D. JACKS ON, A. BAKER, R. GEORGE and S. MOB BS, Eden Nuclear and Environment Ltd, UK

DOI: 10.1533/9780857097446.2.509

Abstract: The United Kingdom has a long history of nuclear development. Waste management principles and strategies have evolved over this period, together with technical developments allowing modified waste management regimes. High and intermediate level wastes reflect both current arisings and legacy wastes, with disposal and storage options being explored and implemented. In recent years, low level waste strategy has been further clarified to expand options available for safe and cost-effective disposal. Challenges with respect to contaminated land and delicensing of decommissioning sites are recognised.

Devolution of waste management responsibilities within the UK is leading to some divergence in national policies, particularly with respect to higher activity wastes.

Key words: Nuclear Decommissioning Agency (NDA), Magnox, advanced gas-cooled reactor (AGR), reprocessing, waste policy.

16.1 Introduction

The United Kingdom has a long history of nuclear development, which, for convenience, can be traced from the post-war weapons programme and, later, the civil use of nuclear power. Research and production sites in England at Harwell (Oxfordshire), Sellafield (Cumbria), Springfields (Lan­cashire) and Capenhurst (Cheshire) were established in the 1940s and, in Scotland, the Dounreay site (Caithness) followed in 1954, initially to develop the fast breeder reactor.

The UK’s first commercial nuclear power reactor began operating in 1956 and, at its peak in 1997, 26% of the nation’s electricity was generated from nuclear power. Nuclear reprocessing facilities were also built to deal with the increasing demand from both military and civil programmes. Since then a number of stations have been closed, and others are scheduled to follow over the next decade. Of the currently operating stations, lifetime exten­sions may be granted for some sites, allowing for continued generation until

replacement generating sources become available. Locations of all major nuclear licensed sites in England and Wales are presented in Fig. 16.1.

This account of radioactive waste (RAW) management in England and Wales is oriented towards the strategic and environmental issues arising from the management of RAW from the nuclear industry. It also addresses the structure of the nuclear industry and the sources, types and classification of RAW.

Approximately one million m3 of solid RAW has been disposed of in the UK to date (NDA and DECC, 2011). Current wastes identified, plus pro­jected wastes over the next century or so, amount to around 4.7 million m3 in the UK. About 97% (4.6 million m3) of the total volume of RAW antici­pated has already been produced. Some has been processed, and is being held in stores, but most is contained within existing nuclear facilities, includ­ing reprocessing plants and nuclear reactors, and will not be processed until these are shut down and dismantled. This waste is the legacy of past and current civil and military nuclear programmes. About 3% (150,000 m3 ) of the radioactive waste total has yet to be produced. This waste is that forecast from the future planned operations of the existing nuclear power industry, from ongoing defence programmes and from the continued use of radioac­tivity for medical and industrial purposes.

Current and projected radioactive waste volumes for England and Wales are summarised in Table 16.1 (NDA and DECC, 2011).

ANDRA’s agents may be producers of waste in their own right: any site remediation results in the generation of waste. Therefore agents must, before the remediation work, measure and characterize the waste from remediation projects. There again, experience shows that taking these issues into account upstream minimizes delays in administrative treatment and hence the storage time on the polluted site for the waste packages awaiting decision. This delay can be tricky if the owner is a private individual.

Similarly, for certain categories of waste, the agent may need to discuss with those responsible for a disposal site (current or planned), defining upstream the best conditions for characterization, packaging and manage­ment of waste arising from remediation sites. In any case, ANDRA as a waste generator must be exemplary in terms of waste and therefore how to take care of it.

Experience also shows that many operations rely on trades from different core businesses than that of the ‘remediator’. In particular, sites often rely on experts for asbestos removal, demolition of buildings, work on hydrol­ogy, management of conventional toxic waste, management of radon in buildings, the maintenance of building structure, etc. ANDRA’s agents have a duty to draw on the external expertise needed to better adress the risks that are poorly controlled or not controlled at all inside ANDRA. Again, any initial savings on these aspects can cost dearly later.

Experience has shown clearly that the initial characterization of sites is paramount. All past projects that have been engaged on the basis of inad­equate initial characterization have ultimately led to hard to overcome technical difficulties and additional costs far higher than the savings attained on the initial characterization of the site. No concessions should be made on the initial characterization of the site. ANDRA’s agents should also not intervene for site remediation on a site that has not been sufficiently characterized.

Cutting, working from heights, working on building structures, the presence of asbestos, the use of electrical systems, work on sites that used chemicals, work on sites often unknown from a chemical point of view mean that actions on contaminated sites present conventional risks, much more dan­gerous in terms of severity, risk of occurrence and kinetics, than the radio­logical ones. ANDRA’s agents are therefore sometimes asked to balance a number of conflicting risks between the need to control conventional risk and radiological hazards. It is therefore necessary, in preparing a site, to reconcile the requirements in terms of both conventional and radiological risk control with the security engineer who will be able, after technical dialogue, to decide how to act and to best manage these risks via a suitable protocol. In any case, priority will be given to systematic conventional risk management except in exceptional cases. Also on the sites of major pollu­tion, the use of a safety coordinator will most often be used.

If might be intellectually satisfying to seek total clean-up, but experience shows that this goal is often illusory and generates unnecessary costs. Indeed, what does total clean-up mean? Should we seek to return to the background noise level, regardless of the cost incurred? The house in Gif — sur-Yvette shows that even having reached a dose rate for Ra-226 in the range of background noise (0.1 mSv/h) in the home, radon levels remain significant and close to the pseudo-limit of 400 Bq/m3. Substantial resources have been committed without the possibility of cleaning the house completely, simply because working on the house itself without addressing the surrounding land amounted to moving the pollution limit without elimi­nating it (radon, in its migration in the ground, ignores administrative boundaries). Total clean-up is only possible for localized pollution. Even then, it is still necessary to agree on a target value for pollution control, and therefore on the residual contamination that is left behind, which de facto contradicts the idea of total clean-up.

Similarly, on an industrial site, considerable sums were spent to treat the site, and thus produced contaminated soil now stored at the CEA (the Cadarache site). The cost of disposal of the soil is assessed at over € 2 million even though the original site is still not completely cleaned up. The pursuit of an illusory goal of total clean-up has led to considerable — and probably unjustified — expense without the goal being reached.

In its communications with the media, ANDRA must refrain from using a term as misleading and meaningless as the ‘total clean-up’.

The logical consequence of the age of the sites and their predominantly urban characteristic (the Paris area is the historic cradle of the radium industry) is that sites have usually been reused for other purposes, including for housing. As a result, the current owners cannot be treated as responsible for the pollution that affects them. These occupied sites are in fact consid­ered as ‘assimilated to orphans’ sites, although they have an owner present. This question raises starkly the two questions of health during the works and inheritance aspects for the management of these sites, aspects that have been neglected in the past.

ANDRA personnel are used to (and are chosen for their ability to) incorporate these aspects in their delicate human relations with residents. However, any difficulties or particular relational situations (and issues potentially difficult to live with) should immediately be shared with man­agement to find adequate answers so that no added burden is put on the personnel involved. In any case, it is important to remain aware of the psychological and social dimension of the remediation of these sites.

Absence of those responsible

Polluted sites are predominantly from the radium mining industry. The industry died out in the 1920s after a boom period in the wake of the work of Marie Curie and medical applications implemented during the First World War. Thus the last radium extraction site stopped in 1928 (in the town of Nogent-sur-Marne). It is thus unrealistic to look for any responsible body still in place (there is now a 30-year proscription applicable to industrial activities following the decision of the State Council on the ‘Allusuissse’ issue). The situations ANDRA inherits are therefore situations from the national industrial heritage, to be managed as best as possible.

The sites of radioactive pollution for which the Agency intervenes are mainly former (ancient) installations having used or made radium or thorium and for most of which the owner can no longer be traced.

In two cases out of three, these sites have their origins in the prosperous interwar radium industry that involved factories for the extraction of radif — erous ore (Gif-sur-Yvette, Nogent-sur-Marne, Saint Denis island) or work­shops using radium products such as radioluminescent paints (e. g., in the watch-making industry or for clock manufacturing). The sites of the watch­making industry may also have tritium pollution following the replacement of radium by tritium in the 1960s. Other contaminated sites arise from rare earth extraction (thorium) and, more recently, manufacture of tracer mol­ecules (tritium and carbon-14, in particular).

The age of these sites frequently raises the problem of records of these activities, and lack of description of what has been allowed in the past (such as inappropriate use of sites from the point of view of radioprotection; see Fig. 15.2). Indeed, some of these sites are in densely housed areas, such as in Gif-sur-Yvette, and others can be found on the site of sensitive activities such as day nurseries, or schools. Other sites are in a safe state and await requalification. The problem of lack of records arises when intervention is envisaged. Mostly archives are unavailable, the owners of the site have often disappeared or died or refuse to communicate their knowledge. The inter­ventions thus have to base themselves on very precise mappings and sound­ings of grounds to know the state of pollution and, if necessary, analysis of

subterranean waters. This stage of characterization is long and expensive, but is essential.

Naturally any zoning of the waste on these sites is impossible. Packages of waste have to be characterized on-site, taking into account the existing radioelements, the nature of the materials and the planned modes of con­ditioning. This can add technical difficulties in the case of lack of space or of raised levels of radiological protection. Most of the time the waste recov­ered is mainly VLLW and to a lesser extent, radiferous. Some cases are made even more complex, such as in the case of mixed chemical and radio­active waste, for which the solutions must be studied separately.

The great majority of sites are in the Paris region and in densely populated urban zones, so that the site cannot be reopened for industrial use. The ques­tion of the requalification of the site is directly linked to the definition of the rehabilitation objectives. This definition is the topic of discussion with the local safety authority. Also, the location of these sites in urban zones raises difficulties linked to the creation of a decommissioning construction site. This requires frequent contact with local authorities to find satisfactory solu­tions to the required limitation of hazards to the local residents. The charac­teristics and problems of these sites are closer to those of chemically polluted sites than to those of decommissioning in a nuclear environment.

ANDRA’ s missions in this domain are similar to those of the environ­mental agency in the field of chemical pollution, with comparable interven­tion mechanisms (although the number of sites is much smaller for ANDRA):

• There are about 20 radioactive contaminated sites for ANDRA and approximately 150 chemically polluted sites for the environmental agency requiring immediate intervention.

• In total there are about 50 sites of radioactive pollution against approxi­mately 4,000 sites of chemical pollution.

Operationally, ANDRA intervenes on sites at the request of public authori­ties. This requisition generally takes the shape of an order from the Depart­ment prefet based on the legislation for industrial landfills. The prefet makes this order after authorization from the Minister for Ecology. The interventions are made in close collaboration with the local administration concerned in the areas of safety, worker safety and industrial safety.

Overview

The sites for remediation are:

• Old industrial sites:

о from the radium industry which flourished in the interwar period о from the production of objects for medical or daily use о from the production or the usage of radium paints for watches, clocks, military instruments

о from the production or the usage of tritium-based paints from 1960

о from the extraction of caesium from monazite о from tracer fabrication (more recently) о where rehabilitation is pending

• Old laboratories dealing with radioactivity.