed in canada and subsequently exported to several countries. Natural uranium fuel with online fuelling high localization potential suitability for small and medium sized electric grids superior safety performance and economics a proven design based on the highly successful candu 6 reactors the enhanced candu 6. Use of natural uranium widens the source of supply and makes fuel fabrication easier.
Cge had developed this design on the basis of its earlier work in the design of npd. An overview of the early candu program, prepared from information provided by john s. Most countries can manufacture the relatively inexpensive fuel. This record is a remarkable achievement for large construction projects. Candus have a number of serious technical, and safety problems, as well as the unique environmental problem of tritium emissions. Candu 3 candu 6 candu 9 moderator coolant number of fuel channels fuel number of elements in bundle. Reduced project implementation risk for candu 9 has been assured by a thorough program of upfront.
Advanced candu reactor acr700 design meeting with the acrs washington dc january, 2004. Latest ccandu andu design design, the the advanced candu reactor reactor acr, will use slightlyenriched uranium. The main goal of this chapter is to provide a basic knowledge of electrical systems in a candu plant, rather than to examine details of a specific plant. The candu reactor design is extremely flexible and with much space to improve, since the core had been originally designed to optimize the performance of natural uranium fuel and to achieve high neutron economy.
From candu, it takes the heavy water moderator, which gives the design an improved neutron economy that. Risks of the candu reactor design introduction the candu canada deuterium uranium reactor is a pressurized heavy water reactor of canadian design. The essential candu is a textbook about nuclear science and engineering pertaining to candu reactors using candu as the reference design. We will keep proven elements of the candu design, while making significant innovations, including. Furthermore, it is important to note that the existing candu reactors can be converted to use thoriumbased fuel with small changes to the design, and the majority of the reactor systems would not need any modification. Aecl responded bi cancelling candu 9 development an movin tae the advanced candu reactor acr design. This was initiated by unene, administered by candu owners group cog and funded by all candu utilities in canada and. Furthermore, it is important to note that the existing candu reactors can be converted to use thoriumbased fuel with small changes to the design, and the majority of the reactor systems would not. This chapter deals with the operating concepts of a candu nuclear power plant. Candu nuclear power stations have consistently proven to be competitive with other types of nuclear power plants, while offering unique advantages to their operators. Candu canada deutrium uranium it is a canadianinvented,heavy water reactor. Since the energy release depends on the fission rate in the bundle, we can write. Introduction to reactor physics candu owners group.
All canadian nuclear reactors are of the candu type but the reactor has also been marketed abroad until october 2011 aecl marketed and. Design, build, and service reactors in canada and around world. Pressure tube design canada did not have a heavy iindustry ndustry capablecapable of manufacturing a pressure vessel of the required size, so a contract was signed to. Aecl responded by cancelling candu 9 development and moving to the advanced candu reactor acr design. It combines features of the existing candu pressurised heavy water reactors phwr with features of lightwater cooled pressurized water reactors pwr. Design and construction of canadian advanced phwrs dr. Candu fuel is much cheaper than light water reactor ffuel uel candu fuelmanufacturing capability can readily be developed by even small ccountries ountries which purchase candu reactors. Key aspects related to plant control are addressed. Nuclear fission and types of water in steam separators positioned above the core, nuclear reactor like all other thermal power plants, nuclear reactors work by generating heat, which boils water to produce steam to drive the turbogenerators. Advanced candu reactor acr700 builds on candu 6 design, project and operational experience retained traditional candu features. Typically there are two fuel and moderator channel changes during the reactor design working life. Acr700 design aecl presentations to acrs future plant design subcommittee on january, 2004, proj0722. Canadian utilities are no longer building candu reactors because of their high cost and poor performance.
Following this successful commercial sale, cge had hoped to expand its. Bromley 19 30 may 2008 aecl, chalk river laboratories canada heavy water reactors. The enhanced candu 6 ec6 is a 700megawatt mwe generation iii reactor based on the highly successful candu 6 reactor, with a number of safety enhancements included to meet the latest canadian and international standards. The essential candu a textbook on the candu nuclear power plant technology. An effort to rationalize the larger units in a fashion similar tae candu 6 led tae the candu 9. The candu900 reactor design was chosen due to its larger core with higher average burnup 9. Week 2 dynamic characteristics of candu reactors 310 h. Candu fundamentals ii 3 radioactivity spontaneous nuclear processes 19. The current candu products are the 700 mw class candu 6 reactor and the 900 mw class candu 9 reactor.
Aecl is assessing the safety, capital cost and maintainability implications of a more extensive use of passive design features in candu reactors. Deuterium is the primary element in heavy water, and uranium is the fuel used in this reactor class. The basic operation of the candu design is similar to other nuclear reactors. The candu 6 reactor design has been chosen as a reference and a brief description of its main components with typical design parameters follows with a comparison with the candu 9 reactor. The candu 9 design complies or can practically be made to comply with licensing requirements in effect, in canada, on january 1, 1995. This reactor has a unique design using natural or lightly enriched uranium as the fuel and heavy water instead of light water as a moderator. The candu, for canada deuterium uranium, is a canadian pressurized heavywater reactor design used tae generate electric pouer. The second category of fuel cycles seeks to eliminate the intermediate step of employing plutonium fuelled reactors, by introducing distinct and separate fuels, and utilizing the known technology of enrichment. The objective is to familiarize you with the basic concepts and ideas, definitions and quantities which.
It is a type of nuclear reactor that uses natural uranium as fuel,pressurised heavy water as coolant,unpressurised heavy water as moderator and uses pressurized tubes to contain the fuel and circulating coolant. Dry storage costs for spent fuel from a candu reactor design have been compared to those for a typical pressurized light water reactor both normalized to a gross power of mwe 3. Candu reactor owners to produce cobalt60 at various sites. Moderator inlet and outlet tubes direct the moderator through the calandria, then to the external heat exchanger for cooling. Cnl is the designer and developer of the canadian deuterium uranium candu reactor. The acronym refers to its deuterium oxide heavy water moderator and its use of originally, natural uranium fuel. Since the early 1990s, six new candu 6 plants were delivered on or ahead of schedule and on budget. Nuclear power plant systems and operation candu owners group. The candu has the ability to refuel while the reactor is still running whereas other reactors must shut down completely, lowering their capacity factor. Chaplin encyclopedia of life support systems eolss the respective models. Aecl has evolved the advanced candu reactor acr design from its highly successful candu6 design. The far future candux, which is not a specific reactor design.
The ec6 uses natural uranium as a fuel, a heavywater moderator and heavywater coolant in a pressuretube design. The traditional approach to teaching nuclear power plant design and operation has been to begin with the scientific theory and mathematical representation of the fundamental processes. The inherent features of a reactor based on multiple pressure tubes, rather than a single pressure vessel, provide candu with considerable flexibilityfor continuous design improvements. Candu stands for canada deuterium uranium, which reflects the key role of deuterium, or heavy water, which acts as the reactors neutron moderator, a unique trait of the candu. In a nuclear reactor, the heat is the product of nuclear fission. It combines some theoretical aspects with basic operating procedures to explain how the plant operates. The design uses heavy water which contains primarily the element deuterium and the main fuel type is uranium. Perturbations such as fuelling, power changes, temperature changes, and so on tend to move the. Chemistry in candu process systems september 2014 neutral point of water is lowered as temperature is increased, as illustrated by simple calculation the ph of neutral water at 250oc is 5. It demonstrates the maturity of the candu technology.
All nuclear power plants in canada are powered by candu reactors. The moderator is the material in the reactor core that slows down the neutrons released from fission so they cause more fission and sustain the chain reaction. Canadian power reactor fuel design and operating data. Online refueling in a candu reactor is a unique trait that is a major advantage over other reactors such as the pressurized water reactors and boiling water reactors. The candu canada deuterium uranium reactor is a pressurized heavy water reactor of canadian design.
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