British Prime Minister Boris Johnson said expanding the use of nuclear power would help cut costs and resist "bullying" from Russia, which dominates the European gas market.
To generate nuclear power, uranium atoms are bombarded with smaller neutron particles in non-military reactors. This causes the atoms to break down and release a lot of energy as heat. This heat is then used to boil water, generate steam, drive turbines and generate electricity. The process causes no greenhouse gas emissions and requires minimal extraction of metals and other resources, but does generate hazardous waste that requires long-term storage.
There are currently six nuclear power plants in the UK that can supply about 20% of the country's electricity needs, of which 15% will be generated in 2020. This number has declined since the 1990s, with several plants reaching the end of their lifespan. Most of the UK's existing reactors will cease operation and be shut down by 2030.
The U.K. government says it wants to offer up to eight new reactors overall, with one approved a year until 2030.
The UK government has already backed the construction of the Hinkley Point C nuclear power plant in Somerset, which will be the UK's largest nuclear power plant. It also confirmed the approval of advanced plans for two new reactors at Sizewell C in Suffolk during this session of Parliament. Wyfla in Anglesey has also been named as the site for a new nuclear power plant in the next parliament.
In addition to large nuclear power plants, the UK government also supports small modular reactors (SMRs), which work in the same way as conventional nuclear reactors, but on a smaller scale.
The Energy Strategy says the UK will work with countries including Canada and the US to accelerate work on advanced nuclear technologies, including SMRs and Advanced Modular Reactors (AMRs).
The construction of nuclear power plants is very expensive and complicated. Hinkley Point C - the UK's newest nuclear power plant planned - is expected to be 30% over budget, to £22bn-£26bn. A much smaller SMR would be cheaper, around £2bn - but would obviously also produce less electricity.
The UK government also hopes a new financial funding model will reduce the cost of new nuclear projects. But that could mean electricity customers have to pay part of the program cost up front through their energy bill.
There is also the question of the price that will be paid for the energy produced by the UK's new nuclear power plants. In 2013, the UK government agreed to pay £92.50 per megawatt-hour for electricity produced at the Hinkley Point C nuclear power plant, a price that would rise with inflation. While this is significantly lower than current prices, which have soared to £195 per MWh due to the energy crisis, critics argue that is still too high.
Prices have been between £25 and £50 per megawatt-hour for the past five years, so a return to that range would make nuclear power expensive.
Critics of nuclear power say they are taking so long to go live too late for Britain's emissions targets or lower energy prices.
In 2016, EDF Energy said construction of the Hinkley Point C nuclear power plant would take 10 years - and last year it said it was on track to open by the end of 2026, although further delays were possible.
Now, a new agency called "Great British Nuclear" is being created to oversee and speed up the time it takes to build and operate nuclear power plants.
The UK government has also said that SMRs can be built faster than larger factories because there are fewer parts involved.
According to the State of the World Nuclear Industry Report, by mid-2021, there are 415 civilian nuclear reactors operating in 33 countries. In 2020, five countries, the United States, China, France, Russia and South Korea, together accounted for 72% of the world's total electricity generation.
Nuclear power's share of the global energy market is steadily declining, the industry report said. But two countries, Belarus and the United Arab Emirates, started their first reactors last year.
The UN-affiliated International Atomic Energy Agency says nuclear power plants are among the "safest and most secure facilities in the world". They are subject to strict international safety standards.
In March, a nuclear power plant in Ukraine - the largest in Europe - was shelled before being taken over by Russia, causing widespread panic.
There have also been some high-profile incidents where large quantities of radioactive material have been released into the environment. In 1986, the Chernobyl nuclear power plant exploded, the worst nuclear accident in history. In 2011, a tsunami caused by a huge earthquake inundated Japan's Fukushima nuclear power plant.
Even under normal circumstances, generating nuclear power produces hazardous radioactive waste that needs to be safely managed and stored for hundreds of years.
But a House of Lords paper in October said the nuclear waste issue remained "unresolved" in the UK.
Currently, it is stored in temporary facilities not designed for permanent storage of so-called "high-level" radioactive waste.
The government's preferred solution is "geological disposal" - burying the waste deep in rock layers to prevent the escape of radioactive material.
However, none of the communities agreed to embrace such a facility.
Unlike fossil fuels, nuclear power plants don't produce greenhouse gases such as carbon dioxide or methane -- and 1 kilogram of nuclear fuel produces millions of times more energy than 1 kilogram of coal. But like fossil fuels, nuclear fuels are non-renewable energy resources.
Building new nuclear power plants of any size also produces emissions -- for example, by making large quantities of steel and other required materials. In addition, the long-term environmental consequences of disposing of nuclear waste are unclear.
