Byron Nuclear Generating Station in Ogle County, Illinois (iStock)

Nuclear Power 101

Although nuclear energy directly emits only small amounts of global warming pollution, nuclear power inflicts significant environmental and global security harms—and comes with increasingly indefensible costs.
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What Is Nuclear Energy?

Nuclear energy comes from the core of an atom. Atoms make up all matter: the device you’re reading this on, the surface it’s resting on, and the air you’re breathing. And within each atom is a nucleus, a tightly packed core that holds protons and neutrons bound together by what’s known as the strong nuclear force. But when a neutron strikes the nucleus of certain atoms—uranium, for example—this atomic center can break into pieces in a process called nuclear fission, releasing enormous energy in the form of heat and radiation.

Nuclear power

Nuclear power is derived from the energy that is released in nuclear fission. Fuel elements are placed in a nuclear reactor core and fissioned. Most nuclear power plants use uranium as fuel for the production of electricity. This fuel contains greater amounts of a certain kind (or isotope) of uranium, U-235, than is found in nature because its atoms are more easily split apart in nuclear reactors. The neutrons that are released by one atomic fission go on to fission other nuclei, triggering a chain reaction that produces heat, radiation, and radioactive waste products. If uncontrolled, that chain reaction could produce so much heat that the core itself could actually melt and release dangerous radiation. Nuclear power plants control the chain reaction primarily by using “control rods” that absorb some of the released neutrons, preventing them from causing further fissions.

The fission of uranium atoms releases energy that heats water, which produces steam. The steam goes on to spin turbines, which then drive generators that produce electricity. It’s the same basic principle used in coal plants, where coal is burned to produce steam.

In the United States, there are 59 commercially operating nuclear power plants running 95 nuclear reactors in 29 states. (Most plants have more than one reactor.) Over the next few years, several units are scheduled to be shut down, including the last reactor at Indian Point in New York (in large part due to safety concerns). California will shut down its last nuclear reactor, at the Diablo Canyon Power Plant, in 2025. Recently, however, the Turkey Point nuclear power plant in Florida won final federal approval to continue to operate through at least 2053. NRDC is in litigation challenging the adequacy of the environmental review of this decision.

Data sourced from U.S. Nuclear Regulatory Commission


What Is Nuclear Power Used For?

We use nuclear power mainly for electricity generation. The United States is the world’s largest producer of nuclear energy, accounting for more than 30 percent of global nuclear electricity generation. One-fifth of the country’s electricity comes from nuclear power. While the energy produced in a nuclear reactor could potentially also be used in other industrial and chemical processes, other uses have not been adopted (except in some isolated cases) due to concerns over safety and security.

As a low-carbon energy source, nuclear power of the future has been heralded as one of the few technologies that can help curb greenhouse gas emissions, decarbonize the economy, and combat climate change. However, new nuclear power plant designs are not demonstrated to be safe, reliable, or economically viable; thus they are not a near-term solution to the climate crisis. Government resources and policies should prioritize solar, wind, and energy efficiency technologies to address climate change.

Why Is Nuclear Power a Problem?

Reactor safety

Although U.S. nuclear power plant regulators monitor operational safety, natural hazards such as hurricanes and earthquakes, human error, mechanical failure, or design flaws can still trigger the release of radioactive contamination. In a nuclear power plant, a specific type of radiation known as ionizing radiation, a form of energy which is capable of removing electrons from atoms, is emitted both naturally from uranium and as part of the nuclear fission process. This radiation has enough energy to affect the air, water, and soil, not to mention humans, animals, and plants.

After a severe accident such as a core meltdown (a kind of accident U.S. nuclear regulators call “Beyond Design Basis”), a reactor may emit radiation into the environment. Immediately after such an accident, plant workers and emergency teams are most at risk of high radiation exposure, which can lead to radiation sickness or acute radiation syndrome (ARS). Symptoms of ARS include skin burns, vomiting, diarrhea, and possibly even coma. The cause of death in most cases of ARS is damage to the bone marrow, which leads to infection and internal bleeding. High exposure to ionizing radiation also damages the DNA, causing cancers and genetic mutations that can be transmitted to future generations. Radiation poisoning also impacts surrounding wildlife and domestic animals.        

A Chernobyl nuclear power plant worker holding a dosimeter to measure radiation level is seen against the background of the under-construction sarcophagus meant to confine the remains of the number 4 reactor unit, Ukraine, 1986.

Volodymyr Repik/AP

There have been three major nuclear reactor accidents since commercial nuclear power began operations in the 1950s. The 1986 accident at the Chernobyl plant in Ukraine (then part of the Soviet Union) is considered the worst nuclear disaster in history. An uncontrolled power surge led to explosions and fire that destroyed Unit 4 of the plant and released radioactive material. The accident killed 31 people directly, including 28 plant workers and firefighters who died of ARS. Ultimately, 134 people were diagnosed with ARS. In 2006 a World Health Organization (WHO) expert group estimated that there may be up to 4,000 additional cancer deaths among the most highly exposed groups over their lifetimes. Due to high levels of radioactive iodine released from the reactor, there was a large increase in the incidence of thyroid cancer among people who were young children and adolescents at the time of the accident and lived in the most contaminated areas of Belarus, the Russian Federation, and Ukraine. Government secrecy and misinformation over the accident put these victims at much greater risk.

In 2011, after an earthquake struck off Japan’s northeastern coast, a tsunami with 30-foot waves disabled the power supply and cooling capacity of three reactors at the Japanese Fukushima Daiichi Nuclear Power Station, causing a nuclear accident that released radioactive material into the surrounding air and water. There were no deaths or cases of radiation sickness from the accident, but more than 100,000 people were evacuated from their homes due to radiation risk. According to a United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) report, 12 plant workers who received the highest radiation doses have an increased risk of developing thyroid cancer and other thyroid disorders. About 160 additional plant workers received radiation doses that slightly raise their risk of developing cancer in the future. The economic cost of the Fukushima accident is staggering, likely to far exceed $100 billion for cleanup and recovery, and the process is expected to take decades.

In 1979 one of the reactors of the Three Mile Island Nuclear Generating Station (TMI) in Pennsylvania partially melted down, releasing radioactive materials into the environment. Hundreds of thousands of people who lived nearby voluntarily evacuated. This was the United States’ worst commercial nuclear power accident and resulted in significant nuclear safety reforms. There were no immediate deaths from the TMI accident, but some epidemiological studies have found inconclusive evidence that the radiation influenced cancer risk.

Roughly speaking, the Fukushima accident was 10 times worse than the TMI accident, and the Chernobyl accident was 10 times as bad as Fukushima. These severe nuclear reactor accidents have led to calls for improved safety and regulatory processes. TMI indicated the importance of human factors; afterward, the Nuclear Regulatory Commission (NRC) released a policy statement on “safety goals.” The Fukushima Daiichi accident illustrated the impact of natural disasters on nuclear power plants, although the Japanese government’s official investigation ultimately found that human error was to blame. The Chernobyl accident was the first to illustrate the importance of an effective regulatory regime, safety culture, and off-site emergency plan, as well as the importance of timely and accurate government information to communities at risk from the radiation release.

Statistically speaking, U.S. regulators report that the number of reactor events with an impact on safety, reliability, or performance (such as degradation of safety equipment) has decreased, from almost 2.5 events per plant in 1985 to fewer than 0.15 events per plant in 2015 in the United States. However, these risks can never be completely eliminated.

Nuclear waste storage at a decommissioned plant

Enrico Salvadori/Alamy

Nuclear waste

Waste is generated at every step in the processing and use of nuclear power, from spent nuclear fuel and uranium mill tailings (radioactive sandy waste containing heavy metals and radium produced at uranium mills) to so-called low-level waste (LLW), such as containers used for shipment, workers’ clothes and shoes, paper, rags, and anything else that might have been used for handling or cleanup of nuclear waste. These items get contaminated with radioactive material or become radioactive through exposure to neutron radiation in the nuclear power plant. The radioactivity from LLW can vary from natural background levels to much greater amounts in certain cases, such as parts from inside a reactor vessel.

Chief among nuclear power’s environmental impacts is nuclear waste—specifically, spent nuclear fuel. As noted above, although nuclear power emits substantially lower levels of harmful greenhouse gases than fossil fuels, spent nuclear fuel is both deadly and long-lasting, remaining dangerous to people’s health and the environment for millennia. The United States Court of Appeals for the D.C. Circuit described it thus: “Radioactive waste and its harmful consequences persist for time spans seemingly beyond human comprehension. For example, iodine-129, one of the radionuclides expected to be buried at Yucca Mountain, has a half-life of seventeen million years.”

The U.S. currently has more than 90,000 metric tons of nuclear waste to dispose of; that number is projected to rise to 140,000 metric tons over the next several decades. Most of this waste is stored where it was generated with no permanent disposal solution. In 1987, for a host of political rather than technical reasons, Yucca Mountain, Nevada, 100 miles northwest of Las Vegas, was chosen as a final repository for the country’s high-level nuclear waste. But the plan was abandoned and has remained in limbo due to an array of concerns—potential leaks at the site, the lack of a waste transportation plan, a failure to ensure protective health and oversight standards that apply to all other forms of environmental law, and the lack of consent from Nevada itself. Since the Obama administration’s U.S. Department of Energy terminated the license application in 2010, there has been no consensus between the executive branch and Congress on what to do with all the nuclear waste. The Trump administration has also rejected Yucca Mountain as a final resting place for the enormous quantity of spent nuclear fuel now stored at both operating and closed reactor sites. NRDC has suggested a path forward based on sound science that could earn public acceptance.

Nuclear power cost

Existing nuclear plants have relatively low operation, maintenance, and fuel costs compared to many fossil fuel plants; however these routine costs still make nuclear power economically uncompetitive in comparison with natural gas, wind, and solar.

New nuclear plants are another matter altogether; their continuing high construction costs make them uneconomical. Between 2002 and 2008, cost estimates for new nuclear plant construction rose from between $2 billion and $4 billion per unit to $9 billion per unit, according to a 2009 report by the Union of Concerned Scientists. In reality, even those astronomical projections have been surpassed. The two new units at the Vogtle Plant in Georgia, the only new nuclear construction in the United States, are now years behind schedule and projected to cost more than twice their original budget of $14 billion. Similarly, it was estimated that Duke Energy’s proposed Levy County Nuclear Power Plant in Florida would cost $5 billion, but projections ballooned to $22 billion. The project was canceled in 2017, and Duke Energy decided to focus on solar energy expansion instead.

Reactors also typically require a long period of planning, licensing, and building. The 2019 World Nuclear Industry Status Report (WNISR) estimates that since 2009 the average construction time for nuclear reactors worldwide was just under 10 years.

The WSINR report also estimates that the cost of generating nuclear energy ranges between $112 and $189 per megawatt-hour (MWh), while solar power costs between $36 and $44 and onshore wind power comes in at $29 to $56.

The turbine deck at Three Mile Island nuclear power plant in Middletown, Pennsylvania, May 22, 2017. (Decommissioned as of 2019)

Matt Rourke/AP

Decommissioning nuclear plants

The United States’ fleet of nuclear power plants is aging. Since 2013 six commercial nuclear reactors have shut down, and an additional eight have announced plans to retire by 2025. America’s oldest operating nuclear power plant, the Oyster Creek Nuclear Generating Station in New Jersey, shut down in September 2018.

Decommissioning nuclear power plants involves several steps: removing and safely storing spent nuclear fuel, decontaminating the plant to reduce residual radioactivity, dismantling plant structures, transferring contaminated materials to disposal facilities, and then releasing the property for other uses once the NRC has determined the site is safe. Typically a nuclear power plant takes decades to decommission, and current lax regulations allow this to stretch to as much as 60 years. The process, compared with the decommissioning of other power plants, is extremely expensive, labor intensive, and time consuming, with heightened health and safety risks, which add to the overall cost of nuclear energy generation. Decommissioning costs are commonly estimated at $500 million per unit. However, the costs can be much higher, running over $1 billion. For example, the Connecticut Yankee Nuclear Power Plant in Haddam Neck, Connecticut, initially had a decommissioning cost estimate of $719 million; this eventually bloated to $1.2 billion due to waste contamination in municipal landfills.

Nuclear proliferation

A major concern about peaceful nuclear power programs is the risk of nuclear proliferation—the spread of nuclear weapons and weapons-usable material, technology, and expertise. The same technology used to make nuclear fuel for power plants can also be used to produce explosive material for nuclear weapons. In other words, if countries have the capability to enrich uranium and reprocess plutonium, then they can also manufacture nuclear warheads. In a number of countries, peaceful nuclear materials and equipment have been diverted to secret nuclear weapons programs.

The United Nations Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which entered into force in March 1970, aims to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy, and eventually to achieve nuclear disarmament. The NPT has nearly universal worldwide participation, with 190 parties, but there are four countries (India, Pakistan, Israel, and North Korea) that have nuclear arms but aren’t part of the NPT. A requirement of the NPT is that countries with nuclear arsenals—the United States, Russia, China, France, and the United Kingdom—must negotiate and reduce their nuclear weapons stockpiles, ultimately eliminating these weapons of mass destruction. Distressingly, nuclear weapons are instead increasing in numbers, and so is the danger that they could be used in war again.

Nuclear Power and the Environment

Uranium mining

In-situ recovery mining in Crow Butte, Nebraska

Courtesy of Cameco Corp.

Uranium from mining is used almost entirely as fuel for nuclear power plants. It has generally been mined in one of three ways: surface or open-pit mining, underground mining, or a chemical process called in-situ leaching (ISL). Each extraction technique has broad impacts on the human and natural environment.

Underground mining exposes workers to high levels of radon gas. Studies have found strong evidence for an increased risk of lung cancer in uranium miners due to exposure to this odorless, colorless radioactive gas formed during the natural breakdown of uranium in soil, rocks, and water. Miners are also exposed to the risk of cave-ins and pneumoconiosis, a lung disease caused by inhaling dust.

Surface or open-pit mining is safer for miners than underground mines, but the process involves blasting 30 times more earth, and the material left over after processing is radioactive and toxic. The surrounding land is also left with increased erosion, landslides, and polluted soil and water.

An open pit uranium mine in McLean Lake, Canada

David Boily/AFP via Getty

ISL mining now accounts for most uranium production in the United States. Rather than dig uranium straight out of the earth, ISL sends liquid underground to dissolve uranium directly from the underground ore. The solution is then pumped to the surface where the mineral can be recovered. ISL operations, located mainly in Wyoming, Texas, and Nebraska, release considerable amounts of radon and produce waste slurries and wastewater during recovery of the uranium from the liquid. The most pressing environmental risk associated with ISL, however, is the contamination of groundwater. Restoring natural groundwater conditions after completion of leaching operations is virtually impossible and has never been achieved.

An abandoned underground uranium mine

Alexey Dozmorov/iStock

Uranium mining in the United States has dropped sharply since its 1980 peak, thanks to the removal of import tariffs. (Today Kazakhstan is the biggest uranium miner, followed by Canada and Australia.) But the Southwest United States is littered with thousands of abandoned uranium mines. Just east of Grand Canyon National Park, in the Navajo Nation, hundreds of abandoned uranium mines remain a threat to the health of the Colorado River. Many communities still suffer from environmental contamination, toxic spills, and under-addressed cancer and disease clusters.

Diablo Canyon Power Plant

Marya via Wikimedia Commons

Climate change

Many have pointed out the role nuclear power can play in the fight against climate change, but nuclear plants themselves are vulnerable to climate change’s impacts. Increasing temperatures can result in reduced nuclear reactor efficiency by directly impacting nuclear equipment or by warming the plant’s source of cooling water, which operators rely on to ensure safety within the core and in spent fuel storage areas. This reliance on water is the reason nuclear plants are often built along coastlines, rivers, and lakes. Inland reactors that use rivers as a source for cooling water are particularly at risk during heat waves, which, according to the Intergovernmental Panel on Climate Change, are “very likely” to occur more often and last longer in the coming decades.

Warming waters have already caused several nuclear power plants to scale back generation. Operators of a number of plants, such as the Millstone plant in Connecticut and Turkey Point in Florida, have sought and obtained permission from the NRC to increase the maximum temperature limit for their cooling water.

Natural hazards, such as hurricanes and flooding, can also cut off access to cooling water, which can cause a nuclear accident and a release of radiation, as witnessed atFukushima. After the events there, the NRC conducted flooding evaluations of U.S. nuclear sites and concluded that 55 of 61 sites faced flooding hazards beyond what they were designed to withstand.

With sea level rise and increasing frequency and severity of extreme weather events, the risks to both operational and decommissioned nuclear plants (which still store nuclear waste onsite) continue to grow. While all power-generating technologies are vulnerable to climate change and changes in water resources, impacts to nuclear power plants can lead to catastrophic accidents with irreversible and widespread health and environmental effects.

Franco Lucato/Shutterstock

Alternatives to Nuclear Power

Nuclear power has beneficial low-carbon attributes, but the significant safety, global security, environmental, and economic risks make the future of nuclear energy in the United States uncertain. The energy sector is now undergoing a major shift toward renewable energy and energy efficiency. Wind farms have become a familiar part of the landscape, and solar panels have spread across rooftops from coast to coast. While it is true that renewable energy is intermittent, dependent on weather, and challenged by storage issues, the technology is improving rapidly. A 2019 report from the International Energy Agency (IEA) predicts renewable power capacity will expand by 50 percent between 2019 and 2024. This is an increase of 1,200 gigawatts, “equivalent to the total installed power capacity of the United States today.”

Solar and onshore wind energy costs have also dropped dramatically in recent years. Since 2015, costs for solar energy have fallen by 33 percent, onshore wind by 22 percent, offshore wind by 40 percent, and battery storage by 49 percent.

Solar, arguably the best known of alternative energy sources, supplies 1.5 percent of U.S. electricity generation. But nearly a third of all new generating capacity came from solar in 2017, second only to natural gas. In its report, the IEA predicted that 60 percent of the growth in renewable energy will be in the solar category.

Solar energy systems do not produce air pollution, water pollution, or greenhouse gases, but there are emissions associated with other stages of the solar life cycle, including manufacturing. However, most estimates show that solar, over its complete life cycle, produces less carbon dioxide equivalent than natural gas, and much less than coal.

And while offshore wind energy, the use of wind farms constructed in bodies of water, is still expensive and tough to maintain, it has huge potential and is advancing rapidly. As with all types of energy development, offshore wind power poses some risks to the environment (construction and operation of wind farms can disrupt wildlife, for example), but these risks can be minimized by choosing sites outside of sensitive wildlife habitats and taking steps to avoid underwater noise, ship strikes, and turbine collisions.

Offshore wind energy, using “high-quality resources available in most major markets,” has the potential to generate more than 18 times the current electricity demand of the entire world, according to the IEA report Offshore Wind Outlook 2019. The IEA projects that global offshore wind capacity will grow to 15 times its current size by 2040, becoming a $1 trillion industry in the process.

These renewable energy technologies are growing, but support for research and development and continual innovation remain critical to improve them and ensure a more economical transition away from nuclear power and toward a cleaner energy system and safer climate future.

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