Select Committee on Science and Technology Third Report



4.1 In this chapter we examine the present United Kingdom policy for the management of nuclear waste, looking first at intermediate and high level waste and then the issues raised by low and very low level waste. We continue with an examination of the technical aspects of the courses of action which focus on geological disposal, then move on to indefinite storage. The organisational changes that are required to implement strategies effectively are discussed in Chapter 6, after consideration of public acceptance in Chapter 5.


4.2 Since the early 1980s, when the decision was taken to focus R&D on disposal of ILW rather than on disposal of HLW, the United Kingdom approach to the long-term management of long-lived wastes has become increasingly fragmented. There are now several types of long-lived wastes, and materials which may be declared to be wastes, for which no long-term management option has been proposed or examined in detail. These wastes and materials include submarine reactor compartments, spent submarine fuel, spent PWR fuel, depleted uranium, surplus plutonium and reactor Stage 3 decommissioning wastes (see Chapter 2). There is a consensus amongst regulators, the nuclear industry, and groups such as Greenpeace and Friends of the Earth that this situation is not satisfactory. The general feeling is that a more integrated approach is needed (see Chapter 3) in which long-term management methods are identified and implemented for all wastes, and decisions are taken on the fate of all other materials held in store.

4.3 An integrated approach is required particularly if geological disposal is to be adopted, and this goes beyond the need to consider 'co-disposal' of ILW and vitrified HLW. The DETR project on a research strategy for HLW and spent fuel disposal is highlighting the necessity to be clear about the wastes which a repository is to be capable of holding before planning a research and development programme[23]. It follows that any new search for potential deep repository sites should be carried out bearing in mind all long-lived wastes and materials that may be declared wastes. Ideally decisions would be made in the near future as to which materials are wastes. This is particularly the case for plutonium because, for reasons connected with criticality risks, its inclusion as a waste would have a significant effect on repository size and design (see also Chapter 7).

4.4 At present it is not clear whether it would be feasible to find a site for one repository which is physically large enough and has sufficient radiological capacity to take everything. QuantiSci have estimated that a vitrified HLW and spent fuel repository could be several times larger than the proposed Nirex ILW repository[24]. This implies that a single repository for all long-lived wastes would require a considerable volume of rock with the appropriate physical and chemical characteristics. It may be that it is only after site investigations that a decision can be taken on whether there should be one deep repository or two. This would have to be declared at the start of a site selection process (see Chapter 6). Similar problems of siting could occur if a strategy of indefinite storage were adopted.

4.5 The United Kingdom inventory of radioactive wastes (see Chapter 1) would be much more valuable as a tool for development of an integrated strategy if it included all the materials which may be declared to be wastes. The current convention of excluding materials such as plutonium, depleted uranium, and spent fuel for which there are no definite plans for reprocessing, can lead to gaps and inconsistencies in national planning for waste storage and disposal.

Reactor decommissioning wastes

4.6 While BNFL Sellafield has adopted a policy of using purpose built stores, British Energy and the Magnox stations (now owned by BNFL) intend to store some wastes in the 'safestore' structures which they plan to erect to enclose their nuclear plants after the initial stages of decommissioning (Q 752). The intention is that these structures will be in place for over a century, while radioactivity levels in the plants decay. They will then be opened, wastes will be retrieved and plants dismantled, and the sites will be completely cleared. This safestore strategy implies that a substantial volume of wastes will not be in a form which is suitable for emplacement in a deep repository until the beginning of the century after next. It would be necessary to examine the safestore, and other decommissioning strategies, because of their influence on any new repository development programme, and to adjust the strategies, or the programme, so that there are no inconsistencies in timing.

Nuclear powered submarines and their spent fuel

4.7 RWMAC and NuSAC have called for all civil and defence waste to be dealt with in a single coherent manner (p 261, QQ 737-738). Much of MoD's waste is subject to civilian regulation and it is relatively straightforward to bring it into an integrated national strategy. This is not true of decommissioned nuclear powered submarines, which are at present stored afloat, nor of the spent submarine fuel which is currently in store at Sellafield and which may be declared to be waste (see Chapter 2). MoD appears to have no firm plans for the long-term management of the submarines and their spent fuel: their present policy is to continue current storage arrangements for decades and review the situation at intervals. This carries the risk that at some unknown date in the future MoD will request space in a store or repository for civilian wastes, when such space cannot be made available. It is essential that this is avoided. The long-term management of submarines and their spent fuel should be considered fully in the development of an integrated national strategy and MoD policy brought into line with this strategy.

Short-lived ILW

4.8 There is also the question of how short-lived intermediate level wastes should be managed. When Nirex was set up it was intended that these wastes would be disposed of in a near-surface engineered facility, as is done in France, Spain and Japan, for example (see Chapter 1). Some witnesses said that the later decision that short-lived wastes should be placed in the proposed deep repository seems to have been taken hurriedly, and for pragmatic rather than strategic reasons (eg Q1017). There is now some support, particularly from HSE and from smaller users of radioactive materials, for a return to the idea of a near-surface disposal facility for short-lived ILW (p 160, p 235, QQ 703-706).

4.9 Nycomed Amersham (a supplier of radiochemicals for use in medicine, biotechnology and other industries) said that there was a good case for building a surface decay store for short-lived ILW from 'small users'. This would provide a safe, cost effective and more easily manageable alternative to deep disposal. The company said that it would then only have to send about one to three percent of its radioactive waste for long-term storage or deep disposal; almost all of the other wastes would decay to background levels in under 50 years (p 234). Nycomed Amersham suggested using an existing waste disposal site (i.e. Drigg or Dounreay) for the short-lived ILW store. Another witness suggested that unused civil defence bunkers, which already had radiation shielding, could be used (p 279).

4.10 BNFL point out that the volumes of their short-lived wastes are small compared to those of long-lived wastes, so it is not worthwhile to develop a separate disposal facility for them (QQ 124-126). One problem in advocating different treatment for short-lived ILW would be the need to segregate it from other wastes. This would also require the waste to be given a new classification based on the half-life.

4.11 Nycomed Amersham (p 234), the Joint Trade Unions (p 190), Sir John Knill (p 198), NuSAC (p 156), HSE (p 160, Q 703) and British Energy (p 28) all called for waste to be reclassified in terms of half life, activity level and other radiological characteristics. This is something that RWMAC also said was worth developing after a preliminary study which it described in its 17th Annual Report (July 1997). British Energy agreed and told us that it would prefer a classification of waste on the basis of radiotoxicity, which would move the emphasis to a biological approach (QQ 768-770). However, BNFL was unsure of what benefits this would bring: if the aim was to allow short-lived ILW to be disposed of at Drigg then all this required was a new authorisation for the site (Q 125). The Joint Trade Unions noted that if Drigg were to take short-lived ILW then a new near surface repository would be required sooner than currently anticipated because Drigg would fill up faster (p 190).

4.12 We consider that it would be impractical for large waste producers to separate out old wastes (in particular those which have already been conditioned) and for them segregation of short-lived ILW from long-lived ILW would have few advantages. However, for small users who only (or mainly) produce short-lived ILW segregation could be simple and might also bring commercial advantages. These small users should commission a study of the options for management of their short-lived ILW, including the provision of a national decay store (from which wastes would be transferred to a LLW disposal facility when their activity had decayed sufficiently), and the direct disposal of their short-lived ILW to Drigg. They would then be in a position to make a formal proposal to regulators and Government.



4.13 There is currently only one major designated facility for disposal of LLW in the United Kingdom. This is the Drigg facility which is close to Sellafield and is owned and operated by BNFL. In the past there has been some disposal of LLW to a facility at Dounreay but the future of this is under review[25].

4.14 We were told when we visited Drigg that its "radiological capacity" will be exhausted by about 2050, i.e. that by then it will not be possible to emplace anymore LLW at the site because of its potential long term radiological impact, although there could well be the physical space to do so. HSE also said that Drigg could close in the period 2030-2050 (p 160). As can be seen from Chapter 2, large volumes of LLW will arise after 2060, when present nuclear power stations are fully dismantled. There could be about 2 million cubic metres of LLW requiring disposal at this time (see Figure 2). It is therefore clear that one or more new disposal facilities for LLW will be needed when Drigg closes.

4.15 At present much of Drigg's capacity is reserved for LLW from Sellafield. There could be advantages in establishing a new disposal facility well before Drigg closes, to take waste from sites other than Sellafield. British Energy have waste which cannot be disposed of at Drigg under the present authorisation and operating regime, but which could be disposed of safely as LLW (p 25). MoD are concerned about wastes which could arise from remediation of contaminated land. They are unable to estimate the volumes of such waste (P 343) and some of it has radioactive and chemical (non-radioactive) contamination (Q 321). The problems associated with waste disposal can strongly influence priorities for land remediation and sale (Q 321).

4.16 As HSE point out (p 160), a new disposal facility for LLW might well encounter some of the public acceptance difficulties associated with a deep repository. These difficulties might be reduced if the site selection process for a LLW facility was subsequent to that for a deep repository. This approach could still lead to the facility being operational before Drigg closes, and help to avoid the consignment of LLW to a deep repository by default, which would be inefficient and costly.

Very Low Level Waste

4.17 In principle the less radioactive LLW, including that which is technically defined as very low level waste (VLLW)[26], can be disposed of to landfills. Nuclear industry use of this disposal route has declined in recent years, although it is still employed to some extent, and it is employed by many organisations outside the nuclear industry (e.g. hospitals, the mineral sands industry). In the 1995 review of radioactive waste management the Government decided not to encourage greater use of this disposal route because of opposition from local authorities, environmental groups and members of the public[27]. We heard from local authorities that there continues to be strong opposition to disposal of nuclear industry LLW to landfills (see, for example, the National Steering Committee of Nuclear Free Local Authorities, p 222, Manchester City Council, p 201, West Dunbartonshire Council, PP 402-403). MoD said that the reluctance of local authorities to sanction landfill disposals of VLLW left them without a nationally approved disposal route for this waste, and that they are considering ways to solve this problem (Q 320).

4.18 We did not receive any evidence on alternatives to landfill disposal, nor have we considered this issue in detail. However, we recommend that the Government does so, in order to produce a national policy that is accepted by local authorities, landfill operators, the nuclear industry, and all those who currently use landfill disposal, rather than leaving matters almost entirely to local negotiations.

23   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

24   RWMAC, The Radioactive Waste Management Committee's Advice on The Interim Report of the High Level Waste and Spent Fuel Disposal Research Project, November 1998. Back

25   HSE and SEPA, Safety Audit of Dounreay, 1998. Back

26   Very low level waste has an activity level below 4 Bq/g. Back

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

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