NUCLEAR

WHAT IS NUCLEAR POWER?

Nuclear power is an alternative power source that uses the nuclear fission of uranium to create heat and, thereby, through a heat transfer mechanism and turbines, create electricity. 

HOW DOES IT WORK?

For a nuclear reactor to create energy it is necessary for nuclear fission to take place. This occurs when an atom is split into smaller particles and an enormous amount of energy is released in the process. Uranium is used as the fuel for the reaction as it is radioactive, and is therefore unstable enough to be broken down into smaller parts. The uranium atom absorbs a neutron and splits into two equal parts and energy is created. This kinetic energy becomes heat energy as the particles slow down, and it is this heat energy, which is used to produce electricity (see Extras / Links for more information on the science involved). The heat is moved through a transfer medium, such as water, and is used to turn water into steam. This steam turns a turbine, which is connected to a generator. As the turbine turns the generator it creates electricity, which is then transferred to the consumers.

 

IS IT RENEWABLE?

Nuclear power is renewable as it doesn't use fossil fuels or other non-renewable resources in the production of energy; however it isn't as renewable as some of the alternatives, such as wind or solar power, which rely solely on natural phenomena to create their power. In the short term it is unlikely that uranium will run out, but eventually it will. Therefore we can say that nuclear power is only renewable in the short term.

APPLICATIONS OF NUCLEAR POWER

About 440 nuclear reactors are used around the world to produce about 17% of the world's electricity but in theory nuclear fission can be used for much more. At the end of the Second World War the Allies secured victory by dropping the atomic bomb on Japan. The bomb uses the same principles of splitting the atom as the nuclear reactors do in creating electricity. On a smaller, less destructive scale, the theories of nuclear fission are used daily in medicine. Scanning devices and the treatment of cancer both use the radiation from splitting an atom.

ADVANTAGES

• As an alternative to normal coal-based electricity production nuclear power is favourable as it is much more efficient than coal (250g of uranium produces 20000 times more electricity than 250g of coal) and is far less polluting, especially to our atmosphere, as no harmful greenhouse gases are emitted. (ie. carbon monoxide, sulphur dioxide, nitrogen oxide etc.).
• It is generally a reliable process that can be counted on to produce electricity for many years (average availability over three years is about 80%).
• The amount of waste produced each year would cover only your dining room table!
• The waste is stored in fire-, water-, and earthquake-proof capsules to ensure safety.

DISADVANTAGES

• There is pollution in the form of radioactive waste but with new technologies the process is becoming cleaner and safer each year.
• The possibility of radiation leakage or plant meltdown. This is possible in theory and has happened in the past (Chernobyl in Russia) but nowadays there are procedures in place to ensure safety.
• There are problems and dangers, which could lead to accidents. The power stations are all manually run and human error could lead to possible accidents.
• The reactors also have a very expensive capital outlay in the beginning, although the costs are cheaper in the long run.
• The plants do require downtime for maintenance (see Interesting Information below).

INTERESTING INFORMATION

One of the common worries of nuclear power is the danger of radiation leaks, espacially after the horrors of Chernobyl. In Cape Town we are fortunate that Koeberg is located on a geologically sound platform, far beyond the internationally prescribed 10km distance from city limits. The walls of reactors are also thick enough to withstand an earthquake or even a plane crash.

As the City of Cape Town has seenthe plants aren't completely reliable. In 2006 there were many blackouts in the Cape Town metropole, caused by faults and breakdowns in the Koeberg plant. Maintenance was being carried out on the one generator when the other generator failed and shut down - causing blackouts for months during winter.

Koeberg is situated the furthest South of any nuclear reactors in the World. 

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The Benefits of Nuclear Energy

Nuclear energy is the world's largest source of emission-free energy. Nuclear power plants produce no controlled air pollutants, such as sulfur and particulates, or greenhouse gases. The use of nuclear energy in place of other energy sources helps to keep the air clean, preserve the Earth's climate, avoid ground-level ozone formation and prevent acid rain. Of all energy sources, nuclear energy has perhaps the lowest impact on the environment, including water, land, habitat, species, and air resources. Nuclear energy is the most eco-efficient of all energy sources because it produces the most electricity relative to its environmental impact.
Nuclear power plants were responsible for nearly half of the total voluntary reductions in greenhouse gas emissions reported by U.S. companies in 1998, the Energy Information Administration reported on January 4, 2000. Emission reductions from nuclear energy usage reported by the electric power sector increased by 43 percent from an estimated 70 million metric tons carbon dioxide equivalent for 1997 to 100 million metric tons carbon dioxide equivalent for 1998. That 100 million metric tons equals 47 percent of the 212 million metric tons of carbon emissions reductions reported nationwide, according to EIA. Between 1973 and 2000, nuclear generation avoided the emission of 66.1 million tons of sulfur dioxide and 33.6 million tons of nitrogen oxides. Each year, U.S. nuclear power plants prevent 5.1 million tons of sulfur dioxide, 2.4 million tons of nitrogen oxide, and 164 million metric tons of carbon from entering the earth's atmosphere.
How do nuclear power plants reduce emissions?
The U.S. Clean Air Act standards assume nuclear energy. The U.S. Clean Air Act of 1970 and related regulations set federally mandated limits on the emission of certain pollutants for states and regions of the country. Both nuclear and fossil power plants operate in those states and regions. Air quality standards established under the Clean Air Act have been calculated, in fact, presuming that 20 percent of the nation's electricity will continue to be produced by non-emitting nuclear energy, and that 30 percent total will be non-emitting generation. This is on a national basis. The percent actually varies from state to state, with many states in "non-attainment" areas that have been unable to achieve air quality standards being more heavily dependent on nuclear energy.
Nuclear plants help regions meet air pollution standards. Air pollution compliance regulations are actually being enforced against the total supply of electricity, not just facilities that emit pollutants. Both emission caps and permits under ambient air quality standards represent a predetermined level of pollution rights available to a range of industrial activities, one of which is electricity production. These restrictions remain fixed, even if the total amount of electricity needed to satisfy demand in the affected regions of the country rises. A state or region can more easily remain within its emission limitations and still meet its energy needs when emission-free sources are used to satisfy a portion of demand.
Nuclear plants also reduce the cost of air pollution control for emitting facilities. But emission-free sources like nuclear energy do more than help in meeting air pollution standards. When some of the electricity generating units do not need air emission permits, like nuclear facilities, which are non-emitting, more allowable tons remain available to emitting facilities in the same location. Reducing the scarcity of allowable tons lowers their price, or reduces the capital expenses needed to reduce emissions. Non-emitting nuclear generation reduces competition for a limited amount of rights to pollute created by law. So, they reduce the actual capital cost of air pollution controls for emitting generation in the same location.
Nitrogen oxides, a precursor of ground-level ozone, provides a good example of how nuclear energy helps the energy industry meet its clean air compliance. Under recent rules, the Environmental Protection Agency established a cap on this controlled pollutant for 21 eastern states. This NOx SIP Call Rule allocates this total cap as an emission limit for each state. The cap for all of these states is 565,000 tons, while actual NOx output in 1997 was 1,346,350 tons. If electricity generation sources that emit harmful gases were to replace nuclear, these states would produce an additional 131,867 tons, even if their emission rate meets the level required by the SIP Call Rule. That replacement generation alone would use up 31 percent of the combined caps for each state even before all other industries are brought into the calculation. Some states would face a significantly greater burden: South Carolina would lose 86 percent, Connecticut 65 percent, Illinois 47 percent, Virginia 46 percent, Pennsylvania 41 percent, and New Jersey 40 percent of their respective caps without nuclear energy.
Environmental benefits
Of all energy sources, nuclear energy has perhaps the lowest impact on the environment especially in relation to kilowatts produced because nuclear plants do not emit harmful gases, require a relatively small area, and effectively minimize or negate other impacts. In other words, nuclear energy is the most "ecologically efficient" of all energy sources because it produces the most electricity in relation to its minimal environmental impact. There are no significant adverse effects to water, land, habitat, species, and air resources.
Nuclear energy is an emission-free energy source because it does not burn anything to produce electricity. Nuclear power plants produce no gases such as nitrogen oxide or sulfur dioxide that could threaten our atmosphere by causing ground-level ozone formation, smog, and acid rain. Nor does nuclear energy produce carbon dioxide or other greenhouse gases suspected to cause global warming. Throughout the nuclear fuel cycle, the small volume of waste byproducts actually created is carefully contained, packaged and safely stored. As a result, the nuclear energy industry is the only industry established since the industrial revolution that has managed and accounted for all of its waste, preventing adverse impacts to the environment.
Nuclear power also provides water quality and aquatic life conservation. Water discharged from a nuclear power plant contains no harmful pollutants and meets regulatory standards for temperature designed to protect aquatic life. This water, used for cooling, never comes in contact with radioactive materials. If the water from the plant is so warm that it may harm marine life, it is cooled before it is discharged to its source river, lake, or bay as it is either mixed with water in a cooling pond or pumped through a cooling tower.
Because the areas around nuclear power plants and their cooling ponds are so clean, they are often developed as wetlands that provide nesting areas for waterfowl and other birds, new habitats for fish, and the preservation of other wildlife as well as trees, flowers, and grasses. Many energy companies have created special nature parks or wildlife sanctuaries on plant sites.
Nuclear power plants provide land and habitat preservation. Because nuclear power plants produce a large amount of electricity in a relatively small space, they require significantly less land for operation than all other energy sources. For instance, solar and wind farms must occupy substantially more land, and must be sited in geographically unpopulated areas far from energy demand. To build the equivalent of a 1,000-megawatt nuclear plant, a solar park would have to be larger than 35,000 acres, and a wind farm would have to be 150,000 acres or larger. By contrast, the Millstone Units 2 and 3 nuclear power plants in Connecticut have an installed capacity of over 1,900 megawatts of power on a 500-acre site designed for three nuclear plants. Also, uranium is a concentrated, low-volume fuel source requiring few incursions into the land for extraction or transport.
Nuclear plants are so environmentally benign that they enable endangered species to live and thrive nearby. Such endangered species as osprey, peregrine falcons, bald eagles, red-cockaded woodpecker, and even the beach tiger beetle have found a home at nuclear power plants. Programs also protect species that are not endangered, such as bluebirds, wood ducks, kestrels, sea lions, wild turkeys, and pheasant. In contrast, certain wind farms pose a hazard to endangered bird species. Bald eagles and other birds of prey are apparently mesmerized by the movement of the propellers and fly directly into them. Moreover, depletion of protected birds of prey results in an increase in the pest population that was their food source. For instance, all the birds of prey in the Altamont pass of California have been killed by a wind farm, and the city of Livermore developed a rodent infestation due to their absence.
Economic Benefits of Nuclear Power
Nuclear power plants provide low-cost, predictable power at stable prices and are essential in maintaining the reliability of the U.S. electric power system. Nuclear power is a major national energy source. Nuclear energy is our nation's largest source of emission-free electricity and our second largest source of power. The 103 U.S. nuclear units supply about 20 percent of the electricity produced in the United States. The only fuel source that produced more electricity was coal.
Nuclear plants also contribute to national energy security and ensure stable nationwide electricity supply. As an integral part of the U.S. energy mix, nuclear energy is a secure energy source that the nation can depend on. Unlike some other energy sources, nuclear energy is not subject to unreliable weather or climate conditions, unpredictable cost fluctuations, or dependence on foreign suppliers. In fact, nuclear energy is a strong domestic as well as international industry, with extensive fuel supply sources. Nuclear power plants are large units that run for extended periods. They help supply the necessary level of electricity, or "baseload generation," for the electricity transmission network, or "grid," to operate. U.S. nuclear power plants are a key element in the stability of our country's electrical grid.
Nuclear power plants have long periods of operation. Nuclear power plants are designed to operate continuously for long periods of time. They can run about 540 days before they are shut down for refueling. The longest continuous run by a light water reactor is Three Mile Island, Unit 1, in Pennsylvania, which completed a 688-day run. The longest run of any type of reactor is 894 days, achieved by the Pickering 7 plant, a heavy-water reactor in Ontario, Canada (Canadian CANDU reactors can be refueled while operating).
An increased capacity factor results in an increase in the production of electricity by nuclear plants. The increase from 1998 to 1999 alone amounted to about 50 billion kilowatt-hours more electricity, for a total of 720 billion kilowatt-hours. That is roughly equivalent to adding six to seven one-thousand-megawatt nuclear reactors to the U.S. nuclear fleet. The increase in electricity produced using nuclear energy from 1990 to 1999, 143 billion kilowatt hours, is the equivalent of adding 19 one-thousand-megawatt nuclear reactors to the U.S. fleet.
The costs involved in producing electricity at a nuclear power plant, operations and maintenance plus fuel, have been declining over the past decade. In 1998 the average production cost for the U.S. nuclear fleet was 2.13 cents per kilowatt-hour, down from 3.04 cents in 1988. In addition, there are no unexpected additional costs.
Power plants have future price stability. A nuclear power plant can leverage its high degree of future price stability by selling at a premium to large users an assured source of electricity supply at a known price. For instance, presently some users in California are willing to pay this premium to protect themselves against the damaging effects of price volatility in the day-ahead market.
Another value of nuclear power, transmission system support, is typically not yet recognized. Nuclear units provide ancillary services such as voltage support, and play a key role in maintaining the reliability of the grid, a service with value in an unbundled market.
Nuclear power plants have significant additional site value, such as switchyards, access to the grid, ingress and egress, and spare cooling capacity. In many cases, they were planned for more units than were built, providing room to build additional non-nuclear generation. Such diverse generation would enable a single site to execute forward sales in the bilateral contract market and participate in the day-ahead market, in particular selling highly profitable 10-minute spinning reserve capacity.
Abundant fuel with low cost and stable price. US nuclear power plants use an enriched form of uranium for fuel. Uranium is a relatively abundant element that occurs naturally in the earth's crust. Uranium oxide is about as common as tin. In 1998, 16 countries produced over 99 percent of the world's total uranium production. Canada's and Australia's uranium mines account for 46 percent. Compared to natural gas, a fuel also used to generate electricity, uranium is already relatively low in cost and less sensitive to fuel price increases. And a little goes a long way: one uranium fuel pellet-the size of the tip of your little finger-is the equivalent of 17,000 cubic feet of natural gas, 1,780 pounds of coal, or 149 gallons of oil.
One example is the Palo Verde Nuclear Generating Station in Arizona. Palo Verde Nuclear Generating Station in Arizona generates more electricity annually than any other US power plant of any kind, including coal, oil, natural gas and hydro. The three-unit, 3,921-megawatt nuclear plant generated 32,095,426 megawatt-hours of electricity in 1999. Today, nuclear power plants, the second largest source of electricity in the United States, supply about 20 percent of the nation's electricity each year. In 2000, US nuclear plants generated a record 753.9 billion kilowatt-hours of electricity. In 1999, they produced 728 billion kWh. The average electricity production cost in 1999 for nuclear energy was 1.83 cents per kilowatt-hour, for coal-fired plants 2.07 cents, for oil 3.24 cents, and for gas 3.52 cents. In the United States, six of the nine largest investor-owned utilities by revenue were nuclear utilities in 1998. The top investor-owned utility by profit was a nuclear utility, and eight of the next nine profit leaders were nuclear utilities.
Despite popular belief, nuclear plants are relatively safe. For years, America's commercial nuclear energy industry has ranked among the safest places to work in the United States. In 2000, its industrial safety accident rate-which tracks the number of accidents that result in lost work time, restricted work or fatalities-was 0.26 per 200,000 worker-hours. By comparison, the accident rate for US private industry was 3.1 per 200,000 worker-hours in 1998-the last year figures are available from the Bureau of Labor Statistics. Even if you lived right next door to a nuclear power plant, you would still receive less radiation each year than you would receive in just one round-trip flight from New York to Los Angeles. You would have to live near a nuclear power plant for over 2,000 years to get the same amount of radiation exposure that you get from a single diagnostic medical x-ray.
Since March 1993, 113 metric tons of uranium from weapons have been transformed into fuel for nuclear power plants. That's the equivalent of 4,500 dismantled nuclear weapons. This is the result of the United States and the Russian Federation signing an agreement on the disposition and purchase of 500 metric tons of highly enriched uranium from dismantled Russian nuclear weapons. 



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What are advantages and disadvantages of nuclear power?

Advantages:

• Almost 0 emissions (very low greenhouse gas emissions).
• They can be sited almost anywhere unlike oil which is mostly imported.
• The plants almost never experience problems if not from human error, which almost never happens anyway because the plant only needs like 10 people to operate it.
• A small amount of matter creates a large amount of energy.
• A lot of energy is generated from a single power plant.
• Current nuclear waste in the US is over 90% Uranium. If reprocessing were made legal again in the US we would have enough nuclear material to last hundreds of years.
• A truckload of Uranium is equivalent in energy to 10,000+ truckloads of coal. (Assuming the Uranium is fully utilized.)
• A nuclear aircraft carrier can circle the globe continuously for 30 years on its original fuel while a diesel fueled carrier has a range of only about 3000 miles before having to refuel.
• Modern reactors have two to ten times more efficiency than the old generation reactors currently in use around the US.
• New reactor types have been designed to make it physically impossible to melt down. As the core gets hotter the reaction gets slower, hence a run-away reaction leading to a melt-down is not possible.
• Theoretical reactors (traveling wave) are proposed to completely eliminate any long-lived nuclear waste created from the process.
• Breeder reactors create more usable fuel than they use.
• Theoretical Thorium reactors have many of the benefits of Uranium reactors while removing much of the risk for proliferation as it is impossible to get weapons-grade nuclear materials from Thorium. 

Disadvantages:

• Nuclear plants are more expensive to build and maintain.
• Proliferation concerns - breeder reactors yield products that could potentially be stolen and turned into an atomic weapon.
• Waste products are dangerous and need to be carefully stored for long periods of time. The spent fuel is highly radioactive and has to be carefully stored for many years or decades after use. This adds to the costs. There is presently no adequate safe long-term storage for radioactive and chemical waste produced from early reactors, such as those in Hanford, Washington, some of which will need to be safely sealed and stored for thousands of years.
• Early nuclear research and experimentation has created massive contamination problems that are still uncontained. Recently, for instance, underground contamination emanating from the Hanford Nuclear Reservation in Washington State in the U.S. was discovered and threatens to contaminate the Columbia River (the largest river in North America west of the continental divide).
• A lot of waste from early reactors was stored in containers meant for only a few decades, but is well past expiration and, resultingly, leaks are furthering contamination.
• Nuclear power plants can be dangerous to its surroundings and employees. It would cost a lot to clean in case of spillages.
• There exist safety concerns if the plant is not operated correctly or conditions arise that were unforeseen when the plant was developed, as happened at the Fukushima plant in Japan; the core melted down following an earthquake and tsunami the plant was not designed to handle despite the world's strongest earthquake codes.
• Many plants, including in the U.S., were designed with the assumption that "rare" events never actually occur, such as strong earthquakes on the east coast (the New Madrid quakes of the 1800s were much stronger than any east coast earthquake codes for nuclear reactors; a repeat of the New Madrid quakes would exceed the designed earthquake resiliency for nuclear reactors over a huge area due to how wide-spread rare but dangerous eastern North American earthquake effects spread), Atlantic tsunami (such as the 1755 Lisbon quake event, which sent significant tsunami that caused damage from Europe to the Caribbean) and strong hurricanes which could affect areas such as New York that are unaccustomed to them (rare, but possibly more likely with global warming)
• Mishaps at nuclear plants can render hundreds of square miles of land uninhabitable and unsuitable for any use for years, decades or longer, and kill off entire river systems