Introduction. Glossary

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2 Introduction The Government s Department for Environment, Food and Rural Affairs (Defra) and United Kingdom Nirex Limited (Nirex) periodically publish an inventory of radioactive waste in the UK. This inventory provides a reference source of information for Government and its agencies, Nirex, and others with a role or interest in the management of radioactive waste. This booklet summarises the 2004 UK Radioactive Waste Inventory, which is the latest public record of information on the sources, quantities and properties of Low Level Waste (LLW), Intermediate Level Waste (ILW) and High Level Waste (HLW) in the UK. The 2004 Inventory contains details of over one thousand individual wastes. Glossary CoRWM Defra The Committee on Radioactive Waste Management, an independent body set up by Government to recommend a strategy for the long-term management of radioactive wastes in the UK. The Government department which, with the environment departments of Wales, Scotland and Northern Ireland, sets policy for UK radioactive waste management. Disposal NDA Nirex The emplacement of waste in a suitable facility without intent to retrieve it at a later date. Retrieval may be possible but, if intended, the appropriate term is storage. The Nuclear Decommissioning Authority, which has responsibility for the UK s public sector civil nuclear liabilities and their subsequent management. It became operational in April A Government owned company responsible for supporting Government policy to develop and advise on safe, environmentally sound and publicly acceptable options for the long-term management of radioactive materials in the UK. Nuclear fuel Fuel used in a nuclear reactor. Most fuel is made of uranium, and produces heat when the uranium atoms split into smaller fragments. Plutonium A radioactive element created in nuclear reactors. It can be separated from spent nuclear fuel by reprocessing. Plutonium is used as a nuclear fuel, in nuclear weapons and as a power source for space probes. Radioactivity The property possessed by some atoms of splitting spontaneously, with release of energy through emission of a charged particle and/or gamma radiation. Reprocessing The chemical extraction of reusable uranium and plutonium from waste materials in spent nuclear fuel. Storage The emplacement of waste in a suitable facility with the intent to retrieve it at a later date. Uranium A radioactive element that occurs in nature. Uranium is used for nuclear fuel and in nuclear weapons. Report prepared for the Department for Environment, Food and Rural Affairs, and United Kingdom Nirex Limited, by: Photographs reproduced by kind permission of British Energy, British Nuclear Fuels, and United Kingdom Atomic Energy Authority. 1

3 What is radioactive waste? Material that has no further use and is above a certain level of radioactivity is known as radioactive waste. Radioactive waste can harm people and the environment and so is carefully controlled. Radioactive waste is divided into three main categories according to how much radioactivity it contains and the heat that this radioactivity produces (see below). Low Level Waste (LLW) Wastes other than those suitable for disposal with ordinary domestic refuse but not exceeding specified levels of radioactivity. Overall, the major components of LLW are soil, building rubble and steel items such as ducting, piping and reinforcement from the dismantling and demolition of nuclear reactors and other nuclear facilities and the clean up of nuclear sites. However, at the present time most LLW is from the operation of nuclear facilities, and this is mainly paper, plastics and scrap metal items. A sub-category of LLW is Very Low Level Waste (VLLW), which arises mainly in small volumes from hospitals and universities. It is disposed of to landfill, either directly or after incineration, under an appropriate regulatory regime. VLLW is not included in the Inventory. Intermediate Level Waste (ILW) Wastes exceeding the upper boundaries for LLW that do not generate sufficient heat for this to be taken into account in the design of waste storage or disposal facilities. The major components of ILW are metal items such as nuclear fuel casing and nuclear reactor components, graphite from reactor cores, and sludges from the treatment of radioactive liquid effluents. High Level Waste (HLW) Wastes in which the temperature may rise significantly as a result of their radioactivity, so this factor has to be taken into account in the design of waste storage or disposal facilities. Initially HLW comprises nitric acid solutions containing the waste products of reprocessing spent nuclear fuels. Monitoring of operational LLW for radioactivity 2

4 How is radioactive waste produced? The nuclear power industry is the source of most radioactive waste in the UK. This includes waste from:! Manufacture of nuclear fuel;! Nuclear power stations;! Reprocessing of spent nuclear fuel;! Research and development programmes. The UK has twelve operating nuclear power stations, and these generate about a fifth of the UK s electricity supply. Seven others, which have stopped producing electricity, are being dismantled, but so far only relatively small amounts of mainly LLW have been removed. Nearly all of the waste from research and development (R&D) into nuclear energy is a legacy of Government-funded programmes stretching back to the 1940s. The manufacture of nuclear fuels produces a relatively small amount of radioactive waste. Sources outside the nuclear power industry that contribute to radioactive waste in the UK include:! Defence activities;! Medical and industrial sources. Removing casing from spent fuel before reprocessing Much of the waste is from reprocessing spent nuclear fuels. Reprocessing now only takes place at Sellafield in Cumbria, where spent fuel from most of the UK s power stations, together with fuel from overseas reactors, undergoes chemical processes to recover uranium and plutonium. The main sources of defence waste are nuclear weapons production and operation of the nuclearpowered submarine flotilla. Smaller quantities arise from general use of radioactive materials within the armed forces and at defence establishments. The remaining waste results from the use of radioactivity in medical diagnosis and treatment, and in industrial applications such as thickness and density measurement and weld checking. Radioactivity in wastes from each activity Nuclear energy R&D 0.7% Spent fuel reprocessing 94% Nuclear power stations 5% Fuel manufacture <0.001% Medical and industrial <0.1% Defence 0.2% Nuclear power station at Sizewell 3

5 Where is radioactive waste produced? Spent fuel reprocessing Vulcan Dounreay Nuclear power reactors Nuclear energy R&D Defence Fuel fabrication & uranium enrichment Medical & industrial Rosyth Clyde Torness Hunterston The map shows the 37 sites of the major waste producers. Northern Ireland has no major waste producers. There are many hospitals and industrial, educational and research establishments that produce small quantities of radioactive wastes; their sites are not shown. About 86% of all radioactive wastes in the UK are produced in England, 10% in Scotland and 4% in Wales. In England the sites that produce the most waste are Sellafield and the nuclear power stations. In Scotland it is the nuclear power stations and Dounreay. In Wales it is the nuclear power stations. Chapelcross Windscale Sellafield Hartlepool Calder Hall Eskmeals Barrow Heysham Springfields Wylfa Capenhurst Trawsfynydd Derby Stafford Donnington The national LLW disposal site is located near the village of Drigg, four miles south of Sellafield. Cardiff Berkeley Oldbury Hinkley Point Winfrith Sizewell Bradwell Culham Amersham Harwell Aldermaston Fort Halstead Dungeness Portsmouth Devonport 4

6 How much radioactive waste is there? The total volume of radioactive waste that exists today and is forecast in the future is 2.3 million cubic metres. This volume is about the same as that of the Millenium Dome at Greenwich. The equivalent weight is 3.1 million tonnes. A further 1 million cubic metres of radioactive waste has already been produced and disposed of. Although 2.3 million cubic metres is a large volume of waste, it is only a small part of the waste the UK produces. The UK produces about 500 million cubic metres of waste every year: this includes about 5 million cubic metres of hazardous waste. About 95% (2.2 million cubic metres) of the radioactive waste total already exists. Some has been processed, and is being held in stores, but much of it is contained within nuclear reactors and other nuclear facilities and will not arise until these are shut down and dismantled. This waste is the legacy of past and current civil and military nuclear programmes. About 5% (100,000 cubic metres) of the radioactive waste total has yet to be produced. This waste is that forecast from the future planned operations of the nuclear power industry, from ongoing defence programmes and from the continued use of radioactivity for medical and industrial purposes. The assumptions supporting the forecast future waste volume are shown in the box opposite. Should these assumptions change, which they might for technical, commercial or policy reasons, the forecast volume would change. Should the use of radioactive materials stop tomorrow, this waste would not be produced. It is known that large volumes of land on some nuclear sites have become contaminated by leaks of radioactive liquids. Whilst most contaminated land has yet to be well characterised, the total volume of radioactive waste could add significantly to the figure of 2.3 million cubic metres. Total waste volumes Wastes from planned future operations 5% Existing wastes 95% Total volume 2.3 million cubic metres Nuclear facility dismantling and demolition Before Dismantling Demolition After 5

7 Assumptions for future waste production Nuclear power stations! Remaining operational power stations shut down over the period from 2006 to 2035! No new nuclear power stations are constructed! Main reactor structures left on site for about 100 years before final site clearance Spent fuel reprocessing! Fuel reprocessing continues until financial year 2012/13 Nuclear energy R&D! Joint European Torus fusion experiment shut down in 2006 Defence! A continuing nuclear defence capability to 2040! A continuing nuclear-powered submarine programme to 2100 Medical and industrial sources! The uses of radioactivity continue as today About 91% (2.1 million cubic metres) of radioactive waste falls into the LLW category. Of this volume, over 1.7 million cubic metres are from the dismantling and demolition of nuclear facilities and the clearance of contaminated ground at nuclear sites. About 9% (220,000 cubic metres) of radioactive waste is in the ILW category, and less than 0.1% (1,300 cubic metres) is in the HLW category. Although the volume of HLW is relatively small, it contains about 95% of all the radioactivity in radioactive wastes. LLW contains less than % of the total radioactivity. Clearing contaminated land Total waste volumes LLW 91% Total, cubic metres LLW 2,100,000 ILW 220,000 HLW 1,300 2,300,000 ILW 9% HLW 0.1% Total volume 2.3 million cubic metres 6

8 How is radioactive waste dealt with? How radioactive waste is dealt with depends on its radioactivity.! Most LLW is disposed of soon after it is produced to the national LLW disposal facility at Drigg in Cumbria;! ILW is stored in tanks, vaults and drums, with most waste requiring concrete to shield operators from the radiation;! HLW is stored as liquid in water-cooled, stainless steel tanks or as glass blocks, and needs thick concrete walls to shield operators from the high radiation. Many radioactive wastes are treated in some way soon after they arise to reduce their volume and so minimise the requirements for storage. Techniques include compaction and incineration (for solid wastes) and evaporation and filtration (for liquid wastes). Other radioactive wastes are stored untreated. A particular concern is historic wastes, largely created in the 1940s, 50s and 60s, held in old facilities. They are often poorly characterised. Some wastes were tipped into vaults and are corroding, whilst other wastes are stored in old corroding drums. Plans are being made to retrieve these wastes, although this will take many years. In time most radioactive wastes will be packaged. This immobilises the radioactivity, and so reduces the hazard the waste presents compared to its untreated or partly treated form. The process of packaging converts the waste into a solid and stable form, within high integrity stainless steel or concrete containers. LLW packages can, in most cases, be disposed at Drigg. Other packaged wastes are placed in purpose-built storage facilities and monitored. Number of waste packages being stored Number of packages HLW ILW LLW At 1 April ,466 - At 1 April ,633 17,027 - LLW Suitable LLW is first supercompacted to minimise its volume. In this process drums or boxes of waste are compacted under high pressure of up to 2,000 tonnes per square metre. The waste is placed in large metal containers, similar to shipping containers. These are then filled with cement and disposed in concrete-lined vaults at Drigg. At 1 April ,281 21, At 1 April ,037 31, LLW drum before supercompaction LLW drum after supercompaction 7

9 ILW For most ILW packaging consists of immobilisation in cement-based materials within 500 litre stainless steel drums. Large items are packaged in higher capacity stainless steel or concrete boxes. Wastes may first be treated to reduce their water content to an optimum level for packaging. Certain materials and small items of equipment can be supercompacted, while other solid wastes are cut up to reduce their size. There are a number of ILW packaging plants operating at Sellafield. These plants are packaging a variety of solid and sludge wastes from spent fuel reprocessing. ILW packaging plants are also operating at Dounreay, Harwell, Windscale and Trawsfynydd. Further packaging plants are being built and planned. Cutaway showing simulated immobilised ILW in a stainless steel container. The container is about 0.8 metres in diameter and 1.2 meters high and holds about 500 litres To date about 16,000 cubic metres of ILW have been packaged and placed in modern engineered stores (see page 10). Nirex sets standards and specifications so as to advise the waste producers on the packaging of ILW. HLW At Sellafield high level liquid waste is being converted into borosilicate glass, using a process called vitrification. It is heated to dryness leaving a fine powder, which is mixed with crushed glass in a furnace to produce a molten product incorporating the waste. This is then poured into stainless steel canisters, which hold approximately 150 litres, and a stainless steel lid is welded on. Fresh waste from reprocessing is blended with existing stored liquid waste and vitrified to an agreed programme imposed by the Health and Safety Executive. To date about 460 cubic metres of vitrified HLW have been produced and placed in a modern, engineered air-cooled store (see page 10). Cutaway showing simulated vitrified HLW in stainless steel container. The container is about 0.4 metres in diameter and 1.3 metres high and holds about 150 litres 8

10 What is the long-term waste management solution? Past Government policies on radioactive waste management have been to:! Dispose of LLW in near-surface facilities;! Develop an ILW repository deep underground;! Store HLW for 50 years. However, these policies are now under review (see below). While the UK has a disposal facility for LLW at Drigg, no facilities for disposing of ILW or HLW have been developed. LLW Since 1959 about 1 million cubic metres of LLW from the nuclear power industry, hospitals, industrial establishments and the defence programmes have been disposed at Drigg. Also, a much smaller volume of LLW has been disposed at Dounreay in the past. Drigg has capacity for a further 800,000 cubic metres, which is well below the forecast volume of LLW that must be dealt with in the future. Drigg will probably be filled by the middle of this century, and either a replacement facility or alternative means of dealing with LLW will need to be found. ILW and HLW remain a potential hazard for thousands of years. The challenge in managing these wastes is to isolate their radioactivity from people and the environment for this length of time. Although there is a broad scientific consensus in favour of some form of disposal deep underground, there remains significant public concern about this option. The present review of Government policies on radioactive waste management involves a programme of research and public consultation that will lead to the development of a long-term strategy for radioactive waste in the UK. The Nuclear Decommissioning Authority (NDA) was established by Government in April 2005 to manage the civil nuclear liabilities in the UK. In their draft strategy document for consultation the NDA states its need to address urgently untreated wastes in ageing facilities at its sites. It fully intends to package all types of waste in accordance with regulatory requirements. A Government review of LLW strategy is underway. Filling LLW disposal containers with cement at Drigg. Each container is about 6 metres by 2.4 metres by 1.2 metres high Drigg LLW disposal site 9

11 ILW All ILW has been stored since it was created, except for a small amount disposed of at sea before In 1997 planning permission for an underground test laboratory near Sellafield was refused. The laboratory was to have investigated the suitability of the geology, and was regarded as an essential first step before the construction of a deep disposal facility for ILW. This decision has led to a fresh look at radioactive waste management policy in the UK, which started with the publication in 2001 of a Government consultation paper entitled Managing Radioactive Waste Safely. The Committee on Radioactive Waste Management (CoRWM) has been appointed to recommend the best technical long-term solution that will inspire public confidence. CoRWM will make its recommendations in Store for packaged ILW drums HLW Current Government policy is that vitrified HLW should be stored for at least 50 years to allow the heat it produces to fall. This makes long-term management less complex. CoRWM has in its remit to consider long-term solutions for HLW as well as for ILW. Not all radioactive materials are classified as waste. Examples are uranium, plutonium and spent nuclear fuel. These materials have potential value. Uranium and plutonium can be used to make nuclear fuel, and spent nuclear fuel can be reprocessed to recover uranium and plutonium for reuse. In the future some or all of these materials might be declared surplus to requirements, and so would need to be managed as wastes. Store for packaged HLW canisters CoRWM has in its remit the consideration of materials like uranium, plutonium and spent fuel as potential wastes for which long-term solutions may be needed. 10

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