Select Committee on Science and Technology Third Report

PART A: the present situation



2.1 The development of methods for the long-term management of radioactive waste is a necessity in all countries which have had nuclear programmes (see Table 1). The scale of the problem, in terms of volume, radioactive content and diversity of physical and chemical forms of the waste, depends on the size of the country's civil and defence nuclear progammes. The problems are greatest in countries which have now, or had in the past, a substantial civil programme and a substantial defence programme. These countries are the US, the former Soviet Union, France and the United Kingdom. In all these countries one important component of the problem is the waste which already exists, especially that arising from plants designed and processes carried out in the 1940s, 1950s, 1960s and early 1970s, when much less attention was paid to long-term waste management than in more recent times. A second important component is 'committed' waste, that is the waste which is bound to arise from the operation or decommissioning of plants which are operating now (and that which is expected to arise from plants which are under construction or for which there is a commitment to start construction).

2.2 This legacy of waste—existing and committed—is very much greater than any current projections of wastes from future nuclear programmes. It has to be dealt with, whether there are future nuclear programmes or not.

Table 1  Nuclear Share of Electricity Generation (as of March 1998)
CountryPercentage of electricity generated by nuclear power stations
Slovak Republic
Republic of Korea
United Kingdom
United States
Czech Republic
Russian Federation
South Africa

Source: From IAEA Bulletin 40/3/1998.


2.3 The United Kingdom maintains an 'inventory' of existing and projected future radioactive wastes. This is a database of information on waste volumes, radioactive contents and physical and chemical characteristics. It is updated regularly (approximately every three years) and is compiled by contractors for both UK Nirex Ltd and the Department of Environment, Transport and the Regions (DETR). The latest version of the inventory was issued in 1996 and refers to wastes existing and projected to arise on the basis of information available in 1994.

2.4 The United Kingdom inventory includes all civil nuclear power and defence wastes, plus wastes which arise from other sources, for example the production and use of radioactive materials in research, health care and non-nuclear industries. It does not include some materials which are held in store, for example plutonium, uranium and some unreprocessed spent fuel. These are considered to be a resource now, but may be declared to be waste in future. Some of them are fissile and their inclusion in the inventory could increase significantly the quantities of waste requiring long-term management. We discuss these materials in Chapters 4 and 7.

2.5 For the purposes of the inventory, and for general description, wastes are divided into three categories according to the concentrations of radioactive materials in them and the way they arise: high level, intermediate level and low level.

2.6 High level waste (HLW) has the greatest concentration of radioactive materials and produces substantial quantities of heat. It arises mainly as a nitric acid solution containing fission products separated from irradiated nuclear fuel during reprocessing. This solution will be 'vitrified' (ie converted into a borosilicate glass) and this process is already in operation. If unreprocessed spent fuel and plutonium were declared to be waste, they would also be classified as high level waste.

2.7 Intermediate level waste (ILW) is less radioactive. It consists primarily of metals, with smaller quantities of cement, graphite, organic materials and inorganic sludges. Most of these arise from dismantling and reprocessing of spent fuel, including treatment of effluents prior to discharge into the environment, and from general operations and maintenance of radioactive plant. ILW (for example, contaminated and activated metals) will also be produced when nuclear plants are dismantled.

2.8 Low level waste (LLW) is the least radioactive. Most of the LLW produced by the nuclear industry at present is metals and organic materials, which arise largely as lightly contaminated miscellaneous scrap. The metals are mostly in the form of redundant equipment; the organic materials are mostly discarded protective clothing, paper towels and plastic wrappings. When nuclear plants are decommissioned there will be large volumes of LLW consisting of building materials and big items of plant and equipment. Most of the radioactive waste produced outside the nuclear industry is LLW. This includes small volumes of waste arising at hospitals and research establishments (eg contaminated glassware and plastic containers). There are also rather larger volumes of waste from industries that deal with materials that are naturally radioactive (eg phospates used in the manufacture of fertilisers and detergents, zircon sands used in making abrasives and refractories, sludges and scales from the off-shore production of oil and gas). Some of this waste is formally defined as "very low level" (ie it has an activity level less than 4 Becquerels per gram) and much of it is disposed of to landfills.

2.9 The term 'conditioning' is used to mean any process by which raw waste is treated prior to disposal or long-term storage. For liquid HLW the chosen conditioning process is vitrification. For most ILW, conditioning consists of immobilisation in cement-based materials, in steel drums. Most LLW is compacted to reduce its volume, and in recent years LLW has been 'supercompacted': drums of raw waste are compacted under high pressure to form 'pucks' which are then loaded into large metal containers and concreted in place.

2.10 Figure 1 shows the volumes of existing and committed United Kingdom HLW, ILW and LLW given in the 1994 inventory (issued in 1996) and the volumes of these wastes which were forecast to arise ('uncommitted'). The total volume in stock in April 1994 was 71,000 cubic metres, of which 2.3 per cent was HLW, 86.6 per cent ILW and 11.1 per cent LLW. Although LLW is produced in the largest quantities most of it is disposed of (to Drigg[6]) soon after it arises, hence the relatively low volume in stock. The uncommitted waste arisings shown in Figure 1 are based on the following scenario:

    ·  a national future nuclear power programme with pressurised water reactors (PWRs), but without reprocessing of spent PWR fuel,

    ·  some future fuel manufacture for existing power stations beyond that already committed, and

    ·  operation of THORP beyond its first ten years (ie beyond 2003).

2.11 As can be seen from the figure, the estimates of total volumes of waste predicted to arise are not very sensitive to the assumptions in this scenario. Of the total volumes, in stock and predicted arisings, 65 per cent of HLW, 88 per cent of ILW and 96 per cent of LLW are committed. (The effects on waste volumes of differing assumptions about reprocessing are discussed in Chapter 7.) On the basis of 1994 inventory information, the cumulative volume of all waste in stock and predicted to arise is 2.2 million cubic metres. Most of this is LLW (see Figure 1) and about 90 per cent of this LLW will arise when present nuclear plants are fully dismantled (see Figure 2).

2.12 Although it has the lowest volume, HLW has the highest radioactive content. The total radioactive content of all waste in stock in April 1994 was 40 million terabecquerels.[7] 90 per cent of this was in the HLW and virtually all the rest in the ILW. During about the first thousand years after production of the HLW its activity falls by a factor of about one thousand as the shorter-lived radionuclides decay (particularly caesium-137 and strontium-90, which have radioactive half-lives of about 30 years). Over about the next ten thousand years the activity of the HLW decreases by about another factor of ten, as americium-241 (half-life about 430 years) decays. After this the activity of HLW decreases more slowly until around three million years, when the quantities of radionuclides such as neptunium-237 (half-life 2.1 million years) and caesium-135 (half-life 2.3 million years) begin to fall substantially.

2.13 When it is first produced HLW emits substantial amounts of heat. As its activity decreases so does its heat output. By about fifty years after the fuel was reprocessed vitrified liquid HLW should be sufficiently cool for it to be placed in a geological repository without excessive temperature rise of the rock.[8]

2.14 As the activity and heat output of HLW decreases it becomes less hazardous. After two or three thousand years the radiotoxicity of HLW is less than that of the uranium ore from which it was derived. Uranium ore is itself hazardous and HLW does not become innocuous when its radiotoxicity falls below that of ore. Safety assessments of HLW disposal (see, for example, the European PAGIS study[9]) indicate that potential risks to humans may still be significant for hundreds of thousands of years.

2.15 For the purpose of description, ILW is often divided into two categories: short-lived and long-lived. The activity of short-lived ILW is dominated by radionuclides such as caesium-137 and strontium-90, so it falls to very low levels within a few hundred years. Ion exchange materials that are used for treatment of liquid effluents are one example of short-lived ILW. In long-lived ILW there are substantial quantities of radionuclides such as plutonium-239 (half-life 24,000 years), americium-241 and its daughter product neptunium-237 (half-life 2.1 million years), or fission and activation products such as technetium-99 (half-life 210,000 years) and chlorine-36 (half-life 300,000 years). Assessments carried out by UK Nirex Ltd show that long-lived ILW could still give rise to significant risks to humans at times longer than one hundred thousand years after its disposal (see, for example, Figure 4.6 in the POST Report1).

2.16 Although the radiotoxicity of waste constituents is the main concern, some of them are also chemically harmful to humans and other organisms. For example, most of the heavy metals are chemically toxic if sufficient quantities are ingested or inhaled. In a few cases, for example depleted uranium, chemical toxicity is of equal or greater concern than radiotoxicity[10].


2.17 Most HLW arises and is stored at BNFL's Sellafield site; the remainder is at UKAEA's Dounreay site. Most of the HLW is still in liquid form (see 2.6). At Sellafield the vitrification plant began operation in 1996. The canisters of vitrified HLW are kept in a purpose built store (the 'Vitrified Product Store', VPS), which has passive cooling and a back-up forced cooling system. The liquid HLW is stored in cooled tanks. In mid-1998 the VPS contained some 1,600 canisters of HLW and BNFL estimated that it would take until about 2015 to vitrify all the liquid HLW in stock. At Dounreay all the HLW is in liquid form but its volume has been reduced through a process of evaporation. Conversion of this into solid form will not start for some years.

2.18 Around 65 per cent of ILW is currently held at Sellafield (p 175). Much of this is still in raw form but a number of plants are operating, or are planned, to condition this waste. The main conditioning plants, with the dates at which they did or will start operating, and the wastes which they deal with, are:

    ·  the Magnox Encapsulation Plant (1990, for Magnox cladding);

    ·  the Waste Encapsulation Plant (1994, for THORP wastes and retrieved solids/sludges);

    ·  the Waste Packaging and Encapsulation Plant (1994, for flocs and sludges);

    ·  the Waste Treatment Plant (1996 for plutonium contaminated material) and

    ·  the Drypac plant (2003, for swarf, sludge and miscellaneous beta/gamma waste).

At Sellafield there are several stores in use and planned to hold the conditioned waste, all of which meet modern safety standards. The stores have design lives of the order of 50 years and BNFL estimate that they could continue to be used safely for 80-100 years (QQ 81, 83-87).

2.19 The remaining ILW is held at various nuclear sites. Much of it is held at nine licensed Magnox power stations, at Dounreay and Harwell, and at Aldermaston (see pp 177-179). Again, most of this waste is in raw form and will need to be conditioned. Waste stores, with design lives of several decades or more, are in operation, under construction or planned at several sites, including Dounreay, Harwell, Winfrith and Rosyth. At the Magnox and advanced gas-cooled reactor (AGR) power stations the preferred strategy is not to build new stores for conditioned wastes. Instead the aim is to place such wastes in the 'safestores' which BNFL (at the former Magnox Electric sites) and British Energy (Nuclear Electric and Scottish Nuclear) plan to build around the reactor and other major buildings when they are decommissioned (Q 752). The safestores would also hold wastes arising from clearance of peripheral plant and buildings. The safestores would remain in place for about 130 years, to allow radioactive decay, then all wastes would be removed and disposed of, and the buildings demolished.

2.20 The only LLW which is stored is that which cannot be disposed of to Drigg (because of its volume, alpha activity or chemical composition). Most of this is at Sellafield but there are small amounts elsewhere (for example at Aldermaston).

2.21 Towards the end of our enquiry the Health and Safety Executive (HSE) published a report that reviews ILW storage in the United Kingdom[11]. The review, carried out by the Nuclear Installations Inspectorate of HSE, confirms the evidence previously given to us that a delay in providing a repository will not cause immediate safety problems for ILW storage. It also concludes that up to 20 modern ILW stores will be required for wastes currently accumulated on major nuclear licensed sites if an operating repository is not available within the next 15-20 years, and that a delay of more than 50 years will require a further costly and difficult programme of store replacements or extensive refurbishments, possibly with the repackaging of wastes.

2.22 The reactor compartments of decommissioned nuclear-powered submarines are a particular type of ILW. At present 11 defuelled submarines are being stored afloat; seven of these are at Devonport and four at Rosyth. By the year 2020 there will be about 20 defuelled submarines to store and this could rise to 50 by 2050. The storage capacity at Devonport will be full by 2016 (Q 352). The spent fuel from submarines is being stored in purpose built ponds at Sellafield, where a new pond is under construction to hold future arisings. This spent fuel has not been declared to be waste because MoD intend to have it reprocessed. RWMAC has raised doubts as to whether it will be technically feasible to reprocess submarine fuel in current plants at Sellafield and has suggested that the fuel may have to be disposed of with other HLW (p 261). For reasons of national security there are no published estimates of the volume or activity content of this fuel but the Ministry of Defence (MoD) have told us that there are at present 51 used submarine reactor fuel cores in store at Sellafield.

Uranium and Plutonium

2.23 In a report published in 1996, AEA Technology estimated that there will be 75,000 tonnes of uranium in stock by the year 2010[12]. This includes irradiated uranium separated during reprocessing, and depleted uranium produced in fuel fabrication. None of this uranium is included in the United Kingdom inventory because it is not yet considered to be waste. The corresponding quantity of separated civil plutonium is expected to be about 100 tonnes.[13] More recently, in a study for DETR, QuantiSci estimated that there could eventually be 100,000 tonnes of uranium and 150 tonnes of plutonium in store.[14]

2.24 The United Kingdom military stocks of uranium and plutonium were announced in the recent Strategic Defence Review (Cm 3999, July 1998). Various amounts of surplus fissile material were also declared. These surpluses will be placed under EURATOM safeguards and will be made subject to inspections by the International Atomic Energy Agency (IAEA) of the United Nations.

2.25 There are also other materials in store, or which may arise in the future, that contain uranium and plutonium and which may in due course be declared to be waste. These include the spent fuel from the Sizewell B PWR, for which no reprocessing contract has yet been signed, and small amounts of fuel from other reactors which does not meet the specifications for reprocessing in current plant.[15]


2.26 It can be seen from the above that the volumes of long-lived waste which exist now, and which will be generated by the present nuclear power programme if reactors continue to operate until the end of their useful lives, are substantial. Closing all existing reactors over the next few years would have little effect on these volumes, nor would the construction of a small number of new reactors. Decisions about the future civil nuclear programme will have little effect on waste volumes and, in this sense, are not strongly linked to the choice of long-term waste management option. The same is true of the future defence programme. This is not to say that there is no link between long-term waste management and future nuclear programmes: as we shall see in Chapter 5 there certainly is a link in terms of the attitudes of some sections of society. The situation for reprocessing, of United Kingdom and of foreign spent fuel, is discussed in Chapter 7.

History of Waste Management in the UK

2.27 The first major Government review of nuclear waste management in the United Kingdom was carried out in the late 1950s and its results published in 1959 in Command Paper 884, The Control of Radioactive Wastes. The next review did not take place until the 1970s, when the Royal Commission on Environmental Pollution issued its sixth report Nuclear Power and the Environment (Command Paper 6618, the "Flowers Report", published in 1976). The following summary of events since then starts with the Government's response to the Flowers Report.


As part of its response to the Flowers report, the Government made the Department of the Environment responsible for radioactive waste management policy (Command Paper 6820). It also increased research into the disposal of HLW and recognised the need for a national disposal facility for ILW. In 1978, it established the Radioactive Waste Management Advisory Committee (RWMAC) and in 1979 published an expert report reviewing Cmnd 884.

As part of the research on HLW disposal, the drilling of boreholes began at a site in Scotland (Altnabreac) in 1979 and later at Harwell in Oxfordshire. The aim of these and planned drilling programmes at other sites was to investigate the properties of various types of rock. The research drilling programme was discontinued in 1981, as a result of public opposition.


In 1982 the Government published another White Paper on radioactive waste management. This established the Nuclear Industry Radioactive Waste Executive (NIREX), which later became United Kingdom Nirex Limited (shortened to Nirex). The remit of Nirex was mainly to construct and operate new land disposal facilities for LLW and ILW, but it was also to run the annual sea dumping operation for LLW and some ILW. The Government stated that it was envisaged that HLW would be stored for about 50 years.

Sea dumping was halted in 1983 when the meeting of the international London Dumping Convention passed a non-binding resolution intended to establish a moratorium on sea dumping. Three international reviews of sea dumping of radioactive wastes were carried out, none of which precluded further dumping but all of which implied changes to dumping practices. In 1985 the London Convention meeting extended the moratorium on dumping indefinitely.

In 1983, Nirex announced its initial choice of potential new land disposal sites: a clay site at Elstow (owned by the Central Electricity Generating Board) for a near-surface facility for LLW and short-lived ILW, and a disused anhydrite mine at Billingham (owned by ICI) for long-lived ILW. There was a great deal of local opposition at Billingham and ICI became unwilling to allow the site to be investigated. In 1984 the Government announced that Nirex would be required to investigate at least three possible sites for a new near-surface facility and at least three sites for a deep repository, excluding Billingham. In 1986 Nirex announced that they wished to investigate four sites for the near-surface facility: Killingholme, Fulbeck, Bradwell and Elstow. Special Development Orders were made for geological investigations at these sites.

In 1986 the House of Commons Environment Committee published a report on radioactive waste.[16] The Government issued its response (Cmnd 9852), which stated that only LLW would be placed in the Nirex near-surface facility, and which reaffirmed the policy of storing HLW for 50 years.


The Government and Nirex decided in 1987 that the investigations at the four potential sites for a near-surface facility should cease, and that both LLW and ILW should be disposed of in a deep repository. The reason given was economic. After publication of a discussion document, responses to it, and a preliminary safety assessment report, Nirex announced in 1989 its intention to investigate Sellafield and Dounreay as potential sites for the repository. Drilling began at both sites and in 1991 the decision was made to focus on Sellafield. In the White Paper This Common Inheritance (Cm 1200, published in 1990) the Government confirmed the choice of disposal in a deep repository as the long-term management option for ILW.

During this period the United Kingdom ceased its research programme on the disposal of HLW beneath (and on) the bed of the deep ocean. The Government also stated that there would be no resumption of sea dumping of ILW and LLW but the option would be kept open for disposal of large items of waste from decommissioning of nuclear plant. 1992-1996

In 1992 Nirex stated its intention to construct a Rock Characterisation Facility (RCF) at Sellafield. Its timetable was to submit the planning application for the RCF in 1993 and then the planning application for the repository in 1998. Nirex hoped that the repository would be operational by 2007. The RCF planning application was eventually submitted in 1994, following delays in gaining approvals to drill more boreholes. The target date for repository operation was stated to be 2010. The application was called in and the Public Inquiry into the RCF was held in 1995-96.

A Government review of radioactive waste management policy was carried out, in parallel with a commercial and economic review of nuclear power in the United Kingdom. The conclusions of this review were published in 1995 as Cm 2919. They were that the policy for radioactive waste management should be, and is, based on sustainable development. Disposal was favoured over indefinite storage and it was concluded that there was no advantage in delaying the development of a repository for ILW. The Department of the Environment was to carry out work on a research strategy for HLW.


In March 1997 the Secretary of State completed his consideration of the Inspector's report on the Public Inquiry into the RCF at Sellafield.

In his report the Inspector recommended that the planning application be refused. He put forward two types of reason: one type concerned straightforward planning matters, which might apply to any type of development; the other type was particular to the RCF and to the repository which might have followed it. The straightforward planning matters included the adverse visual impact of the above ground RCF buildings and spoil heaps, criticisms of road traffic and parking plans, and possible harm to the habitat of a badger clan. The main particular reason was that the proposal to build the RCF was premature. More needed to be known about the hydrogeology and geology of the site before disturbing the rock and groundwater conditions by sinking the shaft for the RCF. Also, the location of the RCF had not been shown to be the best one from the point of view of the location of the repository, and the 'potential repository zone' might be damaged by constructing the RCF.

Underlying these particular reasons were concerns about the process by which the Sellafield site had been selected and about the suitability of the site itself. The Inspector concluded that the site had not been selected in an objective and methodical manner. His Technical Assessor was of the view that the site was more geologically and hydrogeologically complex than would be expected of a choice based principally on scientific and technical grounds. He pointed out that while the preliminary safety case for a repository at the site was certainly not a patent failure, nor were its results so clearly within targets as to command any substantial degree of confidence.

The Secretary of State decided that Nirex should not be allowed to construct the RCF at Sellafield, citing in his letter to Nirex both straightforward planning matters and reasons particular to the RCF. His decision, the Public Inquiry and the events leading up to it hold lessons for the future of nuclear waste management in the United Kingdom which we will address later in this report.

The DETR project to develop a research strategy for HLW disposal began in the spring of 1997. An interim report on the project was issued in 1998. This dealt with work during the first stage of the project: a review of past and present national and international R&D and identification of a potential HLW repository development strategy, in terms of a series of key milestones and the questions that must be answered to achieve these milestones.[17] In the summer of 1997 the Government announced that it accepted the London Dumping Convention moratorium on sea dumping: the United Kingdom would not seek to use this method for disposal of any solid radioactive waste. In November 1997 the Parliamentary Office of Science and Technology (POST) published its report Radioactive Waste—Where Next?

Events during 1998, the period of our enquiry, are discussed throughout the remainder of this report.

6   The 110 acre low level waste disposal site in West Cumbria, owned and operated by BNFL. Back

7   See glossary for explanation of terabecquerels and other units. Back

8   Review of Radioactive Waste Management Policy, Final Conclusions. Command Paper (Cm) 2919, 1995. Back

9   Commission of the European Communities, PAGIS, Performance Assessment of Geological Isolation Systems for Radioactive Waste, report EUR 11775, 1988. Back

10   WHO, Guidelines for drinking water quality, 2nd Edition, Volume 1, Recommendations, 1993. Back

11   Health and Safety Executive Nuclear Safety Directorate, Intermediate Level Radioactive Waste Storage in the UK: A Review by HM Nuclear Installations Inspectorate, November 1998. Back

12   R. Cummings, R P Bush et al, An assessment of partition and transmutation against UK requirements for radioactive waste management. Report DoE/RAS/96.007 for the UK Department of the Environment, 1996. See also QQ 1141-1211. Back

13   The Royal Society: Management of Separated Plutonium, February 1998. Back

14   QuantiSci, High-Level Waste and Spent Fuel Disposal Research Strategy: Project Status at the Half-Way Point, report DETR/RAS/98.006, May 1998. Back

15   ibidBack

16   Radioactive Waste, House of Commons Environment Committee, First Report 1985-86, HC 191 Back

17   QuantiSci, High-Level Waste and Spent Fuel Disposal Research Strategy: Project Status at the Half-Way Point, report DETR/RAS/98.006, May 1998. Back

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