An Introduction to Nuclear Power
Abstract
Nuclear power is a controversial form of power generation based on the exploitation of nuclear reactions. Nuclear power plants do not emit carbon dioxide while generating electricity but they do produce radioactive waste that must be disposed of safely. Safety is also a crucial factor because an accident at a nuclear power station can release radioactive material into the environment and this will potentially have devastating consequences. Nuclear power grew out of the nuclear weapons programs of the early and mid-20th century and the technology saw its greatest growth between the beginning of the 1960s and the beginning of the 1980s. In 2013 nuclear power contributed around 11% of global electricity.
Keywords
Nuclear power; radioactive waste; nuclear fusion; nuclear fission; water-cooled reactor; gas-cooled reactor; breeder reactor; global warming
Nuclear power is the most controversial of all forms of electricity generation. Evaluating its importance involves weighing political, strategic and, often, emotional considerations alongside the more usual technical, economic, and environmental factors that form the core elements of any power technology debate. To complicate the issue further, partisan views are frequently advanced so that balanced, objective decision-making can be difficult, if not impossible.
From a technological point of view, nuclear power offers a tested method of generating electrical power based on exploitation of the energy released during controlled nuclear reactions. However the byproducts of these nuclear processes are a range of extremely toxic radioactive materials, and the nuclear industry has still to develop widely accepted ways of disposing of this waste in a secure manner. An additional, complicating issue is the ability of nuclear technology to be exploited for weapons production as well as power; the overlap between the two makes it very difficult to separate one from the other.
The other great cause of anxiety is the possibility of a nuclear accident. The consequences of an accident at a nuclear power plant that leads to the release of radioactivity into the environment are potentially much more far-reaching that would be the case with an accident at any other type of power plant. This was dramatically demonstrated by the incident at the Fukushima Daiichi nuclear power plant in Japan following a massive undersea earthquake and tsunami in 2011. Both this and the earlier Chernobyl nuclear plant failure have seriously damaged popular confidence in nuclear power and both have had an influence on government policy in several countries, notably Germany, where nuclear power is being phased out as a result of the 2011 accident.
If these issues weigh negatively in the balance, on the positive side nuclear power does offer a carbon-free means of generating electricity and in a world where the control of carbon emissions has become a major requirement if global warming is to be controlled, nuclear technology potentially offers a part of the solution. The International Energy Agency has identified nuclear power as one of the key technologies that will be needed if the globally agreed target of trying to limit global warming to 2°C is to be achieved.1 Whether the organization’s optimistic forecasts for nuclear growth are realistic, given both the negative effect of the 2011 accident and the fall in the cost of power from solar and onshore wind power, which has undercut wholesale power prices in Europe, remains to be seen.
The modern nuclear power industry was born out of the nuclear weapons programs that led to the development of the atom bomb during the 1940s. While weaponry was the aim of the research during World War II, power generation quickly became a secondary, peaceful product of the work and programs were started in both the United States and Russia. Electricity production from nuclear power began on a very small scale at an experimental reactor in the United States in 1951 while in Russia a 5-MW plant designed to generate electricity began operating in 1954. This was followed, in 1956, by a 50-MW dual purpose reactor2 at Calder Hall, in the United Kingdom, while the French began a nuclear program the same year at Marcoule. The first fully commercial nuclear power plant was built at Shippingport, Pennsylvania, in the United States, and started operating in 1957.
From the late 1950s nuclear generating capacity began to grow rapidly with commercial power plant construction programs in the United States, Russia, the United Kingdom, France, and Canada. Other countries such as Germany, Sweden, and Japan also began to invest in the technology. By the beginning of the 1970s, nuclear power was seen as the great hope for the future of electricity generation. In the United States alone, power companies had ordered over 200 nuclear reactors.
Even as the nuclear power industry was booming, there were concerns about nuclear safety and the consequences of an accident. These were brought into sharp relief by an accident at the Three Mile Island nuclear power plant in the United States in 1979, followed by the catastrophic failure at the Chernobyl reactor in Ukraine in 1986. The reaction to these accidents was a tightening of regulatory control of nuclear power, the introduction of new safety measures, and a loss of public confidence in the technology. The tougher safety regulations meant that the cost of nuclear power soared and in the west the construction of new nuclear power plants was virtually abandoned. It slowed elsewhere too so that during the 1990s and early years of the current century new nuclear plant construction was rare.
Meanwhile the industry was hoping for a renaissance. Interest in nuclear power in China provided one ray of hope and at the same time all the major nuclear power plant manufacturers began to develop a new generation of safer reactors. By 2010 it appeared that a renaissance had begun and orders started to roll once more. However the Fukushima accident in 2011 halted this new blossoming and once again the nuclear power industry is having to face a bleak future.
With the absence of new orders, the main support for the industry is coming from the life extension of existing power stations and reactors. In many countries life extension to 60 years is either being contemplated or taking place, although some of the older nuclear technologies such as the United Kingdom’s advanced gas reactors and the Russian RBMK reactors are being phased out completely.
While energy production based on nuclear fission reactions (the splitting of atoms to release energy) may have a limited future, there is another nuclear technology based on nuclear fusion (the fusing of atoms with the release of energy). This technology, too, has its origins in the development of weapons, in this case the hydrogen bomb. Experiments to exploit fusion were started in the 1930s and resumed after an interlude in the 1940s. However, fusion has proved much more difficult to exploit than fission and no commercial scale fusion reactor has been built. Development work continues and hope remains that it can provide an alternative source of energy by the end of the century, if not before.
The History of Nuclear Power
The development of nuclear energy and of nuclear weapons relies on an understanding of atomic structure and of the stability of atomic nuclei. The idea that matter might be composed of atoms was first put forward by Greek philosophers and the name atom is derived from the Greek word atomos, which means indivisible. This concept, which became known as atomism, was taken up by a range of ancient religions and philosophies but in the 17th century it began to develop into a more recognizably modern theory of matter through the work of people like René Descartes and Robert Hooke and their speculations about a mechanical universe. These ideas were also taken up by chemists, particularly with the work of Robert Boyle and this gradually fed during the 18th century into more complex concepts about the nature of chemical reactions.
The empirical basis for atomic theory was first laid out by John Dalton in the early 19th century and although it remained controversial throughout the century, theoretical and experimental evidence to support it grew. By the end of the century, the New Zealand scientist Ernest Rutherford was developing his “disintegration theory,” which proposed that radioactivity, which was by then a well-known phenomenon, was the result of atomic processes. In 1904 he speculated that if the rate of disintegration of these radio elements could be controlled, an enormous amount of energy could be obtained for a small amount of matter.3 This idea was formalized mathematically by Albert Einstein in this famous equation:
which relates mass and energy. Einstein published this equation in a paper in 1905.
Work continued through the early part of the 20th century on the unraveling of the nature of atoms and their structure. However the next milestone in the development of atomic energy came in 1934 when the physicist Enrico Fermi showed that when neutrons were fired at a range of atoms the particles could cause the atoms to split. His experiments indicated that when the element uranium was treated in this way, the result of the fission process was elements that were much lighter than the original uranium. In 1938 German scientists Otto Hahn and Fritz Strassman performed similar experiments and were able to identify the products as elements such as barium with around half the mass of uranium. A colleague, Lise Meitner, who worked in Copenhagen used their work to calculate that there was a small amount of mass missing when all the fragments were added together and she showed that this had emerged as energy, confirming Einstein’s theory and also confirming that atomic fission had taken place.
When a uranium atom is struck by a neutron and splits via a fission reaction, it will commonly produce three more neutrons. This led scientists around the world to begin to speculate about the possibility of putting together enough uranium4 to create a self-sustaining nuclear reaction, a chain reaction, during which the neutrons released by uranium fission could produce additional, multiple fission reactions. Since each fission reaction also released an enormous amount of energy, this concept had potential both as a way of releasing a massive amount of energy, explosively, in a very short space of time and of providing a controlled release of energy in an energy plant. The exploration of the first of these options through the US Manhattan Project led, in 1945, to the development of the first atomic bomb. Alongside the atomic weapons development, the idea of a uranium reactor was under consideration as early as 1941. This led, at the end of 1942, to the first nuclear reactor, called Chicago Pile-1 that demonstrated the possibility of nuclear reaction being controlled in order to generate energy.
As part of the weapons program, scientists had been working on nuclear fast reactors—often called breeder reactors—that would produce new nuclear material during their operation. An experimental reactor of this type was developed at the Argonne National Laboratory in the US state of Idaho after World War II and in 1951 became the first nuclear reactor to generate electricity from nuclear energy. In 1953 the US president Dwight Eisenhower put forward Atoms for Peace program to direct US nuclear research toward energy production.
Russia also had a longstanding nuclear research program that was partly directed toward energy production, and in 1954 an existing reactor designed for plutonium production was modified for heat and electricity generation. This AM-1 reactor with a generating capacity of 5 MW became the first nuclear power station. In the United States, meanwhile, development of a pressurized water reactor (PWR) for naval use was underway, leading to the first nuclear powered submarine in 1954. The design of this reactor led to the first large-scale demonstration nuclear power plant, the 60-MW Shippingport reactor in Pennsylvania that started operating in 1957. Following that, the first fully commercial nuclear station, the 250-MW Westinghouse PWR, Yankee Rowe, started operating in 1960. An alternative design, the boiling water reactor (BWR) was also under development and the first 250-MW station based on this design also started operating in 1960.
In the United Kingdom another design, the gas-cooled Magnox reactor was developed and the first 50-MW dual purpose reactor to this design began operating at Calder Hall in 1956. In France a reactor of similar design started operating in 1956 and commercial plants began to appear in 1959. Russia took slightly longer to develop power plants and it was 1964 before the first two nuclear plants, based on a Russian BWR design started to operate.
In the first decade of the 21st century, while there are still a range of different reactor designs in operation, by far the largest portion of these are now PWRs.
Global Electricity Production From Nuclear Power
From the beginning of the 1970s, the output from the world’s nuclear power plants grew steadily as their numbers increased. However the slowdown in construction that began during the 1990s saw the rise in output slow. Total output peaked during the middle of the first decade of the 21st century and since then it has declined. With output static or declining, the proportion of global electric power generated by nuclear power plants has been falling since the middle of the 1990s.
Table 1.1 shows the number of reactors at the end of 2015, broken down by type. There were 442 operating reactors but three of these were experimental fast breeder reactors; the remaining 439 were commercial power reactors. The largest group comprises 283 PWRs and these make up 64.0% of the total. The alternative BWR accounted for 78 further units or 17.6% of all those in operation. There are 15 light water graphite reactors, found only in countries of the former Soviet Union, and 14 advanced gas-cooled reactors, a design unique to the United Kingdom.
Table 1.1
Nuclear Power Reactors in Operation at the End of 2015
| Reactor Type | Number | Proportion of Total (%) |
| Pressurized water reactor | 283 | 64.0 |
| Boiling water reactor | 78 | 17.6 |
| Pressurized heavy water reactor | 49 | 11.1 |
| Light water graphite reactor | 15 | 3.4 |
| Advanced gas-cooled reactor | 14 | 3.2 |
| Nuclear fast reactor | 3 | 0.7 |
| Total | 442 | 100.0 |
Source: World Nuclear Association.5
Table 1.2 contains figures for the total annual generation from nuclear power plants between 2004 and 2013. Total output in 2004 was 2738 TWh, 15.7% of total global electricity production. Output rose over the next 2 years, reaching 2793 TWh in 2007. Total production continued to hover around 2700 TWh until 2011 when Japanese power plants were shut down following the Fukushima accident. At the end of 2013, total nuclear output was 2478 TWh but with rising global generation, this accounted for only 10.6% of the global total. According to separate figures from the World Nuclear Association, total output in 2015 was 2441 TWh, again around 10% of global production. However figures from the Nuclear Energy Agency indicate that nuclear power in OECD6 countries accounted for 19.0% of the total electricity production in these countries, nearly twice as high as the global figure.
Table 1.2
Annual Global Electricity Production From Nuclear Power Plants
| Year | Global Nuclear Power Generation (TWh) | Total Global Power Generation (TWh) | Nuclear Production as a Proportion of Annual Production (%) |
| 2004 | 2738 | 17,450 | 15.7 |
| 2005 | 2768 | 18,239 | 15.2 |
| 2006 | 2793 | 18,930 | 14.8 |
| 2007 | 2719 | 19,771 | 13.7 |
| 2008 | 2731 | 20,181 | 13.5 |
| 2009 | 2697 | 20,055 | 13.4 |
| 2010 | 2756 | 21,431 | 12.9 |
| 2011 | 2584 | 22,126 | 11.7 |
| 2012 | 2461 | 22,668 | 10.9 |
| 2013 | 2478 | 23,322 | 10.6 |
Source: International Energy Agency.7
Table 1.3 shows figures for the annual total global nuclear generating capacity between 2004 and 2013. Total capacity in 2004 as 357 MW. Capacity rose during the rest of the decade, peaking at 375 MW in 2010. Generating capacity dipped to 369 MW in 2011 but by 2013 it was again 372 MW.
Table 1.3
Annual Global Nuclear Generating Capacity
| Year | Global Nuclear Generating Capacity (GW) |
| 2004 | 357 |
| 2005 | 368 |
| 2006 | 369 |
| 2007 | 372 |
| 2008 | 373 |
| 2009 | 371 |
| 2010 | 375 |
| 2011 | 369 |
| 2012 | 373 |
| 2013 | 372 |
Source: International Energy Agency.8
In Table 1.4 global nuclear electricity output is broken down by country for the top 10 nuclear nations. The country with the largest nuclear production was the United States with 822 TWh. France produced 424 TWh and the Russian Federation 173 TWh. Output in South Korea was 239 TWh, higher than that in China where 112 TWh were produced, while nuclear power plants in Canada generated 103 TWh. Germany produced 97 TWh, Ukraine 83 TWh, the United Kingdom 71 TWh, and Sweden 66 TWh. Production in the rest of the world was 388 TWh. The figures in this table do not include Japan because in 2013 its nuclear power plants were shut down. However in 2010 the last full year of operation of Japan’s nuclear fleet, it produced 288 TWh and was the third largest nuclear generator.
Table 1.4
Nuclear Electricity Production by Country in 2013 (TWh)
| Country | Nuclear Power Production (TWh) | Nuclear Production as a Proportion of National Total (%) |
| United States | 822 | 19.2 |
| France | 424 | 74.7 |
| Russian Federation | 173 | 16.3 |
| South Korea | 139 | 25.8 |
| China | 112 | 2.1 |
| Canada | 103 | 15.8 |
| Germany | 97 | 15.5 |
| Ukraine | 83 | 43.0 |
| United Kingdom | 71 | 19.8 |
| Sweden | 66 | 43.4 |
| Rest of the World | 388 | 7.9 |
| World | 2478 | 10.6 |
Source: International Energy Agency.9
Table 1.4 also shows what proportion of each country’s electricity is generated by nuclear power plants. The highest proportion is found in France where nearly 75% of the nation’s power came from nuclear generation in 2013. Ukraine and Sweden both produced 43% of their electricity from nuclear stations and in South Korea the total was 26%. (The production from Japan’s plants in 2010 was also 26% of its total.) The United Kingdom produced around 20% of its power from its nuclear stations while in the United States it was 19% and in the Russian Federation 16%. Canada generated 16% of its electricity from nuclear plants, as did Germany, while China’s nuclear output accounted for only 2% of its total.
Finally, Table 1.5 shows all the world’s nuclear nations, arranged alphabetically, together with their nuclear capacities in 2013. There are 29 in total. As would be expected from the figures above for generation, the United States had the largest installed capacity, 98,990 MW. France, with the second largest fleet had 63,130 MW while Japan had 40,830 MW. Other nations with large nuclear fleets included China with 26,967 MW, Russia with 26,053 MW, and South Korea with 23,017 MW. Canada had 13,553 MW, Ukraine 13,107 MW, and Germany 10,728 MW. All the other countries in the table had less than 10,000 MW of nuclear capacity.
Table 1.5
Installed Nuclear Capacity by Country
| Country | Operating Reactor Capacity (MW)a |
| Argentina | 1627 |
| Armenia | 376 |
| Belgium | 5943 |
| Brazil | 1901 |
| Bulgaria | 1926 |
| Canada | 13,553 |
| China | 26,967 |
| Czech Republic | 3904 |
| Finland | 2741 |
| France | 63,130 |
| Germany | 10,728 |
| Hungary | 1889 |
| India | 5302 |
| Japan | 40,480 |
| South Korea | 23,017 |
| Mexico | 1600 |
| Netherlands | 485 |
| Pakistan | 725 |
| Romania | 1310 |
| Russia | 26,053 |
| Slovakia | 1816 |
| Slovenia | 696 |
| South Africa | 1830 |
| Spain | 7121 |
| Sweden | 8849 |
| Switzerland | 3333 |
| Ukraine | 13,107 |
| United Kingdom | 8883 |
| United States | 98,990 |
| World Total | 384,006 |
aFigures are for operating reactors on May 1, 2016.
Source: World Nuclear Association.
It is notable that several countries with large nuclear fleets have built them to make up for very limited fossil fuel reserves. These countries include Japan, South Korea, and Sweden. Sweden has a significant hydropower reserve which it also exploits. However, Japan and South Korea have few domestic resources for power generation and both import significant amounts of coal and natural gas in addition to operating nuclear fleets.