Nuclear power debate

Two opposing camps

Two opposing camps have evolved in society with respect to nuclear power, one supporting and promoting nuclear power and another opposing it. At the heart of this divide sit different views of risk and individual beliefs regarding public involvement in making decisions about large-scale high technology. Questions which emerge include: is nuclear power safe for humans and the environment? Could another Chernobyl disaster or Fukushima disaster happen? Can we dispose of nuclear waste in a safe manner? Can nuclear power help to reduce climate change and air pollution in a timely way?

In the 2010 book Why vs. Why: Nuclear Power Barry Brook and Ian Lowe discuss and articulate the debate about nuclear power. Brook makes the following seven arguments in favor of nuclear energy:

Lowe, in turn, makes the following arguments against nuclear power:

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". When asking what the world would be like without it The Economist notes that "(w)ithout nuclear power and with other fuels filling in its share pro rata, emissions from generation would have been about 11 billion tonnes. The difference is roughly equal to the total annual emissions of Germany and Japan combined."

Electricity and energy supplied

The World Nuclear Association has reported that nuclear electricity generation in 2012 was at its lowest level since 1999. The WNA has said that “nuclear power generation suffered its biggest ever one-year fall through 2012 as the bulk of the Japanese fleet remained offline for a full calendar year”.

Data from the International Atomic Energy Agency showed that nuclear power plants globally produced 2346 TWh of electricity in 2012 – seven per cent less than in 2011. The figures illustrate the effects of a full year of 48 Japanese power reactors producing no power during the year. The permanent closure of eight reactor units in Germany was also a factor. Problems at Crystal River, Fort Calhoun and the two San Onofre units in the USA meant they produced no power for the full year, while in Belgium Doel 3 and Tihange 2 were out of action for six months. Compared to 2010, the nuclear industry produced 11% less electricity in 2012.

Brazil, China, Germany, India, Japan, Mexico, the Netherlands, Spain and the U.K. now all generate more electricity from non-hydro renewable energy than from nuclear sources. In 2015, power generation using solar power was 33% of the global total, wind power over 17%, and 1.3% for nuclear power, exclusively due to development in China.

Many studies have documented how nuclear power plants generate 16% of global electricity, but provide only 6.3% of energy production and 2.6% of final energy consumption. This mismatch stems mainly from the poor consumption efficiency of electricity compared to other energy carriers, and the transmission losses associated with nuclear plants which are usually situated far away from sources of demand.

Energy security

For some countries, nuclear power affords energy independence. Nuclear power has been relatively unaffected by embargoes, and uranium is mined in countries willing to export, including Australia and Canada. However, countries now responsible for more than 30% of the world’s uranium production: Kazakhstan, Namibia, Niger, and Uzbekistan, are politically unstable.

One assessment from the IAEA showed that enough high-grade ore exists to supply the needs of the current reactor fleet for 40–50 years. According to Sovacool (2011), reserves from existing uranium mines are being rapidly depleted, and expected shortfalls in available fuel threaten future plants and contribute to volatility of uranium prices at existing plants. Escalation of uranium fuel costs decreased the viability of nuclear projects. Uranium prices rose from 2001 to 2007, before declining.

The International Atomic Energy Agency and the Nuclear Energy Agency of the OCED, in their latest review of world uranium resources and demand, Uranium 2014: Resources, Production, and Demand, concluded that uranium resources would support "significant growth in nuclear capacity," and that: "Identified resources are sufficient for over 120 years, considering 2012 uranium requirements of 61 600 tU."

According to a Stanford study, fast breeder reactors have the potential to provide power for humans on earth for billions of years, making this source sustainable. But "because of the link between plutonium and nuclear weapons, the potential application of fast breeders has led to concerns that nuclear power expansion would bring in an era of uncontrolled weapons proliferation".

Reliability

In 2010, the worldwide average capacity factor was 80.1%. In 2005, the global average capacity factor was 86.8%, the number of SCRAMs per 7,000 hours critical was 0.6, and the unplanned capacity loss factor was 1.6%. Capacity factor is the net power produced divided by the maximum amount possible running at 100% all the time, thus this includes all scheduled maintenance/refueling outages as well as unplanned losses. The 7,000 hours is roughly representative of how long any given reactor will remain critical in a year, meaning that the scram rates translates into a sudden and unplanned shutdown about 0.6 times per year for any given reactor in the world. The unplanned capacity loss factor represents amount of power not produced due to unplanned scrams and postponed restarts.

The World Nuclear Association argues that: "Obviously sun, wind, tides and waves cannot be controlled to provide directly either continuous base-load power, or peak-load power when it is needed,..." "In practical terms non-hydro renewables are therefore able to supply up to some 15–20% of the capacity of an electricity grid, though they cannot directly be applied as economic substitutes for most coal or nuclear power, however significant they become in particular areas with favourable conditions." "If the fundamental opportunity of these renewables is their abundance and relatively widespread occurrence, the fundamental challenge, especially for electricity supply, is applying them to meet demand given their variable and diffuse nature. This means either that there must be reliable duplicate sources of electricity beyond the normal system reserve, or some means of electricity storage." "Relatively few places have scope for pumped storage dams close to where the power is needed, and overall efficiency is less than 80%. Means of storing large amounts of electricity as such in giant batteries or by other means have not been developed."

According to Benjamin K. Sovacool, most studies critiquing solar and wind energy look only at individual generators and not at the system wide effects of solar and wind farms. Correlations between power swings drop substantially as more solar and wind farms are integrated (a process known as geographical smoothing) and a wider geographic area also enables a larger pool of energy efficiency efforts to abate intermittency.

Sovacool says that variable renewable energy sources such as wind power and solar energy can displace nuclear resources. "Nine recent studies have concluded that the variability and intermittency of wind and solar resources becomes easier to manage the more they are deployed and interconnected, not the other way around, as some utilities suggest. This is because wind and solar plants help grid operators handle major outages and contingencies elsewhere in the system, since they generate power in smaller increments that are less damaging than unexpected outages from large plants".

According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world’s electricity within 50 years, with wind power, hydroelectricity and biomass plants supplying much of the remaining generation. "Photovoltaic and concentrated solar power together can become the major source of electricity". Renewable technologies can enhance energy security in electricity generation, heat supply, and transportation.

As of 2013, the World Nuclear Association has said "There is unprecedented interest in renewable energy, particularly solar and wind energy, which provide electricity without giving rise to any carbon dioxide emission. Harnessing these for electricity depends on the cost and efficiency of the technology, which is constantly improving, thus reducing costs per peak kilowatt".

Renewable electricity supply in the 20-50+% range has already been implemented in several European systems, albeit in the context of an integrated European grid system. In 2012 the share of electricity generated by renewable sources in Germany was 21.9%, compared to 16.0% for nuclear power after Germany shut down 7-8 of its 18 nuclear reactors in 2011. In the United Kingdom, the amount of energy produced from renewable energy is expected to exceed that from nuclear power by 2018, and Scotland plans to obtain all electricity from renewable energy by 2020. The majority of installed renewable energy across the world is in the form of hydro power, which has limited opportunity for expansion.

The IPCC has said that if governments were supportive, and the full complement of renewable energy technologies were deployed, renewable energy supply could account for almost 80% of the world's energy use within forty years. Rajendra Pachauri, chairman of the IPCC, said the necessary investment in renewables would cost only about 1% of global GDP annually. This approach could contain greenhouse gas levels to less than 450 parts per million, the safe level beyond which climate change becomes catastrophic and irreversible.

The cost of nuclear power has followed an increasing trend whereas the cost of electricity is declining in wind power. As of 2014, the wind industry in the USA is able to produce more power at lower cost by using taller wind turbines with longer blades, capturing the faster winds at higher elevations. This has opened up new opportunities and in Indiana, Michigan, and Ohio, the price of power from wind turbines built 300 feet to 400 feet above the ground can now compete with conventional fossil fuels like coal. Prices have fallen to about 4 cents per kilowatt-hour in some cases and utilities have been increasing the amount of wind energy in their portfolio, saying it is their cheapest option.

From a safety stand point, nuclear power, in terms of lives lost per unit of electricity delivered, is comparable to and in some cases, lower than many renewable energy sources. There is however no radioactive spent fuel that needs to be stored or reprocessed with conventional renewable energy sources. A nuclear plant needs to be disassembled and removed. Much of the disassembled nuclear plant needs to be stored as low level nuclear waste.

Since nuclear power plants are fundamentally heat engines, waste heat disposal becomes an issue at high ambient temperature. Droughts and extended periods of high temperature can "cripple nuclear power generation, and it is often during these times when electricity demand is highest because of air-conditioning and refrigeration loads and diminished hydroelectric capacity". In such very hot weather a power reactor may have to operate at a reduced power level or even shut down. In 2009 in Germany, eight nuclear reactors had to be shut down simultaneously on hot summer days for reasons relating to the overheating of equipment or of rivers. Overheated discharge water has resulted in significant fish kills in the past, harming livelihood and raising public concern.

New nuclear plants

The economics of new nuclear power plants is a controversial subject, since there are diverging views on this topic, and multibillion-dollar investments ride on the choice of an energy source. Nuclear power plants typically have high capital costs for building the plant, but low direct fuel costs (with much of the costs of fuel extraction, processing, use and long term storage externalized). Therefore, comparison with other power generation methods is strongly dependent on assumptions about construction timescales and capital financing for nuclear plants. Cost estimates also need to take into account plant decommissioning and nuclear waste storage costs. On the other hand, measures to mitigate global warming, such as a carbon tax or carbon emissions trading, may favor the economics of nuclear power.

In recent years there has been a slowdown of electricity demand growth and financing has become more difficult, which impairs large projects such as nuclear reactors, with very large upfront costs and long project cycles which carry a large variety of risks. In Eastern Europe, a number of long-established projects are struggling to find finance, notably Belene in Bulgaria and the additional reactors at Cernavoda in Romania, and some potential backers have pulled out. Where cheap gas is available and its future supply relatively secure, this also poses a major problem for nuclear projects.

Analysis of the economics of nuclear power must take into account who bears the risks of future uncertainties. To date all operating nuclear power plants were developed by state-owned or regulated utility monopolies where many of the risks associated with construction costs, operating performance, fuel price, and other factors were borne by consumers rather than suppliers. Many countries have now liberalized the electricity market where these risks, and the risk of cheaper competitors emerging before capital costs are recovered, are borne by plant suppliers and operators rather than consumers, which leads to a significantly different evaluation of the economics of new nuclear power plants.

Following the 2011 Fukushima Daiichi nuclear disaster, costs are likely to go up for currently operating and new nuclear power plants, due to increased requirements for on-site spent fuel management and elevated design basis threats.

Cost of decommissioning nuclear plants

The price of energy inputs and the environmental costs of every nuclear power plant continue long after the facility has finished generating its last useful electricity. Both nuclear reactors and uranium enrichment facilities must be decommissioned, returning the facility and its parts to a safe enough level to be entrusted for other uses. After a cooling-off period that may last as long as a century, reactors must be dismantled and cut into small pieces to be packed in containers for final disposal. The process is very expensive, time-consuming, dangerous for workers, hazardous to the natural environment, and presents new opportunities for human error, accidents or sabotage.

The total energy required for decommissioning can be as much as 50% more than the energy needed for the original construction. In most cases, the decommissioning process costs between US $300 million to US$5.6 billion. Decommissioning at nuclear sites which have experienced a serious accident are the most expensive and time-consuming. In the U.S. there are 13 reactors that have permanently shut down and are in some phase of decommissioning, and none of them have completed the process.

Current UK plants are expected to exceed £73bn in decommissioning costs."Nuclear decommissioning costs exceed £73bn". 

Subsidies

Critics of nuclear power claim that it is the beneficiary of inappropriately large economic subsidies, taking the form of research and development, financing support for building new reactors and decommissioning old reactors and waste, and that these subsidies are often overlooked when comparing the economics of nuclear against other forms of power generation. Nuclear power proponents argue that competing energy sources also receive subsidies. Fossil fuels receive large direct and indirect subsidies, such as tax benefits and not having to pay for the greenhouse gases they emit. Renewables receive proportionately large direct production subsidies and tax breaks in many nations, although in absolute terms they are often less than subsidies received by other sources.

In Europe, the FP7 research program has more subsidies for nuclear than for renewable and energy efficiency together; over 70% of this is directed at the ITER fusion project. In the US, public research money for nuclear fission declined from 2,179 to 35 million dollars between 1980 and 2000.

A 2010 report by Global Subsidies Initiative compared relative subsidies of most common energy sources. It found that nuclear energy receives 1.7 US cents per kWh of energy it produces, compared to fossil fuels receiving 0.8 US cents per kWh, renewable energy receiving 5.0 US cents per kWh and biofuels receiving 5.1 US cents per kWh.

Indirect nuclear insurance subsidy

Kristin Shrader-Frechette has said "if reactors were safe, nuclear industries would not demand government-guaranteed, accident-liability protection, as a condition for their generating electricity". No private insurance company or even consortium of insurance companies "would shoulder the fearsome liabilities arising from severe nuclear accidents".

The potential costs resulting from a nuclear accident (including one caused by a terrorist attack or a natural disaster) are great. The liability of owners of nuclear power plants in the U.S. is currently limited under the Price-Anderson Act (PAA). The Price-Anderson Act, introduced in 1957, was "an implicit admission that nuclear power provided risks that producers were unwilling to assume without federal backing". The Price-Anderson Act "shields nuclear utilities, vendors and suppliers against liability claims in the event of a catastrophic accident by imposing an upper limit on private sector liability". Without such protection, private companies were unwilling to be involved. No other technology in the history of American industry has enjoyed such continuing blanket protection.

The PAA was due to expire in 2002, and the former U.S. vice-president Dick Cheney said in 2001 that "nobody's going to invest in nuclear power plants" if the PAA is not renewed. The U.S. Nuclear Regulatory Commission (USNRC) concluded that the liability limits placed on nuclear insurance were significant enough to constitute a subsidy, but a quantification of the amount was not attempted at that time. Shortly after this in 1990, Dubin and Rothwell were the first to estimate the value to the U.S. nuclear industry of the limitation on liability for nuclear power plants under the Price Anderson Act. Their underlying method was to extrapolate the premiums operators currently pay versus the full liability they would have to pay for full insurance in the absence of the PAA limits. The size of the estimated subsidy per reactor per year was $60 million prior to the 1982 amendments, and up to $22 million following the 1988 amendments. In a separate article in 2003, Anthony Heyes updates the 1988 estimate of $22 million per year to $33 million (2001 dollars).

In case of a nuclear accident, should claims exceed this primary liability, the PAA requires all licensees to additionally provide a maximum of $95.8 million into the accident pool - totaling roughly $10 billion if all reactors were required to pay the maximum. This is still not sufficient in the case of a serious accident, as the cost of damages could exceed $10 billion. According to the PAA, should the costs of accident damages exceed the $10 billion pool, the process for covering the remainder of the costs would be defined by Congress. In 1982, a Sandia National Laboratories study concluded that depending on the reactor size and 'unfavorable conditions' a serious nuclear accident could lead to property damages as high as $314 billion while fatalities could reach 50,000. A recent study found that if only this one relatively ignored indirect subsidy for nuclear power was converted to a direct subsidy and diverted to photovoltaic manufacturing, it would result in more installed power and more energy produced by mid-century compared to the nuclear case.

Environmental effects

The primary environmental effects of nuclear power come from uranium mining, radioactive effluent emissions, and waste heat. Nuclear generation does not directly produce sulfur dioxide, nitrogen oxides, mercury or other pollutants associated with the combustion of fossil fuels.

Nuclear plants require slightly more cooling water than fossil-fuel power plants due to their slightly lower generation efficiencies. Uranium mining can use large amounts of water — for example, the Roxby Downs mine in South Australia uses 35 million litres of water each day and plans to increase this to 150 million litres per day.

Effect on greenhouse gas emissions

While nuclear power does not directly emit greenhouse gases, emissions occur, as with every source of energy, over a facility's life cycle: mining and fabrication of construction materials, plant construction, operation, uranium mining and milling, and plant decommissioning. A literature survey by the Intergovernmental Panel on Climate Change of 32 greenhouse gas emissions studies, found a median value of 16 g equivalent lifecycle carbon dioxide emissions per kWh for nuclear power.

Climate and energy scientists James Hansen, Ken Caldeira, Kerry Emanuel and Tom Wigley have released an open letter stating, in part, that

Renewables like wind and solar and biomass will certainly play roles in a future energy economy, but those energy sources cannot scale up fast enough to deliver cheap and reliable power at the scale the global economy requires. While it may be theoretically possible to stabilize the climate without nuclear power, in the real world there is no credible path to climate stabilization that does not include a substantial role for nuclear power.

In a published rebuttal to Hansen's analyses, eight energy and climate scholars say that "nuclear power reactors are less effective at displacing greenhouse gas emissions than energy efficiency initiatives and renewable energy technologies". They go on to argue "that (a) its near-term potential is significantly limited compared to energy efficiency and renewable energy; (b) it displaces emissions and saves lives only at high cost and at the enhanced risk of nuclear weapons proliferation; (c) it is unsuitable for expanding access to modern energy services in developing countries; and (d) Hansen's estimates of cancer risks from exposure to radiation are flawed". James Hansen's rebuttal can be found here.

Mark Diesendorf and B.K. Sovacool review the "little-known research which shows that the life-cycle CO2 emissions of nuclear power may become comparable with those of fossil power as the 5.4 million tonnes of high-grade uranium ore is used up over the next several decades and low-grade uranium is mined and milled using fossil fuels". Critics calculate that if nuclear energy were used to rapidly replace existing energy sources, there would be an energy cannibalism effect, which would affect the carbon neutral growth rate of the technology.

As the nuclear power debate continues, greenhouse gas emissions are not decreasing, they are increasing. Predictions estimate that even with draconian emission reductions within the ten years, the world will still pass 650ppm of carbon dioxide and a catastrophic 4C average rise in temperature. Public perception is that renewable energies such as wind, solar, biomass and geothermal are significantly affecting global warming. All of these sources combined only supplied 1.3% of global energy in 2013 as 8 billion tonnes of coal was burned annually. This too little, too late may be a mass form of climate change denial, or an idealistic pursuit of green energy.

High-level radioactive waste

The world's nuclear fleet creates about 10,000 metric tons of high-level spent nuclear fuel each year. High-level radioactive waste management concerns management and disposal of highly radioactive materials created during production of nuclear power. The technical issues in accomplishing this are daunting, due to the extremely long periods radioactive wastes remain deadly to living organisms. Of particular concern are two long-lived fission products, technetium-99 (half-life 220,000 years) and iodine-129 (half-life 15.7 million years), which dominate spent nuclear fuel radioactivity after a few thousand years. The most troublesome transuranic elements in spent fuel are neptunium-237 (half-life two million years) and plutonium-239 (half-life 24,000 years). Consequently, high-level radioactive waste requires sophisticated treatment and management to successfully isolate it from the biosphere. This usually necessitates treatment, followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form.

Governments around the world are considering a range of waste management and disposal options, usually involving deep-geologic placement, although there has been limited progress toward implementing long-term waste management solutions. This is partly because the timeframes in question when dealing with radioactive waste range from 10,000 to millions of years, according to studies based on the effect of estimated radiation doses.

Since the fraction of a radioisotope's atoms decaying per unit of time is inversely proportional to its half-life, the relative radioactivity of a quantity of buried human radioactive waste would diminish over time compared to natural radioisotopes (such as the decay chain of 120 trillion tons of thorium and 40 trillion tons of uranium which are at relatively trace concentrations of parts per million each over the crust's 3×10¹⁹ ton mass). For instance, over a timeframe of thousands of years, after the most active short half-life radioisotopes decayed, burying U.S. nuclear waste would increase the radioactivity in the top 2000 feet of rock and soil in the United States (10 million km²) by ≈ 1 part in 10 million over the cumulative amount of natural radioisotopes in such a volume, although the vicinity of the site would have a far higher concentration of artificial radioisotopes underground than such an average.

Nuclear waste disposal is one of the most controversial facets of the nuclear power debate. Presently, waste is mainly stored at individual reactor sites and there are over 430 locations around the world where radioactive material continues to accumulate. Experts agree that centralized underground repositories which are well-managed, guarded, and monitored, would be a vast improvement. 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 dedicated waste storage sites at the Waste Isolation Pilot Plant in New Mexico and two in German salt mines, the Morsleben Repository and the Schacht Asse II.

Prevented mortality

In March 2013, climate scientists Pushker Kharecha and James Hansen published a paper in Environmental Science & Technology, entitled Prevented mortality and greenhouse gas emissions from historical and projected nuclear power. It estimated an average of 1.8 million lives saved worldwide by the use of nuclear power instead of fossil fuels between 1971 and 2009. The paper examined mortality levels per unit of electrical energy produced from fossil fuels (coal and natural gas) as well as nuclear power. Kharecha and Hansen assert that their results are probably conservative, as they analyze only deaths and do not include a range of serious but non-fatal respiratory illnesses, cancers, hereditary effects and heart problems, nor do they include the fact that fossil fuel combustion in developing countries tends to have a higher carbon and air pollution footprint than in developed countries. The authors also conclude that the emission of some 64 billion tonnes of carbon dioxide equivalent have been avoided by nuclear power between 1971 and 2009, and that between 2010 and 2050, nuclear could additionally avoid up to 80 to 240 billion tonnes.

Accidents and safety

Benjamin K. Sovacool has reported that worldwide there have been 99 accidents at nuclear power plants. Fifty-seven accidents have occurred since the Chernobyl disaster, and 57% (56 out of 99) of all nuclear-related accidents have occurred in the USA. Serious nuclear power plant accidents include the Fukushima Daiichi nuclear disaster (2011), Chernobyl disaster (1986), Three Mile Island accident (1979), and the SL-1 accident (1961). Nuclear-powered submarine mishaps include the K-19 reactor accident (1961), the K-27 reactor accident (1968), and the K-431 reactor accident (1985).

The effect of nuclear accidents has been a topic of debate practically since the first nuclear reactors were constructed. It has also been a key factor in public concern about nuclear facilities. Some technical measures to reduce the risk of accidents or to minimize the amount of radioactivity released to the environment have been adopted. Despite the use of such measures, "there have been many accidents with varying effects as well near misses and incidents".

Nuclear power plants are a complex energy system and opponents of nuclear power have criticized the sophistication and complexity of the technology. Helen Caldicott has said: "... in essence, a nuclear reactor is just a very sophisticated and dangerous way to boil water -- analogous to cutting a pound of butter with a chain saw." The 1979 Three Mile Island accident inspired Charles Perrow's book Normal Accidents, where a nuclear accident occurs, resulting from an unanticipated interaction of multiple failures in a complex system. TMI was an example of a normal accident because it was "unexpected, incomprehensible, uncontrollable and unavoidable".

Perrow concluded that the failure at Three Mile Island was a consequence of the system's immense complexity. Such modern high-risk systems, he realized, were prone to failures however well they were managed. It was inevitable that they would eventually suffer what he termed a 'normal accident'. Therefore, he suggested, we might do better to contemplate a radical redesign, or if that was not possible, to abandon such technology entirely.

Catastrophic scenarios involving terrorist attacks are also conceivable. An interdisciplinary team from MIT have estimated that given a three-fold increase in nuclear power from 2005 to 2055, and an unchanged accident frequency, four core damage accidents would be expected in that period

Proponents of nuclear power argue that in comparison to any other form of power, nuclear power is the safest form of energy, accounting for all the risks from mining to production to storage, including the risks of spectacular nuclear accidents. Accidents in the nuclear industry have been less damaging than accidents in the hydro industry, and less damaging than the constant, incessant damage from air pollutants from fossil fuels. For instance, by running a 1000-MWe nuclear power plant including uranium mining, reactor operation and waste disposal, the radiation dose is 136 person-rem/year, the dose is 490 person-rem/year for an equivalent coal-fired power plant. The World Nuclear Association provides a comparison of deaths from accidents in course of 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. Nuclear power plant accidents rank first in terms of their economic cost, accounting for 41 percent of all property damage attributed to energy accidents.

Chernobyl steam explosion

The Chernobyl steam explosion was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine. A steam explosion and graphite fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. It is considered the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles, crippling the Soviet economy. The accident raised concerns about the safety of the nuclear power industry, slowing its expansion for a number of years.

UNSCEAR has conducted 20 years of detailed scientific and epidemiological research on the effects of the Chernobyl accident. Apart from the 57 direct deaths in the accident itself, UNSCEAR predicted in 2005 that up to 4,000 additional cancer deaths related to the accident would appear "among the 600 000 persons receiving more significant exposures (liquidators working in 1986–87, evacuees, and residents of the most contaminated areas)". Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl disaster.

Fukushima disaster

Following an earthquake, tsunami, and failure of cooling systems at Fukushima I Nuclear Power Plant and issues concerning other nuclear facilities in Japan on March 11, 2011, a nuclear emergency was declared. This was the first time a nuclear emergency had been declared in Japan, and 140,000 residents within 20 km (12 mi) of the plant were evacuated. Explosions and a fire resulted in dangerous levels of radiation, sparking a stock market collapse and panic-buying in supermarkets. The UK, France and some other countries advised their nationals to consider leaving Tokyo, in response to fears of spreading nuclear contamination. The accidents drew attention to ongoing concerns over Japanese nuclear seismic design standards and caused other governments to re-evaluate their nuclear programs. John Price, a former member of the Safety Policy Unit at the UK's National Nuclear Corporation, said that it "might be 100 years before melting fuel rods can be safely removed from Japan's Fukushima nuclear plant".

Three Mile Island accident

The Three Mile Island accident was a core meltdown in Unit 2 (a pressurized water reactor manufactured by Babcock & Wilcox) of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979. It was the most significant accident in the history of the USA commercial nuclear power generating industry, resulting in the release of approximately 2.5 million curies of radioactive noble gases, and approximately 15 curies of iodine-131. Cleanup started in August 1979 and officially ended in December 1993, with a total cleanup cost of about $1 billion. The incident was rated a five on the seven-point International Nuclear Event Scale: Accident With Wider Consequences.

The health effects of the Three Mile Island nuclear accident are widely, but not universally, agreed to be very low level. However, there was an evacuation of 140,000 pregnant women and pre-school age children from the area. The accident crystallized anti-nuclear safety concerns among activists and the general public, resulted in new regulations for the nuclear industry, and has been cited as a contributor to the decline of new reactor construction that was already underway in the 1970s.

New reactor designs

The nuclear power industry has improved the safety and performance of reactors, and has proposed new safer (but generally untested) reactor designs but there is no guarantee that the reactors will be designed, built and operated correctly. Mistakes do occur and the designers of reactors at Fukushima in Japan did not anticipate that a tsunami generated by an earthquake would disable the backup systems that were supposed to stabilize the reactor after the earthquake. According to UBS AG, the Fukushima I nuclear accidents have cast doubt on whether even an advanced economy like Japan can master nuclear safety.

Passive nuclear safety does not require operator actions or electronic feedback in order to shut down safely in the event of a particular type of emergency (usually overheating resulting from a loss of coolant or loss of coolant flow). This is in contrast to older-yet-common reactor designs, where the natural tendency for the reaction was to accelerate rapidly from increased temperatures.

The Union of Concerned Scientists supports a national renewable energy standard which would require utilities to produce a certain percentage of their energy from sources such as wind power, solar energy and geothermal energy. The group also supports a national energy efficiency standard for home appliances. The UCS also acknowledges that nuclear power can reduce greenhouse gas emissions, but maintains that it must become much safer and cheaper before it can be considered a workable solution to global warming. They support increased safety enforcement from the Nuclear Regulatory Commission among other steps to improve nuclear power. UCS has been critical of proposed Generation III reactor designs. Edwin Lyman, a senior staff scientist at UCS, has challenged specific cost-saving design choices made for both the AP1000 and ESBWR. Lyman is concerned about the strength of the steel containment vessel and the concrete shield building around the AP1000. The AP1000 containment vessel does not have sufficient safety margins, says Lyman.

Whistleblowers

This is a list of nuclear whistleblowers. They are mainly former employees of nuclear power facilities who have spoken out about safety concerns.

Health effects on population near nuclear power plants and workers

A major concern in the nuclear debate is what the long-term effects of living near or working in a nuclear power station are. These concerns typically center around the potential for increased risks of cancer. However, studies conducted by non-profit, neutral agencies have found no compelling evidence of correlation between nuclear power and risk of cancer.

There has been considerable research done on the effect of low-level radiation on humans. Debate on the applicability of Linear no-threshold model versus Radiation hormesis and other competing models continues, however, the predicted low rate of cancer with low dose means that large sample sizes are required in order to make meaningful conclusions. A study conducted by the National Academy of Science found that carcinogenic effects of radiation does increase with dose. The largest study on nuclear industry workers in history involved nearly a half-million individuals and concluded that a 1–2% of cancer deaths were likely due to occupational dose. This was on the high range of what theory predicted by LNT, but was "statistically compatible".

The Nuclear Regulatory Commission (NRC) has a factsheet that outlines 6 different studies. In 1990 the United States Congress requested the National Cancer Institute to conduct a study of cancer mortality rates around nuclear plants and other facilities covering 1950 to 1984 focusing on the change after operation started of the respective facilities. They concluded in no link. In 2000 the University of Pittsburgh found no link to heightened cancer deaths in people living within 5 miles of plant at the time of the Three Mile Island accident. The same year, the Illinois Public Health Department found no statistical abnormality of childhood cancers in counties with nuclear plants. In 2001 the Connecticut Academy of Science and Engineering confirmed that radiation emissions were negligibly low at the Connecticut Yankee Nuclear Power Plant. Also that year, the American Cancer Society investigated cancer clusters around nuclear plants and concluded no link to radiation noting that cancer clusters occur regularly due to unrelated reasons. Again in 2001, the Florida Bureau of Environmental Epidemiology reviewed claims of increased cancer rates in counties with nuclear plants, however, using the same data as the claimants, they observed no abnormalities.

Scientists learned about exposure to high level radiation from studies of the effects of bombing populations at Hiroshima and Nagasaki. However, it is difficult to trace the relationship of low level radiation exposure to resulting cancers and mutations. This is because the latency period between exposure and effect can be 25 years or more for cancer and a generation or more for genetic damage. Since nuclear generating plants have a brief history, it is early to judge the effects.

Most human exposure to radiation comes from natural background radiation. Natural sources of radiation amount to an average annual radiation dose of 295 mrem. The average person receives about 53 mrem from medical procedures and 10 mrem from consumer products. According to the National Safety Council, people living within 50 miles of a nuclear power plant receive an additional 0.01 mrem per year. Living within 50 miles of a coal plant adds 0.03 mrem per year.

In its 2000 report, "Sources and effects of ionizing radiation", the UNSCEAR also gives some values for areas where the radiation background is very high. You can for example have some value like 370 nGy/h on average in Yangjiang (meaning 3.24 mSv per year or 324 mrem), or 1,800 gGy/h in Kerala (meaning 15.8 mSv per year or 1580 mrem). They are also some other "hot spots", with some maximum values of 17,000 nGy/h in the hot springs of Ramsar (that would be equivalent to 149 mSv per year pr 14,900 mrem per year). The highest background seem to be in Guarapari with a reported 175 mSv per year (or 17,500 mrem per year), and 90,000 nGy/h maximum value given in the UNSCEAR report (on the beaches). A study made on the Kerala radiation background, using a cohort of 385,103 residents, concludes that "showed no excess cancer risk from exposure to terrestrial gamma radiation" and that "Although the statistical power of the study might not be adequate due to the low dose, our cancer incidence study [...]suggests it is unlikely that estimates of risk at low doses are substantially greater than currently believed."

Current guidelines established by the NRC, require extensive emergency planning, between nuclear power plants, Federal Emergency Management Agency (FEMA), and the local governments. Plans call for different zones, defined by distance from the plant and prevailing weather conditions and protective actions. In the reference cited, the plans detail different categories of emergencies and the protective actions including possible evacuation.

A German study on childhood cancer in the vicinity of nuclear power plants, the KiKK study was published in December 2007. According to Ian Fairlie, it "resulted in a public outcry and media debate in Germany which has received little attention elsewhere". It has been established "partly as a result of an earlier study by Körblein and Hoffmann which had found statistically significant increases in solid cancers (54%), and in leukemia (76%) in children aged less than 5 within 5 km of 15 German nuclear power plant sites. It red a 2.2-fold increase in leukemias and a 1.6-fold increase in solid (mainly embryonal) cancers among children living within 5 km of all German nuclear power stations." In 2011 a new study of the KiKK data was incorporated into an assessment by the Committee on Medical Aspects of Radiation in the Environment (COMARE) of the incidence of childhood leukemia around British nuclear power plants. It found that the control sample of population used for comparison in the German study may have been incorrectly selected and other possible contributory factors, such as socio-economic ranking, were not taken into consideration. The committee concluded that there is no significant evidence of an association between risk of childhood leukemia (in under 5 year olds) and living in proximity to a nuclear power plant.

Safety culture in host nations

Some developing countries which plan to go nuclear have very poor industrial safety records and problems with political corruption. Inside China, and outside the country, the speed of the nuclear construction program has raised safety concerns. Prof He Zuoxiu, who was involved with China's atomic bomb program, has said that plans to expand production of nuclear energy twentyfold by 2030 could be disastrous, as China was seriously underprepared on the safety front. China's fast-expanding nuclear sector is opting for cheap technology that "will be 100 years old by the time dozens of its reactors reach the end of their lifespans", according to diplomatic cables from the US embassy in Beijing. The rush to build new nuclear power plants may "create problems for effective management, operation and regulatory oversight" with the biggest potential bottleneck being human resources – "coming up with enough trained personnel to build and operate all of these new plants, as well as regulate the industry". The challenge for the government and nuclear companies is to "keep an eye on a growing army of contractors and subcontractors who may be tempted to cut corners". China is advised to maintain nuclear safeguards in a business culture where quality and safety are sometimes sacrificed in favor of cost-cutting, profits, and corruption. China has asked for international assistance in training more nuclear power plant inspectors.

Nuclear proliferation and terrorism concerns

According to Mark Z. Jacobson, the growth of nuclear power has "historically increased the ability of nations to obtain or enrich uranium for nuclear weapons, and a large-scale worldwide increase in nuclear energy facilities would exacerbate this problem, putting the world at greater risk of a nuclear war or terrorism catastrophe". The historic link between energy facilities and weapons is evidenced by the secret development or attempted development of weapons capabilities in nuclear power facilities in Pakistan, India, Iraq (prior to 1981), Iran, and to some extent in North Korea.

Four AP1000 reactors, which were designed by the American Westinghouse Electric Company are currently, as of 2011, being built in China and a further two AP1000 reactors are to be built in the USA. Hyperion Power Generation, which is designing modular reactor assemblies that are proliferation resistant, is a privately owned US corporation, as is Terrapower which has the financial backing of Bill Gates.

Vulnerability of plants to attack

Nuclear reactors become preferred targets during military conflict and, over the past three decades, have been repeatedly attacked during military air strikes, occupations, invasions and campaigns:

According to a 2004 report by the U.S. Congressional Budget Office, "The human, environmental, and economic costs from a successful attack on a nuclear power plant that results in the release of substantial quantities of radioactive material to the environment could be great." The United States 9/11 Commission has said that nuclear power plants were potential targets originally considered for the September 11, 2001 attacks. If terrorist groups could sufficiently damage safety systems to cause a core meltdown at a nuclear power plant, and/or sufficiently damage spent fuel pools, such an attack could lead to a widespread radioactive contamination.

If nuclear power use is to expand significantly, nuclear facilities will have to be made extremely safe from attacks that could release massive quantities of radioactivity into the environment and community. New reactor designs have features of passive safety, such as the flooding of the reactor core without active intervention by reactor operators. But these safety measures have generally been developed and studied with respect to accidents, not to the deliberate reactor attack by a terrorist group. However, the US Nuclear Regulatory Commission does now also require new reactor license applications to consider security during the design stage.

Use of waste byproduct as a weapon

An additional concern with nuclear power plants is that if the by-products of nuclear fission (the nuclear waste generated by the plant) were to be left unprotected it could be stolen and used as a radiological weapon, colloquially known as a "dirty bomb". There were incidents in post-Soviet Russia of nuclear plant workers attempting to sell nuclear materials for this purpose (for example, there was such an incident in Russia in 1999 where plant workers attempted to sell 5 grams of radioactive material on the open market, and an incident in 1993 where Russian workers were caught attempting to sell 4.5 kilograms of enriched uranium.), and there are additional concerns that the transportation of nuclear waste along roadways or railways opens it up for potential theft. The United Nations has since called upon world leaders to improve security in order to prevent radioactive material falling into the hands of terrorists, and such fears have been used as justifications for centralized, permanent, and secure waste repositories and increased security along transportation routes.

Proponents state that the spent fissile fuel is not radioactive enough to create any sort of effective nuclear weapon, in a traditional sense where the radioactive material is the means of explosion. Nuclear reprocessing plants also acquire uranium from spent reactor fuel and take the remaining waste into their custody.

Public opinion

There is little support across the world for building new nuclear reactors, a 2011 poll for the BBC indicates. The global research agency GlobeScan, commissioned by BBC News, polled 23,231 people in 23 countries from July to September 2011, several months after the Fukushima nuclear disaster. In countries with existing nuclear programmes, people are significantly more opposed than they were in 2005, with only the UK and US bucking the trend. Most believe that boosting energy efficiency and renewable energy can meet their needs.

Just 22% agreed that "nuclear power is relatively safe and an important source of electricity, and we should build more nuclear power plants". In contrast, 71% thought their country "could almost entirely replace coal and nuclear energy within 20 years by becoming highly energy-efficient and focusing on generating energy from the Sun and wind". Globally, 39% want to continue using existing reactors without building new ones, while 30% would like to shut everything down now.

In 2011, Deutsche Bank analysts concluded that "the global impact of the Fukushima accident is a fundamental shift in public perception with regard to how a nation prioritizes and values its populations health, safety, security, and natural environment when determining its current and future energy pathways". As a consequence, "renewable energy will be a clear long-term winner in most energy systems, a conclusion supported by many voter surveys conducted over the past few weeks. At the same time, we consider natural gas to be, at the very least, an important transition fuel, especially in those regions where it is considered secure".

European Union

A poll in the European Union for February–March 2005 showed 37% were in favour of nuclear energy and 55% opposed, leaving 8% undecided. The same agency ran another poll in Oct-Nov 2006 that showed 14% favoured building new nuclear plants, 34% favoured maintaining the same number, and 39% favoured reducing the number of operating plants, leaving 13% undecided. This poll showed that respondents with a lower level of education and that women were less likely to approve.

Japan

In June 2011, both Ipsos Mori and the Japanese Asahi Shimbun newspaper found drops in support for nuclear power technology in most countries, with support continuing in a number including the US. The Ipsos Mori poll found that nuclear had the lowest support of any established technology for generating electricity, with 38%. Coal was at 48% support while solar energy, wind power and hydro all found favour with more than 90% of those surveyed.

Sweden

A 2011 poll found that skepticism over nuclear power had grown in Sweden following Japan's nuclear crisis. 36 percent of respondents wanted to phase-out nuclear power, up from 15 percent two years previous. An equal percentage of 36 percent were in favor of keeping nuclear power at its present level, and another 21 percent favored increasing nuclear power, with 7% undecided.

United States

What had been growing acceptance of nuclear power in the United States was eroded sharply following the 2011 Japanese nuclear accidents, with support for building nuclear power plants in the U.S. dropping slightly lower than it was immediately after the Three Mile Island accident in 1979, according to a CBS News poll. Only 43 percent of those polled after the Fukushima nuclear emergency said they would approve building new power plants in the United States.

A Gallup poll in the US in March 2015 found support for nuclear power at 51%, with 43% opposed. This was the lowest level of support for nuclear since 2001, and significantly down from the 2010 peak of 62% in favor, versus 33% opposed. Similarly, a Roper poll in 2013 found support for new nuclear power plants at 55%, with 41% opposed, down from the peak level of support in 2010 of 70% in favor versus 27% opposed.

The two energy sources that attracted the highest levels of support in the 2007 MIT Energy Survey were solar power and wind power. Outright majorities would choose to "increase a lot" use of these two fuels, and better than three out of four Americans would like to increase these fuels in the U. S. energy portfolio. Fourteen per cent of respondents would like to see nuclear power "increase a lot".

Trends and future prospects

As of May 15, 2011, a total of 438 nuclear reactors were operating in 30 countries, six fewer than the historical maximum of 444 in 2002. Since 2002, utilities have started up 26 units and disconnected 32 including six units at the Fukushima Daiichi nuclear power plant in Japan. The current world reactor fleet has a total nominal capacity of about 372 gigawatts (or thousand megawatts). Despite six fewer units operating in 2011 than in 2002, the capacity is still about 9 gigawatts higher. The numbers of new operative reactors, final shutdowns and new initiated constructions according to International Atomic Energy Agency (IAEA) in recent years are as follows:

Stephanie Cooke has argued that the cost of building new reactors is extremely high, as are the risks involved. Most utilities have said that they won't build new plants without government loan guarantees. There are also bottlenecks at factories that produce reactor pressure vessels and other equipment, and there is a shortage of qualified personnel to build and operate the reactors, although the recent acceleration in nuclear power plant construction is drawing a substantial expansion of the heavy engineering capability.

Following the Fukushima Daiichi nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035. Platts has reported that "the crisis at Japan's Fukushima nuclear plants has prompted leading energy-consuming countries to review the safety of their existing reactors and cast doubt on the speed and scale of planned expansions around the world". In 2011, The Economist reported 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 September 2011, German engineering giant Siemens announced it will withdraw entirely from the nuclear industry, as a response to the Fukushima nuclear disaster in Japan. The company is to boost its work in the renewable energy sector. Commenting on the German government's policy to close nuclear plants, Werner Sinn, president of the Ifo Institute for Economic Research at the University of Munich, stated: "It is wrong to shut down the atomic power plants, because this is a cheap source of energy, and wind and solar power are by no means able to provide a replacement. They are much more expensive, and the energy that comes out is of inferior quality. Energy-intensive industries will move out, and the competitiveness of the German manufacturing sector will be reduced or wages will be depressed."

In 2011, Mycle Schneider spoke of a global downward trend in the nuclear power industry:

The international nuclear lobby has pursued a 10-year-long, massive propaganda strategy aimed at convincing decision-makers that atomic technology has a bright future as a low-carbon energy option... however, most of the high-flying nuclear plans never materialized. The historic maximum of reactors operating worldwide was achieved in 2002 with 444 units. In the European Union the historic peak was reached as early as 1988 with 177 reactors, of which only 134 are left. The only new projects underway in Europe are heavily over budget and much delayed.

As Time magazine rightly stated in March, "Nuclear power is expanding only in places where taxpayers and ratepayers can be compelled to foot the bill." China is building 27 -- or more than 40 percent -- of the 65 units officially under construction around the world. Even there, though, nuclear is fading as an energy option. While China has invested the equivalent of about $10 billion per year into nuclear power in recent years, in 2010 it spent twice as much on wind energy alone and some $54.5 billion on all renewables combined.

In contrast, proponents of nuclear power argue that nuclear power has killed by far the fewest number of people per terawatt hour of any type of power generation, and it has a very small effect on the environment with effectively zero emissions of any kind. And this even taking into account the Chernobyl and Fukushima accidents, in which few people were killed directly and few excess cancers will be caused by releases of radioactivity to the environment. Some proponents acknowledge that most people will not accept this sort of statistical argument nor will they believe reassuring statements from industry or government. Indeed, the industry itself has created fear of nuclear power by pointing out that radioactivity can be dangerous. Improved communication by industry might help to overcome current fears regarding nuclear power, but it will be a difficult task to change current perceptions in the general population.

But with regard to the proposition that "Improved communication by industry might help to overcome current fears regarding nuclear power", M.V. Ramana says that the basic problem is that there is "distrust of the social institutions that manage nuclear energy", and a 2001 survey by the European Commission found that "only 10.1 percent of Europeans trusted the nuclear industry". This public distrust is periodically reinforced by safety violations by nuclear companies, or through ineffectiveness or corruption on the part of nuclear regulatory authorities. Once lost, says Ramana, trust is extremely difficult to regain. Faced with public antipathy, the nuclear industry has "tried a variety of strategies to persuade the public to accept nuclear power", including the publication of numerous "fact sheets" that discuss issues of public concern. Ramana says that none of these strategies have been very successful.

In March 2012, E.ON UK and RWE npower announced they would be pulling out of developing new nuclear power plants in the UK, placing the future of nuclear power in the UK in doubt. More recently, Centrica (who own British Gas) pulled out of the race on 4 February 2013 by letting go its 20% option on four new nuclear plants. Cumbria county council (a local authority) turned down an application for a final waste repository on 30 January 2013 — there is currently no alternative site on offer.

In terms of current nuclear status and future prospects:

Brazil, China, India, Japan and the Netherland now all generate more electricity from wind energy than from nuclear sources. New power generation using solar power grew by 33% in 2015, wind power over 17%, and 1.3% for nuclear power, exclusively due to development in China.