‘‘One may suppose how radium could become very dangerous in criminal hands and here we might ask ourselves if it is to mankind’s advantage to know the secrets of nature, if we are mature enough to profit from them or if that knowledge will harm us’’.158

hThe CEGB had claimed that funds for decommissioning were being set aside and that when decommissioning was to start the appropriate technology would be in place. However, it tran­spired that such funds were just a ‘‘bookkeeping exercise’’ with the money having been given back to HM Treasury, with no obvious mechanism for their return to fund decommissioning.155

Concerns over the potential malevolent use of nuclear materials have been on-going since the discovery of radiation over 100 years ago. In the present day, potential threats from malfunctions in nuclear reactors and/or from nuclear waste pale in comparison to the threats posed by the proliferation of nuclear materials and nuclear weapons. The series of threats never vanished with the end of the Cold War but continues to haunt us today, if not with more urgency than during the cold war itself. Nuclear weapons proliferation has been a concern since the birth of nuclear energy, given that the very purpose of the first nuclear reactors was to extract plutonium from the spent fuel for nuclear weapons. By contrast, today the objective is to minimize the proliferation risks of nuclear fuel cycle operation.159

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) came into effect in 1968. It stated that those states that already possessed nuclear weapons should not transfer atomic weapons to ‘‘non nuclear weapons states’’. The NPT also sought to invoke the discourse of human rights and development to justify nuclear energy, such that it was ‘‘the inalienable right of all the Parties to the Treaty to… use nuclear energy for peaceful purposes’’.lu Mohamed El Baradei, Director General of the IAEA, labels the enrichment and reprocessing cap­abilities of countries the ‘‘Achilles’ heel’’ of the non-proliferation regime,160 given that countries which possess such technologies have a virtual weapons programme. llu This is increasingly a problem as countries adapt or express an interest in developing Fast Breeder Reactors. The shortcomings of the NPT have led some observers to question the logic of a worldwide nuclear renais­sance. Why is the expansion of nuclear energy a potential problem? The PUREX method of extracting plutonium from spent fuel is well known and easily accessible. At present there is 1000 tonnes of plutonium worldwide.

Countries which adopt PUREX/MOX may neither have the infrastructure or funds to control its spread. That said, there are real, though not insur­mountable challenges for ‘‘rogue states’’ once they have acquired weapons grade material to actually develop weapons technology, which is much more of a technical challenge than commonly assumed162 One solution is for the USA and other nuclear supplier group countries to lease fuel to countries with small nuclear programmes. A recent overview of the functioning of the NPT con­cluded that:

“The somewhat frayed non-proliferation regime will require serious re­examination and strengthening to face the challenge of the global growth scenario, recognizing that fuel cycle associated proliferation would greatly reduce the attraction ofexpanded nuclear power as an option for addressing global energy and environmental challenges’’.163

lnThe NPT is seen to have three pillars: (1) non proliferation, (2) disarmament, and (3) the right to peaceful nuclear technology.

lmThe NPT is seen by some to encapsulate a ‘‘nuclear orientalism’’ in which ‘‘nuclear weapons are represented so that theirs are a problem whereas ours are not’’.161

We have seen through the birth, expansion, decline and renaissance of nuclear power, a number of claims that have sustained interest in the technology: from being too cheap to meter, to being means of securing energy independence and energy security, and as a solution to climate change. However, each of these claims has also had to deal with the challenges posed by the relatively high cost of building nuclear plants; persistent concerns over its safety to the perennial problem of finding a solution and site for the disposal of nuclear waste; as well as concerns over the proliferation risks inherent in the fuel cycle.

Part of the appeal of nuclear power today is the need to develop and foster low carbon energy sources in order to help mitigate climate change, coupled with this is the realisation that renewable energy sources (wind and solar) are not coming online quickly enough to enable a straightforward transition from a carbon dominated energy regime to a low carbon energy regime. As a result countries have either opted for a new nuclear build programme, sometimes after years of stagnation, or have opted to extend the lifetime of existing reactors. Whilst there has been relative stagnation in Europe and North America, a number of developing countries are embracing nuclear power not just for environmental reasons but as an integral part of their industrialisation process, to cope with the extraordinary growth in demand for electricity, a problem acutely facing China and India. The case for nuclear power also increases in parallel to arguments for the electrification of the transport and home/business heating sectors, again to mitigate climate change through development of a low carbon transport system. With technological develop­ments such as the electric-powered car and bus becoming central to dec­arbonising the transport sector, carbon-free sources of electricity production will be privileged, with renewables (primarily wind) and nuclear power heading the list of sources. There are other non-economic factors at work in the desire for nuclear power, namely national status and prestige. Nuclear power becomes a means of political and social policy, strengthening the political legitimacy of the state in developing nations in particular.164

Given the overall resource limits and challenges we have identified, however, nuclear fission may only be able to play a short — to medium-term role in meeting these environmental and economic needs, as an enabling technology with a so — called ‘‘bridging role’’.165 Even then, nuclear energy will face some significant problems as identified above, many of which have not yet been adequately addressed. Policymakers have designed a host of measures to try and address the more pressing concerns, such as creating loan guarantees, tax breaks and arti­ficially raising the cost of carbon, all in an attempt to make nuclear more competitive in comparison with fossil fuels. We have shown that from its inception, nuclear energy has needed state support either directly through state funds or indirectly by intervening to structure markets in their favour.

A range of economic, technical and social challenges continue to plague the industry. Waste disposal is a prime example. Only in Finland is a deep geolo­gical facility under construction after years of discussion and debate with local

communities, here public acceptance and trust is vital, with trust being more of a scarce commodity in some countries than others. The US waste disposal policy is in considerable disarray with profound disagreements among residents in Nevada, the proposed site of the storage facility. The problem of waste and spent fuel disposal is linked to the additional concern of proliferation. Given the weaknesses of the non-proliferation treaty, the expansion of nuclear power, particularly to countries with no history of nuclear energy, and the ability of states to use the PUREX process to extract plutonium, this is particularly wor­risome. There are legitimate concerns that the expansion of nuclear power may also raise the risk of a serious accident in the core of a reactor, risks which are lessened given the improved design of the current generation of LWRs being built. However as we discussed above such risks are still too high and additional design changes to the LWR as well as alternative reactor designs must be developed to reduce the risk still further to within acceptable levels.

As the recent disaster at the Fukushima nuclear plant illustrates it is not just reactor design that needs to be improved but also regulatory oversight and senior management practises. We have seen at Fukushima how neglect of maintenance and safety rules can contribute to prolonging and intensifying the consequences of a natural disaster. Such consequences have been exacerbated by the failures of regulation in an age of privatization and the downsizing of government, as well as the inevitable, prosaic failure of organizations.172 The building of new nuclear plants that are currently underway is unevenly geo­graphically distributed but the challenges that states and corporations face are similar, the speed and scale at which the ‘‘nuclear renaissance’’ will occur depends on whether new reactors can demonstrate ‘‘better economics, improved safety, successful waste management, and low proliferation risk, and if public policies place a significant value on electricity production that does not produce CO2’’.166

RICHARD KIMBER,* FRANCIS R. LIVENS AND JONATHAN R. LLOYD

ABSTRACT

The widespread spread use of nuclear materials over the past 60 years has lead to anthropogenic release of radionuclides into the environment. The release of such contaminants is currently of great public concern and scientific interest worldwide. Contamination has arisen on sites involved in both military and civilian uses of nuclear material through leakages, spills, controlled discharges and munitions use. The management of this nuclear legacy is a global priority as governments seek to decommission and reclaim land contaminated by the use of nuclear facilities. The scale of contamination presents a serious financial burden with the cleanup of US sites expected to cost up to a trillion dollars. In the UK, the problem exists on a smaller but significant scale with associated cleanup costs estimated to be in the order of £100 billion. A wide range of disciplines are required to understand the behaviour of radionuclides and co­contaminants in these contaminated environments in order for effective remediation techniques to be utilised. Potential remediation strategies cover a range of biological, chemical and physical methods which can be used to treat the complex contamination scenarios found at nuclear sites. A number of these remediation techniques have been trialled at several sites managed by the United States Department of Energy with some success in treating radionuclide contamination.

* Corresponding author

Issues in Environmental Science and Technology, 32 Nuclear Power and the Environment Edited by R. E. Hester and R. M. Harrison © Royal Society of Chemistry 2011

Published by the Royal Society of Chemistry, www. rsc. org

The industrial production of nuclear materials and their subsequent use, both militarily and civilian, since the 1940s has left behind a legacy of contamination and hazardous waste. Management of this legacy is now a global priority as many governments seek to decommission and reclaim land once used by their nuclear facilities. However, the storage and disposal of contaminated equip­ment and spent nuclear material, compounded with the widespread dispersion of radionuclides and co-contaminants at these sites makes this a challenging and expensive undertaking.

Many former nuclear facilities were shut down at the end of the Cold War in the 1990s as the demand for nuclear weapon production decreased. These sites are now the focus of remediation, decommissioning and decontamination efforts for governments and agencies worldwide. Substantial quantities of land, groundwater, and equipment have been contaminated by the former operations of these sites, the details of which will be discussed in this chapter. A number of sites which are still in operation, often dealing with the reprocessing of nuclear material, are also the focus of ongoing remediation efforts. Contamination issues have arisen from various sources including accidental release, the con­trolled discharge of nuclear waste and the use of radionuclide-containing munitions. The accidental release of radionuclides can occur through the leakage and spills of radioactive material, as well as from incidents (such as explosions) which have occurred on site. Off site contamination is a concern in cases where both on site accidents and natural transport processes have spread radionuclides further afield. Hydraulic flow presents an ongoing problem for the containment of on site contaminants as groundwater plumes threaten to spread contamination to aquifers used in the irrigation of crops or for public drinking water. For this reason, the mobility of radionuclides, heavy metals and toxic organics is a key factor in determining the risk that each contaminant presents to the environment and general public. Understanding the mechanisms which affect contaminant mobility is therefore vital in developing effective remediation strategies. Numerous techniques are available for treating con­taminated land and groundwater, generally falling under either biological (bioremediation) or chemical processes. This chapter will outline some of the key techniques available, along with their associated advantages and disadvantages. A number of key case studies relating to former nuclear facilities will also be discussed where a variety of techniques have been applied in field scale studies.

3.2.1 Suitable Host Geologies

Globally, at least 39 countries have produced significant amounts of HAW and of these, 25 have chosen geological disposal as their long term HAW management pathway, and a further six have expressed a preference for geological disposal. However, whilst the current implementation pathway for geological disposal is relatively recent in the UK, several countries are more advanced in the implementation of their geological disposal strategies (see Table 1). Typically, these strategies have developed over several decades and all have included detailed geological characterisation programmes, often including construction of in situ rock testing laboratories to assess the

Stage: advanced — incep­tion in mid 1970s; two suitable host geologies have been identified; generic geodisposal concepts developed;

Site: final site has not been decided but two suitable geolo­gies have been identified.

Geologies: boom clay

HLW (vitrified waste from fuel reproces­sing).

Long-lived ILW.

Vitrified HLW/spent fuel (contained in steel with silica glass frit used to fill voids) placed in carbon steel super-

HLW/spent fuel: void space between super-container and tunnel wall will be filled with cementi — tous material.

rock characterisation has been was conducted an in situ testing facil­ities have been con­structed in both rock types; the sedimentary assessment (Opalinus clay/NAGRA) is pre­sented here; material and host rock feasibility tests have been con­ducted.

Repository, access tunnels leading to disposal tun­nels; waste is emplaced axially; all waste will be disposed of in one facility; waste emplace­ment will be phased with retrievability considered.

Germany/DBE Stage: advanced — his-

Technology6,11,25 torically, salt rock was considered optimal for German HAW storage; final site (Government approved) selected in the late 1970s after

Table 1 Continued.

Country/Responsible Current stage and Waste types managed

body Repository type Site/Geology by geodisposal Waste package Buffer/Backfill

suitability of regional geologies. As a consequence, several generic host lithologies have been deemed suitable for HAW disposal (see Table 1). For example, the Belgian and French programmes have identified suitable clay formations; the Finnish and Swedish programmes have identified crystalline host rocks; the Germans have suggested potential evaporite deposits; and the Swiss have identified both crystalline and sedimentary formations (see review by Baldwin et al. 2008; ref. 6). Furthermore, Sweden has successfully advanced to the stage of choosing their likely geodisposal site, and Finland has begun pre-construction of their facility pending final government approval (see Table 1). Interestingly, the most successful national pro­grammes have had public participation during site selection at the core of their implementation programmes. They also have less complicated nuclear legacies compared with that of the UK.

Radionuclides in the environment lead to plants and animals being exposed both externally and internally to ionising radiation. Internal exposure arises from radionuclides incorporated into the organism by the processes described

Amphibian Annelid Arthropod Bird Grasses & Mammal Reptile Tree

Herbs

Figure 1 Example CRwo values for different radionuclide-wildlife group combina­tions (data reproduced from draft IAEA TRS).41 Am: reptile — carnivorous only, Co: mammal — omnivorous only, Pu: grasses only, no herbs.

in the previous section. In addition to the activity concentration in an organ­ism, internal exposure depends upon the organism size and the type and energy of emitted radiation. External exposure is largely determined by the con­tamination levels in the environment, habitat (the geometric relationship between the radiation source and the organism and the shielding properties of the medium), organism size, and the physical properties of the radionuclides.

The interaction of radiation with matter leads to the excitation and ionisa­tion of the target material (tissue). The unit of absorbed dose is the Gray (Gy), where one Gy = one Joule of absorbed energy per kg material (Jkg-1). Dose conversion coefficients (DCCs), defined as absorbed dose rate (pGyh-1) per unit activity concentration in an organism (Bqkg-1 fw; where fw = fresh weight) or medium (Bq per unit media fw), are used to relate organism and medium activity concentrations of an absorbed dose.

In the simplest case, an organism is assumed to be in an infinite homogeneous medium with the same density as itself, with the radionuclide distributed homogenously throughout all its tissues. Under these conditions, both internal (DCCint) and external (DCCext) dose conversion coefficients for mono-energetic radiation can be expressed as a function of the absorbed fraction, as follows:

Where E (eV) is the energy of a mono-energetic source and f(E) is the absorbed fraction for the energy E.

The equations assume that the organism and the surrounding medium are of similar density and elemental composition. If the radiation is not mono­energetic, the above definition can be generalised by summing the terms over the different radionuclide decay energies, weighted by the branching ratios of each transition. For external exposure, if the organism receives contributions from various environmental media (which may not always be assumed to have the same density as the organism), the equation also needs to sum these individual contributions.

The key quantity for estimating internal absorbed doses is the absorbed fraction (f), defined as the fraction of energy emitted by a radiation source that is absorbed by an organism. The uncertainty associated with the heterogeneous distribution of some radionuclides in organisms has been assessed.45 The conclusions were that: (i) for photons, the uncertainty due to a possible non­homogeneous radionuclide distribution is lower than 20-25% in the considered cases; and (ii) for electrons, uncertainty is below 30% and likely to be negligible below an energy of 0.5 MeV.

As outlined earlier, a large proportion of spent uranium fuel is potentially reusable. The vast majority is still uranium which, although reduced in fissile content, contains residual enrichment and can be recycled. Plutonium can also be recovered for use in MOX or other fuels. In addition, recycling of used fuel may reduce waste volumes for disposal and/or allow removal of high hazard radionuclides for separate treatment. Separation of used fuel on an industrial scale is, however, a complex and challenging technology.

Biological treatments, referred to as bioremediation, encompass several tech­niques which can involve the redox transformation, biological accumulation or breakdown of a contaminant. Chemical speciation (oxidation state and com­plex form) is one of the primary controls on the mobility of metal contaminants in the environment, affecting both their solubility and reactivity with surfaces. For example, the metal chromium is mobile and highly toxic in the Cr(vi) state, but is both less mobile and up to 1000 times less toxic as the Cr(iii) oxidation state.59 The radionuclide, 60Co can form a stable and mobile complex with

Can be performed in situ.

No additional nutrients required.

Relatively low cost compared to physiochemical methods. Not governed by physiological constraints of living cells. No secondary waste produced.

Metal recovery is possible, especially from process waters. Specific contaminants can be targeted.

Can be performed in situ.

Relatively low cost compared to physiochemical methods. No secondary waste produced.

Specific contaminants can be targeted e. g. Cs1 transported by K1-uptake processes.

Potential for re-oxidation and re-mobilisation of metals and radionuclides.

Complex groundwater or soil chemistry can complicate or prohibit treatment.

Regular monitoring required to assess effectiveness.

Can only operate in conditions required for cell growth (i. e. limited pH range).

Early saturation can require metals desorption to continue use.

No potential for degradation of compounds.

Targeting certain contaminants may require the cultivation and introduction of species not natively present.

Very limited commercial application.

Requires subsurface conditions favourable for microbial metabolism.

Toxicological effect on cell may inhibit cell metabolism or lead to cell death.

Targeting certain contaminants may require the cultivation and introduction of species not natively present.

Very limited commercial application.

May only operate over a specific pH range in certain cases. Mineral precipitation may clog pore spaces restricting groundwater flow to contaminants further from injection wells.

Treatment is limited to the surface area and depth of the plant roots.

Possibility of contaminants entering the food chain.

Slow growth and low biomass require long-term commitment. Saturation of contaminants may lead to toxicity affecting plant survival.

ethylenediaminetetraacetic acid (EDTA) in the Co(iii) state, but is less stable and hence less mobile in the Co(ii) state.60

It has long been established that microorganisms are able to reduce metals,61,62 with more recent work showing they are able to use such processes to conserve energy for growth. Focussing on reductive transformations, microbes are able to use some metals as the terminal electron acceptor during anaerobic respiration, in environments where oxygen has been depleted. Thus, stimulating their activity in the subsurface can cause the reduction of high oxidation state metal contaminants to less soluble forms and hence retard their migration. The mechanisms involved in microbial metal and radionuclide reduction are described in detail elsewhere.59,63 Microorganisms are also able to reduce and degrade some organic contaminants through analogous respiratory processes when supplied with a suitable electron donor. For example, almost 98% of tetrachloroethylene (PCE) underwent complete reductive dechlorina­tion to ethane when a laboratory column experiment used Rhine river sediment supplied with lactate as an electron donor.64 Trichloroethylene (TCE), an industrial solvent and common subsurface contaminant,65 was also shown to be degraded by the methanotrophic bacterium Methylosinus trichosporium OB3b in a co-metabolic process in a copper deficient medium.66 The reader is directed towards a recent review by Pant and Pant, for a detailed account on the microbial remediation of TCE.67

Metal and radionuclide transport can also be restricted through precipitation with enzymatically generated ligands, such as sulfide68,69 and phosphate (see Figure 1).63 If supplied with an excess of these ligands then most of the metal should be removed from solution. An advantage to this method is that high concentrations of ligand are generated close to the cell surface which can act as nucleation foci for the onset of metal precipitation. An integrated approach to metal remediation using sulfur-cycling bacteria has been demonstrated.70

In this study, a number of metals were leached from artificially contaminated soil through the production of sulfuric acid by sulfur-oxidising bacteria. This lea­chate was then applied to a bioreactor containing sulfate-reducing organisms where greater than 80% of the metals were precipitated as solid metal sulfides.

The bacterial strains Rahnella sp. and Bacillus sp. were both shown to be capable of hydrolysing sufficient organophosphate to remove up to 95% of uranium in a simulated groundwater system. The system was most efficient between pH 5.0 and 7.0 with EXAFS spectroscopy identifying the uranyl phosphate precipitate as an autunite/meta-autunite group mineral.71 This builds on earlier work on a Citrobacter (now classified as a Serratia) strain which coupled the efflux of phosphate driven by phosphotase-mediated breakdown of glycerol-2-phosphate to efficient uranium precipitation.72 A case study involving phosphate biomineralisation at the Hanford site is discussed in detail later in this chapter. The biosorption and bioaccumulation of metals may act as a component in metal remediation through sorption of metals to cell surfaces or uptake into the cell. This can occur as a physiochemical, metabolic — independent mechanisms whereby metals sorb onto the surface of biomass or via metabolic-dependent processes in which the metal is taken up into the cell where it may precipitate locally and accumulate. Both processes have been reviewed extensively but a lack of commercial development has weakened continued research into this field.73 76

These techniques can be achieved through several different methods. Bios­timulation involves the addition of key nutrients, such as an electron donor and carbon source, to the subsurface to stimulate the native microorganisms, usually done via injection wells. Advantages of such a method include the sti­mulation of extant bacteria that are already well suited to the environmental conditions and distributed throughout the subsurface. Relying on the local geology and hydrogeology to distribute the nutrients evenly can however, prove to be a disadvantage.

If the native bacteria do not have the metabolic capability to remediate a par­ticular contaminant then bioaugmentation can be employed where by specialised microorganisms are added to the subsurface, along with the required nutrients, in order to remediate the contaminant. A number of reviews are available on the processes involved in bioaugmentation.77,78 Both the aforementioned techniques operate in situ but ex situ bioremediation is also a possibility. Ex situ treatment involves the excavation of contaminated soil or pumping of groundwater into an above ground facility where the biological conditions can be better controlled. Although excavation and pumping is more expensive than in situ treatments, benefits include being able to adjust to aerobic or anaerobic conditions as required. The ability to operate in aerobic conditions allows certain bacteria to utilise organic contaminants, such as petroleum hydrocarbon mixtures and polycyclic aromatic hydrocarbons, as their source of carbon and energy thus potentially degrading the contaminants completely to CO2 and H2O. A further advantage of ex situ remediation is the ability to homogenise and continuously monitor the soil to ensure complete treatment occurs. Numerous studies exam­ining the effectiveness of ex situ bioremediation have been performed.79 81

Phytoremediation, which utilises the ability of plants to degrade or accu­mulate contaminants, can also be employed in the remediation of soil and groundwater. The cost-effectiveness and non-environmentally disruptive nature of phytoremediation offers advantages over other bioremediation techniques. Further advantages include the ability to easily monitor the plants and the possibility of recovering and re-using valuable, accumulated metals. However, there are a number of disadvantages associated with this process which includes remediation being limited to the surface area and depth of the plant roots, the possibility of contaminants entering the food chain and the usually long period of time phytoremediation requires for completion. For further details, the reader is directed to a number of recent reviews.82,83

The other major source of radioactive waste and contamination is the nuclear fuel cycle.2,7 By volume, the largest source of contamination arises from uranium mining and milling.15 Uranium mining has produced an estimated 937 x 106m3 of tailings, with activities ranging from <1 to > 100 Bq g 1.16 The waste contains not only uranium, but also uranium decay products, including radon, a radioactive gas. Although current tailings are well maintained, there are many old abandoned sites, particularly in eastern European countries and the former Soviet Union that require remediation.4,16

Contamination also arises from the handling and reprocessing of spent nuclear fuel (from either civil or military programmes) and can cause high localised levels of contamination.1,17 Release to the environment can arise from authorised discharges to the atmosphere and to surface and groundwater (see Tables 2 and 3), accidental release and leakage of storage tanks.18 21 At the Sellafield site, UK, authorised discharges to atmosphere and sea have occurred for over 40 years.2 Historically, the major sources of liquid effluent for dis­charge (via pipelines into the Irish Sea) were process liquors from reprocessing and fuel storage pond water; discharges for selected radionuclides from 1952 to 1992 are shown in Figure 2.22 The level of activity discharged to sea peaked in the mid to late 1970s, and in most cases has been declining ever since.

Leakage from storage facilities can also cause significant localised con­tamination. At the Hanford site (a former plutonium production facility) in the

USA, an estimated 570 m3 of waste containing 3.7 x 104 TBq of radioactivity has been released into the subsurface from leaking underground storage tanks.7

Releases to the atmosphere arising from the nuclear fuel cycle are lower than from nuclear weapons, but can arise from several stages of the cycle. Uranium mining and milling releases radon gas and windborne dispersion of waste materials can also spread contamination.23,24

There are two different approaches to applying the principle of justification in situations involving occupational and public exposures, which depend upon whether or not the source can be directly controlled. The first approach is used in the introduction of new activities where radiological protection is planned in advance and the necessary actions can be taken in relation to the source. Application of the justification principle to these situations requires that no planned exposure situation should be introduced unless it produces sufficient net benefit to the exposed individuals, or to society, to offset the radiation detriment it is expected to cause. The second approach is used where exposures can be controlled primarily by action to modify the pathways of exposure, and not by acting directly on the source. This is likely to be the case in existing and emergency exposure situations. In these circumstances, the principle of justifi­cation is applied when making the decision as to whether or not to take action to avert further exposure. Any decision taken to reduce doses — which will almost always have some disadvantages — should also be justified, in the sense that they should do more good than harm.

In both approaches, the responsibility forjudging the “justification” usually falls on governments, or national authorities, to ensure an overall benefit in the broadest sense to society and thus not necessarily to each individual. However, input to the justification decision may include many aspects that could be informed by users or other organisations, or persons outside of government. As such, justification decisions are often informed by some form of public consultation, depending upon, among other things, the size of the source concerned. There are many aspects of justification, and different organisations may be involved and responsible. In this context, radiological protection considerations serve only as one input to the broader decision process.

JOHN WALLS

ABSTRACT

In this paper we outline the origins of the nuclear power industry in the nuclear weapons programme of the Second World War, and chart the growth of the nuclear industry through the 1950s and 1960s, and its subsequent decline during the 1970s and 1980s as a result of increasing costs and economic crisis, coupled with high profile accidents at nuclear plants at Three Mile Island and Chernobyl. We then explore the claim that we are witnessing a ‘‘nuclear renaissance”, characterised by a growth in the construction of new nuclear plants in the West but particularly in Asia. Three main factors have led to arguments for nuclear energy gaining greater traction: concerns over climate change and the need to promote low carbon energy technologies; the need to enhance energy security; and the need to meet large increases in demand for electricity particularly in developing countries. We then outline six variables that have the potential to impose limits on any large scale expansion of nuclear energy. Finally we explore to what extent the March 2011 disaster at the Fukushima nuclear plant in Japan is likely to negatively impact the ‘‘nuclear renaissance”.

‘This research was funded in part by the Economic and Social Research Council under The Waste of the World programme (RES000230007). My thanks to Dr Galina Walls and Professor Roy Harrison for comments on earlier drafts.

1 Introduction

Up until a few years ago, it appeared that nuclear power no longer had a place in the energy future of the West. In the aftermath of the accident at Three Mile Island and the Chernobyl disaster, as well as the problem of significant cost overruns for new nuclear plants, and the continuing problem of nuclear waste disposal and spiralling decommissioning costs, nuclear appeared to be an industry with no viable future.1 However in recent years we have seen the return of nuclear power as an attractive option given the urgent need to meet the increased demand for electricity, especially in developing countries, as a potential mitigation strategy against climate change and to bolster energy security. With 55 nuclear reactors currently under construction and many more ordered we fre­quently hear talk of a ‘‘Nuclear Renaissance’’.2 Enthusiasm for new nuclear build at present is concentrated in Asia and Russia with a much slower devel­opment in Europe and North America.11

In this paper, we outline the origins of the nuclear energy industry in the nuclear weapons programme of the Second World War; discuss the expansion of nuclear energy into the post war period and its role in the modernisation and industrialisation process; then chart the declining fortunes of the industry and its contemporary resurgence as a potential means of mitigating climate change. We suggest that whilst new nuclear plants will come on line in increasing numbers over the next few decades, they will be built at a much smaller pace than desired and anticipated, due to a range of factor which we explore below. Nonetheless nuclear power will continue to play a role in the energy systems of many developed and developing countries, as they try and move toward more sus­tainable energy systems. The extent of this role will depend on the ability of nation states to navigate the challenges that face plans for new nuclear plants.

1.1 Events Leading to the Accident

In the early hours of the morning on the 10th of October 1957 a reactor (Number 1 of the two Windscale ‘‘Piles’’), developed to produce plutonium and tritium for the UK’s atomic bomb programme, caught fire. The fire occurred during a procedure to release so-called ‘‘Wigner’’ energy from the reactor core.

Wigner energy is chemical potential energy stored in the lattice structure of the graphite moderator during operation of this type of nuclear reactor. The operators at Windscale routinely released this stored energy (to prevent an uncontrolled release) by an annealing process in which the core temperature was temporarily raised. This procedure normally released the Wigner energy in the graphite resulting in a temporary heating, then cooling of the core. On the day of the accident, however, the annealing process caused the temperature of some parts of the core to rise substantially. This, possibly coupled with rupture of a fuel element, caused the reactor to set on fire. After failed attempts to remove the overheated fuel elements and to put out the fire by carbon dioxide, the reactor was flooded with water on the following day (11th of October). The operators believed at the time that use of water carried the risk of a hydrogen explosion as it contacted red-hot metal, but it was felt that the risk of breach of containment by the burning reactor core was greater. By the evening of the 11th, the fire was fully extinguished.

The fire resulted in the release of ‘‘some of the fission products and activation products contained in a few percent of the core’’.1 The releases from the Windscale fire have recently been re-evaluated,1 giving estimates for a wide range of radionuclides including 1.8 PBq of 131I; 0.18 PBq of 137Cs and 0.042 PBq of 210Po. As with TMI and Chernobyl, large quantities of noble gases (including 26 PBq of 133Xe) were released, though these were less radiologically significant.