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. The basic operation of the candu design is similar to other nuclear reactors. The candu canada deuterium uranium is a canadian pressurized heavywater reactor design used to generate electric power. All nuclear power plants in canada are powered by candu reactors. It is based on advances made in nuclear power utilization and computational methods over the past 40 years, covering core design of boiling water reactors and pressurized water reactors, as well as fast reactors and hightemperature gascooled reactors. A short history of the candu nuclear power system 5 revision 2, december 2002. 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 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. I will highlight some of the achievements in the development of candu, taken from the new book canada enters the nuclear age. The growing trend towards more competitive electricity markets worldwide will also discourage candu sales, because nuclear power. The advanced candu reactor acr 1,2,3,4 represented the continuing evolution of candu design to match changing market conditions. Candu reactor explained everything explained today.
All canadian nuclear reactors are of the candu type but the reactor has also been marketed abroad until october 2011 aecl marketed and. The phenomena of the accidents is coupled to the logicprobabilistics of the plant, including plant systems and operator actions. 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. Nov 07, 2014 candu6 heattransport system design reactor coolant parameters outlet header pressure 10 mpa outlet header temperature 310. Candu reactors are unique in that they use natural, unenriched uranium as a fuel. This extracts a further 3040% energy from the uranium. Kuran vp, advanced fuel candu reactor workshop on advanced reactors, neaoecd paris, france, april 2017. December 31, 1969 every nuclear reactor is a disaster waiting to happen and candu reactors are no exception.
In short, it would be quite possible for a potential proliferator to make a nuclear explosive from reactorgrade plutonium using a simple design that would be assured of having a yield in the range of one to a. This was initiated by unene, administered by candu owners group cog and funded by all candu utilities in canada and offshore with prof. Candu was designed for natural uranium with only 0. Cge had developed this design on the basis of its earlier work in the. Like the candu 6, the candu 9 is essentially a repackaging of the bruce design, so that it can be built as a singlereactor unit. Exporting disaster the cost of selling candu reactors 1. The basic parts of a nuclear reactor are the core, a moderator, control rods, a coolant, and shielding. The reactor, refueling machine, and fuel designs are illustrated and. With a more sophisticated design, weapons can be built with reactorgrade plutonium that would be assured of having higher yields. Business business, international chemicals, plastics and rubber fuel reprocessing nuclear reactors analysis nuclear fuels nuclear industry production management nuclear power plants plutonium usage pressurized water reactors thermodynamics reactor fuel reprocessing. Investigation of candu reactors as a thorium burner. Candu energy enacts contingency plans as workers hit the. The candu canada deuterium uranium is a canadian pressurized heavy water reactor. It combines features of the existing candu pressurised heavy water reactors phwr with features of lightwater cooled pressurized water reactors pwr.
Canada deuterium uranium candu reactors use heavy water as a coolant instead of regular old light water. The essential candu a textbook on the candu nuclear power plant technology. The term heavy water reactor is a catch all term as it includes a broad range of reactor designs running from the rmbk right the way over to the candu design. Fortunately, the candus basic design means the rods in ontarios reactors are already surrounded by a huge pool of cool water, says jerry hopwood, vicepresident of product development at. A heavywater design can sustain a chain reaction with a lower concentration of fissile atoms than lightwater reactors, allowing it to use some alternative fuels. Nuclear power plant systems and operation candu owners group. The candu reactor, however, has pressure tubes rather than a pressure vessel enclosing the reactor core, which makes refuelling under load possible by disconnecting individual pressure tubes onpower refuelling. Diagrams and text have also been based on various aecl and ontario hydro training. Analysis of control rod drop accidents for the canadian scwr using coupled 3dimensional neutron kinetics and thermal hydraulics. From candu, it takes the heavy water moderator, which gives the design an improved neutron economy that. However, the open literature describing these established methods is quite sparse, especially with regard to the unique advantages in operability and safety that arise from the computerdriven reactor regulating system rrs. Contrary to the myth of candu superiority, in 1995, the load factor for candu reactors worldwide was 61. 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. Nuclear reactor design an advanced course in nuclear.
Candu fuel cycle advantages operational reactors nue candu reactor inherent safety features new build reactors afcr future with water coolant dr. The enhanced candu 6tm reactor generation iii candu medium size global reactor s. Apr 01, 2011 fortunately, the candus basic design means the rods in ontarios reactors are already surrounded by a huge pool of cool water, says jerry hopwood, vicepresident of product development at. By 1994, the average lifetime capacity factor at ontario hydros 20 reactors was 73. The material for this text is based principally on the candu 9 480nu technical description, aecl document 69071ted001 rev.
The reactor, refueling machine, and fuel designs are illustrated and discussed under candu reactor and fuel design. Controlled fission in the several hundred fuel channels of a candu reactor generates heat. The present book is an attempt to approach dynamic psa in generic candu 6 reactor design. The candu 9 uses the same 37element fuel bundle design as the other operating. The acr was introduced as a lowerpriced option compared to a larger version of the candu design then being considered, the candu 9. The acronym refers to its deuterium oxide heavy water moderator and its use of originally, natural uranium fuel. Heavy water reactors an overview sciencedirect topics. The calandria tubes, made of zircalloy2, are arranged in square arrays in the d 2 o moderator at low temperature 9 the candu reactor design imposes a combination of neutron stress, pressure stress, erosion and fretting on the fuel channels and related coolant flow path components. All canadian nuclear reactors are of the candu type but the. The candu reactor consists of the horizontal cylinder called the calandria. A candu reactor design 1 fuel bundle, 2 calandria, 3 adjuster rods, 4 heavy water pressure reservoir, 5 steam generator, 6 light water pump, 7 heavy water pump, 8 fueling machines, 9 heavy water moderator, 10 pressure tube, 11 steam going to steam turbine, 12 cold water returning from turbine, containment building source. This book focuses on core design and methods for design and analysis. As a result, a candu reactor has a positive void coefficient of reactivity. Heavy water reactors use heavy water d 2 0 deuterium as opposed to hydrogen as both a moderator, and in many cases a coolant also.
Candu is the most efficient of all reactors in using uranium. Fission reactions in the reactor core heat pressurized water in a primary cooling loop. Reduced project implementation risk for candu 9 has been assured by a thorough program of upfront. During operation some state variables change and others are manipulated, causing the reactors state vector operating trajectory to wander like a worm in the ndimensional space as time progresses. What is the best book to study the reactor design, foglar. Being able to always maintain control of the nuclear chain reaction at all times is very important. The heavy water in the moderator system is normally not highly pressurized. It enables those new to candu to learn about candu as an overall system and to pursue specialized topics in depth.
The cool heavy water in the calandria can be seen in pink, along with partially inserted. The current candu products are the 700 mw class candu 6 reactor and the 900 mw class candu 9 reactor. Candu heavy water reactors use natural uranium, of which 0. Approaching dynamic psa within candu 6 npps paperback may 9. Candu reactors were first developed in the late 1950s and 1960s by a partnership between atomic energy of canada limited aecl. Phw power reactor fuel bundle design, and describes the various designs. The candu reactors cooling water tubes are pressurized to 1525 pounds per square inch, lower than pressurized water designs. Canducanada deutrium uranium it is a canadianinvented,heavy water reactor. In the candu design, the heavy water moderator circulates through a large tank called the calandria and through the. The primary loop is in yellow and orange, the secondary in blue and red. The enhanced candu 6tm reactor generation iii candu.
Assume that the reactor has been designed to operate under design center conditions. The phenomena of the accidents is coupled to the logicprobabilistics of. There have been two major types of candu reactors, the original design of around. The name refers to its design power in the 1,000 mwe class, with the baseline around 1,200 mwe. Like the candu 6, the candu 9 is essentially a repackaging of the bruce design so it can be built as a singlereactor unit. Acr was slightly larger but less expensive to build and run.
A short history of the candu nuclear power system 3 revision 2, december 2002 canada made two early entries into the international power reactor supply field. One of the contributing factors leading up to the accident at the chernobyl nuclear power plant was the design of. The chapter includes a note on the advantages of the candu. Part 5 heavy water and candu reactors daryanenergyblog. Candu advantages candu stands for canada deuterium uranium, because it was invented in canada, uses deuterium oxide also known as heavy water as a moderator, and uranium as a fuel. The paper investigates the prospects of exploiting the rich world thorium reserves in candu reactors. Candu reactor article about candu reactor by the free.
Capacity factor is the reactors actual electricity production divided by perfect output what the reactor would produce if it always operated at its design rating. Yu, evolutionary candu 9 plant improvements, international. These combined stresses limit the fuel channel working life to about 20 years and the reactor working life to about 60 years. Candu power reactor designers and operators are fully aware of the need for caution in starting up power reactors. The first step is the design of the reactor itself. The fuel assemblies lie horizontally in tubes through which heavywater coolant flows under pressure. This candu textbook is suitable for students, educators, trainers and working professionals at a target level of senior undergraduate year university engineering and science. Through the 1980s and 1990s the nuclear power market suffered a major crash, with few new plants being. The essential candu is brought to you by unene with administrative and sponsorship support from cog. Aecl has evolved the advanced candu reactor acr design from its highly successful candu6 design. Given that nobody is advocating the building of more rmbks, indeed its difficult to believe the. Risks of the candu reactor design introduction the candu canada deuterium uranium reactor is a pressurized heavy water reactor of canadian design. As was the case for the development of the pickering design into the candu 6, the bruce design was also developed into the similar candu 9.
This record is a remarkable achievement for large construction projects. Id say fogler, for problems and easy comprehension of the fundamentals of ideal reactor design chapters 1 9, levenspiel is an excellent book once youve adquired basic knowledge, and it. Canadian utilities are no longer building candu reactors because of their high cost and poor performance. Since there is a smaller fraction of fissile material in natural uranium, a somewhat larger reactor core was needed. The candu canada deuterium uranium reactor is a pressurized heavy water reactor phwr designed and built by canadian nuclear laboratories since the 1950s. Moderator inlet and outlet tubes direct the moderator through the calandria, then to the external heat exchanger for cooling. Since the early 1990s, six new candu 6 plants were delivered on or ahead of schedule and on budget. It demonstrates the maturity of the candu technology. The neutronic calculations are based on a gentillyii design modified to a canduthorium reactor, as described in refs. Aecl is currently offering a new version of the candu design concept.
With the successful candu6 design well established, aecl is developing two further candu designs, a smaller 450 mw candu3 and a larger candu 9 in the 900. An important operational feature of the candu reactor design is that it can be refuelled while. These were invented and developed in canada in the 1960s, when canada decided that they did not want to build enrichment plants. It is based on advances made in nuclear power utilization and computational methods over the past 40 years, covering core design of boiling water reactors and pressurized water reactors, as well as. Risks of operating candu 6 nuclear power plants banktrack. The canadian supercritical watercooled reactor scwr design is the result of the fusion of a candu reactor and a boiling water reactor bwr 1. The enhanced candu 6 ec6 is a 740 mwe class heavy water moderated pressure tube reactor, designed to provide safe, reliable, nuclear power. The candu canada deuterium uranium reactor is a pressurized heavy water reactor of canadian design. 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. Candu canada deutrium uranium it is a canadianinvented,heavy water reactor. Reactor grade plutonium can be used as a booster fissile fuel material in the form of mixed tho 2 puo 2 fuel in a candu fuel bundle in order to assure reactor criticality.
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