Uranium Uranium

Keith BeckerKeith Becker

Grace AmicoGrace Amico

Bryan ParkBryan Park

BasicsBasics

Heaviest of all naturally occurring Heaviest of all naturally occurring elements.elements.

Metal substance that is easily fissionable. Metal substance that is easily fissionable.

Found in rocks all over the world (uranium Found in rocks all over the world (uranium ore). ore).

Abundant but nonrenewable.Abundant but nonrenewable.

Developed in WW II era.Developed in WW II era.

IsotopesIsotopes

U 235U 235

Used for energy Used for energy production.production.

Easily split when Easily split when bombarded by bombarded by neutrons causing a neutrons causing a chain reaction. chain reaction.

Releases heat energy Releases heat energy and radiation. and radiation.

U 238U 238

Not easily split and Not easily split and therefore inefficient therefore inefficient for energy production. for energy production.

Nuclear Fuel CycleNuclear Fuel Cycle

Nuclear energy is released through fusion Nuclear energy is released through fusion or fission. or fission.

Fission is the only viable source as Fission is the only viable source as humans have yet to develop efficient humans have yet to develop efficient fusion technology. fusion technology.

To get usable uranium fuel requires:To get usable uranium fuel requires:

Mining, milling, conversion, enrichment, Mining, milling, conversion, enrichment, and fuel fabrication. and fuel fabrication.

Mining Mining

First step in process.First step in process.

Uranium ore is mined from underground Uranium ore is mined from underground and surface mines. and surface mines.

One ton of uranium ore in the US yields 3-One ton of uranium ore in the US yields 3-10 pound of pure uranium. 10 pound of pure uranium.

MillingMilling

Ore is crushed and mixed with acid.Ore is crushed and mixed with acid.

Uranium is dissolved while other Uranium is dissolved while other substances such as rock remain solid.substances such as rock remain solid.

Acid solution is then drained and dried into Acid solution is then drained and dried into “yellowcake”. “yellowcake”.

ConversionConversion

Yellowcake is converted into a gas called Yellowcake is converted into a gas called uranium hexafluoride. uranium hexafluoride.

This is then shipped to a gaseous diffusion This is then shipped to a gaseous diffusion plant. plant.

EnrichmentEnrichment

Uranium must be processed in order to Uranium must be processed in order to increase concentrations. increase concentrations.

Enrichment increases concentration Enrichment increases concentration anywhere from 1-5%. anywhere from 1-5%.

This process removes U 238This process removes U 238

Fuel FabricationFuel Fabrication

U made solid and formed into ceramic U made solid and formed into ceramic pellets. pellets. One pellet has the same amount of One pellet has the same amount of energy as 150 gallons of oil. energy as 150 gallons of oil. Pellets are sealed into 12 foot tubes Pellets are sealed into 12 foot tubes called fuel rods.called fuel rods.Rods are then grouped into fuel Rods are then grouped into fuel assemblies.assemblies.

Nuclear ReactorNuclear Reactor

Fission takes place in the reactor Fission takes place in the reactor core.core.

Surrounding the core of the reactor is Surrounding the core of the reactor is a shell called the reactor pressure a shell called the reactor pressure vessel. vessel.

Nuclear Reactor Cont. Nuclear Reactor Cont.

There are 200 fuel assemblies in each reactor There are 200 fuel assemblies in each reactor core. core. Moveable control rods are placed in between Moveable control rods are placed in between assemblies to absorb neutrons and slow down assemblies to absorb neutrons and slow down the nuclear reaction. the nuclear reaction. Reaction produces heat which is used to create Reaction produces heat which is used to create steam just as in a coal or oil power plant. steam just as in a coal or oil power plant. Steam turns turbine generators which produce Steam turns turbine generators which produce electricity. electricity. Water is also used to cool the reactor. Water is also used to cool the reactor.

Used Fuel StorageUsed Fuel Storage

Fuel rods much be replaced every 12-18 months Fuel rods much be replaced every 12-18 months to reduce radioactive waste in the reactor. to reduce radioactive waste in the reactor. Used fuel is a mix of radioactive waste and Used fuel is a mix of radioactive waste and unused fuel. unused fuel. Stored in a deep pool of water called a “used Stored in a deep pool of water called a “used fuel pool”. fuel pool”. In 3 months the waste loses 50% of its In 3 months the waste loses 50% of its radioactivity due to decay. 1 year= 80% and 10 radioactivity due to decay. 1 year= 80% and 10 years = 90%. years = 90%. Then deposited into a permanent federal Then deposited into a permanent federal disposal site. disposal site.

ReprocessingReprocessing

1/3 of the fuel is unused when the fuel rod 1/3 of the fuel is unused when the fuel rod is replaced. is replaced.

Reprocessing separates unused fuel from Reprocessing separates unused fuel from radioactive waste. radioactive waste.

Reprocessing is more expensive than Reprocessing is more expensive than making new fuel, so most companies don’t making new fuel, so most companies don’t do it. do it.

Waste RepositoryWaste Repository

Believed that storing nuclear waster deep Believed that storing nuclear waster deep underground is safest.underground is safest.The 1982 Nuclear Waste Policy Act led to the The 1982 Nuclear Waste Policy Act led to the designing and construction of the first U.S. first designing and construction of the first U.S. first repository, which opens this year. The repository, which opens this year. The repository will store waste from nuclear plants repository will store waste from nuclear plants and defense weapons plants.and defense weapons plants.People who use electricity from nuclear power People who use electricity from nuclear power plants pay 1/10 cent for each kilowatt/hr of plants pay 1/10 cent for each kilowatt/hr of electricity (the average house pays $7.50).electricity (the average house pays $7.50).

Nuclear Energy UseNuclear Energy Use

20% of electricity in US comes from 20% of electricity in US comes from nuclear power. nuclear power. 18% of world electricity comes from 18% of world electricity comes from nuclear power. nuclear power. Leading countries in nuclear energy Leading countries in nuclear energy production are the US, France, Japan and production are the US, France, Japan and Germany. Germany. 75% of France’s electricity comes from 75% of France’s electricity comes from nuclear power. nuclear power.

Radiation Radiation

Natural: cosmic rays from space, minerals, Natural: cosmic rays from space, minerals, and radon in the air.and radon in the air.

Man-made: x-ray equipment, smoke Man-made: x-ray equipment, smoke detectors, color TV, and luminous dial detectors, color TV, and luminous dial clocks.clocks.

Ionizing RadiationIonizing Radiation

Ionizing radiation can be harmful Ionizing radiation can be harmful because it can destroy or damage because it can destroy or damage cells.cells.

Alpha radiation: slowest form, can be stopped by Alpha radiation: slowest form, can be stopped by a sheet of paper or skin.a sheet of paper or skin.

Beta radiation: can pass through an inch of Beta radiation: can pass through an inch of water or skin.water or skin.

Gamma radiation: electromagnetic wave that Gamma radiation: electromagnetic wave that has no weight and can pass through lead, has no weight and can pass through lead, concrete, and large amounts of water.concrete, and large amounts of water.

LicensingLicensing

Permits are needed in order to start Permits are needed in order to start construction of a nuclear plant and construction of a nuclear plant and licenses are needed to begin the licenses are needed to begin the operation.operation.The plans and reports must be sent to the The plans and reports must be sent to the Nuclear Regulatory Commission.Nuclear Regulatory Commission.Before construction begins, local hearings Before construction begins, local hearings are held so that people may voice their are held so that people may voice their opinions about the project.opinions about the project.

Nuclear SafetyNuclear Safety

Two main examples of Nuclear Energy Two main examples of Nuclear Energy Plants going wrong-Plants going wrong-– Three Mile Island (United States, 1979)Three Mile Island (United States, 1979)– Chernobyl (Ukraine, 1986)Chernobyl (Ukraine, 1986)

Three Mile IslandThree Mile Island

Water was accidentally cut off to the Water was accidentally cut off to the reactor core which caused the Uranium reactor core which caused the Uranium fuel to melt.fuel to melt.

The result was that some radioactive The result was that some radioactive material escaped, but no one was injured material escaped, but no one was injured because of the plant’s many safety because of the plant’s many safety barriers.barriers.

ChernobylChernobyl

Two explosions blew off the top of the reactor Two explosions blew off the top of the reactor building and a large amount of radioactive building and a large amount of radioactive material was introduced to the area.material was introduced to the area.

100,000 people were evacuated from their 100,000 people were evacuated from their homes, 200 workers were treated for radiation homes, 200 workers were treated for radiation sickness and burns, and 31 people died.sickness and burns, and 31 people died.

However, Chernobyl was extremely rare and it is However, Chernobyl was extremely rare and it is highly unlikely that a similar incident would highly unlikely that a similar incident would repeat due to better security.repeat due to better security.

Miscellaneous InformationMiscellaneous Information

Radiation is measured by rem and millirem. The Radiation is measured by rem and millirem. The average American is exposed to about 360 average American is exposed to about 360 millirem a year (harmless amount).millirem a year (harmless amount).

80% of the Uranium in the U.S. is imported.80% of the Uranium in the U.S. is imported.

In 2007 Uranium cost $75 per pound.In 2007 Uranium cost $75 per pound.

Nuclear plants have high up-front costs, but Nuclear plants have high up-front costs, but save money and resources in the long run.save money and resources in the long run.

Miscellaneous InformationMiscellaneous Information

Nuclear electricity costs about 2 cents per Nuclear electricity costs about 2 cents per kilowatt/hr.kilowatt/hr.Our Uranium resources could last us for another Our Uranium resources could last us for another 500 years, and through a process called 500 years, and through a process called “breeding,” which converts Uranium into “breeding,” which converts Uranium into Plutonium, we could extend Uranium reserves Plutonium, we could extend Uranium reserves for millions of years but it is currently only being for millions of years but it is currently only being used in France.used in France.Nuclear power plants create no air pollution and Nuclear power plants create no air pollution and water used for cooling processes is recycled.water used for cooling processes is recycled.