World Uranium Mining Production

(Updated July 2013)
http://www.world-nuclear.org/

About 64 percent of the world's production of uranium from mines is from Kazakhstan, Canada and Australia.
An increasing proportion of uranium, now 45%, is produced by in situ leaching.
After a decade of falling mine production to 1993, output of uranium has generally risen since then and now meets 86% of demand for power generation.

Kazakhstan produces the largest share of uranium from mines (36.5% of world supply from mines in 2012), followed by Canada (15%) and Australia (12%).

Production from mines (tonnes U)

Country	2005	2006	2007	2008	2009	2010	2011	2012
Kazakhstan	4357	5279	6637	8521	14020	17803	19451	21317
Canada	11628	9862	9476	9000	10173	9783	9145	8999
Australia	9516	7593	8611	8430	7982	5900	5983	6991
Niger (est)	3093	3434	3153	3032	3243	4198	4351	4667
Namibia	3147	3067	2879	4366	4626	4496	3258	4495
Russia	3431	3262	3413	3521	3564	3562	2993	2872
Uzbekistan	2300	2260	2320	2338	2429	2400	2500	2400
USA	1039	1672	1654	1430	1453	1660	1537	1596
China (est)	750	750	712	769	750	827	885	1500
Malawi					104	670	846	1101
Ukraine (est)	800	800	846	800	840	850	890	960
South Africa	674	534	539	655	563	583	582	465
India (est)	230	177	270	271	290	400	400	385
Brazil	110	190	299	330	345	148	265	231
Czech Republic	408	359	306	263	258	254	229	228
Romania (est)	90	90	77	77	75	77	77	90
Germany	94	65	41	0	0	8	51	50
Pakistan (est)	45	45	45	45	50	45	45	45
France	7	5	4	5	8	7	6	3
total world	41 719	39 444	41 282	43 764	50 772	53 671	53 493	58 394
tonnes U₃O₈	49 199	46 516	48 683	51 611	59 875	63 295	63 084	68 864
percentage of world demand*	65%	63%	64%	68%	78%	78%	85%	86%

*WNA Market Report data

Mining methods have been changing. In 1990, 55% of world production came from underground mines, but this shrunk dramatically to 1999, with 33% then. From 2000 the new Canadian mines increased it again, and with Olympic Dam it is now 37%. In situ leach (ISL, or ISR) mining has been steadily increasing its share of the total, mainly due to Kazakhstan. In 2012 production was as follows:

Method	tonnes U	%
Conventional underground (except Olympic Dam)*	16,324	27.9%
Conventional open pit	11,906	20.4%
In situ leach (ISL)	26,263	45.0%
By-product*	3851	6.6%

* Considering Olympic Dam as by-product rather than in underground category

Conventional mines have a mill where the ore is crushed, ground and then leached with sulfuric acid to dissolve the uranium oxides. At the mill of a conventional mine, or the treatment plant of an ISL operation, the uranium then separated by ion exchange before being dried and packed, usually as U3O8. Some mills and ISL operations use carbonate leaching instead of sulfuric acid, depending on the orebody. Where uranium is recovered as a by-product, eg of copper or phosphate, the treatment process is likely to be more complex.

During the 1990s the uranium production industry was consolidated by takeovers, mergers and closures, but this has diversified in recent years with Kazakhstan's diverse ownership structure. In 2012, eight companies marketed 88% of the world's uranium mine production:

Company	tonnes U	%
KazAtomProm	8863	15
Areva	8641	15
Cameco	8437	14
ARMZ - Uranium One	7629	13
Rio Tinto	5435	9
BHP Billiton	3386	6
Paladin	3056	5
Navoi	2400	4
Other	10,548	18
Total	58 394	100%

The largest-producing uranium mines in 2012 were:

Mine	Country	Main owner	Type	Production (tU)	% of world
McArthur River	Canada	Cameco	underground	7520	13
Olympic Dam	Australia	BHP Billiton	by-product/ underground	3386	6
Ranger	Australia	ERA (Rio Tinto 68%)	open pit	3146	5
Arlit	Niger	Somair/ Areva	open pit	3065	5
Tortkuduk (est)	Kazakhstan	Katco JV/ Areva	ISL	2661	5
Rossing	Namibia	Rio Tinto (69%)	open pit	2289	4
Budenovskoye 2	Kazakhstan	Karatau JV/Kazatomprom-Uranium One	ISL	2135	4
Kraznokamensk	Russia	ARMZ	underground	2011	3
Langer Heinrich	Namibia	Paladin	open pit	1955	3
South Inkai	Kazakhstan	Betpak Dala JV/ Uranium One	ISL	1870	3
Inkai	Kazakhstan	Inkai JV/Cameco	ISL	1701	3
Central Mynkuduk	Kazakhstan	Ken Dala JV/ Kazatomprom	ISL	1622	3
Akouta	Niger	Cominak/ Areva	underground	1506	3
Rabbit Lake	Canada	Cameco	underground	1479	3
Budenovskoye 1&3	Kazakhstan	Akbastau JV/ Kazatomprom-Uranium One	ISL	1203	2
Top 15 total				37 549	64%

Source:World Nuclear Association

New Mines

Since the recovery of uranium prices since about 2003, there has been a lot of activity in preparing to open new mines in many countries. The WNA reference scenario projects world uranium demand as about 72,680 tU in 2015, and most of this will need to come directly from mines (in 2010, 22% came from secondary sources and this shrunk to 14% in 2012).

Some of the new mines expected to reach substantial production in the next few years are:

Vitimsky	Russia	2013
Four Mile	Australia	2013
Cigar Lake	Canada	2013
Talvivaara (by-product)	Finland	2014
Imouraren	Niger	2015
Husab	Namibia	2015

Estimated future production from existing mines plus new projects such as these is however not sufficient to meet the demand requirements to 2030 in the WNA 2011 Market Report (2030 demand 137,000 tU in upper scenario, 108,000 tU in reference scenario; 2030 primary production 97,000 tU in upper scenario, 89,000 tU in reference scenario). However, price signals leading to increased production and also secondary sources will close the gap.

Known Recoverable Resources of Uranium 2011

http://www.world-nuclear.org/Nuclear-Basics/

	tonnes U	percentage of world
Australia	1,661,000	31%
Kazakhstan	629,000	12%
Russia	487,200	9%
Canada	468,700	9%
Niger	421,000	8%
South Africa	279,100	5%
Brazil	276,700	5%
Namibia	261,000	5%
USA	207,400	4%
China	166,100	3%
Ukraine	119,600	2%
Uzbekistan	96,200	2%
Mongolia	55,700	1%
Jordan	33,800	1%
other	164,000	3%
World total	5,327,200

Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/11, from OECD NEA & IAEA, Uranium 2011: Resources, Production and Demand ("Red Book").
The total to US$ 260/kg U is 7,096,600 tonnes U, and Namibia moves up ahead of Niger.

Sources:

World Nuclear Association

Nuclear Basics

Answering some of the key questions about nuclear energy

Did you know...? Nuclear energy is used to generate around 11% of the world's electricity, with almost no greenhouse gas emissions.

Did you know...? A single uranium fuel pellet contains as much energy as 480 cubic metres of natural gas, 807 kilos of coal or 149 gallons of oil.

Did you know...? Nuclear energy is used by more than 30 countries around the world. Nuclear technologies have many uses, including powering Mars rovers.

Did you know...? Nuclear power plants can generate electricity continuously for many months at a time, without interruption.

Electricity generation - what are the options?

Every form of electricity generation has its strengths and weakness. The global demand for electricity is rising, and future electricity generation will need a range of options, although they must be low carbon if greenhouse gas emissions are to be reduced. Nuclear generation provides reliable supplies of electricity, with very low carbon emissions and relatively small amounts of waste that can be safely stored and eventually disposed of.

Electricity is vital to modern life. It powers our lights and appliances at home. It powers many industry processes. It is used to power trains and to charge electric vehicles.

Globally, electricity use is rising rapidly as new major economies develop in places such as China and India.

This need for electricity drives a growing demand for electricity generation, with thousands of new power plants needed across the world over the coming decades.

For many decades almost all the electricity consumed in the world has been generated from three different forms of power plant - fossil, hydro and nuclear. Renewables currently generate a relatively small share of the world's electricity, although that share is growing fast.

Fossil

Fossil fuel power plants burn carbon fuels such coal, oil or gas to generate steam that drives large turbines that produce electricity. These plants can generate electricity reliably over long periods of time. However, by burning carbon fuels they produce large amounts carbon dioxide, which causes climate change. They can also produce other pollutants, such as sulphurous oxides, which cause acid rain.

Fossil fuel plants require huge quantities of coal, oil or gas. These fuels may need to be transported over long distances. The price of fuels can rise sharply at times of shortage, leading to unstable generation costs.

Large hydro

Large hydro power plants generate electricity by storing water in vast reservoirs behind massive dams. Water from the dams flows through turbines to generate electricity, and then goes on to flow through rivers below the dam.

Hydro dams can generate large amounts of electricity. However, dry periods can drain the reservoirs. The flooding of reservoirs behind dams and slowing of the flow of the river below the dam can have a serious impact on the ecology around the dam. The number of sites suitable for new dams is limited.

Nuclear

Nuclear power plants use the heat produced by nuclear fission to generate steam that drives turbines, like in fossil fuel plants. However, no greenhouse gases are produced in this fission process, and only small amounts are produced across the whole fuel cycle.

Nuclear fuel can be used in a reactor for several years. The used fuel that remains after this time must be stored and then either recycled to make new fuel or carefully disposed of. However, because the amount of fuel used to generate electricity is so much less than that used in fossil fuel plants it is much more practical to do this with used nuclear fuel than with the wastes and emissions from fossil fuels.

Nuclear power plants can run for many months without interruption, providing reliable and predictable supplies of electricity.

Nuclear power plants can generate electricity "24/7" for many months at a time, without interruption. Nuclear generation is one of the safest and least environmentally damaging forms of electricity generation

Renewables

Renewables such as wind, solar and small scale hydro produce electricity with no greenhouse gas emissions at the point of generation and very low amounts of greenhouse gas emissions across their entire lifecycle.

The cost of electricity generation from many renewables tends to be higher than other forms of generation, often requiring subsidies to compete with other forms of generation, although these costs are coming down.

Many renewables do not produce electricity predictably or consistently. Electricity generation from wind turbines varies with the wind speed, and if that wind is too weak or too strong no electricity is produced at all. The output of solar panels is reliant on the strength of the sunshine, which depends on the time of day and the amount of cloud cover. This means that renewables have to be backed up by other forms of electricity generation, often fossil fuel generation with their resultant greenhouse gas emissions.

What is radiation?

http://www.world-nuclear.org/Nuclear-Basics/What-is-radiation-/#.UhbYHn-N6So

Radiation is energy travelling through space.

Sunshine is one of the most familiar forms of radiation. It delivers light, heat and suntans. While enjoying and depending on it, we control our exposure to it.

Beyond ultraviolet radiation from the sun are higher-energy kinds of radiation which are used in medicine and which we all get in low doses from space, from the air, and from the earth and rocks.

Collectively we can refer to these kinds of radiation as ionising radiation. It can cause damage to matter, particularly living tissue. At high levels it is therefore dangerous, so it is necessary to control our exposure.

While we cannot feel this radiation, it is readily detected and measured, and exposure can easily be monitored.

Living things have evolved in an environment which has significant levels of ionising radiation.

Furthermore, many people owe their lives and health to such radiation produced artificially. Medical and dental X-rays discern hidden problems. Other kinds of ionising radiation are used to diagnose ailments, and some people are treated with radiation to cure disease.

Ionising radiation, such as occurs from uranium ores and nuclear wastes, is part of our human environment, and always has been so. At high levels it is hazardous, but at low levels such as we all experience naturally, it is harmless. Considerable effort is devoted to ensuring that those working with nuclear power are not exposed to harmful levels of radiation from it. Standards for the general public are set about 20 times lower still, well below the levels normally experienced by any of us from natural sources.

Background radiation is that ionizing radiation which is naturally and inevitably present in our environment. Levels of this can vary greatly. People living in granite areas or on mineralised sands receive more terrestrial radiation than others, while people living or working at high altitudes receive more cosmic radiation. A lot of our natural exposure is due to radon, a gas which seeps from the Earth's crust and is present in the air we breathe.

Radioactivity in material

Apart from the normal measures of mass and volume, the amount of radioactive material is measured in Becquerel (Bq), which enables us to compare the typical radioactivity of some natural and other materials. A Becquerel is one atomic decay per second, so a household smoke detector with 30,000 Bq contains enough americium to produce that much disintegration per second. A kilogram of coffee or granite might have 1000 Bq of activity and an adult human 7000 Bq. Each atomic disintegration produces some ionizing radiation.

Ionising radiation - alpha, beta and gamma

Ionising radiation comes from the nuclei of atoms, the basic building blocks of matter. Most atoms are stable, but certain atoms change or disintegrate into totally new atoms. These kinds of atoms are said to be 'unstable' or 'radioactive'. An unstable atom has excess internal energy, with the result that the nucleus can undergo a spontaneous change. This is called 'radioactive decay'.We all experience radiation from natural sources every day

An unstable nucleus emits excess energy as radiation in the form of gamma rays or fast-moving sub-atomic particles. If it decays with emission of an alpha or beta particle, it becomes a new element. One can describe the emissions as gamma, beta and alpha radiation. All the time, the atom is progressing in one or more steps towards a stable state where it is no longer radioactive.

Alpha particles consist of two protons and two neutrons, in the form of atomic nuclei. Alpha particles are doubly charged (arising from the charge of the two protons). This charge and the relatively slow speed and high mass of alpha particles means that they interact more readily with matter than beta particles or gamma rays and lose their energy quickly. They therefore have little penetrating power and can be stopped by the first layer of skin or a sheet of paper. But inside the body they can inflict more severe biological damage than other types of radiation.

Beta particles are fast-moving electrons ejected from the nuclei of many kinds of radioactive atoms. These particles are singly charged (the charge of an electron), are lighter and ejected at a much faster speed than alpha particles. They can penetrate up to 1 to 2 centimetres of water or human flesh. They can be stopped by a sheet of aluminium a few millimetres thick.

Gamma rays, like light, represent energy transmitted in a wave without the movement of material, just like heat and light. Gamma rays and X-rays are virtually identical except that X-rays are generally produced artificially rather than coming from the atomic nucleus. But unlike light, these rays have great penetrating power and can pass through the human body. Mass in the form of concrete, lead or water is used to shield us from them.

The effective dose of all these kinds of radiation is measured in a unit called the Sievert, although most doses experienced are much lower than a Sievert, so figures are given in millisieverts (mSv), which are one-thousandth of a Sievert.

How uranium ore is made into nuclear fuel

http://www.world-nuclear.org/Nuclear-Basics/How-is-uranium-ore-made-into-nuclear-fuel-/#.UhbYu3-N6So

Uranium is a naturally-occurring element in the Earth's crust. Traces of it occur almost everywhere, although mining takes place in locations where it is naturally concentrated. To make nuclear fuel from the uranium ore requires first for the uranium to be extracted from the rock in which it is found, then enriched in the uranium-235 isotope, before being made into pellets that are loaded into the nuclear fuel assembly.

Mining

Uranium mines operate in some twenty countries, though about half of world production comes from just ten mines in six countries, in Canada, Australia, Niger, Kazakhstan, Russia and Namibia.

At conventional mines, the ore goes through a mill where it is first crushed. It is then ground in water to produce a slurry of fine ore particles suspended in the water. The slurry is leached with sulphuric acid to dissolve the uranium oxides, leaving the remaining rock and other minerals undissolved.

However, nearly half the world's mines now use a mining method is in sit leaching (ISL). This means that the mining is accomplished without any major ground disturbance. Groundwater with a lot of oxygen injected into it is circulated through the uranium ore, extracting the uranium. The solution with dissolved uranium is pumped to the surface.

Both mining methods produce a liquid with uranium dissolved in it. This is filtered and the uranium then separated by ion exchange, precipitated from the solution, filtered and dried to produce a uranium oxide concentrate (U₃O₈), which is then sealed in drums. This concentrate is a bright yellow colour, and is known as 'yellowcake'.

The U₃O₈ is only mildly radioactive. (The radiation level one metre from a drum of freshly-processed U₃O₈ is about half that - experienced from cosmic rays - on a commercial jet flight.)

U3O8 or Yellowcake

Enrichment

The vast majority of all nuclear power reactors require 'enriched' uranium fuel in which the proportion of the uranium-235 isotope has been raised from the natural level of 0.7% to about 3.5% to 5%. The enrichment process needs to have the uranium in gaseous form, so on the way from the mine it goes through a conversion plant which turns the uranium oxide into uranium hexafluoride (UF₆).

The enrichment plant removes about 85% of the uranium by separating gaseous uranium hexafluoride into two streams: One stream is enriched to the required level and then passes to the next stage of the fuel cycle. The other stream is depleted in U-235 and is called 'tails'. It is mostly uranium-238 and has little immediate use.

Today's enrichment plants use the centrifuge process, with thousands of rapidly-spinning vertical tubes. Research is being conducted into laser enrichment, which appears to be a promising new technology.

A small number of reactors, notably the Canadian CANDU reactors, do not require uranium to be enriched.

Fuel fabrication

27 tonnes of fresh fuel is required each year by a 1000 MWe nuclear reactor. In contrast, a coal power station requires more than two and a half million tonnes of coal to produce as much electricity. ₍₁₎Enriched UF₆ is transported to a fuel fabrication plant where it is converted to uranium dioxide (UO₂) powder. This powder is then pressed to form small fuel pellets, which are then heated to make a hard ceramic material. The pellets are then inserted into thin tubes to form fuel rods. These fuel rods are then grouped together to form fuel assemblies, which are several meters long.

The number of fuel rods used to make each fuel assembly depends on the type of reactor. A PWR (pressurised water reactor) may use between 121-193 fuel assemblies, each consisting of between 179-264 fuel rods. A BWR (boiling water reactor) has between 91-96 fuel rods per assembly, with between 350-800 fuel assemblies per reactor.

Nuclear Fuel Assembly

(1) http://www.iaea.org/Publications/Booklets/Development/devnine.html

How a nuclear reactor makes electricity

http://www.world-nuclear.org/Nuclear-Basics/How-does-a-nuclear-reactor-make-electricity-/#.UhbZan-N6So

A nuclear reactor produces and controls the release of energy from splitting the atoms of uranium.

Uranium-fuelled nuclear power is a clean and efficient way of boiling water to make steam which drives turbine generators. Except for the reactor itself, a nuclear power station works like most coal or gas-fired power stations.

The Reactor Core

Several hundred fuel assemblies containing thousands of small pellets of ceramic uranium oxide fuel make up the core of a reactor. For a reactor with an output of 1000 megawatts (MWe), the core would contain about 75 tonnes of enriched uranium.

In the reactor core the U-235 isotope fissions or splits, producing a lot of heat in a continuous process called a chain reaction. The process depends on the presence of a moderator such as water or graphite, and is fully controlled.

The moderator slows down the neutrons produced by fission of the uranium nuclei so that they go on to produce more fissions.

Two examples of fission of a Uranium-235 atom

Some of the U-238 in the reactor core is turned into plutonium and about half of this is also fissioned similarly, providing about one third of the reactor's energy output.

The fission products remain in the ceramic fuel and undergo radioactive decay, releasing a bit more heat. They are the main wastes from the process.

The reactor core sits inside a steel pressure vessel, so that water around it remains liquid even at the operating temperature of over 320°C. Steam is formed either above the reactor core or in separate pressure vessels, and this drives the turbine to produce electricity. The steam is then condensed and the water recycled.

PWRs and BWRs

The main design is the pressurised water reactor (PWR) which has water in its primary cooling/heat transfer circuit, and generates steam in a secondary circuit. The less popular boiling water reactor (BWR) makes steam in the primary circuit above the reactor core, though it is still under considerable pressure. Both types use water as both coolant and moderator, to slow neutrons.

Diagram of Pressurised Water Reactor

To maintain efficient reactor performance, about one-third or half of the used fuel is removed every year or two, to be replaced with fresh fuel.

The pressure vessel and any steam generators are housed in a massive containment structure with reinforced concrete about 1.2 metres thick. This is to protect neighbours if there is a major problem inside the reactor, and to protect the reactor from external assaults.

Because some heat is generated from radioactive decay even after the reactor is shut down, cooling systems are provided to remove this heat as well as the main operational heat output.

Natural Prehistoric Reactors

The world's first nuclear reactors operated naturally in a uranium deposit about two billion years ago in what is now Gabon. The energy was not harnessed, since these were in rich uranium orebodies in the Earth's crust and moderated by percolating rainwater.

Nuclear energy's contribution to global electricity supply

Nuclear energy supplies some 14% of the world's electricity. Today 31 countries use nuclear energy to generate up to three quarters of their electricity, and a substantial number of these depend on it for one quarter to one half of their supply. Almost 15,000 reactor-years of operational experience have been accumulated since the 1950s by the world's 440 nuclear power reactors (and nuclear reactors powering naval vessels have clocked up a similar amount).

What are nuclear wastes and how are they managed?

http://www.world-nuclear.org/Nuclear-Basics/What-are-nuclear-wastes-/#.UhbaSX-N6So

The most significant high-level waste from a nuclear reactor is the used nuclear fuel left after it has spent three years in the reactor generating heat for electricity. Low-level waste is made up of lightly-contaminated items like tools and work clothing from power plant operation and makes up the bulk of radioactive wastes. Items disposed of as intermediate-level wastes might include used filters, steel components from within the reactor and some effluents from reprocessing.

	By Volume	By Radioactive Content
High Level Waste	3%	95%
Intermediate Level Waste	7%	4%
Low Level Waste	90%	1%

Generating enough electricity for one person produces just 30 grams of used fuel each year.

High level wastes make just 3% of the total volume of waste arising from nuclear generation, but they contain 95% of the radioactive content. Low level wastes represent 90% of the total volume of radioactive wastes, but contain only 1% of the radioactivity.

Managing used fuel

Used nuclear fuel is very hot and radioactive. Handling and storing it safely can be done as long as it is cooled and plant workers are shielded from the radiation it produces by a dense material like concrete or steel.

Water can conveniently provide both cooling and shielding, so a typical reactor will have its fuel removed underwater and transferred to a storage pool. After about five years it can be transferred into dry ventilated concrete containers, but otherwise it can safely remain in the pool for up to 50 years.

Nuclear fuel storage pool

But this used fuel is also a valuable resource, and 96% of it can be recycled. Currently, but means that the sustainability of nuclear power is enhanced. In this case about 1% of the fuel is recycled promptly into mixed oxide fuel (MOX), the rest is usually stored for the future while about 3% of the original mass remains as waste to be disposed of.

The high-level wastes (whether as used fuel after 50 years cooling, or the separated 3% of such fuel) will be disposed of deep underground in geological repositories.

Intermediate and low-level wastes

Intermediate- and low-level wastes are disposed of closer to the surface, in many established repositories. Low-level waste disposal sites are purpose built, but are not much different from normal municipal waste sites.

Nuclear power is not the only industry that creates radioactive wastes. Other industries include medicine, particle and space research, oil and gas, and mining - to name just a few. Some of these materials are not produced inside a reactor, but rather are concentrated forms of naturally occurring radioactive material.

Civil nuclear wastes from nuclear power plants have never caused any harm, nor posed an environmental hazard, in over 50 years of the nuclear power industry. Their management and eventual disposal is straightforward.

Low-level and Intermediary-level waste (LLW/ILW) repository at TVO's Olkiluoto site in Finland.

One characteristic of all radioactive wastes which distinguishes them from the very much larger amount of other toxic industrial wastes is that their radioactivity progressively decays and diminishes. For instance, after 40 years, the used fuel removed from a reactor has only one thousandth of its initial radioactivity remaining, making it very much easier to handle and dispose of.

Disposal

The categorization - high, intermediate, low - helps determine how wastes are treated and where they end up. All radioactive waste facilities are designed with numerous layers of protection to make sure that the environment remains protected for as long as it takes for radioactivity to reduce to background levels. Low-level and intermediate wastes are buried close to the surface. For low-level wastes disposal is not much different from a normal municipal landfill. High-level wastes can remain highly radioactive for thousands of years. They need to be disposed of hundreds of metres underground in heavily engineered facilities built in stable geological formations. While no such facilities currently exist, there feasibility has been demonstrated and there are several countries now in the process of designing and constructing them.

Number of nuclear reactors operable and under construction

http://www.world-nuclear.org/Nuclear-Basics/Global-number-of-nuclear-reactors/#.UhbbJX-N6So

There are currently 432 operable civil nuclear power nuclear reactors around the world, with a further 68 under construction. (This under construction total recent changes including Shin Hanul 2, Barakah 2, V.C. Summer 2 and Vogtle 3. The number of operable reactors excludes Kewaunee, which shut down on 7 May 2013, and San Onofre 2 & 3).

A list of reactors operable, under construction, planned and proposed can be found in this information paper World Nuclear Power Reactors and Uranium Requirements.

Details of individual reactors operable and under construction can be found in our Nuclear Reactor Database, which uses information supplied by the International Atomic Energy Agency.

Why do different sources give slightly different figures?

There can be some variation in the assessment of the operational status of a reactor. For example, the Monju reactor in Japan generated electricity for a short time in 1994 and again in 2010. Some organizations consider that Monju entered full operation and is current in a period of long-term shutdown. Others consider that it is still under construction. Also in Japan, although many reactors were unaffected by the earthquake and tsunami of 3 March 2011 and continued operations all had to eventually shut down for refuelling. However, only two have been allowed to return to service, while others seek permission to restart operations.These reactors are still counted as operable by most sources, although others consider them to be in long-term shutdown.

For reactors under construction there may be differences in interpretation of when construction starts. Considerable construction work is done prior to pouring first nuclear concrete. For example, some considered the Vogtle 3 plant to already be under construction in late 2012, although at that time nuclear concrete had not been poured.

Construction can also stop, temporarily or permanently, on reactors. Whether construction will restart and the plant enter operation can be uncertain. In the US construction on the Watts Bar 2 reactor was stopped in 1988, due to lower than expected demand. Construction restarted in 2007. In Russia construction stopped on the Khmelnitski 3 and 4 reactors in 1990, but is now planned to restart.

Finally, with construction starting on new projects, new reactors beginning operations and older reactors being retired throughout the year figures may vary simply because they are updated more or less frequently than others.

The following guide explains some of the definitions.

What is meant by "operable"

An operable reactor is one that is connected to the electricity grid. In most cases these reactors will be generating and supplying electricity to consumers. However, for short periods reactors don't supply electricity to the grid, for example during a scheduled outage for refuelling or maintenance.

What is meant by "under construction"

WNA uses the convention that a reactor is under construction only once 'nuclear concrete' has been poured. This is concrete of a specific grade or specification that is used in the construction of the nuclear facilities on a reactor site. It would not include planned reactors when site preparations are under way or concrete is being used for ancillary buildings or cooling towers.

What is meant by "civil nuclear power reactors"

Civil nuclear power reactors are those reactors used to generate electricity that is supplied to customers through electricity grids. There are hundreds of other nuclear reactors in operation around the world. These include research reactors used at universities and other research establishments, reactors used to power ships and submarines and reactors used to make medical isotopes.

Electricity Supplied by Nuclear Energy

In 2011 the world's nuclear reactors supplied 2518 TWh of electricity (2518 billion kilowatt hours)^a. This represents around 13% of global electricity consumption.^b

The percentage of electricity supplied by nuclear generation and amount of electricity supplied in TWh for those countries with nuclear generation in 2011 is shown below:

	Percentage share	Electricity Supplied TWh
Argentina	5	5.9
Armenia	33.2	2.4
Belgium	54	45.9
Brazil	3.2	14.8
Bulgaria	32.6	15.3
Canada	15.3	88.3
China Mainland	1.8	82.6
Czech Rep	33	26.7
Finland	31.6	31.6
France	77.7	423.5
Germany	17.8	102.3
Hungary	43.2	14.7
India	3.7	28.9
Japan	18.1	156.2
Mexico	3.6	9.3
Netherlands	3.6	3.9
Pakistan	3.8	3.8
Romania	19	10.8
Russia	17.6	162.0
Slovakia	54	14.3
Slovenia	41.7	5.9
South Africa	5.2	12.9
South Korea	34.6	147.8
Spain	19.5	55.1
Sweden	39.6	58.1
Switzerland	40.8	25.7
Taiwan	19	40.4
UK	17.8	62.7
Ukraine	47.2	84.9
USA	19.2	790.4

Past values for nuclear shares of electricity production are given in the Information Library document Nuclear generation by country

Sources

a) IAEA PRIS database http://www.iaea.org/PRIS/WorldStatistics/WorldTrendinElectricalProduction.aspx

b) CIA The World Factbook https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html.

Greenhouse gas emissions avoided through use of nuclear energy

There are many different electrical generation methods, each having advantages and disadvantages with respect to operational cost, environmental impact, and other factors.

In relation to greenhouse gas (GHG) emissions, each generation method produces GHGs in varying quantities through construction, operation (including fuel supply activities), and decommissioning. Some generation methods such as coal fired power plants release the majority of GHGs when their carbon-containing fossil fuels are burnt, producing carbon dioxide (CO₂). Others, such as wind power and nuclear power, give rise to much less emissions, these being during construction and decommissioning, or mining and fuel preparation in the case of nuclear.

Accounting for emissions from all phases of the project (construction, operation, and decommissioning) is called a lifecycle approach. Comparing the lifecycle emissions of electrical generation allows for a fair comparison of the different generation methods on a per kilowatt-hour basis. The lower the value, the fewer GHG emissions are released.

WNA has carried out a review of over twenty studies assessing the greenhouse gas emission produced by different forms of electricity generation. The results summarised in the chart below show that generating electricity from fossil fuels results in greenhouse gas emissions far higher than when using nuclear or renewable generation.

Greenhouse gas emissions from electricity generation

In 2011 the world's nuclear power plants supplied 2518 TWh (billion kWh) of electricity. The following table shows the additional emissions that would have been produced if fossil fuels had been used to generate the same amount of electricity.

	Average lifecycle GHG emissions (tonnes/GWh)	Emissions produced from generating 2518 TWh of electricity	Additional emissions avoided through use of nuclear electricity in place of fossil fuel
Lignite	1054	2654 million tonnes CO₂	2581 million tonnes CO₂
Coal	888	2236 million tonnes CO₂	2163 million tonnes CO₂
Oil	733	1846 million tonnes CO₂	1773 million tonnes CO₂
Natural Gas	499	1256 million tonnes CO₂	1183 million tonnes CO₂
Nuclear	29	73 million tonnes CO₂	-

Comparison of emissions from nuclear and renewable generation

The WNA review of lifecycle emissions from nuclear and renewable generation showed that lifecycle emissions from all the major forms of renewables (solar, wind, biomass, hydroelectric) and nuclear were similiar. Replacing generation from nuclear or renewables with fossil fuels would lead to similar rises in greenhouse gas emissions.

Sources

WNA Report: Comparison of Lifecycle Greenhouse Gas Emissions of Various Electricity Generation Sources
IAEA PRIS database http://www.iaea.org/PRIS/WorldStatistics/WorldTrendinElectricalProduction.aspx
CIA The World Factbook https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html.

Other Uses of Nuclear Technology

Nuclear technology is not just used to supply electricity to the grid; it is in a wide variety of other uses such as medicine, heating and space travel.

Nuclear Medicine

Nuclear medicine uses radiation to allow doctors to make a quick, accurate diagnosis of the functioning of person's specific organs, or to treat them. Radiotherapy can be used to treat some medical conditions, especially cancer, using radiation to weaken or destroy particular targeted cells.

Tens of millions of patients are treated with nuclear medicine each year
Over 10,000 hospitals worldwide use radioisotopes in medicine, and about 90% of the procedures are for diagnosis. The most common radioisotope used in diagnosis is technetium-99, with some 30 million procedures per year, accounting for 80% of all nuclear medicine procedures worldwide.

Modern industry also uses radioisotopes in a variety of ways. Sealed radioactive sources are used in industrial radiography, gauging applications and mineral analysis.

Heat for Desalination

Heat from nuclear reactors can be used directly, instead or as well as being used to generate electricity. This heat can be used for district heating, as process heat for industry or for desalination plants, used to make clean drinkable water from seawater.

Space Missions

Radioisotope thermal generators are used in space missions. The heat generated by the decay of a radioactive source, often Plutonium-238, is used to generate electricity. The Voyager space probes, the Cassini mission to Saturn, the Galileo mission to Jupiter and the New Horizons mission to Pluto all are powered by RTGs. The Spirit and Opportunity Mars rovers have used a mix of solar panels for electricity and RTGs for heat. The latest Mars rover, Curiosity, is much bigger and uses RTGs for heat and electricity as solar panels would not be able to supply enough electricity.

In the future electricity or heat from nuclear power plants could be used to make hydrogen. Hydrogen can be used in fuel cells to power cars, or can be burnt to provide heat in place of gas, without producing emissions that would cause climate change.

The Nuclear Industry

http://www.world-nuclear.org/Nuclear-Basics/The-Nuclear-Industry/#.UhbdWX-N6So

The nuclear industry is global, and comprises many diverse participants from individuals to companies, industry associations to UN and other inter-governmental bodies, and also appointed bodies responsible to national governments.

Nuclear reactor builders and operators

Central to it are the companies and government corporations or utilities set up to generate electricity. These are usually also responsible for building the nuclear power plants, and draw upon reactor and other vendor companies and a wide range of contractors to achieve this.

Mines, Nuclear Fuel, Storage and Waste

Servicing the electricity generation are companies providing fuel. These range from mining companies through companies providing services to prepare the fuel for use in reactors – conversion, enrichment and fuel fabrication are the three main categories.

After the fuel is used in a reactor it is initially stored there, but another range of service companies then play roles in management, possibly reprocessing, and disposal of final wastes.

Most of these companies have a technology or engineering base, but there are also trading companies involved with fuel supply, connecting these.

Regulators

Any major industry in any country is subject to regulation by governments, and for nuclear power the national regulators appointed by them play an important role in approving the technology used, where it is sited, and how it is operated.

Research and Development

Behind all the above front-line roles are organisations responsible for research and development (R&D), for setting engineering standards, and for design of equipment.

Finance

Nuclear plants need a lot of investment to build, and the financial services sector has a vital role in providing finance for capital works. Related to this are insurance of plants and third party liability insurance, without which plants cannot operate.

The industry as a whole receives income through the sales of electricity generated in its nuclear power plants.

National and International Organisations

Beyond the role of national governments is that of the UN’s International Atomic Energy Agency (IAEA) which is responsible for implementing international agreements specific to nuclear power, notably the Nuclear Non-Proliferation Treaty (NPT) which enables international collaboration on the peaceful uses of atomic energy while providing mutual assurance that civil programs remain so.

At a less formal level there is a lot of international collaboration through the World Association of Nuclear Operators (WANO) which plays a major role in improving the safety and reliability of reactor operation and keeping it at a high standard. In some countries there are corresponding national organisations linking different operators.

The World Nuclear Association (WNA) is the international trade association linking companies and organisations worldwide to address matters of common concern collaboratively. In each country and for Europe collectively there are corresponding industry associations which have a mutual support and lobbying function to interface with governments.

All this adds up to a major and diverse collections of corporate and government players who together make the industry function efficiently.

Glossary

(updated January 2011)

The following is a list of terms which are commonly used in discussion of the the nuclear fuel cycle.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Actinide: An element with atomic number of 89 (actinium) to 103. Usually applied to those above uranium - 93 up (also called transuranics). Actinides are radioactive and typically have long half-lives. They are therefore significant in wastes arising from nuclear fission, e.g. used fuel. They are fissionable in a fast reactor. Minor actinides are americium, curium and neptunium.

Activation product: A radioactive isotope of an element (e.g. in the steel of a reactor core) which has been created by neutron bombardment.

Activity: The number of disintegrations per unit time inside a radioactive source. Expressed in becquerels.

ALARA: As Low As Reasonably Achievable, economic and social factors being taken into account. This is the optimisation principle of radiation protection.

Alpha particle: A positively-charged particle emitted from the nucleus of an atom during radioactive decay. Alpha particles are helium nuclei, with 2 protons and 2 neutrons.

Atom: A particle of matter which cannot be broken up by chemical means. Atoms have a nucleus consisting of positively-charged protons and uncharged neutrons of almost the same mass. The positive charges on the protons are balanced by a number of negatively-charged electrons in motion around the nucleus.

TOP

Background radiation: The naturally-occurring ionising radiation which every person is exposed to, arising from the earth's crust (including radon) and from cosmic radiation.

Barn: see Cross section.

Base load: That part of electricity demand which is continuous, and does not vary over a 24-hour period. Approximately equivalent to the minimum daily load.

Becquerel: The SI unit of intrinsic radioactivity in a material. One Bq indicates one disintegration per second and is thus the activity of a quantity of radioactive material which averages one decay per second. (In practice, GBq or TBq are the common units).

Beta particle: A particle emitted from an atom during radioactive decay. Beta particles are generally electrons (with negative charge) but may be positrons.

Biological shield: A mass of absorbing material (eg thick concrete walls) placed around a reactor or radioactive material to reduce the radiation (especially neutrons and gamma rays respectively) to a level safe for humans.

Boiling water reactor (BWR): A common type of light water reactor (LWR), where water is allowed to boil in the core thus generating steam directly in the reactor vessel. (cf PWR)

Breed: To form fissile nuclei, usually as a result of neutron capture, possibly followed by radioactive decay.

Breeder reactor: see Fast Breeder Reactor and Fast Neutron Reactor.

Burn: The process of undergoing fission (analogous to burning a fossil fuel) or otherwise becoming denatured in the reactor core.

Burnable absorber, burnable poison: A neutron absorber included in the fuel which progressively disappears and compensates for the loss of reactivity as the fuel is consumed. Gadolinium is commonly used, and erbium may also be used.

Burnup: Measure of thermal energy released by nuclear fuel relative to its mass, typically Gigawatt days per tonne of fuel (GWd/t).

TOP

Calandria: (in a PHWR reactor) a cylindrical reactor vessel which contains the heavy water moderator. It is penetrated from end to end by hundreds of calandria tubes which accommodate the pressure tubes containing the fuel and coolant.

CANDU: CANadian Deuterium Uranium reactor, moderated and cooled by heavy water (except for the ACR design, which is cooled by light water). These are the most common PHWRs (cf heavy water reactor).

Centrifuge: A cylinder spinning at high speed to physically separate gas components of slightly different mass, e.g. uranium hexafluoride with U-235 and U-238 atoms.

Chain reaction: A reaction that stimulates its own repetition, in particular where the neutrons originating from nuclear fission cause an ongoing series of fission reactions.

Cladding: The metal tubes containing oxide fuel pellets (cf zircaloy).

Concentrate: See Uranium oxide concentrate (U₃O₈).

Control rods: Devices to absorb neutrons so that the chain reaction in a reactor core may be slowed or stopped by inserting them further, or accelerated by withdrawing them.

Conversion: Chemical process turning U₃O₈ into UF₆ preparatory to enrichment.

Conversion ratio: (in a nuclear reactor) the ratio of new fissile nuclei to fissioned nuclei. In a normal reactor this as around 0.6, at high neutron energy in a fast reactor it may exceed 1.0, due to more neutrons per fission, making it a net breeder. (Above about 0.1 MeV, ie fast neutron spectrum, the number of neutrons released per fission increases from around 2.5, and at 10 MeV it reaches about 4.)

Coolant: The liquid or gas used to transfer heat from the reactor core to the steam generators or directly to the turbines.

Core: The central part of a nuclear reactor containing the fuel elements and any moderator.

Critical mass: The smallest mass of fissile material that will support a self-sustaining chain reaction under specified conditions.

Criticality: Condition of being able to sustain a nuclear chain reaction.

Cross section: see neutron cross-section.

TOP

Decay: Disintegration of atomic nuclei resulting in the emission of alpha or beta particles (usually with gamma radiation). Also the exponential decrease in radioactivity of a material as nuclear disintegrations take place and more stable nuclei are formed.

Decommissioning: Removal of a facility (eg reactor) from service, also the subsequent actions of safe storage, dismantling and making the site available for unrestricted use.

Deconversion: The chemical process of turning UF6 into uranium oxide. Typically depleted UF6 may be processed for long-term storage in a more stable chemical form. HF is a by-product.

Delayed neutrons: neutrons released by fission products up to several seconds after fission. These enable control of the fission in a nuclear reactor.

Depleted uranium: Uranium having less than the natural 0.7% U-235. As a by-product of enrichment in the fuel cycle it generally has 0.25-0.30% U-235, the rest being U-238. Can be blended with highly-enriched uranium (eg from weapons) to make reactor fuel.

Deuterium: "Heavy hydrogen", a stable isotope having one proton and one neutron in the nucleus. It occurs in nature as 1 atom to 6500 atoms of normal hydrogen, (Hydrogen atoms contain one proton and no neutrons).

Disintegration: natural change in the nucleus of a radioactive isotope as particles are emitted (usually with gamma rays), making it a different element.

Dose: The energy absorbed by tissue from ionising radiation. One gray is one joule per kg, but this is adjusted for the effect of different kinds of radiation, and thus the sievert is the unit of dose equivalent used in setting exposure standards.

TOP

Electron volt: 1.6 x 10^-19 joules, the amount of kinetic energy gained by a single electron when it accelerates through an electrostatic potential difference of one volt.

Element: A chemical substance that cannot be divided into simpler substances by chemical means; atomic species with same number of protons (being the atomic number of the element).

Enriched uranium: Uranium in which the proportion of U-235 (to U-238) has been increased above the natural 0.7%. Reactor-grade uranium is usually enriched to about 3.5% U-235, weapons-grade uranium is more than 90% U-235.

Enrichment: Physical process of increasing the proportion of U-235 to U-238. See also SWU.

TOP

Fast breeder reactor (FBR): A fast neutron reactor (q.v.) configured to produce more fissile material than it consumes, using fertile material such as depleted uranium in a blanket around the core.

Fast neutron: neutron released during fission, travelling at very high velocity (20,000 km/s) and having high energy (c 2 MeV).

Fast neutron reactor: A reactor with no moderator and hence utilising fast neutrons. It normally burns plutonium while producing fissile isotopes in fertile material such as depleted uranium (or thorium).

Fertile (of an isotope): Capable of becoming fissile, by capturing neutrons, possibly followed by radioactive decay; eg U-238, Pu-240.

Fissile (of an isotope): Capable of capturing a slow (thermal) neutron and undergoing nuclear fission, e.g. U-235, U-233, Pu-239.

Fission: The splitting of a heavy nucleus into two, accompanied by the release of a relatively large amount of energy and usually one or more neutrons. It may be spontaneous but usually is due to a nucleus absorbing a neutron and thus becoming unstable.

Fissionable (of an isotope): Capable of undergoing fission: If fissile, by slow neutrons; otherwise, by fast neutrons.

Fission products: 'Daughter' nuclei resulting either from the fission of heavy elements such as uranium, or the radioactive decay of those primary daughters. Usually highly radioactive.

Fossil fuel: A fuel based on carbon presumed to be originally from living matter, eg coal, oil, gas. Burned with oxygen to yield energy.

Fuel assembly: Structured collection of fuel rods or elements, the unit of fuel in a reactor.

Fuel fabrication: Making reactor fuel assemblies, usually from sintered UO₂ pellets which are inserted into zircalloy tubes, comprising the fuel rods or elements.

TOP

Gamma rays: High energy electro-magnetic radiation from the atomic nucleus, virtually identical to X-rays.

Genetic mutation: Sudden change in the chromosomal DNA of an individual gene. It may produce inherited changes in descendants. Mutation in some organisms can be made more frequent by irradiation (though this has never been demonstrated in humans).

Giga: One billion units (eg one gigawatt is 10⁹ watts or one million kW).

Graphite: Crystalline carbon used in very pure form as a moderator, principally in gas-cooled reactors, but also in Soviet-designed RBMK reactors.

Gray (Gy): The SI unit of absorbed radiation dose, one joule per kilogram of tissue.

Greenhouse gases: Radiative gases in the Earth's atmosphere which absorb long-wave heat radiation from the Earth's surface and re-radiate it, thereby warming the Earth. Carbon dioxide, methane and water vapour are the main ones.

TOP

Half-life:The period required for half of the atoms of a particular radioactive isotope to decay and become an isotope of another element.

Heavy water: Water containing an elevated concentration of molecules with deuterium ("heavy hydrogen") atoms.

Heavy water reactor (HWR): A reactor which uses heavy water as its moderator, eg Canadian CANDU (q.v.) which is a pressurised HWR (PHWR).

High-level wastes (HLW): Extremely radioactive fission products and transuranic elements (usually other than plutonium) in used nuclear fuel. They may be separated by reprocessing the used fuel, or the spent fuel containing those isotopes may be regarded as high-level waste. HLW requires both shielding and cooling.

High-enriched uranium (HEU): Uranium enriched to 20% U-235 or more. (That in weapons is about 90% U-235.)

TOP

In situ leaching (ISL): The recovery by chemical leaching of minerals from porous orebodies without physical excavation. Also known as in situ recovery (ISR) or solution mining.

Intermediate-level waste (ILW): Radioactive waste which requires shielding to protect people nearby, but not cooling.

Ion: An atom or molecule that is electrically-charged because of loss or gain of electrons.

Ionising radiation: Radiation (including alpha particles) capable of breaking chemical bonds, thus causing ionisation of the matter through which it passes and damage to living tissue.

Irradiate: Subject material to ionising radiation. Irradiated reactor fuel and components have been subject to neutron irradiation and hence become radioactive themselves.

Isotope: An atomic form of an element having a particular number of neutrons. Different isotopes of an element have the same number of protons but different numbers of neutrons and hence different atomic masses, eg. U-235, U-238. Some isotopes are unstable and decay (qv) to form isotopes of other elements.

TOP

Laser enrichment: Uranium enrichment using tuned laser beams to cause photo-dissociation of UF6 to solid UF5⁺ so that the ionised UF5 (with U-235) can be separated.

Light water: Ordinary water (H₂0) as distinct from heavy water.

Light water reactor (LWR): A common nuclear reactor cooled and usually moderated by ordinary water. It is s generic designation including BWR and PWR types.

Low-enriched uranium (LEU): Uranium enriched to less than 20% U-235. (That in power reactors is usually 3.5 - 5.0% U-235.)

Low-level wastes: Mildly radioactive material usually disposed of by incineration and burial.

Low-level waste (LLW): Radioactive waste which can be handled safely without shielding.

TOP

Megawatt (MW): A unit of power, = 10⁶ watts. MWe refers to electric output from a generator, MWt to thermal output from a reactor or heat source (eg the gross heat output of a reactor itself, typically around three times the MWe figure).

Metal fuels: Fuels using natural uranium metal, as used in a gas-cooled reactor.

Micro: one millionth of a unit (eg microsievert is 10^-6 Sv).

Milling: Process by which minerals are extracted from ore, usually at the mine site, to produce a mineral concentrate for sale.

Mixed oxide fuel (MOX): Reactor fuel which consists of both uranium and plutonium oxides, usually about 5% Pu, which is the main fissile component.

Moderator: A material such as light or heavy water or graphite used in a reactor to slow down fast neutrons by collision with lighter nuclei so as to expedite further fission.

TOP

Natural uranium: Uranium with an isotopic composition as found in nature, containing 99.3% U-238, 0.7% U-235 and a trace of U-234. It can be used as fuel in heavy water-moderated or graphite-moderated reactors.

Neutron: An uncharged elementary particle found in the nucleus of every atom except hydrogen. Solitary mobile neutrons travelling at various speeds originate from fission reactions. Slow (thermal) neutrons can in turn readily cause fission in nuclei of "fissile" isotopes, e.g. U-235, Pu-239, U-233; and fast neutrons can cause fission in nuclei of "fertile" isotopes such as U-238, Pu-239. Sometimes atomic nuclei simply capture neutrons.

Neutron cross-section: An indication of the probability of an interaction between a particle and a target nucleus, expressed in barns (1 barn = 10^-24 cm²).

Nuclear reactor: A device in which a nuclear fission chain reaction occurs under controlled conditions so that the heat yield can be harnessed or the neutron beams utilised. All commercial reactors are thermal reactors, using a moderator to slow down the neutrons.

Nuclide: elemental matter made up of atoms with identical nuclei, therefore with the same atomic number and the same mass number (equal to the sum of the number of protons and neutrons).

TOP

Oxide fuels: Enriched or natural uranium in the form of the oxide UO₂, used in many types of reactor.

Operation and Maintenance (O&M) costs: The operational costs of running a nuclear power plant excluding fuel and any capital costs.

TOP

Plutonium: A transuranic element, formed in a nuclear reactor by neutron capture. It has several isotopes, some of which are fissile and some of which undergo spontaneous fission, releasing neutrons. Weapons-grade plutonium is produced in special reactors to give >90% Pu-239, reactor-grade plutonium contains about 30% non-fissile isotopes. About one third of the energy in a light water reactor comes from the fission of Pu-239, and this is the main isotope of value recovered from reprocessing used fuel.

Pressurised water reactor (PWR): The most common type of light water reactor (LWR), it uses water at very high pressure in a primary circuit and steam is formed in a secondary circuit.

TOP

Radiation: The emission and propagation of energy by means of electromagnetic waves or particles. (cf ionising radiation)

Radioactivity: The spontaneous decay of an unstable atomic nucleus, giving rise to the emission of radiation.

Radionuclide: A radioactive isotope of an element.

Radiotoxicity: The adverse health effect of a radionuclide due to its radioactivity.

Radium: A radioactive decay product of uranium often found in uranium ore. It has several radioactive isotopes. Radium-226 decays to radon-222.

Radon (Rn): A heavy radioactive gas given off by rocks containing radium (or thorium). Rn-222 is the main isotope, from decay of radium-226.

Radon daughters: Short-lived decay products of radon-222 (Po-218, Pb-214, Bi-214, Po-214).

Reactor pressure vessel: The main steel vessel of a nuclear reactor containing the reactor fuel, moderator and coolant under pressure.

Repository: A permanent disposal place for radioactive wastes.

Reprocessing: Chemical treatment of used reactor fuel to separate uranium and plutonium and possibly transuranic elements from the small quantity of fission products, leaving a much reduced quantity of high-level waste. (cf Waste, HLW).

TOP

Separative Work Unit (SWU): This is a complex unit which is a function of the amount of uranium processed and the degree to which it is enriched, ie the extent of increase in the concentration of the U-235 isotope relative to the remainder. The unit is strictly: Kilogram Separative Work Unit, and it measures the quantity of separative work (indicative of energy used in enrichment) when feed and product quantities are expressed in kilograms.

Eg, to produce one kilogram of uranium enriched to 3.5% U-235 requires 4.3 SWU if the plant is operated at a tails assay 0.30%, or 4.8 SWU if the tails assay is 0.25% (thereby requiring only 7.0 kg instead of 7.8 kg of natural U feed).

About 100-120,000 SWU is required to enrich the annual fuel loading for a typical 1000 MWe light water reactor. Enrichment costs are related to electrical energy used. The gaseous diffusion process consumes some 2400 kWh per SWU, while gas centrifuge plants require only about 60 kWh/SWU.

Sievert (Sv): Unit indicating the biological damage caused by radiation dose measured in Gray (q.v.). One Gray of beta or gamma radiation absorbed has 1 Sv of biological effect; 1 Gy of alpha radiation has 20 Sv effect and 1 Gy of neutrons has 10 Sv effect. cf Dose.

Spallation: the abrasion and removal of fragments of a target which is bombarded by protons in an accelerator. The fragments may be protons, neutrons or other light particles.

Spent fuel: Used fuel assemblies removed from a reactor after several years use and treated as waste. Often it is another term for used fuel.

Stable: Incapable of spontaneous radioactive decay.

TOP

Tailings: Ground rock remaining after particular ore minerals (e.g. uranium oxides) are extracted.

Tails: Depleted uranium (cf. enriched uranium), with about 0.2 to 0.3% U-235.

Temperature coefficient of reactivity: The change in reactivity due to changed temperature in the fuel. A negative temperature coefficient means that the reactivity is diminished as the temperature rises, so as to reduce the rate of fission and hence reduce the temperature - a natural negative feedback. Fast reactors have a strong negative temperature coefficient which is the basis of automatic power regulation and even load-following.

Thermal reactor: A reactor in which the fission chain reaction is sustained primarily by slow neutrons, and hence requiring a moderator (as distinct from Fast Neutron Reactor).

Transmutation: Changing atoms of one element into those of another by neutron bombardment, causing neutron capture and/or fission. In an ordinary reactor neutron capture is the main event, in a fast reactor fission is more common and therefore it is best for dealing with actinides. Fission product transmutation is by neutron capture.

Transuranic element: A very heavy element formed artificially by neutron capture and possibly subsequent beta decay(s). Has a higher atomic number than uranium (92). All are radioactive. Neptunium, plutonium, americium and curium are the best-known.

TOP

Uranium (U): A mildly radioactive element with two isotopes which are fissile (U-235 and U-233) and two which are fertile (U-238 and U-234). Uranium is the basic fuel of nuclear energy.

Uranium hexafluoride (UF₆): A compound of uranium which is a gas above 56°C and is thus a suitable form in which to enrich the uranium.

Uranium oxide concentrate (U₃O₈): The mixture of uranium oxides produced after milling uranium ore from a mine. Sometimes loosely called yellowcake. It is khaki in colour and is usually represented by the empirical formula U₃O₈. Uranium is normally sold in this form.

Used fuel: Fuel assemblies removed from a reactor after several years' use.

TOP

Vitrification: The incorporation of high-level wastes into borosilicate glass, to make up about 14% of it by mass. It is designed to immobilise radionuclides in an insoluble matrix ready for disposal.

Void coefficient of reactivity: The change in reactivity due to boiling of coolant or moderator in the actual core. A negative void coefficient means that the reactivity is diminished, and the blanace of the chain reaction is affected so as to reducte the rate of fission and hence reduce the temperature - a natural negative feedback.

TOP

Waste:

High-level waste (HLW) is highly radioactive material arising from nuclear fission. It can be what is left over from reprocessing used fuel, though some countries regard spent fuel itself as HLW. It requires very careful handling, storage and disposal.

Intermediate-level waste (ILW) comprises a range of materials from reprocessing and decommissioning. It is sufficiently radioactive to require shielding and is disposed of in engineered facilities underground.

Low-level waste (LLW) is mildly radioactive material usually disposed of by incineration and burial.

TOP

Yellowcake: Ammonium diuranate, the penultimate uranium compound in U₃O₈ production, but the form in which mine product was sold until about 1970. See also Uranium oxide concentrate.

TOP

Zircaloy: Zirconium alloy used as a tube to contain uranium oxide fuel pellets in a fuel rod (part of a reactor fuel assembly).

Kamis, 22 Agustus 2013

World Uranium Mining Production

New Mines

Known Recoverable Resources of Uranium 2011

http://www.world-nuclear.org/Nuclear-Basics/

Nuclear Basics

Electricity generation - what are the options?

Fossil

Large hydro

Nuclear

Renewables

What is radiation?

http://www.world-nuclear.org/Nuclear-Basics/What-is-radiation-/#.UhbYHn-N6So

Radioactivity in material

Ionising radiation - alpha, beta and gamma

How uranium ore is made into nuclear fuel

Mining

Enrichment

Fuel fabrication

How a nuclear reactor makes electricity

The Reactor Core

PWRs and BWRs

Natural Prehistoric Reactors

Nuclear energy's contribution to global electricity supply

What are nuclear wastes and how are they managed?

Managing used fuel

Intermediate and low-level wastes

Disposal

Number of nuclear reactors operable and under construction

Why do different sources give slightly different figures?

What is meant by "operable"

What is meant by "under construction"

What is meant by "civil nuclear power reactors"

Electricity Supplied by Nuclear Energy

Sources

Greenhouse gas emissions avoided through use of nuclear energy

Comparison of emissions from nuclear and renewable generation

Sources

Other Uses of Nuclear Technology

Nuclear Medicine

Heat for Desalination

Space Missions

The Nuclear Industry

Nuclear reactor builders and operators

Mines, Nuclear Fuel, Storage and Waste

Regulators

Research and Development

Finance

National and International Organisations

Glossary

Tidak ada komentar:

Posting Komentar