Nuclear power has been providing affordable electricity in various parts of the world since the 1950’s and this electricity is produced with comparatively low carbon emissions.
Nuclear power around the world
Reactor numbers
At October 2011 there were 432 commercial nuclear power reactors operating in 30 countries, with 368,500 MWe of total capacity.
The installed capacity of 368,500 MWe is around 16% of global installed generation capacity. The percentage of nuclear generating capacity varies from country to country, with some countries such as France and Belgium producing more than half of their electricity from nuclear.The UK currently produces just under 1/5 of its energy needs through nuclear power.
Further details can be found on the World Nuclear Association website.
Reactions planned, proposed and under construction
Many countries with existing nuclear power programs have plans to build new power reactors. In all, over 150 power reactors with a total net capacity of some 172,000 MWe are planned and over 340 more are proposed. Rising gas prices and greenhouse constraints on coal, coupled with energy security concerns, have combined to put nuclear power back into consideration for developing future capacity.
A number of countries are reviewing their plans following the accident in Fukushima, Japan in March 2011.
UK nuclear industry
UK nuclear development and experience
The UK nuclear industry has been engaged in the development of civil nuclear power for around half a century. The world’s first commercial nuclear power station was opened at Calder Hall in Cumbria in 1956. Recent figures published by the IAEA show that, in terms of accumulated reactor years, the UK is the third most experienced reactor operator in the world behind the US and France.
Nuclear electricity production
In terms of the production of nuclear generated electricity, the UK is currently the world's ninth largest. In 2011, electricity generated in nuclear power plants was 62.1 TWh net, or 17.8% of total electricity produced from all sources.
Currently there are 9 nuclear power stations operating in the UK, but the published lifetimes indicate the capacity will decline significantly over the next 10 to 15 years – see DECC website: Existing nuclear power stations
UK reactor systems
Historically, the UK selected gas cooled reactors with firstly the Magnox and then Advanced Gas-Cooled Reactor (AGR) systems. This led to the UK nuclear industry being isolated from the benefits gained from design developments; standardisation and operating experience from the Light Water Reactor (LWR) systems which are the most commonly used systems in the rest of the world. The UK switched to the Pressurised Water Reactor System (PWR) system with the start of operation of Sizewell ‘B’ in 1995.
UK nuclear capacity
The UK nuclear power stations currently have an installed capacity of around 10GW. The current planned retirement programme will reduce this capacity to 1.2 GW by 2023 with the closure of the Magnox and AGR stations and to zero by 2035 with the closure of Sizewell B. Life extensions are being considered by the operator and government for all these plants, with the aim to achieve five to nine years beyond this across the fleet.
There are also significant plans for new nuclear build to replace capacity with new reactors planned for completion by end of this decade with further additions in the early 2020's.
Safety record
As in other industries, the design and operation of nuclear power plants aims to minimise the likelihood of accidents, and avoid major human consequences when they occur.
The UK’s nuclear reactors have been developed and operated safely for over five decades, and the industry’s occupational safety record is very good when compared to other industries. The Government’s own independent inspectors in the Office for Nuclear Regulation (ONR) exist to licence Nuclear Installations and to enforce safety standards.
From the outset, there has been a strong awareness of the potential hazard of both nuclear criticality and release of radioactive materials from generating electricity with nuclear power. Although the safety record of the world’s nuclear power industry is impressive generally and continues to improve there have been several significant accidents.
There have been four major reactor accidents in the history of civil nuclear power – Windscale, Three Mile Island, Chernobyl and Fukushima.
The accident at the Fukushima Dai-Ichi nuclear power plant in Japan, in 2011, was rated as Level 7 on the IAEA’s International Nuclear and Radiological Event Scale (INES) following an earthquake and tsunami which damaged 4 of 6 reactors at the site. This resulted in the release of radioactive material into the atmosphere. The effects and total release of radiation are still being assessed. Since the accident occurred the Operator has brought the affected plants to a state of cold shutdown, treat contaminated water and minimise releases of radioactive materials. The UK responded promptly to the initial event, quickly performing a review across the fleet of reactors at in the UK this confirmed that they are immediately safe however a paper produced by the government’s Chief Nuclear Inspector Mike Weightmann highlighted a number of key areas which should be worked on to improve the current situation. Operators continue to work proactively with their own and the government reviews to learn from the events at Fukushima.
The accident at an RBMK reactor at the Chernobyl nuclear power plant in the former Soviet Union, in 1986, had widespread environmental and human health effects, and was rated as Level 7.
The accident at the Three Mile Island nuclear power plant in the United States in 1979 resulted in a severely damaged reactor core, and was a Level 5.
In 1957, in the early stages of development of the UK nuclear programme, an accident occurred at the United Kingdom Atomic Energy Authority's (UKAEA) site at the Windscale (now Sellafield) facility in Cumbria, which involved an external release of radioactive fission products. On the basis of the off-site impact, it was rated at Level 5, and is the highest rated accident to have happened in the UK.
Security of supply
Nuclear power contributes significantly to security of supply through:
- adding to the diversity of energy sources;
- using uranium feedstock which is plentiful and comes from stable countries such as Australia and Canada;
- by providing reliable baseload generating capacity; and
- by ensuring fuel stocks can be made available through creating strategic stocks piles either of the finished fuel or of the raw uranium feedstock.
Baseload capability
Nuclear reactors provide a constant, un-faltering source of electricity generation. Like coal or gas plants they can be left on constantly with power output increased and decreased when demand is higher. This is in contrast to renewable sources which only produce electricity when the wind blows, or when the sun-shines. For this reason they cannot produce the constant electricity necessary for the base load of the network.
Impact on the environment
Carbon emissions
Nuclear power is regularly promoted as a low carbon source of energy generation. Throughout the operational life time of a power plant nuclear is comparable to wind or solar energy. As the only associated emissions come from transport of fuel or maintenance.
However, when considering carbon emissions for energy sources we must assess the power plant throughout its entire lifetime from construction to decommissioning. The beginning and end of a nuclear power plant’s lifetime is where the majority of CO2 and other gasses are emitted. When considering this lifetime and comparing the gas emitted with the energy produced nuclear still favours highly and in some instances beats solar panels which require high amounts of energy to mine the materials needed to create the cells.
Nuclear generation currently reduces national carbon emissions by between 7% and 14%.
Nuclear waste
Nuclear waste is generally considered the main concern over nuclear power. While this is a problem in the long term (100+ years) over the short term it has already been proven that it is possible to store spent fuel safely and securely, with some of the waste being recycled. Interim safe stores already exist and are demonstrable evidence that wastes associated with nuclear power can be cost-effectively and safely managed over the short – medium term. The USA and Sweden are currently developing long-term underground storage solutions which will house intermediate and high level waste for hundreds of thousands of years. This gives confidence that a long term solution can be developed in the UK; even though this may be several decades into the future.
As well as from commercial power stations nuclear waste has accumulated from research reactors and from the UK’s nuclear defence programme. These come in a variety of forms and since the 1950’s we have become better at managing the processes which create the products leading to more efficient processes in the current industry.
Waste volumes
The volume of nuclear waste produced by the nuclear industry is very small when compared with with wastes from other electricity generation. Each year, nuclear power generation facilities worldwide produce about 200,000 m3 of low- and intermediate-level radioactive waste, and about 10,000 m3 of high-level waste including used fuel.
A typical 1000 MWe light water reactor will generate 200-350 m3 low and intermediate-level waste per year. It will also discharge about 20 m3 (27 tonnes) of used fuel per year, which corresponds to a 75 m3 disposal volume following encapsulation if it is treated as waste and not reprocessed. Where that used fuel is reprocessed, only 3 m3 of vitrified waste (glass) is produced, which is equivalent to a 28 m3 disposal volume following placement in a disposal canister. This compares with an average 400,000 tonnes of ash produced from a coal-fired plant of the same power capacity.
Whilst the volumes of nuclear wastes produced are very small, the most important issue for the nuclear industry is managing their toxic nature in a way that is environmentally sound and presents no hazard to both workers and the general public.
Managing nuclear waste
The methods and processes for managing waste produced by the nuclear industry are comprehensively regulated in the UK. This regulation governs how nuclear operators manage waste from existing plants and how waste from proposed new plants will be managed. Transport of spent fuels and wastes is also highly regulated.
Nuclear waste products are classified into three categories – high, intermediate and low-level – based on their level of residual radioactivity. The categories define how each waste product must be treated.
High-level waste (HLW)
The main source of HLW from nuclear reactors is from the reprocessing of spent fuel. After an appropriate period of cooling on-site, spent fuel from the advanced gas-cooled reactor (AGR) fleet is sent to Sellafield where it is either reprocessed or stored.
All HLW and spent fuel is highly regulated and securely stored until a long-term Geological Disposal Facility (GDF) is made available by the UK Government.
Additionally the spent fuel from Sizewell B’s PWR is stored on the Sizewell B site until a GDF is available.
Intermediate-level waste (ILW)
ILW is currently stored on-site at the nuclear power stations. When the operator decommissions a reactor in, ILW will continue to be stored on the decommissioned site until a disposal facility is available.
Reprocessing of nuclear fuel also produces ILW and LLW which is managed at Sellafield.
Low-level waste (LLW)
Items which have become contaminated with small amounts of radioactivity, such as paper, rags, tools and protective clothing, are classified as low-level waste. This is transported to the LLW Repository in Drigg, Cumbria for disposal. LLW gases and liquids are discharged into the air or sea under strict guidelines and discharge authorisations from the UK Environment Agencies.
Geological disposal facility
The process of selecting appropriate deep geological repositories is now under way in several countries with the first commissioned in 2010. Finland and Sweden are well advanced with plans and site selection for direct disposal of spent fuel.
In the UK the Nuclear Decommissioning Authority (NDA) has set up a Radioactive Waste Management Directorate (RWMD) to develop plans for a deep geological repository for high- and intermediate-level wastes and evolve into the entity that builds and operates it. The GDF is expected to cost around £12 billion from conception, through operation from about 2040, to closure in 2100, at which point all waste is sealed inside the facility. The government has invited communities to volunteer to host the GDF. The next steps are to undertake a geological study; surface research and a period of underground research, construction and commissioning. In these steps the NDA seek to enable operation from 2029.
The government is planning for the GDF to accommodate waste from new build as well as legacy waste. Operators of new plants will be charged a fixed unit price for disposal of intermediate-level wastes and used fuel in the GDF.
Nuclear generating costs
In support of the 2008 Energy White Paper the UK government assessed the costs of many electricity generating technologies including nuclear power.
DECC commissions regular updates by independent consultants on estimated electricity generation costs for nuclear and other technologies. Cost data considers the lifetime of a plant, from planning costs right through construction and operating costs to eventual decommissioning costs. The latest independent report for non-renewable technologies published in August 2011 is available on the DECC website: Electricity Generation Cost Model. Work is also currently being undertaken on Electricity Market Reform, it is hoped that this will provide greater clarity and assurances of the cost for generating electricity from low carbon sources over the long term.
There are non-market costs and benefits associated with security of supply and reduction in carbon dioxide and other emissions which are provided by nuclear generation which are not accounted for in the cost figures.
New nuclear
Following the announcement in early 2008 by the UK Government that Nuclear Power should form part of our future energy mix, the Office for Nuclear Regulation is conducting a Generic Design Assessment of the EDF/AREVA EPR and the Westinghouse AP 1000 reactor designs. In July 2011, a series of National Policy Statements were finally laid before parliament following an extensive consultation process. This includes information on those sites considered suitable for developement of new nuclear power stations by 2018.
The plans include the construction of eight new reactors (amounting to 19GWe) at 5 sites across the UK with the first being built at Hinkley Point in Somerset by EDF.
In early 2011 Horizon, one of the consortia planning to build power plants at Wylfa in Anglesey and Oldbury in Gloucestershire announced they were unable to continue the process of construction on these sites. The two sites remain considerations for new nuclear development with potential consortia currently in discussions with government.