Nuclear power and the nuclear fuel chain

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What is nuclear power?
Concerns related to the use of nuclear power
Nuclear power: no solution to the climate crisis
Regulation of nuclear energy use
Information sources
Further reading

What is nuclear power?

Nuclear energy is the energy in the nucleus, or core, of an atom. Atoms are tiny units that make up all matter in the universe, and energy is what holds the nucleus together. There is a huge amount of energy in an atom's dense nucleus. If released from the atom, nuclear energy can be used to create electricity. This process is called nuclear fission, whereby atoms are split to release the energy.

A nuclear reactor, or power plant, is a series of machines that can control nuclear fission to produce electricity. The fuel that nuclear reactors use to produce nuclear fission is pellets of the element uranium. In a nuclear reactor, atoms of uranium are forced to break apart. As they split, the atoms release tiny particles called fission products. Fission products cause other uranium atoms to split, starting a chain reaction. The energy released from this chain reaction creates heat. The heat created by nuclear fission warms the reactor's cooling agent. A cooling agent is usually water, but some nuclear reactors use liquid metal or molten salt. The cooling agent, heated by nuclear fission, produces steam. The steam turns turbines, or wheels turned by a flowing current. The turbines drive generators, or engines that create electricity. 

Dwight Eisenhower’s landmark speech made to the United Nations General Assembly on 8 December 1953 addressed the world’s widespread fear and discontent over recently developed atomic technology and weapons. His “Atoms for Peace” speech, as it came to be known, proposed that a nuclear regulatory agency be created, which led to the establishment of the International Atomic Energy Agency (IAEA). Eisenhower sought to transform nuclear technology into a peaceful and humanitarian pursuit by focusing on nuclear energy development, but his promotion of nuclear energy led to its proliferation across the US and the world.  

While the nuclear electricity generation kept rising during the 1990s, the use of nuclear energy for electricity has been decreasing as of 2006. In 1996 for instance, at the height of the nuclear power industry, nuclear power provided 17.6 per cent of the world’s electricity.  A significant drop in the operation of nuclear power reactors occurred after the Fukushima nuclear reactor disaster in 2011. As of March 2020, about 10 per cent of the world’s electricity comes from nuclear power, generated by around 440 nuclear power reactors worldwide.  

The “food” for nuclear energy: Uranium

Low-enriched uranium (LEU) is the principal fuel for nuclear reactors and the main raw material for nuclear weapons. This is because uranium atoms split apart relatively easily.

Uranium is a common element found in rocks all over the world. However, the specific type of uranium used to produce nuclear energy, uranium-235 (U-235) is very rare. It makes up less than one per cent of the uranium in the world.

When uranium is mined from the earth it contains only about 0.7 per cent uranium-235. Industrial processes enrich uranium by concentrating the amount of U-235 to 3 per cent or more for use as reactor fuel. Uranium with more than 20 per cent U-235 is called highly-enriched uranium (HEU).

The production of nuclear weapons requires HEU of at least 90 per cent of U-235. Enriching uranium is both technically difficult and expensive, as it requires separating isotopes that have very similar chemical and physical properties. The enrichment process is thus the main barrier to producing uranium suitable for use in nuclear weapons.

Uranium mining

Traditionally, uranium has been extracted from underground and open pit mines. In 2019, the largest uranium mines were in Canada, Namibia, Australia, Kazakhstan, and Niger, producing over 50 per cent of all uranium.

Natural uranium has to be mined from the earth like any other natural element. Yet, unlike other natural elements, uranium is radioactive. As a result, every aspect of uranium production, from mining to transportation, has damaging environmental and health effects.

Uranium enrichment

In order to be used in a reactor, the uranium must be enriched, increasing the percentage of radioactive U-235 in the sample. Typical civilian power plants require uranium to be enriched from 0.7 per cent to 3-5 per cent U-235 in their fuel.

After mining the uranium mineral is refined to uranium oxide, called yellowcake. This natural uranium is processed and then enriched. Numerous technologies have been developed to enrich uranium, such as gaseous-diffusion, centrifuges, and electromagnetic separation. All of these technologies require a large initial investment and large amounts of energy to operate.


After four to five years, the fuel for nuclear reactors becomes less efficient. The used fuel, also referred to as “spent fuel,” is taken out of the nuclear reactors. Reprocessing is a series of chemical reactions that separates plutonium and uranium from other spent fuel. The separated uranium is turned into powdered form, processed into fuel pellets and sent back for use in nuclear reactors. Plutonium can be combined with uranium and turned into a mixed oxide fuel called Mox.

Plutonium is also used for nuclear weapons production. The countries that have civilian reprocessing plants include United Kingdom, France, India, Japan, and Russia. China is operating a pilot civilian reprocessing facility. The countries with military plutonium separation sites include India, Pakistan, Israel, and the Democratic People’s Republic of Korea.

Concerns related to the use of nuclear power

While the vast majority of countries are against the development and use of nuclear weapons, attitudes vary when it comes to the development and use of nuclear power. But the use of nuclear energy has a vast range of environmental, health, and security risks.


One risk of nuclear energy use includes the possibility of accidents. There have been countless accidents in nuclear power plants since the first recorded one in 1952 at Chalk River in Ontario, Canada. In 2011, the Guardian identified 33 incidents to be “serious,” but noted that the International Atomic Energy Agency (IAEA), the principal international body tasked to regulate nuclear energy use, has failed to keep a complete historical database.

Below are examples of the three worst recorded accidents in history.


In 2011, a powerful earthquake and tsunami led to the world’s most recent grave nuclear accident in Fukushima, northern Japan. Tsunami waves damaged the backup generators, and the loss of power caused cooling systems to fail in each of the reactors within the first few days of the disaster. Rising residual heat within the reactors caused partial melt down of the fuel rods, leading to the release of radiation. There were also three explosions within a couple of days, resulting from the buildup of pressurised hydrogen gas, which led to higher levels of radiation. In the months following the disaster, an area of roughly 207 square kilometers was designated for evacuation. The accident killed more than 18,000 people, and forced 160,000 residents to evacuate.

Parts of the area surrounding the power plant have been completely deserted since, while other areas in the region have started a partial recovery after the Japanese government declared them safe for residents. According to local officials, residents will be able to return in 2022, when the city’s water supply and other infrastructure will have been restored. But concerns exist over the release of radioactive water. The Japan Center for Economic Research, a source supportive of nuclear power, estimated the long-term costs of the accident to be about US$750 billion.


In 1986, a devastating nuclear accident happened in northern Ukraine, Chernobyl, as a reactor at a nuclear power plant exploded and burnt, killing 28 people as a direct result of the accident, while injuring more than 100. The United Nations Scientific Committee on the Effects of Atomic Radiation has reported that more than 6,000 children and adolescents developed thyroid cancer after being exposed to radiation from the incident, although some experts have challenged that claim. International researchers have predicted that ultimately, around 4,000 people exposed to high levels of radiation could succumb to radiation-related cancer, while about 5,000 people exposed to lower levels of radiation may suffer the same fate. Almost 40 years on, scientists estimate the zone around the former plant will not be habitable for up to 20,000 years.

Three Mile Island

Seven years earlier, in 1979, the Three Mile Island nuclear power plant in the US released small amounts of radioactive gas, a few days after a cooling malfunction caused part of one reactor’s core to melt. While there are no recorded health impacts of the accident, the extent of the damage and the amount of radioactivity released into the environment during that period is still disputed in the scientific community. Even so, the events at Three Mile Island illustrate how quickly a functioning nuclear reactor can deteriorate into a near meltdown. It also reveals the life-threatening consequences of basic human error on the part of even the best-trained nuclear technicians.   

Environmental and health concerns

Proponents of nuclear energy tout it as a form of “clean” energy since it releases virtually none of the harmful CO2 emissions associated with fossil fuel. However, the construction of nuclear power plants does emit great amounts of CO2, as construction instruments and processes, such as trucks, cranes, and front-end loaders rely on other sources of energy – especially fossil fuels. Research has also shown that considering the entire nuclear fuel cycle, between 34 and 60 grams of CO2 are emitted per generated kilowatt hour (kWh). Estimates place the CO2 per unit of energy at 4­–5 times higher than the average quantities of CO2 produced from renewable energy sources.

Next to its CO2 emission, nuclear power usage is problematic at each stage of its cycle.

Uranium mining 

For every ton of uranium oxide produced, thousands of tons of wastes, or tailings, are left behind. Often the tailings are simply dumped on the land near the mine and left to the effects of the elements. Wind carries radon gas and radioactive dust from these tailings for many miles. Contaminated rainwater enters the soil, the watershed, and, eventually, the food chain, endangering the health of people, animals, and the planet. Uranium mining on indigenous and tribal peoples' lands has devastated local communities and environments in North America, Australia, Africa, and Asia.

In Northern Saskatchewan, Canada, where the world's largest and most concentrated known uranium reserves are located, routine releases and accidental spills of contaminated water from mining and milling operations have poisoned major fisheries and threatened the health and livelihood of indigenous communities.

In Niger and Namibia, uranium tailings are dumped on the desert sand, contaminating the air, food, and drinking water of nomadic tribes.

In the Southwestern US, mining wastes abandoned on indigenous peoples' land have damaged the health of their communities. It is little known that the second worst nuclear disaster in US history was the spilling of uranium mine tailings in the Rio Puerco River in New Mexico in the 1980s.

As well, uranium miners are exposed to higher risks of cancer, especially lung cancer, birth defects in fetuses and infants, and risk of increase of leukemia and other blood diseases.

Radioactive waste 

Nuclear energy produces massive amounts of toxic, radioactive waste, and reprocessing generates the largest amount of radioactive waste. The most dangerous of this waste is called high-level waste—a liquid waste stream carrying chemicals used in reprocessing along with many radioactive isotopes from the spent fuel or other material. Some of the underground tanks, where liquid waste from past reprocessing is stored, have leaked, and storage of the waste in this form poses risks of fire or explosion resulting from chemical reactions inside the tanks.

In the US, for instance, the production of nuclear energy currently results in approximately 2,000 metric tons of highly radioactive waste per year. Waste from nuclear energy production must be safely and securely stored for between 10,000 years and 240,000 years in order to prevent health and environmental disasters from radioactive contamination. This means that any living thing coming into contact with plutonium waste during this long period of time will be exposed to potentially harmful radiation. This implies that for this entire time it must be isolated from all living organisms and from the water, land, and air upon which they depend.

None of the 30 countries with nuclear reactors has a solution to the waste problem and to the present day, all proposed solutions have failed or are burdened with problems: dropping the nuclear waste into the deep ocean, storing it in the ice of Antarctica, launching it into outer space, injecting liquid waste under ground-water bearing layers and different variants of underground storage have all been taken into consideration.
This means that the waste is either kept in "temporary", above-ground storage facilities or buried in shallow pits. Waste has been dumped directly into the ground, lakes, and oceans of the world. In particular, indigenous peoples' lands have been used to dump radioactive wastes and to conduct nuclear test explosions, both above-ground and below-ground, resulting in massive radioactive contamination.

Proliferation risks

As alluded to above, there are also security risks of nuclear weapon proliferation and nuclear terrorism. Once the technology and machinery for creating nuclear energy are gained, it is possible to begin developing weapons technology. Uranium for nuclear power use needs to be enriched to >5 per cent. Military-grade uranium needs to be enriched to >90 per cent. While this discrepancy is great, a person or state with the technology to enrich uranium for energy has the potential to move towards weapons development.

Another relationship between nuclear energy and nuclear weapons is the ability to “recycle” spent atomic fuel, in the form of plutonium, into weapons technology. The conversion of mixed oxide fuel (MOX) into weapons-grade plutonium metal is feasible. Only 8 kilograms of plutonium (the size of a large orange) is needed for an explosion. Thus, the existence of a reprocessing plant is what gives a country the ability to produce plutonium for nuclear weapons.

Examples of nuclear energy proliferation

Recent and long-term risks of real and perceived nuclear proliferation in countries such as Iraq, Iran, and theDemocratic People’s Republic of Korea have underscored the risks and links between nuclear energy and nuclear weapons production.


In the early 1990s, following Iraq’s defeat in the Gulf War, inspectors of the International Atomic Energy Agency (IAEA) discovered a clandestine nuclear weapons programme in Iraq which it had failed to discover under the Comprehensive Safeguards Agreement. Iraq had maintained that the programme was intended for peaceful nuclear purposes only. By 1997, the IAEA concluded that the Iraqi weapons of mass destruction (WMD) programmes had been incapacitated. Inspectors returned for a follow-up visit in November 2002, but were evacuated in March 2003, preceding the US-led invasion “Operation Iraqi Freedom.” The United States invaded the country accusing Iraq of its continued WMD programme, including nuclear weapons. In its 2004 report, the Iraq Survey Group concluded that Iraq had not directed a coordinated effort to restart its WMD programme after its dismantlement in the 1990s.

Democratic People’s Republic of Korea (DPRK)

The DPRK acceded the nuclear Non-Proliferation Treaty in 1985 but only concluded the safeguards agreement with the IAEA in 1992. In 1993, IAEA inspectors discovered discrepancies in North Korea’s “initial report” on its nuclear programme, asked for clarification on several issues, and demanded special inspections of two sites that were believed to store nuclear waste. The DPRK refused the IAEA’s request. It therefore declared that it could not guarantee that the DPRK’s nuclear material was not diverted for non-peaceful uses. In 1994, faced with the DPRK’s announced intent to withdraw from the NPT, the United States and the DPRK signed the Agreed Framework. It committed the latter to freezing its illicit plutonium weapons programme in exchange for aid. Following the collapse of this agreement in 2002, the DPRK claimed that it had withdrawn from the NPT in January 2003 and once again began operating its nuclear facilities. The Six-Party Talks, initiated in 2003 by China, Japan, DPRK, Russia, South Korea, and the United States, led to the DPRK’s agreement to return to the NPT and abandon existing nuclear programmes. However, the talks broke down in 2009, following disagreements over verification and an internationally condemned DPRK rocket launch. In 2018, DPRK’s leader Kim Jong Un announced that its nuclear programme is “complete”. Recent attempts of rapprochement in 2019 by the US and DPRK administrations have not yielded positive results. As of 2020, US-DPRK nuclear negotiations have completely stalled. 


Iran ratified the NPT in 1970, making its nuclear programme subject to the IAEA’s verification mechanism. The IAEA first publicly outlined its concerns about Iranian activities related to the development of a nuclear weapon in its November 2011 quarterly report on Iran’s nuclear programme. In November 2013, Iran and the IAEA announced a Joint Framework for Cooperation in which Iran agreed to take several steps to address the IAEA’s concerns, including providing information and access to research reactors and production plants. This Framework was suspended in 2015 by the Roadmap for the clarification of past and present outstanding issues regarding Iran’s nuclear programme. The 2015 Roadmap was announced alongside the nuclear deal between Iran and China, France, Germany, Russia, the UK, and the US. The agreement, also referred to the Joint Comprehensive Plan of Action (JCPOA), guaranteed the lifting of sanctions contingent on Iran’s cooperation with the IAEA’s nuclear verification in the country, imposing restrictions on Iran’s civilian nuclear enrichment programme. Since the adoption of the agreement, the IAEA consistently found Iran to be in compliance with the JCPOA. Despite this, on 8 May 2018, the US administration announced its withdrawal from the JCPOA, claiming that the agreement failed to address Iran’s ballistic missile program and its role in regional wars. It has since reinstated sanctions on Iran. This has prompted Iran to resume some of its nuclear activities. Following the US killing of Iranian military commander Qasem Soleimani in January 2020, Iran announced plans to halt most of its commitments to the JCPOA.  A June report by the IAEA, provided to member states, detailed how Iran has exceeded limits agreed in the nuclear deal. However, the Agency also listed Iran’s activities that continue to honour ongoing safeguards obligations and additional verification measures agreed to by the JCPOA. This means that there is still hope for continued implementation by the remaining parties to the agreement.

Nuclear power: No solution to the climate crisis

This section is based on WILPF’s report Costs, risks, and myths of nuclear power

Nuclear power is often presented as a solution to the problem of climate change, which is caused by greenhouse gas emissions from fossil energy use and other sources. Nuclear energy has been proposed as a carbon-free technology with the potential for a safe, clean, and cheap supply of electric power that is able to mitigate climate change.

Firstly, given the high economic costs of nuclear power, nuclear energy is not commercially competitive compared to advanced renewable energies that receive similar government subsidies. Funding diverted to new nuclear power plants deprives investment in sustainable climate crisis solutions such as solar, wind and geothermal energy of essential resources.

Secondly, because of the long planning cycles and its inadequacy for use in combustion and as transportation fuel, nuclear energy cannot replace in a reasonable timeframe the large amounts of fossil fuel currently consumed.

Thirdly, since uranium resources are limited, a sustainable energy supply based on nuclear energy cannot be realised. Even a drastic increase in nuclear energy could not compensate for the current growth in energy consumption; it would come too late for preventing climate change and lead to an enormous increase in plutonium stocks. As well, even without a massive expansion of nuclear energy, uranium resources will be consumed within the next five decades.

Fourthly, and as mentioned above, nuclear power is not carbon-free if the whole life-cycle of electricity production is taken into consideration. For instance, a 1 GWe nuclear power reactor plant in Germany causes indirect emissions of 200,000 tonnes of CO2 per year, which is comparable to hydropower, lower than photovoltaic, and higher than for wind or improved efficiency of electricity generation and use.

Other environmental risks related to nuclear waste, and the nuclear fuel chain, are elaborated on above.

Given the safety and security risks of nuclear power and its limited ability and economic viability in addressing global warming, replacing fossil fuels with nuclear fuels is not a feasible alternative.

Rather than burying or correcting the consequences of nuclear and fossil energies through nuclear waste disposal and climate engineering, we should establish a nuclear-free, carbon-free, and sustainable energy system.

Regulation of nuclear energy use

There are over a dozen treaties created under the auspices of the IAEA relating to nuclear safety and security, nuclear science and technology, technical cooperation, and nuclear liability.

As part of the framework for these agreements, the nuclear Non-Proliferation Treaty (NPT) was developed as a means to curb and control the production and proliferation of nuclear weapons and nuclear weapons materials. It entered into force in 1970. While imposing restrictions on nuclear weapons development, Article IV of the NPT establishes access to nuclear technology for peaceful purposes as an “inalienable right”. Following the adoption of the NPT, the IAEA has become the instrument with which to verify that the “peaceful use” commitments made under the NPT or similar agreements are kept through performing what is known as its “safeguards” role. The NPT has made it obligatory for all its non-nuclear-armed state parties to submit all nuclear material in nuclear activities to IAEA safeguards, and to conclude a comprehensive safeguards agreement with the Agency. The more than 180 non-nuclear-armed states parties to the NPT have pledged not to develop or otherwise acquire nuclear weapons. The IAEA’s initial failure to detect Iraq’s nuclear weapons programme in the early 1990s led to the development of the Model Additional Protocol (AP) in 1997, a more stringent and intrusive inspections regime. As of February 2020, APs are in force with 136 states; and another fourteen states have signed an AP but have yet to bring it into force. 

Information sources

The Institute for Energy and Environmental Research (IEER) provides activists, policy-makers, journalists, and the public with understandable and accurate scientific and technical information on energy and environmental issues, including in relation to nuclear energy.

The membership organisation Beyond Nuclear aims to educate and activate the public about the connections between nuclear power and nuclear weapons and the need to abandon both to safeguard our future. It hosts a diverse range of fact sheets, reports, and articles.

The Gender + Radiation Impact Project works at the intersection of public health, medicine, and public policy. It brings together thinkers to understand the role biological sex plays in harm from radiation.

The Canadian Coalition for Nuclear Responsibility (CCNR) is a non-governmental organisation dedicated to the education and research on all issues related to nuclear energy, whether civilian or military, including non-nuclear alternatives. 

The Nuclear Information and Resource Service (NIRS) is an organisation devoted to a nuclear-free, carbon-free world. It as an information and networking hub for people and organisations concerned about nuclear power, radioactive waste, radiation, and sustainable energy issues since 1978.

The Bulletin of Atomic Scientists is a media organisation, and features a wide range of news articles and feature-length reports on different aspects of nuclear security and its risks.

The Lawyers Committee on Nuclear Policy is a non-profit educational association of lawyers and legal scholars that engages in research and advocacy in support of the global elimination of nuclear weapons and also hosts resources on nuclear energy. 

The Arms Control Association is a US nonpartisan membership organisation dedicated to promoting public understanding of and support for effective arms control policies. It features a range of fact sheets related to issues around nuclear energy.

The International Physicians for the Prevention of Nuclear War (IPPNW) is a non-partisan federation of national medical groups in 64 countries working for the abolishing of nuclear weapons. It features different fact sheets related to health and environmental impacts of uranium mining.

Recommended reading

Lindsay Krall, Nuclear waste disposal: Why the case for deep boreholes is… full of holes, Bulletin of the Atomic Scientists, 26 March 2020 

2019 in review: Nuclear power is a false “solution” to the climate crisis, Beyond Nuclear, 1 January 2020

Tatsujiro Suzuki, An update from Fukushima, and the challenges that remain there, Bulletin of the Atomic Scientists, 11 November 2019

Edwin Lyman, Aging nuclear plants, industry cost-cutting, and reduced safety oversight: a dangerous mix, Bulletin of the Atomic Scientists, 29 August 2019 

Pete Roche et al., The global crisis of nuclear waste, Greenpeace France, January 2019

Marshall Brain, Robert Lamb and Patrick J. Kiger, How nuclear power works, HowStuffWorks

Claire Greensfelder et al., Safe energy handbook: Towards a solar economy future, 2015, INOCHI

Video: Uranium mining, International Physicians for the Prevention of Nuclear War (IPPNW) Germany, 24 September 2014

Claus Biegert, The death that creeps from the earth: Indigenous peoples warn us: uranium is a mineral beyond our control, International Physicians for the Prevention of Nuclear War (IPPNW) Germany

Various authors, Costs, risks, and myths of nuclear power: NGO world-wide study on the implications of the catastrophe at the Fukushima Dai-ichi Nuclear Power Station, Women’s International League for Peace and Freedom (WILPF), 2011

John Burroughs, Truth-telling about nuclear technology, DisarmamentActivist.org, 16 March 2011

Health effects of uranium mining, IPPNW, 26 August 2010

Michael Spies, Controlling the nuclear fuel cycle, Disarmament Times, Volume 31, No.1, Spring 2008

Arjun Makhijani, Carbon-free and nuclear-free: A roadmap for US energy policy, IEER Press, 2010 (third edition)

Michael Spies, Climate change and nuclear power, Nuclear Disorder or Cooperative Security?, Lawyers’ Committee on Nuclear Policy, Western States Legal Foundation, Reaching Critical Will of the Women’s International League for Peace and Freedom, 2007

Michael Spies, Iran and the nuclear fuel-cycle, Nuclear Disorder or Cooperative Security?, Lawyers’ Committee on Nuclear Policy, Western States Legal Foundation, Reaching Critical Will of the Women’s International League for Peace and Freedom, 2007 

Arjun Makhijani and Scott Saleska, The nuclear power deception: US nuclear mythology from electricity “too cheap to meter” to “inherently safe” reactors, Apex Press, 1999

Mark Stencel, 20 years later: A nuclear nightmare in Pennsylvania, Three Mile Island Special Report, 27 March 1999

Nuclear energy and the Non-Proliferation Treaty: An authorized albatross? Comments on Article IV of the Treaty on the Non-Proliferation of Nuclear Weapons, Lawyers’ Committee on Nuclear Policy, April 1998

Jan Thomas et al., Safe energy handbook, Plutonium Free Future, CA:INOCHI, 1997