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Nuclear power and energy generation

This briefing sheet aims to provide accurate and up to date information on nuclear power generation in the UK and worldwide.  

UK nuclear power stations currently have an installed capacity of around 10GW
UK nuclear power stations currently have an installed capacity of around 10GW

Nuclear Power around the World

Reactor numbers

Nuclear power has been providing affordable electricity in various parts of the world since the 1950s and this electricity is produced with virtually no carbon emissions. As of 2014 there are currently 435 commercial nuclear power reactors operating in 30 countries.

The installed capacity of 368,500MWe 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.

Further details can be found on the World Nuclear Association website.

Reactors planned, proposed or under construction

Many countries with existing nuclear power programmes have plans to build new power reactors. In all 174 power reactors with a total net capacity of some 190,000MWe are planned and over 300 more are proposed. Gas prices and environmental constraints on coal, coupled with energy security concerns, have combined to put nuclear power back on the agenda for projected new capacity in many countries.

A number of countries are reviewing their plans following the Fukushima accident 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 over 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 2012, electricity generated in nuclear power plants was 70TWh net, or 19% of total electricity produced from all sources.

Currently there are nine nuclear power stations operating in the UK, but the published lifetimes indicate the capacity will decline significantly over the next 10-15 years as the power stations reach the end of their operating lives.

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 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), an LWR 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 6.0GW by 2023 with the closure of the Magnox and the older AGR stations and tapering to zero by 2035 with the planned closure of Sizewell B. Life extensions are being taken into account by the operator for the AGR and PWR plants, based on achieving five to nine years extended life across the fleet.

There are also significant plans for new nuclear build to replace capacity with new reactors planned for completion by 2023 and beyond.

Safety Record

As in other industries, the design and operation of nuclear power plants aims to minimise the likelihood of accidents, and to 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 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 INES (International Nuclear Event Scale used by the IAEA) Level 7 following an earthquake and tsunami which damaged four of six reactors at the site, resulting in the release of radioactive material into the atmosphere. Since the accident occurred the operator has made progress to achieve a cold shutdown condition, treat contaminated water and minimise releases of radioactive materials. The UK responded promptly to the initial event, performing a review across the fleet of reactors in the UK which confirmed that they are safe in the light of the challenges faced at Fukushima. Some improvements to preparedness for extreme emergencies were identified and are now in place. 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.

These are the only major accidents to have occurred in over 14,500 cumulative reactor-years of commercial nuclear power operation in 32 countries.

Security of Supply

Nuclear power contributes significantly to security of supply via a number of benefits:

  • Adding to the diversity of energy sources
  • Using uranium feedstock which is plentiful and comes from stable countries such as Australia and Canada
  • Providing reliable baseload generating capacity
  • Fuel availability can be assured through retention of strategic stocks either of finished fuel or of raw uranium feedstock

Baseload capability

Nuclear stations deliver very high energy density, when generating capacity and land requirements are compared. Coupled with the high reliability (load factors around 90% for PWRs), this enables nuclear units to provide the grid with baseload generation.

Impact on the Environment

Gaseous emissions

Nuclear power compares favourably with other sources for a wide range of gaseous emissions and future nuclear generation would generate wastes with relatively little environmental impact when compared objectively with other sources of generation.

Nuclear generation currently reduces the UK’s carbon emissions by between 7-14% (compared to generating the same volume of electricity using conventional coal or gas power stations).

Nuclear waste

Dealing with nuclear waste is cited by many as a major challenge. However, it has already been proved that it is possible to store spent fuel, or else recycle it, and condition the waste arising into safe forms for storage over many decades (and arguably over centuries). Interim safe stores already exist and there is demonstrable evidence that wastes associated with nuclear power can be cost-effectively and safely managed. In Finland, the USA and Sweden, long term storage solutions are also in development. This gives confidence that a long term solution can be developed in the UK, even though this may be several decades into the future.

It is important to distinguish between legacy wastes in the UK and the wastes which will be generated from any new nuclear power stations. The old Magnox and AGR stations were built by the UK government. Since these stations were publicly owned, the cost of decommissioning them and dealing with the waste is also publicly funded. Between 2014-2114, decommissioning old legacy stations, Sellafield, and the associated wastes is expected to cost £60bn (approximately £600m per year, less than 0.1% of total Government annual spending).

Current UK Government policy is that any new nuclear power stations must be privately funded. As such, the liability for decommissioning rests with the owners of the sites, not the tax payer. The costs of decommissioning these new stations will paid for by investing a small percentage of the profits into a Funded Decommissioning Programme.

Waste volumes

The volume of nuclear waste produced by the nuclear industry is very small compared with other wastes generated. Each year, nuclear power generation facilities worldwide produce about 200,000m3 of low- and intermediate-level radioactive waste, and about 10,000m3 of high-level waste including used fuel.

A typical 1000MWe light water reactor will generate 200-350m3 low and intermediate-level waste per year. It will also discharge about 20m3 (27 tonnes) of used fuel per year, which corresponds to a 75m3 disposal volume following encapsulation if it is treated as waste. Where that used fuel is reprocessed, only 3m3 of vitrified waste (glass) is produced, which is equivalent to a 28m3 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 the radiological hazard in a way that is environmentally sound and presents minimal risk to both workers and the general public.

Legacy wastes

It is important to recognise that the quantity of waste generated by a modern LWR is significantly less compared to the older Magnox or AGR reactors.

It is also important to distinguish between waste from commercial power stations and historic wastes which have arisen because of decisions taken for the UK to have an independent nuclear deterrent and, consequently, that it would have a power programme using a fuel cycle that included reprocessing. The total waste arisings from a new series of 10 advanced PWRs operating for 60 years and utilising spent fuel storage would make only a small increase to the current UK nuclear waste inventory.

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 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.

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. 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 subsidiary called ‘Radioactive Waste Management Ltd’ 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 Geological Disposal Facility (GDF) is expected to cost around £12 billion from conception, through operation from about 2040, to closure in 2100. 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 earlier 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 would be charged a fixed unit price for disposal of intermediate-level wastes and used fuel in the GDF.

Nuclear Generating Costs

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 DECC report published in July 2013 is available on the DECC website: DECC Electricity Generation Costs 2013.

Note that under Energy Act 2008 the operators of new nuclear power stations must have secure financing arrangements in place to meet the full costs of decommissioning and their full share of waste management and disposal costs.

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 UK Government announcement in 2008 that nuclear power should form part of the UK’s future energy mix, the nuclear industry has the following plans to develop around 16GW of new nuclear power:

  • EDF Energy intends to build 4 new EPRs (6.4GWe) at Hinkley Point in Somerset and at Sizewell in Suffolk
  • Hitachi Ltd has confirmed plans to build 2 or 3 new ABWRs (Advance Boiling Water Reactors) at Wylfa on Anglesey and the same at Oldbury, in South Gloucestershire
  • NuGeneration plans to build up to 3.6GWe of new nuclear capacity using Westinghouse’s AP1000 reactor at Moorside, near Sellafield

The Office for Nuclear Regulation is conducting a Generic Design Assessment of the proposed designs. The assessments are at various stages, with the EPR design granted regulatory approval develop the Hinkley Point EPR project.

Further Reading

World Nuclear Association

DECC Policy - Increasing the use of low carbon technologies

UK Government and industry strategy for the future of the nuclear sector in the UK

Nuclear Decommissioning Authority