Environmental effects of nuclear power

The environmental impact of nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

results from the nuclear fuel cycle

Nuclear fuel cycle

The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in...

, operation, and the effects of nuclear accidents.

The routine health risks and greenhouse gas emissions from nuclear fission power are small relative to those associated with coal, but there are "catastrophic risks": the possibility of over-heated fuel releasing massive quantities of fission products to the environment, and nuclear weapons proliferation. The public is sensitive to these risks and there has been considerable public opposition to nuclear power. The 1979 Three Mile Island accident

Three Mile Island accident

The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

and 1986 Chernobyl disaster

Chernobyl disaster

The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine , which was under the direct jurisdiction of the central authorities in Moscow...

, along with high construction costs, ended the rapid growth of global nuclear power capacity.

In March 2011 an earthquake and tsunami caused damage that led to explosions and partial meltdowns at the Fukushima I Nuclear Power Plant

Fukushima I Nuclear Power Plant

The , also known as Fukushima Dai-ichi , is a disabled nuclear power plant located on a site in the towns of Okuma and Futaba in the Futaba District of Fukushima Prefecture, Japan. First commissioned in 1971, the plant consists of six boiling water reactors...

in Japan. Concerns about the possibility of a large scale radiation leak resulted in 20 km exclusion zone being set up around the power plant and people within the 20-30km zone being advised to stay indoors. John Price, a former member of the Safety Policy Unit at the UK's National Nuclear Corporation, has said that it "might be 100 years before melting fuel rods can be safely removed from Japan's Fukushima nuclear plant".

Waste streams

Nuclear power has at least four waste streams that may harm the environment:

(1) they create spent nuclear fuel
Spent nuclear fuel
Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor...

at the reactor site (including plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

waste)
(2) they produce tailings at uranium mines and mills
(3) during operation they routinely release small amounts of radioactive isotopes
(4) during accidents they can release large quantities of dangerous radioactive materials

The nuclear fuel cycle involves some of the most dangerous elements and isotopes known to humankind, including more than 100 dangerous radionuclide

Radionuclide

A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...

s and carcinogens such as strontium-90

Strontium-90

Strontium-90 is a radioactive isotope of strontium, with a half-life of 28.8 years.-Radioactivity:Natural strontium is nonradioactive and nontoxic, but 90Sr is a radioactivity hazard...

, iodine 131 and cesium -137, which are the same toxins found in the fall out of nuclear weapon

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

s".

High-level waste

Around 20–30 tons of high-level waste

High level waste

High level waste is a type of nuclear waste created by the reprocessing of spent nuclear fuel. It exists in two main forms:* First and second cycle raffinate and other waste streams created by nuclear reprocessing....

are produced per month per nuclear reactor. The world's nuclear fleet creates about 10,000 metric tons of high-level spent nuclear fuel each year. Several methods have been suggested for final disposal of high-level waste, including deep burial in stable geological structures, transmutation, and removal to space. So far, none of these methods have been implemented. There is an "international consensus on the advisability of storing nuclear waste in deep underground repositories", but no country in the world has yet opened such a site. There are some 65,000 tons of nuclear waste now in temporary storage throughout the U.S., but in 2009, President Obama "halted work on a permanent repository at Yucca Mountain in Nevada, following years of controversy and legal wrangling".

Nuclear reprocessing

Nuclear reprocessing

Nuclear reprocessing technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel. Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally reprocessing was used solely to extract plutonium for producing...

may reduce the volume of high-level waste, but by itself does not reduce radioactivity or heat generation and therefore does not eliminate the need for a geological waste repository. Reprocessing has been politically controversial because of the potential to contribute to nuclear proliferation

Nuclear proliferation

Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...

, the potential vulnerability to nuclear terrorism

Nuclear terrorism

Nuclear terrorism denotes the use, or threat of the use, of nuclear weapons or radiological weapons in acts of terrorism, includingattacks against facilities where radioactive materials are present...

, the political challenges of repository siting (a problem that applies equally to direct disposal of spent fuel), and because of its high cost compared to the once-through fuel cycle. The Obama administration has disallowed reprocessing of nuclear waste, citing nuclear proliferation concerns.

Nine U.S. states have "explicit moratoria on new nuclear power" until a long-term storage solution emerges.

Other waste

Moderate amounts of low-level waste are produced through chemical and volume control system (CVCS). This includes gas, liquid, and solid waste produced through the process of purifying the water through evaporation. Liquid waste is reprocessed continuously, and gas waste is filtered, compressed, stored to allow decay, diluted, and then discharged. The rate at which this is allowed is regulated and studies must prove that such discharge does not violate dose limits to a member of the public (see radioactive effluent emissions).

Solid waste can be disposed of simply by placing it where it will not be disturbed for a few years. There are three low-level waste disposal sites in the United States in South Carolina, Utah, and Washington. Solid waste from the CVCS is combined with solid radwaste that comes from handling materials before it is buried off-site.

Radioactive gases and effluents

Most commercial nuclear power plants release gaseous and liquid radiological effluents into the environment as a byproduct of the Chemical Volume Control System, which are monitored in the US by the EPA and the NRC. Civilians living within 50 miles (80.5 km) of a nuclear power plant typically receive about 0.1 μSv

Sievert

The sievert is the International System of Units SI derived unit of dose equivalent radiation. It attempts to quantitatively evaluate the biological effects of ionizing radiation as opposed to just the absorbed dose of radiation energy, which is measured in gray...

per year. For comparison, the average person living at or above sea level receives at least 260 μSv from cosmic radiation.

The total amount of radioactivity released through this method depends on the power plant, the regulatory requirements, and the plant's performance. Atmospheric dispersion models combined with pathway models are employed to accurately approximate the dose to a member of the public from the effluents emitted. Effluent monitoring

Airborne particulate radioactivity monitoring

Continuous particulate air monitors have been used for years in nuclear facilities to assess airborne particulate radioactivity . In more recent times they may also be used to monitor people in their homes for the presence of manmade radioactivity. These monitors can be used to trigger alarms,...

is conducted continuously at the plant.

Limits for the Canadian plants are shown below:

Regulatory limits on Radioactive Gaseous Effluents from Canadian Nuclear Power Plants
Effluent	Tritium	Iodine-131	Noble Gases	Particulates	Carbon-14
Units	(TBqb × 10⁴)	(TBq)	(TBq-MeVc × 10⁴)	(TBq)	(TBq × 10³)
Point Lepreau Nuclear Generating Station Point Lepreau Nuclear Generating Station Point Lepreau Nuclear Generating Station is a Canadian nuclear power station located 2 km northeast of Point Lepreau, New Brunswick. The facility was constructed between 1975-1983 by NB Power, the provincially-owned public utility....	43.0	9.9	7.3	5.2	3.3
Bruce Nuclear Generating Station Bruce Nuclear Generating Station Bruce Nuclear Generating Station is a Canadian nuclear power station located on the eastern shore of Lake Huron, in the communities of Inverhuron and Tiverton, Ontario. It occupies 932 ha of land. The facility derives its name from Bruce County in which it is located, in the former Bruce Township... A	38.0	1.2	25.0	2.7	2.8
Bruce B	47.0	1.3	61.0	4.8	3.0
Darlington	21.0	0.6	21.0	4.4	1.4
Pickering Nuclear Generating Station Pickering Nuclear Generating Station Pickering Nuclear Generating Station is a Canadian nuclear power station located on the north shore of Lake Ontario in Pickering, Ontario. The facility derives its name from the City of Pickering in which it is located.... A	34.0	2.4	8.3	5.0	8.8
Pickering B	34.0	2.4	8.3	5.0	8.8
Gentilly-2	44.0	1.3	17.0	1.9	0.91

Effluent emissions for Nuclear power in the United States are regulated by 10 CFR 50.36(a)(2). For detailed information, consult the Nuclear Regulatory Commission

Nuclear Regulatory Commission

The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...

's database.

Tritium Effluent Limits
Country	Limit (Bq/L)
Australia	76,103
Finland	30,000
WHO	10,000
Switzerland	10,000
Russia	7,700
Ontario, Canada	7,000
United States	740
European Union	1001
California Public Health Goal	14.8

Tritium

A leak of radioactive water at Vermont Yankee in 2010, along with similar incidents at more than 20 other US nuclear plants in recent years, has kindled doubts about the reliability, durability, and maintenance of aging nuclear installations in the United States.

Tritium

Tritium

Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

is a radioactive isotope of hydrogen that emits a low-energy beta particle and is usually measured in becquerel

Becquerel

The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...

s (i.e. atoms decaying per second) per liter (Bq/L). Tritium becomes dissolved in ordinary water when released from a nuclear plant. The primary concern for tritium release is the presence in drinking water, in addition to biological magnification leading to tritium in crops and animals consumed for food.

Legal concentration limits have differed greatly to place to place (see table right). For example, in June 2009 the Ontario Drinking Water Advisory Council recommended lowering the limit from 7,000 Bq/L to 20 Bq/L. According to the NRC, tritium is the least dangerous radionuclide because it emits very weak radiation and leaves the body relatively quickly. The typical human body contains roughly 3,700 Bq of potassium-40

Potassium-40

Potassium-40 is a radioactive isotope of potassium which has a very long half-life of 1.248 years, or about 39.38 seconds.Potassium-40 is a rare example of an isotope which undergoes all three types of beta decay. About 89.28% of the time, it decays to calcium-40 with emission of a beta particle...

. The amount released by any given plant also varies greatly; the total release for plants in the United States in 2003 was at least counted to be 0 and at most 2,080 curies (77 TBq).

Uranium mining

Uranium mining can use large amounts of water — for example, the Roxby Downs mine in South Australia uses 35,000 m³ of water each day and plans to increase this to 150,000 m³ per day.

Risk of cancer

There have been several epidemiological studies that claim to demonstrate increased risk of various diseases, especially cancers, among people who live near nuclear facilities. A widely cited 2007 meta-analysis

Meta-analysis

In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...

by Baker et al. of 17 research papers was published in the European Journal of Cancer Care. It offered evidence of elevated leukemia rates among children living near 136 nuclear facilities in the United Kingdom, Canada, France, United States, Germany, Japan, and Spain. However this study has been criticized on several grounds - such as combining heterogeneous data (different age groups, sites that were not nuclear power plants, different zone definitions), arbitrary selection of 17 out of 37 individual studies, exclusion of sites with zero observed cases or deaths, etc. Elevated leukemia rates among children were also found in a 2008 German study by Kaatsch et al. that examined residents living near 16 major nuclear power plants in Germany. This study has also been criticised on several grounds. These 2007 and 2008 results are not consistent with many other studies that have tended not to show such associations. The British Committee on Medical Aspects of Radiation in the Environment issued a study in 2011 of children under five living near 13 nuclear power plants in the UK during the period 1969-2004. The committee found that children living near power plants in Britain are no more likely to develop leukemia than those living elsewhere

Comparison to coal-fired generation

In terms of net radioactive release, the National Council on Radiation Protection and Measurements

National Council on Radiation Protection and Measurements

The National Council on Radiation Protection and Measurements is a U.S. organization. It has a congressional charter under Title 36 of the United States Code, but this does not imply it has any sort of oversight or supervision from Congress; it is not a government entity.This text appears on the...

(NCRP) estimated the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons. With 154 coal plants in the United States, this amounts to emissions of 0.6319 TBq per year for a single plant.

In terms of dose to a human living nearby, it is sometimes cited that coal plants release 100 times the radioactivity of nuclear plants. This comes from NCRP Reports No. 92 and No. 95 which estimated the dose to the population from 1000 MWe coal and nuclear plants at 4.9 man-Sv

Collective dose

Collective dose is a measure of the total amount of effective dose multiplied by the size of the exposed population. Collective dose is usually measured in units of person-rem or person-sieverts, or man-rem or man-sievert.-References:**-See also:...

/year and 0.048 man-Sv/year respectively (a typical Chest x-ray

Chest X-ray

In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...

gives a dose of about 0.06 mSv for comparison). The Environmental Protection Agency

United States Environmental Protection Agency

The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

estimates an added dose of 0.3 µSv per year for living within 50 miles (80.5 km) of a coal plant and 0.009 milli-rem for a nuclear plant for yearly radiation dose estimation. Nuclear power plants in normal operation emit less radioactivity than coal power plants.

Unlike coal-fired or oil-fired generation, nuclear power generation does not directly produce any sulfur dioxide, nitrogen oxides, or mercury (pollution from fossil fuels is blamed for 24,000 early deaths each year in the U.S. alone). However, as with all energy sources, there is some pollution associated with support activities such as manufacturing and transportation.

Contrast of radioactive accident emissions with industrial emissions

Proponents argue that the problems of nuclear waste "do not come anywhere close" to approaching the problems of fossil fuel waste. A 2004 article from the BBC states: "The World Health Organization

World Health Organization

The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

(WHO) says 3 million people are killed worldwide by outdoor air pollution annually from vehicles and industrial emissions, and 1.6 million indoors through using solid fuel." In the U.S. alone, fossil fuel waste kills 20,000 people each year. A coal power plant releases 100 times as much radiation as a nuclear power plant of the same wattage. It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as the Three Mile Island accident

Three Mile Island accident

The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

. The World Nuclear Association

World Nuclear Association

The World Nuclear Association , formerly the Uranium Institute, is an international organization that promotes nuclear power and supports the many companies that comprise the global nuclear industry...

provides a comparison of deaths due to accidents among different forms of energy production. In their comparison, deaths per TW-yr of electricity produced from 1970 to 1992 are quoted as 885 for hydropower, 342 for coal, 85 for natural gas, and 8 for nuclear.

Waste heat

As with some thermal power station

Thermal power station

A thermal power station is a power plant in which the prime mover is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this...

s, nuclear plants exchange 60 to 70% of their thermal energy by cycling with a body of water or by evaporating water through a cooling tower

Cooling tower

Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or in the case of closed circuit dry cooling towers rely...

. This thermal efficiency is somewhat lower than that of coal fired power plants, thus creating more waste heat

Waste heat

Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...

.

The cooling options are typically once-through cooling with river or sea water, pond cooling, or cooling towers. Many plants have an artificial lake like the Shearon Harris Nuclear Power Plant

Shearon Harris nuclear power plant

The Shearon Harris Nuclear Generating Station is a nuclear power plant with a single Westinghouse designed pressurized-water nuclear reactor operated by Progress Energy. It was named in honor of W. Shearon Harris, former president of Carolina Power & Light...

or the South Texas Nuclear Generating Station

South Texas Nuclear Generating Station

The South Texas Project Electric Generating Station , is a nuclear power station southwest of Bay City, Texas, United States. The STP occupies a 12,200 acre site on the Colorado River about 90 miles southwest of Houston...

. Shearon Harris uses a cooling tower but South Texas does not and discharges back into the lake. The North Anna Nuclear Generating Station

North Anna Nuclear Generating Station

The North Anna Nuclear Generating Station is a nuclear power plant on a site in Louisa County, Virginia. The site is operated by Dominion Generation company and is jointly owned by the Dominion Virginia Power corporation and by the Old Dominion Electric Cooperative .The plant has two Westinghouse...

uses a cooling pond or artificial lake, which at the plant discharge canal is often about 30°F warmer than in the other parts of the lake or in normal lakes (this is cited as an attraction of the area by some residents). The environmental effects on the artificial lakes are often weighted in arguments against construction of new plants, and during droughts have drawn media attention.

The Turkey Point Nuclear Generating Station

Turkey Point Nuclear Generating Station

Turkey Point Nuclear Generating Station is a twin reactor nuclear power station located on a 3,300-acre site 2 miles east of Homestead, Florida, United States, next to Biscayne National Park located about 25 miles south of Miami, Florida near the southernmost edge of Miami-Dade...

is credited with helping the conservation status of the American Crocodile

American Crocodile

The American crocodile is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas. Populations occur from the Atlantic and Pacific coasts of southern Mexico to South America as far as Peru and Venezuela. It also lives...

, largely an effect of the waste heat produced.

The Indian Point

Indian Point Energy Center

Indian Point Energy Center is a three-unit nuclear power plant station located in Buchanan, New York just south of Peekskill. It sits on the east bank of the Hudson River, 38 miles north of New York City...

nuclear power plant in New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

is in a hearing process to determine if a cooling system other than river water will be necessary (conditional upon the plants extending their operating licenses).

It is possible to use waste heat in cogeneration

Cogeneration

Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....

applications such as district heating

District heating

District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...

. The principles of cogeneration and district heating with nuclear power are the same as any other form of thermal power production

Thermal power station

. One use of nuclear heat generation was with the Ågesta Nuclear Power Plant

Ågesta Nuclear Power Plant

The nuclear power station Ågesta was the first Swedish commercial nuclear power plant. Construction started in 1957 and ended in 1962, operations began in 1964 and continued until 1974. The station primarily provided district heating for the Stockholm suburb Farsta, as well as a small amount of...

in Sweden. In Switzerland, the Beznau Nuclear Power Plant

Beznau Nuclear Power Plant

The Beznau Nuclear Power Plant is located in the municipality Döttingen on an artificial island in the Aar river...

provides heat to about 20,000 people. However, district heating with nuclear power plants is less common than with other modes of waste heat generation: because of either siting regulations

Zoning

Zoning is a device of land use planning used by local governments in most developed countries. The word is derived from the practice of designating permitted uses of land based on mapped zones which separate one set of land uses from another...

and/or the NIMBY

NIMBY

NIMBY or Nimby is an acronym for the phrase "not in my back yard". The term is used pejoratively to describe opposition by residents to a proposal for a new development close to them. Opposing residents themselves are sometimes called Nimbies...

effect, nuclear stations are generally not built in densely populated areas. Waste heat is more commonly used in industrial applications.

During Europe's 2003

2003 European heat wave

The 2003 European heat wave was the hottest summer on record in Europe since at least 1540. France was hit especially hard. The heat wave led to health crises in several countries and combined with drought to create a crop shortfall in Southern Europe...

and 2006 heat waves

2006 European heat wave

The 2006 European heat wave was a period of exceptionally hot weather that arrived at the end of June 2006 in certain European countries. The United Kingdom, France, Belgium, Netherlands, Luxembourg, Italy, Poland, the Czech Republic, Hungary, Germany and western part of Russia were most affected....

, French, Spanish and German utilities had to secure exemptions from regulations in order to discharge overheated water into the environment. Some nuclear reactors shut down.

Environmental effects of accidents

The worst accidents at nuclear power plants have resulted in severe environmental contamination. However, the extent of the actual damage is still highly debated.

Fukushima disaster

In March 2011 an earthquake and tsunami caused damage that led to explosions and partial meltdowns at the Fukushima I Nuclear Power Plant

Fukushima I Nuclear Power Plant

in Japan.

Radiation levels at the stricken Fukushima I power plant have varied spiking up to 1,000 mSv/h (millisievert per hour), which is a level that can cause radiation sickness

Radiation Sickness

Radiation Sickness is a VHS by the thrash metal band Nuclear Assault. The video is a recording of a concert at the Hammersmith Odeon, London in 1988. It was released in 1991...

to occur at a later time following a one hour exposure. Significant release in emissions of radioactive particles took place following hydrogen explosions at three reactors, as technicians tried to pump in seawater to keep the uranium fuel rods cool, and bled radioactive gas from the reactors in order to make room for the seawater.

Concerns about the possibility of a large scale radiation leak resulted in 20 km exclusion zone being set up around the power plant and people within the 20-30km zone being advised to stay indoors. Later, the UK, France and some other countries told their nationals to consider leaving Tokyo, in response to fears of spreading nuclear contamination. New Scientist has reported that emissions of radioactive iodine and cesium from the crippled Fukushima I nuclear plant have approached levels evident after the Chernobyl disaster

Chernobyl disaster

in 1986. On March 24, 2011, Japanese officials announced that "radioactive iodine-131 exceeding safety limits for infants had been detected at 18 water-purification plants in Tokyo and five other prefectures". Officials said also that the fallout from the Dai-ichi plant is "hindering search efforts for victims from the March 11 earthquake and tsunami".

According to the Federation of Electric Power Companies of Japan, "by April 27 approximately 55 percent of the fuel in reactor unit 1 had melted, along with 35 percent of the fuel in unit 2, and 30 percent of the fuel in unit 3; and overheated spent fuels in the storage pools of units 3 and 4 probably were also damaged". As of April 2011, water is still being poured into the damaged reactors to cool melting fuel rods. The accident has surpassed the 1979 Three Mile Island accident

Three Mile Island accident

The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

in seriousness, and is comparable to the 1986 Chernobyl disaster

Chernobyl disaster

. The Economist reports that the Fukushima disaster is "a bit like three Three Mile Islands in a row, with added damage in the spent-fuel stores", and that there will be ongoing impacts:

Years of clean-up will drag into decades. A permanent exclusion zone could end up stretching beyond the plant’s perimeter. Seriously exposed workers may be at increased risk of cancers for the rest of their lives...

John Price, a former member of the Safety Policy Unit at the UK's National Nuclear Corporation, has said that it "might be 100 years before melting fuel rods can be safely removed from Japan's Fukushima nuclear plant". The Economist says that nuclear power "looks dangerous, unpopular, expensive and risky", and that "it is replaceable with relative ease and could be forgone with no huge structural shifts in the way the world works".

In the second half of August 2011, Japanese lawmakers announced that Prime Minister Naoto Kan

Naoto Kan

is a Japanese politician, and former Prime Minister of Japan. In June 2010, then-Finance Minister Kan was elected as the leader of the Democratic Party of Japan and designated Prime Minister by the Diet to succeed Yukio Hatoyama. On 26 August 2011, Kan announced his resignation...

would likely visit the Fukushima Prefecture to announce that the large contaminated area around the destroyed reactors would be declared uninhabitable, perhaps for decades. Some of the areas in the temporary 12 miles (19.3 km) radius evacuation zone around Fukushima were found to be heavily contaminated with radionuclides according to a new survey released by the Japanese Ministry of Science and Education. The town of Okuma was reported as being over 25 times above the safe limit of 20 millesievers

Sievert

per year.

Chernobyl disaster

The 1986 Chernobyl disaster

Chernobyl disaster

in the Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

was the world's worst nuclear power plant accident. Estimates of its death toll are controversial and range from 4,056 to 985,000. Large amounts of radioactive contamination

Radioactive contamination

Radioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...

were spread across Europe, and cesium and strontium contaminated many agricultural products, livestock and soil. The accident necessitated the evacuation of 300,000 people from Kiev, rendering an area of land unusable to humans for an indeterminate period.

As radioactive materials decay, they release particles that can damage the body and lead to cancer, particularly cesium-137 and iodine-131. In the Chernobyl disaster, releases of cesium-137 contaminated land. Some communities were abandoned permanently. Thousands of people who drank milk contaminated with radioactive iodine developed thyroid cancer.
In Britain and Norway, as of 2011, "slaughter restrictions remain for sheep raised on pasture contaminated by radiation fallout". Germany has "banned wild game meat because of contamination linked to radioactive mushrooms".

Greenhouse gas emissions

Nuclear power plant operation emits no or negligible amounts of carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

. However, all other stages of the nuclear fuel chain – mining, milling, transport, fuel fabrication, enrichment, reactor construction, decommissioning and waste management – use fossil fuels and hence emit carbon dioxide. There has been a debate on the quantity of greenhouse gas emissions from the complete nuclear fuel chain.

Many commentators have argued that an expansion of nuclear power would help combat climate change

Climate change

Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

. Others have pointed out that it is one way to reduce emissions, but it comes with its own problems, such as risks related to severe nuclear accidents the challenges of more radioactive waste disposal. Other commentators have argued that there are better ways of dealing with climate change than investing in nuclear power, including the improved energy efficiency

Efficient energy use

Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature...

and greater reliance on decentralized and renewable energy

Renewable energy

Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

sources.

According to an analysis by Mark Z. Jacobson

Mark Z. Jacobson

Mark Z. Jacobson is professor of civil and environmental engineering at Stanford University and director of the Atmosphere and Energy Program there...

, nuclear power results in 9-25 times more carbon emissions than wind power

Wind power

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....

, "in part due to emissions from uranium refining and transport and reactor construction, in part due to the longer time required to site, permit, and construct a nuclear plant compared with a wind farm (resulting in greater emissions from the fossil-fuel electricity sector during this period), and in part due to the greater loss of soil carbon due to the greater loss in vegetation resulting from covering the ground with nuclear facilities relative to wind turbine towers, which cover little ground".

Various life cycle analysis (LCA) studies have led to a large range of estimates. Some comparisons of carbon dioxide emissions show nuclear power

Nuclear power

Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

as comparable to renewable energy

Renewable energy

sources. On another hand, a 2008 meta analysis of 103 studies, published by Benjamin K. Sovacool

Benjamin K. Sovacool

Benjamin K. Sovacool is a Visiting Associate Professor at Vermont Law School and founding Director of the Energy Justice Program at their Institute for Energy and Environment. He was formerly an Assistant Professor and Research Fellow at the National University of Singapore.Sovacool's research...

, determined that renewable electricity technologies are "two to seven times more effective than nuclear power plants on a per kWh basis at fighting climate change".

Decommissioning

Both nuclear reactors and uranium enrichment facilities must be carefully
decommissioned using processes that are occupationally dangerous, and hazardous to the natural environment, expensive, and time-intensive.