Assessment and management of ageing of major nuclear. Candu fundamentals i table of contents 1 objectives 1 1. Each end shield comprises an inner and an outer tubesheet joined by lattice tubes at. Up to this pointwe looked at details ofthe reactor regulating system.
This cns course will present an extensive overview of the important disciplines in candu reactor technology and safety. 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. A candu reactor employs several hundred horizontal fuel channels, only two being shown in figure 1. This text has been prepared to support the nuclear power plant systems and operation course, which has the following main components. Candu reactors are currently operated by several canadian and foreign utilities. The gentilly2 candu 6 reactor is owned and operated by hydro. Introduction this is a descriptive course on the physics of candu reactors. In orderto better understand the overall design ofa candu reactor, itis necessary to discuss the two shutdown systems. This candu textbook is suitable for students, educators, trainers and working professionals at a target level of senior undergraduate year university engineering and. The tubes contain fuel bundles to pick up heat generated from the nuclear fission taking place in the core. Candu canada deuteriumuranium key candu characteristics pressure tubes containing fuel bundles located in cylindrical, low pressure moderator tank or calandria heavy water moderated natural uranium candus are heavy water cooled advanced candu reactor acr is light water cooled 43 units based on the candu. Nuclear power plant systems and operation candu owners group. These were invented and developed in canada in the 1960s, when canada decided that they did not want to build enrichment plants or large pressure vessel manufacturing capabilities. Candu fundamentals ii 3 radioactivity spontaneous nuclear processes 19.
December 31, 1969 every nuclear reactor is a disaster waiting to happen and candu reactors are no exception. The history and current state of canadas candu nuclear reactor. The essential candu is brought to you by unene with administrative and sponsorship support from cog. All nuclear power plants in canada are powered by candu reactors. These reactors are heavy water cooled and moderated pressurized water reactors. Canadian utilities are no longer building candu reactors because of their high cost and poor performance. The temelin nuclear power plant, south bohemia, czech republic. Intro to materials scienceguided inquiry uva 21,999 views.
Figure 11 illustrates how candu reactors produce electricity. Nuclear reactors are used as research tools, as systems for producing radioactive isotope s, and most prominently as energy sources for nuclear power plants. In the heavy water systems of the candu reactor, the proper equations describing the dissociation of heavy water. The calandria is closed and supported by end shields at each end. It is owned and operated by new brunswick power nb power and supplies approximately 30% of the provinces electricity. The company said thursday that a chinese expert panel has given a. Check the cogonline calendar or the downloadable at a glance pdf on cogonline under events to get involved. Candu reactor the candu short for canada deuterium uranium reactor is a canadiandeveloped, pressurized heavy water reactor used for generating. The candu reactor uses either light or heavy water for its coolant. Nuclear reactor types many different reactor systems have been proposed and some of these have been developed to prototype and commercial scale. Apr 01, 20 molten salt reactors the next generation of nuclear power duration. This text has been prepared to support the candu overview. Simply put, a nuclear reactor is a device, which produces heat. 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.
The objective is to familiarize you with the basic concepts and ideas, definitions and quantities which are important in the understanding of reactor physics. Candu stands for canada deuterium uranium, which reflects the key role of deuterium, or heavy water, which acts as the reactor s neutron moderator, a unique. The basic operation of the candu design is similar to other nuclear reactors. Canducanada deutrium uranium it is a canadianinvented,heavy water reactor. Candu, short for canada deuterium uranium, is a nuclear reactor that uses heavy water as a moderator and coolant and natural uranium as a fuel source. Pwr reactor pressure vessels 10, pwr reactor vessel internals 11 and metal components of bwr containment systems 12. The candu reactor design or phwr pressurized heavy water reactor has been developed since the 1950s in canada, and more recently also in india. The candu 6 design as implemented at sites in canada has been chosen as the reference because it is the most widely deployed candu design worldwide. To be followed for a new reactor, or for a mature reactor after very long shutdown. The calandria is filled with non pressurized heavy water acting as moderator. The heat transport system hts circulates the coolant through the reactor to remove the heat of fission from the fuel. The water moderator also functions as the primary coolant in light water reactors. The candu reactor core is a horizontal cylinder known as a calandria. The history and current state of canadas candu nuclear.
Fission reactions in the reactor core heat pressurized water in a primary cooling loop. Risks of the candu reactor design introduction the candu canada deuterium uranium reactor is a pressurized heavy water reactor of canadian design. Nuclear reactor, any of a class of devices that can initiate and control a selfsustaining series of nuclear fission s. The candu is a pressurized heavy water reactor phwr using heavy water deuterium as both a moderator and coolant. A list of existing candu and pressurised heavy water reactors phwrs is given in table i. From candu, it takes the heavy water moderator, which gives the design an improved neutron economy that. Candu reactor purchasers should no longer be concerned about long term storage of used candu fuel because various parties in canada are working on implementation of the ottensmeyer plan to dispose of used candu fuel by recycling this used fuel through liquid sodium cooled fast neutron reactors.
Coolant circulates through a nuclear reactor core to transfer the heat away from it and prevent a meltdown that would halt energy production. In a nuclear power station, the reactor performs the same work as a boiler in a coal, gas or oilfired station. Pdf performance of pressure tubes in candu reactors. Point lepreau was the first candu 6 reactor to be licensed for operation, the first to achieve criticality and first to begin commercial operation. These were invented and developed in canada in the 1960s, when canada decided that they did not want to build enrichment plants. Candu reactor article about candu reactor by the free. Nuclear power energy in pakistan the main part of the plant is designed on the model of chasma nuclear power plant and candu reactor. Candu reactors that have, or are still producing cobalt60, include pickering a, pickering b, gentilly 2, embalse in argentina, and bruce b. A candu reactor requires, in total, between 460 and 592 metric tonnes 1 tonne kg of heavy water, a little more than half of this in the moderator and the rest in the pressurized coolant for example, a candu 6 reactor uses 265 metric tonnes in its moderator and 192 metric tonnes in its coolant.
Heat transfer from fuel to coolant a fuel channel in a candu reactor is normally supplied with up to 25 kgs of coolant and produces up to 7 mw of power. Having been developed to use natural uranium in conve niently small fuel bundles, the candu reactor. Subscribers can get the latest information on specific topic areas for selected candu and industry activities. 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. While candu energy is trying to entice jordan and china to purchase candu reactors, within canada it is unsure whether the newest nuclear plant to be built in ontario will be a candu reactor. Introduction to reactor physics candu owners group. The candu, for canada deuterium uranium, is a canadiandeveloped, pressurized heavy water reactor used to generate electric power. Nov 06, 2014 candu energy says its new nuclear technology, which is able to use spent fuel from other reactors, has cleared a hurdle in china. The basic parts of a nuclear reactor are the core, a moderator, control rods, a coolant, and shielding. Heavy water reactors, hwr candu d 2 o is less effective as a moderator but has much lower neutron cross section. Weaker absorption of neutrons allows the use of natural uranium 0.
Nuclear power nuclear power plant types of reactors candu heavy water reactor. Candu fuel cycle advantages operational reactors nue candu reactor inherent safety features new build reactors afcr future with water coolant dr. 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. Conduct normal and abnormal operations on a simulated candu 9 generating unit, including. It combines features of the existing candu pressurised heavy water reactors phwr with features of lightwater cooled pressurized water reactors pwr. Introduction overall design ofa candu reactor, itis. This candu textbook is suitable for students, educators, trainers and working professionals at a target level of senior undergraduate year university engineering and science.
All canadian nuclear reactors are of the candu type but the. Atomic energy of canada limited aecl developed the candu reactor technology starting in the 1950s. When the external neutron source strength is very low in a candu reactor this state exists before the reactor is first started up, or after a very long reactor shutdown period. Working together on refurbishment candu owners group. Candus have a number of serious technical, and safety problems, as well as the unique environmental problem of tritium emissions. During reactor operation, pressure tube material is subject to high pressure up to 11. Kuran vp, advanced fuel candu reactor workshop on advanced reactors, neaoecd paris, france, april 2017. Candu reactor owners to produce cobalt60 at various sites. Assessment and management of ageing of major nuclear power.
The heavy water coolant is pumped through the reactor cores tubes in a closed loop. It enables those new to candu to learn about candu as an overall system and to pursue specialized topics in depth. The development of the first candu reactor began in 1954 through a partnership between atomic energy of canada ltd. It will also present the major systems in a nuclear plant, as well as the important candu reactor safety principles and. This steam spins large turbines, which in turn drive the generators that produce electricity. Jan 22, 2016 candu reactor the candu short for canada deuterium uranium reactor is a canadiandeveloped, pressurized heavy water reactor used for generating electric power. Because the candu reactor was designed to work with natural uranium, candu fuel can be manufactured from the used depleted uranium found in light water reactor lwr spent fuel. A tsunamitripped power outage and backup generator failures cut off pumps that basted cooling water over the japanese reactor cores, causing at. Candu canada deutrium uranium it is a canadianinvented,heavy water reactor. The essential candu a textbook on the candu nuclear power plant technology. The candu canada deuterium uranium reactor is a pressurized heavy water reactor phwr designed and built by canadian nuclear laboratories since the 1950s. Candu stands for canadian deuterium uranium reactor playing on the north american boast of capability, can do. At the candu owners group coginternational atomic energy agency iaea technical workshop on best practices in candu refurbishment, held dec.
Candu heavy water reactors use natural uranium, of which 0. Typically this recovered uranium ru has a u235 enrichment of around 0. Each fuel channel contains 12 or small fuel bundles, each of which is 50 cm long and 10 cm in diameter, and weighs about 24 kg. Candu energy says its new nuclear technology, which is able to use spent fuel from other reactors, has cleared a hurdle in china. Six types of reactor magnox, agr, pwr, bwr, candu and rbmk have emerged as the designs used to produce commercial electricity around the world. Canada deuterium uranium candu reactors use heavy water as a coolant instead of regular old light water. Known as karachi nuclear power plant kanupp, the commercial power plant is a small 7mw candu reactor, a canadian pressurized heavy water reactor. Candu reactors were first developed in the late 1950s and 1960s by a partnership between atomic energy of canada limited aecl, the hydroelectric. The candu reactor has a modular core, made up of fuel channels. The candu reactor utilizes a pressure tube concept with heavy water moderator and coolant, natural uranium fuel and onpower refueling.
Instead of using a single large reactor vessel as in a pwr or bwr, the. There are also a number of candu type fuel channel design pressurized heavy water reactor phwr units in india, and one in pakistan. Contrary to rrs, the shutdown systems are not active. With no heavy reactor pressure vessel and the possibility of modular construction the erection time of a candu reactor can be shorter than that of some other reactor systems.
Search 63 candu jobs now available on, the worlds largest job site. A heat exchanger, also known as a steam generator, transfers the heat to a secondary cooling loop, which powers a steam turbine with an electric generator attached to it for a typical rankine thermodynamic cycle. The acronym refers to its deuterium oxide heavy water moderator and its use of originally, natural uranium fuel. The course provides an introduction to the basic design, technology, and operation of nuclear reactors. Candu is a pressurized heavy water reactor phwr that uses heavy water deuterium oxide d2o as a moderator and coolant, and natural uranium as its fuel. Reactor assembly the candu 6 reactor assembly, shown in the figure opposite, includes the fuel channels contained in and supported by a horizontal cylindrical tank known as the calandria. Molten salt reactors the next generation of nuclear power duration. Inspection of candu reactor pressure tubes using ultrasonics.