why do nuclear power plants use uranium
Uranium is a silvery-white metal and a primary energy source. After raw uranium is mined and milled, it is processed to make fuel for nuclear reactors to generate electricity. Nuclear energy is a major part of the Canadian landscape from coast to coast. Nuclear power stations operate in Ontario and New Brunswick. Uranium mining, refining and fuel fabrication steps are completed in Saskatchewan and Ontario. There is a strong nuclear science and technology presence across Canada, including the production of isotopes for medical and industrial applications. Uranium is primarily used to produce fuel for nuclear power plants (more than 99% of total use). Other uses of uranium (less than 1%) include the production of medical isotopes and fuel for research reactors. Canadian production of uranium was 14 kilotonnes in 2016. All uranium comes from mines in Saskatchewan and has an annual value of approximately $2 billion
Further refining and conversion of uranium occurs in Ontario to produce uranium hexafluoride and uranium dioxide. Approximately 88% of Canadaвs uranium production is exported. In 2016, these exports had a total value of over $1. 8 billion. Based on long-term contracts (whose values can vary based on changes in regional demand), uranium from Canadian mines is generally sold in Asia (49%), North America/Latin America (31%) and Europe (20%). In 2016, 22% of uranium purchased by U. S. nuclear reactors came from Canada, making Canada the largest foreign supplier of uranium to the U. S. Domestic use in Canadaвs CANDU reactors in Ontario and New Brunswick is approximately 12% of production.
There are 6 nuclear power stations in Canada, which have a combined capacity of 14,299 megawatts. The Bruce generating station is the largest operating nuclear power plant in the world. The majority of Canadian uranium production is sold via long-term contract, as opposed to the spot market. In the short term, spot prices do not have a significant impact on the annual value of Canadaвs uranium production. The average monthly spot market uranium price declined steadily throughout 2015 and 2016 to reach a 12-year low of US$18 per pound before rebounding to US$20 per pound by the end of 2016. Canada has nuclear research and development capabilities that are supported by academic research centres, the private sector and government laboratoriesвincluding Chalk River Laboratories, Canadaвs largest science and technology complex. Nuclear energy research is focused on supporting existing reactor technologies as well as next-generation nuclear energy systems. Canada is also a leader in nuclear R D for areas such as nuclear medicine, pharmacology, environmental protection and wastewater treatment, among others. Small modular reactors (SMRs) are nuclear reactors that operate at a smaller scale than current nuclear power plants. Although not yet commercially proven in Canada, they may have future applications as a replacement to fossil fuel power plants or as load-following units equipped with systems for storing excess electricity to complement larger shares of variable renewables. SMRs may also have applications in the production of heat and electricity at both on- and off-grid industrial sites, and to help off-grid northern and remote communities reduce their reliance on diesel.
Canada has developed a unique and is one of roughly half a dozen countries that offer domestic-designed reactors to the open commercial market. In addition to Canada, CANDU reactors have been sold to India, Pakistan, Argentina, South Korea, Romania and China. CANDU technology continues to evolve to enable the use of alternative fuels. Work is under way in Chinese CANDU reactors to demonstrate that they can recycle used fuel from other nuclear power plants, reducing the volume of nuclear waste. Learn more about. See Large, John H: Radioactive Decay Characteristics of Irradiated Nuclear Fuels, January 2006. In the oxide, intense temperature gradients exist which cause to migrate. The tends to move to the centre of the fuel where the is highest, while the lower-boiling fission products move to the edge of the pellet. The pellet is likely to contain lots of small -like pores which form during use; the fission migrates to these voids. Some of this xenon will then decay to form, hence many of these bubbles contain a large concentration of Cs. In the case of mixed oxide ( ) fuel, the xenon tends to diffuse out of the plutonium-rich areas of the fuel, and it is then trapped in the surrounding uranium dioxide. The tends to not be mobile. Also metallic particles of an of Mo-Tc-Ru-Pd tend to form in the fuel. Other solids form at the boundary between the uranium dioxide grains, but the majority of the fission products remain in the as.
A paper describing a method of making a non- "uranium active" simulation of spent oxide fuel exists. Pu (also indirect products in the ); these are considered or may be separated further for various industrial and medical uses. The fission products include every element from through to the ; much of the fission yield is concentrated in two peaks, one in the second transition row (, Mo, Tc, ) and the other later in the periodic table (, Nd). Many of the fission products are either non-radioactive or only short-lived. But a considerable number are medium to long-lived radioisotopes such as Sr, Cs, I. Research has been conducted by several different countries into segregating the rare isotopes in fission waste including the "fission platinoids" (Ru, Rh, Pd) and silver (Ag) as a way of offsetting the cost of reprocessing; however, this is not currently being done commercially. The fission products can modify the properties of the uranium dioxide; the oxides tend to lower the thermal conductivity of the fuel, while the nanoparticles slightly increase the thermal conductivity of the fuel. Pu and U, which may be considered either as a useful byproduct, or as dangerous and inconvenient waste. One of the main concerns regarding is to prevent this plutonium from being used by states, to produce nuclear weapons. If the reactor has been used normally, the, not weapons-grade: it contains more than 19% Pu, which makes it not ideal for making bombs. If the irradiation period has been short then the plutonium is weapons-grade (more than 80%, up to 93%).
U. Usually U would be less than 0. 83% of the mass along with 0. 4% U. will contain, which is not found in nature; this is one isotope which can be used as a for spent reactor fuel. If using a fuel to produce fissile U-233, the SNF (Spent Nuclear Fuel) will have U-233, with a half-life of 159,200 years (unless this uranium is removed from the spent fuel by a chemical process). The presence of U-233 will affect the long-term of the spent fuel. If compared with, the activity around one million years in the cycles with thorium will be higher due to the presence of the not fully decayed U-233. For fuel: Fissile component starts at 0. 71% U concentration in natural uranium. At discharge, total fissile component is still 0. 50% (0. 23% U, 0. 27% fissile Pu, Pu) Fuel is discharged not because fissile material is fully used-up, but because the have built up and the fuel becomes significantly less able to sustain a nuclear reaction. Some natural uranium fuels use chemically active cladding, such as, and need to be reprocessed because long-term storage and disposal is difficult. Traces of the are present in spent reactor fuel. These are other than uranium and plutonium and include, and. The amount formed depends greatly upon the nature of the fuel used and the conditions under which it was used. For instance, the use of MOX fuel ( Th matrix). For highly enriched fuels used in and, the isotope inventory will vary based on in-core fuel management and reactor operating conditions.
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