William Walker

Department of International Relations
St. Andrews University, Scotland

Centre for the Study of Terrorism and Political Violence
St. Andrews University, Scotland

July 1997

Special ISIS Report on the Future of UK Nuclear Weapons, Fissile Materials, Arms Control and Disarmament Policy, No.2 (of three), June 1997.

Three main issues need to be addressed by the Labour Government:

1. The future status and regulation of military plutonium and HEU inventories in the UK, how those inventories can be better characterised, how they would be effected by the proposed Fissile Material Cut-Off Treaty, and whether the government should encourage the negotiation of that Treaty.

2. The future of civil reprocessing in Britain; whether its planned expansion can be justified in view of the loss of market demand for plutonium, the chaotic state of Britain's nuclear waste disposal policies, and the difficulties of returning plutonium and waste products to foreign customers; and if reprocessing is not justified, whether a consensus can be formed domestically and with foreign governments and utilities around long-term storage of the spent fuels that have already been delivered to Sellafield.

3. The disposition of surplus fissile materials: how much material in military stocks is now excess to defence requirements; and whether, how and when a major programme should be launched to dispose of the large stocks of separated plutonium, and of spent submarine fuels, that are currently held in store at Sellafield.

1. Introduction

Plutonium and highly enriched uranium (HEU) are the essential 'fissile materials' used in nuclear weapons. Since 1945, about 3000 tonnes of these materials have been produced world-wide, of which some 2000 tonnes (1760 tonnes of HEU and 230 tonnes of plutonium) have been produced for military purposes and 1000 tonnes (almost entirely plutonium) have arisen within the civilian fuel-cycle. ₁ The regulation of fissile materials now occupies a central place in nuclear arms control and non-proliferation policy. Furthermore, any act of nuclear disarmament, as events in Iraq and South Africa have recently shown, must entail the appropriate verification of all fissile materials acquired by the country in question. To be plausible, a project of global disarmament would therefore hinge upon the ability and willingness of all nation states to reveal their material inventories, submit them and associated production facilities to rigorous international verification, and dispose of residual stocks.

Next to the US and former Soviet Union, and along with France, Britain has been the most important player in the global politics and economics of fissile materials. In the 1940s and 1950s, its scientists and engineers played a significant part in the development of the main production techniques (reactors, reprocessing and enrichment); British companies have been prominent since the outset in uranium mining and processing; since 1958, Britain and the US have engaged in a unique and highly secretive military trade in plutonium, HEU and tritium; through its heavy investment in Magnox reactors and its construction of large-scale reprocessing plants, Britain was the world's largest separator of civil plutonium (domestic and foreign) before being overtaken by France in the mid-1990s; Britain probably has the widest experience of any country of decommissioning reactors and fuel-cycle facilities; it has contributed in important ways to the development of safeguards and physical protection techniques; and among the nuclear weapon states (NWS), Britain has gone to the greatest lengths to submit its civil nuclear activities to international safeguards.

This history gives Britain significant influence over policies towards fissile materials and, thereby, over the development of arms control and fuel-cycle strategies. But it also presents the new British government with a series of issues that need to be addressed with some urgency.

The first concerns the future status and regulation of fissile material production, stocks and infrastructures in the UK, the other four NWS (Russia, the US, China and France) and the three de facto nuclear weapon states (India, Israel and Pakistan). The importance of increasing transparency and bringing their various nuclear assets under more extensive multilateral control is widely acknowledged, and necessary measures have been identified, the most prominent being the Fissile Material Cut-Off Treaty (FMCT) and the verification of warhead dismantlement envisaged in START III. However, most diplomatic initiatives in this field are currently in the doldrums. The new government has a choice. Either it can maintain the predominantly inactive stance of previous Conservative Administrations, or it can attempt through example, innovation and political leverage to bring fresh energy and movement to the international agenda.

Secondly, the civil reprocessing programme in which Britain has invested so heavily since the 1950s is in serious difficulty. Recent events at home and abroad mean that the THORP reprocessing plant may only operate at low levels of throughput, if at all; and the reprocessing of Magnox fuels is likely to cease within the next ten to fifteen years as the ageing Magnox reactors are closed down. So the end of reprocessing in Britain is probably in sight. However, this prospect has yet to be reflected in any shift in policy: the previous government continued to proclaim the benefits, and necessities, of reprocessing. Painful though the changes may be, policies on spent fuel management need to be reassessed both internally and externally in co-operation with foreign customers.

Thirdly, Britain faces a substantial disposal task, of two kinds. One is the decommissioning of facilities, including reprocessing plants at Sellafield and Dounreay and elderly processing facilities at Aldermaston and Burghfield (where nuclear warheads and components have been fabricated). The other task is the disposition of excess fissile material, including the large stockpile (nearly 50 tonnes) of reactor-grade plutonium that is held in store at Sellafield. The first of these tasks has begun to be addressed, the second has not.

Three particular challenges lie ahead:

To submit Britain's military stocks, infrastructures and practices to greater international verification. Transparency and verification would initially apply around the edges of the military domain, but as further restrictions are placed on the acquisition, deployment and usage of nuclear arms through bilateral and multilateral agreements, would become more extensive. If and when global nuclear disarmament is embraced, verification would have to become comprehensive.

To shift Britain's nuclear institutions from a culture of plutonium separation and accumulation to one of plutonium storage and disposition. This entails recognition that the great majority of plutonium held in Britain is now surplus to any conceivable civil or military requirement. It is a waste, and has to be dealt with as such.

To become more active abroad, particularly in co-operation with the US and European allies, in the search for new policy and diplomatic solutions to the problems that currently beset this vital area of international security.

2. Britain's acquisition programmes

Britain has acquired fissile materials from many sources, domestic and foreign, and for many purposes over the past half century. Although the sizes of its inventories are subject to many uncertainties, the story of their acquisition can now be sketched in some detail. It needs to be recounted because of its importance to an understanding of the current situation. As will become apparent, more is known about Britain's plutonium inventories than about its HEU inventories.

2.1 Acquisition of highly enriched uranium for military purposes

Britain's first nuclear weapons were implosion devices constructed with plutonium. HEU production began in the mid-1950s with the construction of a gaseous diffusion enrichment plant at Capenhurst in Cheshire. The production of HEU became an imperative when the Macmillan government instructed weapon designers to produce fission bombs that would give high yields when tested. It wished to impress the US with the sophistication of Britain's weapon capabilities, thereby encouraging the US to look more favourably upon co-operation in weapon design.

Remarkably, the enormous and costly facility at Capenhurst only operated for five years at anything approaching full capacity before the bulk of the plant was shut down in 1962, by which date between four and five tonnes of HEU could have been produced. The reasons for its closure are still obscure, but appear to have been connected to the US offer of comparatively cheap enrichment services to the UK for anticipated power reactor designs which would use enriched fuels, and to the wide-ranging nuclear co-operation agreement reached by the two governments in the late 1950s (the US-UK Mutual Defence Agreement of 1958, as amended in 1959). ₂ This agreement involved the bartering of US HEU and tritium for British plutonium, over and above the wide-ranging co-operation on the design and testing of nuclear weaponry.

In the mid-1970s, the agreement on fissile materials, which was customarily renewed every five years, fell into abeyance due to the Carter administration's concerns that it ran counter to US non-proliferation policy. As a result, the British government financed the construction of a centrifuge enrichment plant at Capenhurst in order to secure future military supplies. It began operating in 1984 or 1985 but only ever produced Low-Enriched Uranium, never HEU. When Mrs Thatcher became Prime Minister, she successfully persuaded President Reagan to restore the exchange agreement. Thereafter, the Capenhurst plant sent intermediate-level (usually 4.5%) enriched uranium to the US for re-enrichment to the levels required for defence purposes. ₃ The plant ceased producing enriched uranium under contract to the Ministry of Defence in 1992 and was transferred to Urenco which has since operated it for civil purposes under international safeguards. ₄

Information on Britain's acquisition of HEU from all sources is classified. In January 1996, however, the US Department of Energy announced in its 'Openness Initiative' that it had supplied 6700 kilograms of HEU to the UK under the barter arrangements. ₅ In addition, it is believed that the UK also 'swapped' low-enriched uranium produced at Capenhurst in the mid-1980s for weapon-grade uranium (containing equivalent numbers of Uranium-235 atoms), and that it purchased some HEU directly from the US for its nuclear submarine programme. Although these quantities have not been declassified by the US government, it is estimated that Britain acquired between two and six tonnes of HEU by these means.

In total, the UK may therefore have acquired, according to these estimates, around 15 tonnes of HEU (4.4 tonnes from the Capenhurst diffusion plant, and 6.7 plus 4 tonnes from the US). The error margins are high. It is possible that acquisitions of HEU from the US in the 1980s and 1990s have been considerably larger, possibly encouraged by concerns that an FMCT might bring an end to the transatlantic trade.

Britain's consumption of HEU - 'Draw-downs' - has to be taken into account when assessing its current inventory. This has mainly comprised an estimated 5.8 tonnes used in submarine reactor cores, one tonne used in explosive testing, and 0.5 tonne lost in processing. ₆ Taking these draw-downs into account, Table 1 shows that the current inventory would be around 8 tonnes (this is a central estimate).

If Britain's total nuclear arsenal comprises 200 to 300 warheads (according to best estimates of the previous Government's plans), and assuming that each warhead contained 15-20 kg of HEU, this would require 3-6 tonnes of HEU. This would leave about 2-5 tonnes for future naval requirements. If, however, the Labour government honours its pre-election commitment to 'ensure that Trident carries no more warheads than Polaris', and if the total number of warheads on the Polaris/Chevaline force lay between 96 and 144, then the requirement for HEU would only be half as much (1.4 to 2.9 tonnes). ₇ This would then leave over five tonnes for naval reactors.

The number of nuclear submarines in the British fleet is being reduced and the efficiency of their reactor cores raised significantly with each new design. Reactors are now being designed that need no refuelling, in which case five tonnes would be enough to fuel 50 new boats throughout their lifetimes. Nevertheless, the Ministry of Defence has appeared concerned about shortages of HEU, and about the vulnerability of the submarine fleet (and of plans for its future development) if US supplies dried up. Although a FMCT will not forbid the production of HEU for submarines, Britain no longer has an indigenous enrichment plant that can supply HEU outside international safeguards. Steps may already have been taken to acquire additional HEU from the US or France which both have large surpluses. If so, eight tonnes may be a conservative estimate of the current inventory.

Table 1. Britain's military inventory of HEU

Central estimates in tonnes, 31 December 1995

InventoryEstimate

SupplyCapenhurst diffusion plant4.4From the US

Barter provision

Under contract

6.7

4.0Sub-total15.1

Draw-downsNuclear submarines5.8Nuclear tests1.0Processing losses (3% of supply)0.5Sub-total7.3

Inventory for weapons and submarines

7.8 ± 25%

Source: David Albright, Frans Berkhout and William Walker, SIPRI, Plutonium and Highly Enriched Uranium 1996 (Oxford University Press: Oxford, 1997), Table 4.9.

2.2 Plutonium acquisition for weapons

Unlike HEU, all plutonium used in Britain's nuclear weapons has been produced in the UK. Some of Britain's plutonium output has however been transferred to the US, and a minority of plutonium discharged from Britain's military production reactors has been weapon-grade. ₈ It is again difficult to provide accurate estimates of the quantities currently held in weapons and in stocks, although the margins of error are less than with HEU. All information on military plutonium in Britain remains classified.

Calder Hall and Chapelcross

Britain's plutonium production began at Windscale (later renamed Sellafield) in 1951. Between 1951 and 1957, around 400 kilograms of weapon-grade plutonium were discharged from the two original reactor piles at Windscale. In the early 1950s, it was decided to construct two sets of four Magnox production reactors - the Calder Hall reactors on the Sellafield site, and the Chapelcross reactors at Annan in Dumfriesshire.

The Magnox reactors at Calder Hall and Chapelcross are together estimated to have provided three tonnes of weapon-grade plutonium for the British bomb programme.

The Calder Hall reactors are believed to have supplied weapon-grade plutonium during three periods: between 1956 and 1964, when they provided material for Polaris and for the growing arsenal of tactical weapons; in the late 1970s when they supplied additional material for the Chevaline warhead programme; and in the mid- to late-1980s when they supplied plutonium for the planned modernisation of the British nuclear arsenal with Trident. As the final production and/or separation of weapon-grade plutonium occurred in 1993, some additional amounts may have been extracted in the early 1990s.

The Chapelcross reactors came into operation slightly later than those at Calder Hall. It is believed that they were only used to supply weapon-grade plutonium between 1959 and 1964. From the early 1980s onwards, Chapelcross became the main source of the tritium used in Britain's nuclear weapons.

Weapon-grade plutonium contains few of the even-numbered isotopes of plutonium which are heavy neutron emitters and cause problems for weapon designers. This grade of plutonium is produced by irradiating uranium with neutrons in reactors for comparatively short periods. Typically, the Calder Hall and Chapelcross reactors were operated on yearly cycles when producing plutonium for weapons (around 300 days' operation followed by 70 days' shut-down to allow for the removal of plutonium-containing spent fuel and for refuelling). When weapon-grade plutonium was not required, the reactors were re-optimised to provide electricity for sale to the grid, entailing much longer irradiation periods. As a result, substantial quantities of fuel- and reactor-grade plutonium containing relatively large proportions of even-numbered isotopes have also been produced at Calder Hall and Chapelcross. Although not used in weapons, they are still held outside international safeguards and form part of Britain's military inventory.

Initial discharges from civil power reactors

Civil Magnox reactors were the final source of weapon-grade plutonium for the British bomb programme. Before ownership of these reactors was transferred from the UK Atomic Energy Authority to the Central Electricity Generating Board and South of Scotland Electricity Board (the state-owned utilities) in 1971, weapon-grade plutonium extracted from their initial discharges was offered for sale to the Ministry of Defence. ₉ It is estimated that around 230 kg of plutonium were supplied to the weapon programme under these arrangements.

Barter arrangements with the US

Under the above-mentioned barter arrangements with the US, 5.4 tonnes of fuel- and reactor-grade plutonium crossed the Atlantic in return for HEU and tritium. ₁₀ It is estimated that 4.1 tonnes were derived from pre-1971 civil reactor discharges, and 1.3 tonnes from Chapelcross and Calder Hall which may have been transferred in the 1980s. Most of the material has been used in US research facilities, notably the Fast Flux Test Facility (FFTF) at Hanford and the Zero Power Physics Reactor at Argonne National Laboratory. However, the US Department of Energy blended some or all of the material from Chapelcross and Calder Hall with supergrade plutonium to increase the US stock of weapon-grade material. ₁₁ This occurred in the early- to mid-1980s when the Reagan administration was seeking to expand the US nuclear arsenal and was concerned that it might have insufficient fissile material.

The resulting British inventory of military plutonium is shown in Table 2.

Table 2. Britain's military inventory of plutonium

Central estimates in tonnes, 31 December 1995

Source Tonnes

Windscale piles

0.4Calder Hall and Chapelcross 3.0Initial discharges from civil reactors 0.2

Subtotal 3.6

Losses in reprocessing and weapon production (c. 3%) -0.1Losses through weapon testing -0.3Transfers to the US -0.1

Subtotal, weapon-grade  3.1

Fuel- or reactor-grade plutonium production

transfers to the US

exported to other countries for civil purposes 10.7

-1.3

-0.7

Subtotal, fuel- and reactor-grade

TOTAL, all grades 8.7

11.8 ±15%

Source: David Albright, Frans Berkhout and William Walker, SIPRI, Plutonium and Highly Enriched Uranium 1996 (Oxford University Press: Oxford, 1997), Table 3.13.

A total inventory of 3.1 tonnes of weapon-grade plutonium leaves the UK with a substantial margin above its weapon needs. If 300 warheads is taken as an upper bound of the warhead deployments on Trident submarines, the total British arsenal could be served by an inventory of around 1.5 tonnes of weapon-grade material. ₁₂ Less than one tonne would be sufficient to sustain a nuclear arsenal comprising 96-144 warheads.

2.3 Tritium acquisition for weapons

Before the 1980s, most tritium used in Britain's nuclear warheads was acquired from the US under the Mutual Defence Agreement. ₁₃ In January 1996, the US Department of Energy announced in its 'Openness Initiative' that it had supplied 6.7 kilograms of tritium to the UK under the barter arrangements. Since the early 1980s, however, tritium has been mainly acquired through neutron bombardment of lithium targets at the Chapelcross reactor. The tritium has been extracted from the targets in a chemical processing facility constructed on the Chapelcross site. The quantities of tritium produced at Chapelcross have not been disclosed.

Without detailed knowledge of fuelling arrangements at Chapelcross, Britain's tritium production is very difficult to estimate. Even if warhead numbers were known, the amounts of tritium contained in them could not be judged without knowledge of warhead designs. The total tritium inventory at any time may be only a few hundred grammes, but unlike plutonium and HEU it needs constant replenishment due to tritium's comparatively short half-life.

It should be noted that the Chapelcross reactor has already operated for 35 years and is approaching the end of its lifetime. If Britain is to maintain its deterrent beyond the next 20 years, it will need either to build a large strategic stockpile of tritium or to find alternative sources of supply. As the possible alternative sources are all expensive or controversial, the assembly of a stockpile seems the more likely approach. It is therefore possible that Chapelcross is currently being operated to produce tritium at rates well above the annual requirement.

2.4 Acquisition of HEU for civil purposes

No detailed studies of Britain's production and usage of HEU for civil research purposes have been published, and information on current and past inventories has not been released by governments. ₁₄ The UK may have used some of the HEU produced at Capenhurst in the 1950s for these research purposes. A study by the US Nuclear Regulatory Commission asserted that a total of just over two tonnes of HEU had been exported to the UK for use in research reactors. ₁₅

Matters are complicated by British exports or re-exports of HEU, and by the separation of HEU at Dounreay from irradiated fuels. Britain is known to have supplied small amounts of HEU fuel to a few countries, especially in the 1950s and 1960s at the height of the research reactor 'boom', although the precise quantities and destinations have not been published. An article in the journal Atom reported that the UK had recovered more than 1.7 tonnes of HEU from thermal research reactor fuel (domestic and foreign) through reprocessing at Dounreay, although it did not reveal the amount of 235U contained in the recovered material nor its fate.

In the civil as in the military sector, it is therefore not easy to make sense of Britain's acquisition and usage of HEU. Because Britain has relied so heavily on imports from the US, large uncertainties will persist until the British and/or US governments declassify information relating to them.

No HEU is currently being used to fuel British research reactors. Recent attempts to keep the Dounreay reprocessing plants in operation by importing spent research reactor fuels seem likely to end in failure, due to the legacy of accidents and technical difficulties at Dounreay and to the US' recent reversal of an earlier decision not to take back and to store US-origin fuels irradiated in foreign research reactors.

3. Civil Reprocessing

3.1 Reprocessing of domestic spent fuels

Between 1961 and 1993, just over 62 tonnes of plutonium were discharged in spent fuels from Britain's civil power reactors, making it the fifth largest producer behind the US (236 tonnes), France (111 tonnes), Japan (80 tonnes) and Canada (67 tonnes). However, among these countries Britain has separated a disproportionately large quantity of plutonium from civil spent fuels. The main explanations for its heavy commitment to reprocessing lie firstly in the construction in the 1950s and 1960s of Magnox reactors which use a metallic fuel element that corrodes in water and then has to be reprocessed, and secondly in the influence that the UK Atomic Energy Authority and then British Nuclear Fuels Ltd (BNFL) have exerted over successive governments and over utilities. ₁₆ BNFL's influence has emanated from its monopolistic position in British fuel-cycle markets, its large foreign earnings, and its involvement in the production, storage and processing of fissile materials for the nuclear deterrent.

Early on, Britain adopted a policy of 'total reprocessing' to which it is still formally attached, despite the adoption of Advanced Gas-Cooled Reactors (AGRs) and Light-Water Reactors (LWR) in subsequent investment programmes. ₁₇ Spent fuels from these reactors can be stored in air or water over long periods. Thus Britain had separated about 59 tonnes of plutonium from domestic fuels by the end of 1996, with a further 12 tonnes anticipated by the end of the year 2000. In comparison, the US had separated just two tonnes, having adopted a 'once-through' fuel-cycle which dispensed with reprocessing. France is the only other country that has consistently reprocessed all of its domestic fuels. Russia has only reprocessed fuel from its light-water reactors - RBMK fuels have been stored - and Germany and Japan have been forced by circumstance to rely on British and French reprocessors and to store increasing amounts of spent fuel.

What makes Britain unique is its lack of any current plans to utilise the plutonium separated through reprocessing. It was envisaged in the 1950s and 1960s that plutonium would increasingly be required by the fast breeder programme. However, Britain's fast reactor programme was abandoned in 1994 by which time only 5 tonnes of plutonium had been used in one reactor, the Prototype Fast Reactor at Dounreay. Furthermore, no British plutonium has been recycled in conventional power reactors ('thermal recycling'), ostensibly because of the technical and economic unsuitability of plutonium usage in AGRs. This contrasts with the situation in France, Germany, Japan and other countries where utilities have striven to develop MOX recycling programmes in order to absorb plutonium as it is separated. Britain alone has appeared unconcerned about stockpiling plutonium.

As a consequence, Britain has amassed the world's second largest stockpile of civil plutonium (France alone has surpassed it). According to the latest government figures, 45.5 tonnes of civil plutonium separated from British reactor fuels were being stored at Sellafield at the end of March 1996. ₁₈

3.2 British reprocessing of foreign spent fuels

Britain began reprocessing foreign fuels after supplying the Latina and Tokai Magnox reactors to Italy and Japan respectively in the early 1960s. The spent fuels were routinely dispatched to Sellafield for reprocessing in the B205 plant. Of around 5 tonnes of plutonium separated from these Italian and Japanese fuels, some 1.7 tonnes are still held in store at Sellafield and may not be repatriated. The return of separated products (plutonium and wastes) was not mandatory under these early contracts.

In the 1960s the UKAEA, which operated the Sellafield site until 1971, began bidding for foreign contracts to reprocess the oxide fuels used in light-water reactors which were being built in large numbers around the world. The B204 and B205 plants were adapted for the purposes, but an accident in 1973 caused the B204 facility to be shut down permanently. ₁₉ It was then decided to build a new dedicated plant at Sellafield (the Thermal Oxide Reprocessing Plant, THORP), partly encouraged by the US decision in the mid-1970s to abandon civil reprocessing which had left a large unrequited demand for reprocessing services from Japanese and German utilities in particular.

The contracts secured from the late 1970s onwards are shown in table 3. Around 64 tonnes of plutonium, of which 44 tonnes would be foreign-owned, would be separated if these contracts were fulfilled. ₂₀

Construction of the THORP plant was recommended by Mr Justice Parker when the Windscale Inquiry was concluded in 1978. The then Labour government accepted the recommendation and construction began soon afterwards. In June 1997, nearly 20 years later, it has still not been fully commissioned. Indeed, there are now doubts that the plant will be operated as planned.

The fundamental problem for THORP's operators and advocates is that there is no longer a market demand for its products. Because world supplies of uranium and

Table 3. Contracts for fuel reprocessing at THORP, end of 1995

Figures are in tonnes of heavy metal (spent fuel)

Country1994-2004 ('baseload')Post-2004

UK

Nuclear Electric

Scottish Nuclear

1540

618

1520

1080Germany 884 703Italy 143 -Japan 2673 -Netherlands 53 -Spain 145 -Switzerland 422 -Total 6478 3303

Estimated plutonium content (tonnes)

46

18

Source: David Albright, Frans Berkhout and William Walker, SIPRI, Plutonium and Highly Enriched Uranium 1996 (Oxford University Press: Oxford, 1997), Table 6.4. See the footnotes to that table for a full explanation of the above figures. The plutonium content is derived from estimates elsewhere in the book.

enriched uranium are so plentiful, and their prices are so low, plutonium cannot compete as a reactor fuel in normal circumstances. Furthermore, it was once believed that the separation of waste products, and the concentration of the most radioactive materials in relatively small volumes of 'high-level wastes' (HLW), through reprocessing would greatly ease the task of waste disposal. This has not turned out to be the case. Reprocessing increases rather than decreases the volumes of waste material requiring disposal; the underground space required for the disposition of HLW is little different from that required by unreprocessed spent fuel; and reprocessing leaves behind a contaminated plant which is difficult and costly to disassemble.

Foreign utilities initially signed contracts with BNFL because they believed that plutonium fuels would be cost-effective, especially in fast breeder reactors. The attraction to utilities of these contracts today rests largely on their ability to use Sellafield as a storage site for spent fuel, plutonium and waste. Because utilities face difficulties in expanding spent fuel storage at home, and because transporting plutonium and high level wastes back home (especially to Germany and Japan) is problematic, they would probably be content if the great majority of spent fuel dispatched to Sellafield could remain there and not be reprocessed.

Although BNFL continues to try to implement the reprocessing contracts, it looks increasingly likely that Sellafield will evolve into a long-term spent fuel storage site, and that the amounts of spent fuel reprocessed there will decrease rather than increase over the coming 10 to 20 years. This prospect has been made still more likely by the operating and regulatory difficulties now besetting THORP. The ability to reprocess foreign fuels in THORP has been jeopardised by the last government's decision to deny NIREX permission to develop a site for the disposal of intermediate-level wastes in the vicinity of Sellafield; ₂₁ and there have been reports that THORP's throughput is currently being constrained by a mistake made in calculations of tritium emissions to the atmosphere, the consequence of which is that BNFL is having to keep throughputs to low levels to keep within the current licensing consent. ₂₂

For all these reasons, BNFL may soon be obliged to enter discussions with foreign utilities on the alternatives to reprocessing. There are two main options. One is to retain the spent fuel already delivered to Sellafield (the great majority of that which has been contracted for) in store over the long term, with the option of reprocessing possibly being retained in case conditions in energy markets change. The other, less likely option, is to return the spent fuel to its sender. Complex issues, contractual and otherwise, would have to be addressed if reprocessing did not proceed as planned, partly because foreign utilities have already spent large amounts of money on the construction of THORP. However, an outcome satisfactory to all parties can be imagined since the foreign utilities will remain beholden to BNFL for storage services.

THORP's future, and by extension the future of reprocessing and indeed of BNFL, will present the new Labour government with difficult decisions, not least because of Sellafield's location within a cabinet minister's parliamentary constituency and because of strong Trades Union representation on the site. Although the financial and institutional implications are complex, and there will be pressure on the government to continue resisting change, a fundamental reassessment of Britain's spent fuel management and disposal policies is overdue.

3.3 Reprocessing of Submarine spent fuels

Hitherto, the spent fuels discharged from Britain's nuclear submarines have not been reprocessed. As a result, the enriched uranium left after the irradiation of HEU has not been recovered, and substantial quantities of spent submarine fuel have accumulated in storage ponds at Sellafield. The decision to store rather than reprocess this fuel may be due to the presence of contaminants which make the re-use of separated enriched uranium unattractive. As with the decommissioned submarines in dock at Rosyth the MoD seems to be at a loss to deal with these residues from the past.

4. Summary: Britain's military and civil inventories in perspective

Maintaining confidence that fissile materials are not being acquired covertly by state or sub-state actors is a central objective of nuclear arms control. Under the NPT, all parties without nuclear weapons are obliged to submit their nuclear facilities and materials to international safeguards. The situation in nuclear weapon states, where the bulk of nuclear material is located, is much less satisfactory. The extent to which their nuclear materials and facilities should be submitted to international verification has become controversial since the end of the Cold War.

Military Inventories

Britain's military inventories of fissile material may amount to about 8 tonnes of HEU and 12 tonnes of plutonium (one-quarter weapon-grade and three-quarters reactor-grade). These stocks are on a par with those held by France and China, but are dwarfed by the US and Russian stocks which are together estimated to comprise 1700 tonnes of HEU and 230 tonnes of plutonium.

The scale of the excesses of fissile material held by the NWS is becoming an important political and regulatory issue. To date, the US and Russia have declared excesses that total just over 700 tonnes of fissile material. ₂₃ British government officials have hitherto claimed that the UK possesses no excess material.

Because so little is known about HEU acquisitions from the US, the estimated quantity of HEU acquired by the UK carries an especially large error margin. If the quantities that are now held by the UK amount to less than 10 tonnes, the excess over requirements for both weapons and submarine reactor fuelling may be slight. If the quantities exceed 10 tonnes, Britain could probably safely declare an excess.

Where plutonium is concerned, over ten tonnes may confidently be regarded as excess to weapon requirements. This includes at least 1.5 tonnes of weapon-grade material, together with the entire stock of fuel- and reactor-grade material that is held outside safeguards.

Official claims that the UK possesses no excess fissile material in its military inventories are therefore not credible. It is possible that part of the plutonium surplus is being held in reserve to keep open the option of bartering it for additional supplies of HEU and tritium from the US under the Mutual Defence Agreement. Policies towards the plutonium excess may therefore be affected by an HEU shortfall, if one exists.

Civil inventories

The government has announced that 48.5 tonnes of separated civil plutonium are held in store in the UK, of which 3 tonnes are owned by foreign utilities. If operated according to plan, THORP would separate around 46 tonnes under the first ten years' contracts, of which some 20 tonnes would be of British origin. Together with continued reprocessing of Magnox fuels, and in the absence of a disposition policy, Britain's stock of civil separated plutonium could approach 70 tonnes by 2010. The plutonium stockpile would be considerably larger if materials were separated from foreign fuels and were not repatriated.

Britain's civil inventory of separated plutonium therefore dwarfs its military inventory (the obverse of the situation in Russia and the US) and is likely to remain considerably larger than France's inventory because France has an established recycling policy which seeks to maintain a balance between supply and demand. However, France also faces the prospect of storing foreign separated plutonium that cannot be repatriated.

The government has published no information on Britain's civil inventory of HEU. However, such information is routinely assembled by the Department of Trade and Industry and transmitted to the Euratom Safeguards Directorate (see below). There are thus no practical reasons why it should not be published.

5. Disposition of Excess Civil Plutonium

Disposing of excess stocks of military plutonium and HEU will be a formidable task for Russia and the US. Together, they possess some 1300 tonnes of HEU and 150 tonnes of plutonium that are surplus to any anticipated military requirement. The same does not apply to the UK, where only a few tonnes of material are involved.

It should be noted, however, that an undeclared quantity of spent submarine fuel, containing undeclared quantities of depleted HEU, is being held in store at Sellafield. What are the Ministry of Defence's plans for dealing with this material? Comparatively small, but possibly troublesome, quantities of plutonium and HEU may also be present in contaminated buildings, equipment, scraps and wastes at Aldermaston and Burghfield in particular. There is no public information on these inventories, nor on MoD's policies towards them.

The main difficulties for Britain lie with the stock of 50 or so tonnes of reactor-grade plutonium that has accumulated over many years, especially at Sellafield. The scale of this disposition problem is similar to that facing the US and Russia in regard to weapon-grade material. To date, British governments have developed no plans for disposing of this stock of surplus plutonium. Indeed, it appears that they have not even addressed the issue. Insofar as a policy exists, it is one of indefinite storage, with the vague prospect held out that the material might one day be needed in Britain's reactors.

Hitherto, there has been little internal or external pressure on Britain to engage in plutonium disposition. This is unlikely to last, for three reasons. Firstly, the difficulties facing reprocessing will itself focus political attention on the fissile materials located at Sellafield, whether they be held in spent fuel or in separated form. Even if continuing storage provides the only immediate solution, what should happen to those materials in the medium and long terms? Some form of disposal, preceded by steps to achieve conformity with the spent fuel standard (see below), may be considered the only prudent option, especially where plutonium is concerned.

Secondly, Britain's lack of a disposition policy will become more evident if policies are implemented by Russia and the US in particular. While their disposition strategies will focus on weapon-grade materials, there may be political linkage to other stocks, especially if the US also presses Russia to dispose of large surplus stocks of civil plutonium, and if China makes an issue of Japan's stock as a condition for supporting disposition strategies.

Thirdly, the closer the world moves towards nuclear disarmament, the more sensitivity will be attached to the stockpiling of weapons-usable materials. In a nuclear weapon-free world, a likely presumption is that all countries should avoid such stockpiles and should take steps to eliminate them wherever they have accumulated.

In considering how to deal with excess plutonium, the US National Academy of Sciences (NAS) argued persuasively in favour of a 'spent fuel standard':

'Options for the long-term disposition of weapons plutonium should seek to meet a 'spent fuel standard' - that is, to make this plutonium roughly as inaccessible for weapons use as the much larger and growing stock of plutonium in civilian spent fuel.' ₂₄ 

NAS carried out a detailed assessment of two technical approaches to meeting the standard. One was to burn plutonium in mixed uranium-plutonium oxide (MOX) fuel in power reactors. The other option was to blend plutonium with high-level wastes that had already been separated through reprocessing. In effect, this would restore the isotopic mixture contained in the spent fuel from power reactors, the resulting mixture being vitrified prior to long-term storage or disposal. This technique is often referred to in the US as plutonium 'immobilisation'.

Achieving the spent fuel standard through a dual strategy of MOX recycling and plutonium-waste blending has since become the policy of the US government. Pursuit of both options has been accepted as a desirable objective in most international discussions on plutonium disposition.

In the British case, only a very small proportion of the current stock of plutonium could be disposed of through recycling. It would take over a century to burn this material in Britain's only light-water reactor (Sizewell B); and it is a fair assumption that no other country would take on the task of recycling the material on Britain's behalf. The second option - blending the material with the substantial quantities of high-level wastes that have accumulated from reprocessing operations - is therefore the only one that provides a plausible alternative to long-term storage.

Beyond paper studies, no work is being done in the UK to develop such blending and disposal techniques. Why? One reason is that storage has become a well established practice at Sellafield: the techniques work, storage generates a steady income for BNFL from the utilities that own the plutonium, and storage in well engineered facilities appears safe and secure. The other main reason is that a disposition policy other than recycling is bound to involve plutonium being regarded and dealt with as a waste. As a result, the development of even the option to pursue this policy might fatally damage the rationale that underpins reprocessing. Why separate plutonium, except where the corrosion of Magnox fuels makes reprocessing unavoidable for safety and environmental reasons, if plutonium is a waste and thus has negative value?

Whatever the explanation, a research and development (R&D) programme on plutonium immobilisation deserves to be established to make up for this neglect. Co-operative links might beneficially be sought with the extensive R&D programme that has already been launched in the US.

A civil plutonium disposition strategy for the UK might therefore begin with three steps:

1. examination of the scope for substituting a policy of long-term storage of British spent fuels for the current policy of reprocessing, together with storage of foreign spent fuels where there is little confidence that plutonium separated from it will be returned, thereby avoiding further unnecessary accumulations of plutonium;

2. the launch of an R&D programme, possibly in co-operation with the US and other countries, to develop techniques for bringing surplus plutonium into conformity with the spent fuel standard, including the option of blending plutonium with high-level wastes and vitrifying the resulting product;

3. exploration of the scope for recycling plutonium in Sizewell B or in foreign reactors, and the financial and other conditions under which their operators might be prepared to burn British plutonium.

6. Transparency and international safeguards in the UK

No formal statement has been made by this or preceding governments on Britain's policy towards the transparency and safeguarding of fissile materials in the UK. The prevailing approach may be summarised as follows:

1. All civil materials produced, used or stored in the UK will be placed under international safeguards. When facilities no longer serve military purposes, they too will be placed under international safeguards, together with their products. When facilities serve a dual civil-military purpose, the civil materials processed therein may be submitted to international safeguards.

   All safeguards-relevant information concerning Britain's civil materials and activities is therefore made transparent to international safeguards agencies.

2. No materials acquired historically for military purposes, nor produced in dedicated military facilities, are currently under international safeguards. All information relating to them is classified.

   At the NPT Extension Conference in May 1995, Britain and the other NWS Parties accepted, when consenting to the Principles and Objectives, that 'fissile material transferred from military use to peaceful nuclear activities should, as soon as practicable, be placed under IAEA safeguards, in the framework of the voluntary safeguards agreements in place with the nuclear-weapon States'. However, no material produced for military purposes has yet been declared excess to requirements by the government and transferred to peaceful nuclear activities. Until that happens, this obligation will not alter the actual scope of safeguarding in Britain.

As will be discussed below, Britain has gone further than any other NWS in making its non-military nuclear materials and activities available to international safeguards.

Nevertheless, the British policy on transparency remains fundamentally conservative. Information on fissile materials required for defence purposes, and information on the operation of associated production or processing facilities, remains classified. It is revealed neither to the British public nor to safeguards agencies. Unlike the US government, the British government has not embarked on a programme of declassification since the end of the Cold War. Nor has it been prepared to identify stocks of material that have become surplus to military requirements. I shall return to this issue.

6.1 The civil domain: international safeguards in the UK

In most respects, the situation concerning nuclear safeguards in the UK (and France) is far superior to that pertaining in China, Russia and the US where very few facilities are under routine international safeguards. This is largely due to the application of safeguards in Britain under the Euratom Treaty. ₂₅

Under Chapter VII of this Treaty the Euratom Safeguards Directorate, which is part of the European Commission, is required to ensure that nuclear materials "are not diverted from their intended uses as declared by the users". ₂₆ All materials that are declared as serving civil purposes must therefore be placed under Euratom safeguards in all member states of the European Union (EU). Mandatory safeguards are therefore applied to civil materials and their associated production activities in non-nuclear and nuclear weapon states within the EU. However, only peaceful uses are affected as Article 84 of the Euratom Treaty states that "safeguards may not extend to materials intended to meet defence requirements". ₂₇ This same Article is also cited when France and the UK invoke rights to withdraw materials from Euratom safeguards.

The IAEA safeguards system does not place the NWS under the same obligations. Article III of the NPT only requires non-nuclear weapon state parties to submit to IAEA safeguards. During the NPT's negotiation, however, many states argued that this exemption would be unfair and discriminatory in both political and commercial respects. In order to assuage such concerns, the British and US governments offered in 1967 to submit peaceful nuclear activities to international safeguards on a voluntary basis. As a result, they and France concluded 'voluntary offer' agreements with the Agency in the second half of the 1970s. The Soviet Union and China followed suit in the mid- to late-1980s.  ₂₈

These agreements are voluntary in two respects. The NWS voluntarily declare the facilities (on a 'facilities list') which may be submitted to IAEA safeguards, and the IAEA chooses which of those facilities it wishes to 'designate' for inspection. ₂₉ The IAEA may terminate that particular inspection, just as the NWS may withdraw facilities from the facilities list, and materials from the agreement.

In 1970, the IAEA Board of Governors announced the criteria (the 'Timbs criteria') that would be used when selecting facilities at which safeguards would be applied in the IAEA. Plants of advanced design would be selected if the IAEA could thereby gain experience of value to safeguarding in Non-Nuclear Weapon States (NNWS), or if the plants were foci for commercial competition between NWS and NNWS. It was also specified that the selection of plants would be rotated where possible, so that they would not be placed permanently under safeguards.

There are, however, two contexts in which IAEA safeguards are mandatory in the UK. Firstly, the UK, Australia, Germany, Holland, Japan and US, in conjunction with Euratom and the IAEA, concluded an agreement (the Hexapartite Safeguards Project) in 1983 whereby all civil centrifuge enrichment plants must be subjected to permanent IAEA inspection. ₃₀ The centrifuge facilities at Capenhurst are therefore constantly monitored by the IAEA. Secondly, Japanese fissile materials that are located in the UK must be placed under IAEA inspection according to a pre-NPT safeguards agreement between Japan, the UK and the IAEA which is still extant. Under it, all Japanese plutonium at Sellafield (or an amount equivalent to it) must be placed under IAEA safeguards. ₃₁

Attention should be paid to two recent occasions on which the UK government has been drawn into clarifying its stance on the scope and application of IAEA safeguards. In the Principles and Objectives agreed at the 1995 NPT Extension Conference, the nuclear weapon states made the commitment that 'nuclear fissile materials transferred from military use to peaceful nuclear activities should, as soon as practicable, be placed under IAEA safeguards', implicitly making those inventories transparent. If and when such transfers occur, the UK will therefore be obliged to submit them to IAEA as well as to Euratom safeguards.

The other occasion involved the agreement in May 1997 by the IAEA Board of Governors on the Model Protocol which concludes the IAEA's 93+2 Programme. The British representative informed the Board about the respects in which the new measures, which are applicable primarily to NNWS Parties to the NPT, will be applied by and within the UK. The details need not be rehearsed here. Britain has pledged inter alia to accept more intrusive measures at designated facilities, and to provide more information about facilities that are open to safeguards. However, they do not fundamentally change the terms under which IAEA safeguards are applied in the UK or, for that matter, in the other NWS. The British government's stated position at the meeting in May 1997 was that:

"implementation of the Protocol measures in the United Kingdom is founded on the proposition that we should be ready to accept those measures which, when implemented by the UK, would either:

1. contribute to increasing the Agency's capability to detect undeclared nuclear activities in non-nuclear weapon states; or

2. improve the effectiveness or efficiency of Agency safeguards at facilities in the UK designated for Agency inspection.

A further principle we have adopted is that, where information is provided on activities at a particular location, access by Agency inspectors to that location would also be granted, subject to the same conditions that would apply to non-nuclear weapon States under the Model Protocol." ₃₂

Current scope of Euratom and IAEA safeguards in the UK

The UK signed the Euratom Treaty in 1972 and safeguards were gradually extended across civil nuclear facilities and materials in the years that followed. This was not a straightforward operation, not least because Britain's fuel-cycle facilities were not originally designed for stringent safeguarding and several of them were dual-purpose, supplying both military and civilian requirements. For example, the B205 plant reprocessed spent fuel from the Calder Hall and Chapelcross production reactors as well as from civil power reactors. The need to apply Euratom safeguards led BNFL to run distinct civil and military reprocessing campaigns, as well as to introduce new measurement and recording techniques at the B205 facility.

Since the government's announcement in early 1995 that Britain's production of enriched uranium and plutonium for military purposes had ceased, steps have been taken to bring facilities formerly involved in this production under Euratom safeguards. The military centrifuge enrichment plant at Capenhurst had already been transferred to civilian production, and was thus eligible for international safeguards, in the late 1980s; the Calder Hall production reactors were placed under Euratom safeguards in 1996; and all plutonium separation carried out in the UK (at Sellafield and Dounreay) is now under the same safeguards, with the single exception of plutonium from the Chapelcross reactor which is Britain's source of tritium and is being kept outside Euratom and IAEA safeguards as a consequence.

Table 4 shows the coverage of Euratom safeguards in Britain today. Facilities that remain outside these safeguards include the reactors and tritium processing facilities at Chapelcross; fuel fabrication facilities at Ansty where submarine fuels are manufactured; certain plutonium, HEU and submarine fuel stores at Sellafield, Ansty and elsewhere; the Vulcan submarine reactor research facility at Dounreay; and the entire Aldermaston and Burghfield sites where warhead components and warheads are assembled and disassembled.

Table 4. International safeguards status of main nuclear sites and facilities in the UK, May 1997

Sites/facilitiesEuratom safeguardsIAEA safeguards

Power reactor sitesCivil Magnox, AGRs, LWRYesNot designated

Sellafield

B205 reprocessing plant

Yes (less Chapelcross materials)

Not designatedTHORPYesReceipt & storage ponds;Plutonium storesYes (civil-origin only)Store 9; THORP stores (eventually) Calder Hall reactorsYesNot designatedSpent submarine fuel storesNoNo

Chapelcross

Reactors

Tritium extraction plant

Uranium stores

No

No

Yes

No

No

Not designated

SpringfieldsFuel fabrication plantsYesNot designatedFeedstock for Chapelcross & submarine fuelsNoNo

CapenhurstEnrichment plantsYesYesDepleted uranium storesYes (civil-origin only)No

AnstySubmarine fuel fabrication and HEU storesNoNo

HarwellAll facilities & materials Yes (except some samples)Not designated

DounreayAll civil facilities & materialsYesNot designatedVulcan naval research facilityNoNo

Aldermaston

All facilities & materials

No

No

Burghfield

All facilities & materials

No

No

The scope of IAEA safeguards in the UK is both more limited and more complicated, as Table 4 indicates. Only three facilities are currently under IAEA inspection: the Capenhurst enrichment plants, the THORP receipt and storage ponds (due to the presence of foreign plutonium-bearing fuels), and 'store 9' containing separated plutonium (due to the presence of foreign plutonium and the need to practise substitution). However, all British power reactors, and nearly all facilities and materials at Sellafield, Dounreay, Harwell and Springfields are under Euratom safeguards and are available to be designated for inspection by the IAEA. Material accounting information from these facilities is routinely passed from Euratom to the AEA, and the safeguards rules and procedures applied at these sites are fully in accordance with IAEA practices.

Table 4 shows that there are still large parts of the British nuclear infrastructure that lie outside international safeguards. Nevertheless, an extensive international safeguards 'culture' has been established in Britain since the early 1970s embracing most of the major nuclear sites and involving dedicated administrative units within industrial firms and within the Department of Trade and Industry. The extent to which this culture, or elements of this culture, now extends to sites operated by the Ministry of Defence (notably Aldermaston and Burghfield), and to MoD bureaucracies, is unknown. But there is no doubt that Britain, along with France, has a much deeper experience of international safeguards than the US, Russia or China. This will stand it in good stead with regard to future verification provisions of an FMCT, and indeed for the verification of nuclear disarmament in the longer term.

6.2 The military domain: transparency and verification

Previous British governments have gone to great lengths over many years to increase the transparency of civil nuclear activities and to submit them to international safeguards. This has extended to the regular publication of statistics on plutonium inventories at a level of detail surpassed since 1994 only by Japan. For several years, the Department of Trade and Industry has provided Parliament with an annual report on Britain's holdings of civil plutonium. Partly in recognition of this by now established tradition, a British official has held the chair at the 'Informal Discussions on Plutonium-Related Issues' convened by the IAEA in Vienna since their inception in 1994. ₃₃ These discussions have mainly focused on transparency issues.

Where fissile materials in the military sector are concerned, the situation is very different. There is no transparency and no international verification in the UK. Nor is there public accountability beyond broad ministerial responsibility to a parliament which has little grip on these matters because it lacks information and analysis. In these respects the UK now lags well behind the US. In particular, it has not followed the example set by the US government in its 'Openness Initiative' whereby every site involved in the production, storage and usage of plutonium and HEU for military purposes has been submitted to meticulous scrutiny. The US Department of Energy's objective has been to establish and publish complete inventories of material, site by site. In January 1996, detailed inventories of plutonium were published, to be followed by inventories of HEU later in 1997 or in 1998.

Why have British governments held to the policy of withholding all information about fissile materials in the military sector? There are two main reasons. The first is that the number of warheads in the British arsenal has long been a sensitive issue. Because the arsenal was so much smaller than the Soviet arsenal during the Cold War, maintaining uncertainty about capabilities was important to the credibility of Britain's 'minimum deterrent'. Throughout this period, large strategic reserves of fissile material were not held by the UK, so that information on trends in fissile material production and stocks might have been useful to foreign powers wishing to estimate current and future warhead numbers. ₃₄ The classification of information on fissile materials became standard practise within the Ministry of Defence as a consequence.

It is also worth noting that Britain has not participated in arms control processes that have involved the limitation or reduction of nuclear weaponry, and that have entailed verification and thus a degree of mutual transparency. Because the UK has not been Party to SALT or INF or START treaties, officials in Whitehall have not become accustomed to telling others about Britain's nuclear capabilities (the same applies to France and China).

Probably the most important contemporary reason for the policy of opaqueness is that transparency might cause political and administrative inconvenience, reduce the autonomy of the elites that take decisions, and affect the options available to them. There are histories that have not been told (e.g., relating to the US-UK Mutual Defence Agreement) and that might more conveniently be left untold; and there are decisions (e.g., relating to tritium supplies) that might become more complicated if opened to public discussion. Transparency is an invitation to the uninitiated to acquire influence over outcomes. Where decision-making elites can avoid it, they will avoid it, irrespective of the possible consequences for the quality of their decisions.

The British government's policies on the classification of information relating to fissile materials in the military sector seem less justifiable today. If it is true that Britain now possesses large excess stocks of fissile material, the size of its inventories will no longer provide such insights into the size of the nuclear arsenal. In any case, the size of that arsenal is rapidly becoming a non-secret as government statements gradually narrow down the range of uncertainty. There is now more public knowledge about Britain's nuclear warhead deployments than about fissile material inventories. Where is the logic in this?

The habit of opaqueness in Britain, as in other NWS where it still applies, has increasing costs. Transparency has acquired still greater importance as an instrument of international security in recent years. The measures taken to strengthen the IAEA safeguards system under the '93+2 Programme' provide the most important example in our context. There is now pressure on the NWS to take steps under the banner of 'universality' to increase transparency, initially in relation to those parts of military inventories and infrastructures that are 'excess' to requirement, and ultimately in relation to their entire assets as they fulfil their treaty obligations to engage in nuclear disarmament. Despite the present British government's above-mentioned statement in Vienna on 15 May, it has yet to make any concessions on the transparency or verification of military inventories. So long as nuclear weapon states resist calls for transparency in their own backyards, non-nuclear weapon states will grudge their support for the reformed safeguards system.

This is not the only cost. Transparency has a double purpose: it raises confidence among states in their good behaviour and intentions; and it is an administrative driver within states. The Ministry of Defence claims that its material accounting practices are as effective and stringent as those established in the civil sector. However, there has been no parallel to the effort expended by US government officials and site operators under the Openness Initiative which has led, for the first time, to the assembly of a comprehensive, centralised and fully detailed register of US holdings of fissile materials. It should be recognised that even if it wished to declare Britain's own inventories it would be unable to do so, since it cannot know what those inventories comprise - in the detail that is desirable - without conducting a thorough review of production history.

One of the Openness Initiative's revelations concerned the scale of the 'inventory differences' that remained at US sites. An 'inventory difference', as defined by DoE, is a euphemism for 'material unaccounted for' (MUF) in the standard terminology of safeguards agencies. It is defined as the difference between book inventories (the materials logged during production and transfer) and physical inventories (the actual quantities measured in situ).

At seven sites, DoE found that the book inventory exceeded the physical inventory of plutonium by a total of 2.75 tonnes. The implication was that the US government could not, in January 1996, declare the fully accurate 'initial inventory' of fissile materials that is required from non-nuclear weapon states parties to the NPT in their agreements with the IAEA - and that would be required of all states in conditions of complete nuclear disarmament. The inventory discrepancies were largely caused by lax procedures in the first three decades of production. However, they have now been recognised, and great efforts are being devoted to finding their sources. Without the Openness Initiative, the differences would not have attracted attention and explanations would not have been sought. ₃₅

Robin Cook, the new Foreign Secretary, stated in 1995 when in opposition that "confidence-building requires transparency and verification. As a starting point, the nuclear weapons states should declare their existing inventories of plutonium and highly enriched uranium to the IAEA, and open to inspection their nuclear production facilities". ₃₆ Although this statement requires clarification, it implies that the new Labour government will be less conservative than its predecessor and will act to increase transparency.

Absolute transparency cannot be the objective. As always, care has to be taken to ensure that information useful to foreign powers, and in particular to nuclear weapon designers, would not be released. What is being asked is that the government should begin to distinguish, through honest internal inquiry, between that material which is and is that which is not required for defence purposes, and between information that would and would not assist an adversary or nuclear proliferator. The answer that all material is required and no information can be divulged no longer suffices. The aim should be to come as close as possible to matching the US example of compiling a comprehensive historical record of fissile material production and acquisition for defence purposes.

By following the US example, Britain would help to establish a new behavioural norm among nations with nuclear weapon programmes. Even though their military programmes would remain outside international safeguards, those nations would be expected to compile, and as far as prudent to publish, comprehensive material inventories. This would demonstrate their commitment to maintaining tight control over fissile materials, so as to minimise risks of theft or diversion by state or sub-state actors (including terrorists). It would also demonstrate their commitment to preparing the ground for more comprehensive verification as the arms reduction process is taken further.

An important footnote: this initiative should be embarked upon at the earliest possible date as knowledge (and records?) held by the officials and operators involved in production in the early decades may soon be lost as old age takes its toll. Their knowledge may be vital to the assembly of coherent histories, and those histories may be vital to achieving the ultimate goal of verified nuclear disarmament. ₃₇

7. The Fissile Material Cut-Off Treaty

On 18 April 1995, Douglas Hurd, the then Foreign Secretary, made the following statement about British policies and intentions in his speech to the NPT Extension Conference:

"We want to see an early start to negotiation of a Cut-Off Convention. To remove all doubts about our commitment to this process, I can announce today that the United Kingdom has ceased the production of fissile material for explosive purposes." ₃₈ 

Britain's official support for the Fissile Material Cut-Off Treaty (FMCT) was expressed again in its endorsement of the Principles and Objectives at the end of the NPT Extension Conference. Article 4(b) called for 'the immediate commencement and early conclusion of negotiations on a non-discriminatory and universally applicable Convention banning the production of fissile material for nuclear weapon or other nuclear explosive purposes'.

At that time, the FMCT was still viewed with some scepticism in Whitehall. Every NWS, bar China, had announced an end to the production of fissile materials for weapons. As a consequence, it was claimed that the FMCT's primary value lay in the restriction of India's and Pakistan's nuclear weapon programmes. But it was considered unlikely that India and Pakistan would join the FMCT (much as they refused to join the CTBT in 1996). And there was concern about the extra regulatory burden that the FMCT would bring in its wake, including the increasing expenditure on IAEA safeguarding. The FMCT's costs might therefore exceed its benefits.

In my experience, this attitude has changed in at least some parts of Whitehall, where scepticism has given way to moderate enthusiasm for two reasons. One is the growing recognition of the important part that an FMCT would play in driving regulatory improvements in Russia, China and the US. The other is the realisation that Britain is best placed among the NWS to implement an FMCT, due to its already wide application and experience of international safeguards. For instance, all fuel-cycle facilities in the UK are today under international safeguards, whereas none are under safeguards in these other countries. Depending on the FMCT's scope, a wider range of facilities would have to come under IAEA safeguards, but those facilities would probably already have been submitted to Euratom safeguards over long periods.

Implementation of an FMCT would therefore probably be more straightforward for the UK than for any of the other NWS, with the possible exception of France which also has long experience of international safeguards through its membership of the Euratom Treaty. However, there are at least two issues that might be problematic, the second of which, although shared by the US, could be uniquely troublesome to the UK:

1. Verification of dual-purpose tritium/plutonium production reactors. The Chapelcross reactor, and material discharged from it, are being kept outside international safeguards because of the tritium produced therein for Britain's nuclear warheads. Under a Cut-Off Treaty, how would it be verified that plutonium produced in such reactors could not be used for military purposes?

2. Exchanges of fissile material under the US-UK Mutual Defence Agreement. Britain would continue to have access to a huge reservoir of weapon-grade material if those parts of this Agreement relating to fissile materials survive the FMCT, and if the US is prepared to continue responding to British requests for supplies. In such circumstances, an FMCT would not limit the future size of Britain's inventories of fissile material.

   The unofficial British position on this issue is that the FMCT only affects acquisition through production - it does not affect acquisition through transfers from stocks, wherever those may be held and whomsoever possesses them. Transactions under the Mutual Defence Agreement would therefore be permissible. While this may be a correct reading of the FMCT (as currently envisaged), it would almost certainly pose political difficulties for Britain or any other NWS to maintain the right to acquire fissile material for weapons purposes from another NWS. As noted earlier, this prospect might already be encouraging Britain to seek further imports of HEU from the US in advance of the FMCT.

   One option might be to announce that no further transfers of fissile materials for weapons purposes would occur under the Mutual Defence Agreement. This would leave open the door to transfers of material for naval reactors, but would presumably require verification.

At the time of writing, the FMCT is becalmed in Geneva. Non-aligned countries in the UN Conference on Disarmament (CD), with India in the vanguard, are refusing to allow negotiations to begin until an Ad Hoc Committee on Disarmament is also established by the CD. ₃₉ Apart from China, the NWS are refusing to accede to this demand. Furthermore, controversy has developed over the FMCT's scope. Should it include fissile material stocks as well as production? The narrow interpretation, reflected in the wording of the CD's mandate and the Principles and Objectives, is that the FMCT would only have a bearing on stocks produced after the Treaty's conclusion. A broader interpretation favoured by Germany among other NNWS is that the huge stocks amassed during the Cold War should also come under the FMCT's purview. Since those stocks would act as surrogate production systems, would an FMCT have any value if they were excluded from it?

On both of these issues, the previous British government adopted a rigid stance. It would not sanction the formation of an Ad Hoc Committee on Disarmament. Nor would it allow past stocks to be encompassed in the FMCT negotiations. Nor would it contemplate involvement in negotiation of a parallel 'excess stocks regime' that the author and others have advocated as ways out of that impasse. ₄₀ Its attitude was that the British positions on excess stocks and on the Ad Hoc Committee were non-negotiable.

There is a real danger that the international commitment to negotiate the FMCT will be aborted. Despite what the sceptics say, this would be a serious setback for arms control and disarmament. It would allow the regulatory situation in the NWS, and especially in Russia, to stagnate; an opportunity to limit the nuclear competition in South Asia, and to introduce further restraints into the Middle East, North Asia and elsewhere, would be missed; and the Treaty remains indispensable to any project of nuclear disarmament. It should also be recalled that the negotiation of this Treaty has been formally recognised by NPT Parties as being "important in the full realisation and effective implementation of Article VI". Abandoning this objective would set a bad precedent: it would imply that the Principles and Objectives, and any successor document, is a menu from which states can pick and choose.

It is therefore incumbent on the new British government to seek new ways of rebuilding enthusiasm for the Treaty and overcoming the current impasse over its negotiation. While it is understandable that the NWS will have reservations about the proposed Ad Hoc Committee on Disarmament, the possibility of making concessions in this direction to the non-aligned movement deserves to be explored in earnest rather than rejected out of hand. And although there are clear disadvantages in keeping excess stocks outside the FMCT's scope, the issue will not go away. It is too important. The British government should therefore encourage discussion of the means by which the regulation of these stocks might be addressed by the international community, and show a willingness to acknowledge that it too possesses stocks that would have to be put into the frame.

8. Conclusions: Questions that new Ministers might like to ask

Britain's regulatory policies on fissile materials have, since the early 1970s, rested upon the assumption that there are two domains, one military and the other civil, and that those domains are subject to different rules of governance and lines of authority. In particular, all activities and holdings in the civil domain are transparent and open to international verification, whereas all activities and holdings in the military domain are classified and closed to international verification.

Britain's fuel-cycle management policies have rested upon the assumption that all spent fuels discharged from power reactors should be reprocessed, irrespective of developments in markets for separated materials or in assessments of the best approaches to waste management and disposal. In the civil sector, it has also been assumed that supplies of plutonium need not balance demand: surpluses can be stockpiled, and their disposition can be postponed or evaded indefinitely.

These assumptions are unlikely to hold in the future. This observation must be the starting point in any reassessment of fissile material policies by the new British government. Transparency and verification, here as in other nuclear weapon states, will increasingly have to reach into the military domain as arms control initiatives are implemented and regimes are intensified. Reprocessing is yesterday's approach to the management of spent fuels, and the disposition of excess civil plutonium, civil or military, will replace its production as the international community's primary concern.

The implication is that big changes in policy should lie ahead. In considering those changes Ministers might begin by seeking answers to the following questions:

Defence Ministers

1. What are the current and anticipated UK military requirements for plutonium and HEU, and what are the anticipated excesses to those requirements? How much material, and which material, might be declared excess to requirements without impinging on the effectiveness of the nuclear deterrent? How much material in current stocks could therefore be brought under international safeguards?

2. How much plutonium and HEU has been acquired for military purposes? With which levels of accuracy can inventories of material at weapon sites, including inventories in wastes, be established? What are the outstanding 'inventory differences' (how much material is 'unaccounted for'?), site by site?

3. Why cannot or should not Britain follow the example of the US, in its Openness Initiative, and establish its total historic acquisitions of plutonium and HEU for military purposes? What would be gained and lost by publishing the results of this survey.

4. Would it be politically feasible to exchange fissile materials with the US under the US-UK Mutual Defence Agreement if a Fissile Material Cut-Off Treaty (FMCT) were negotiated? Is this exchange still pertinent in view of the reductions in Britain's nuclear arsenal and submarine fleet, and consequent reductions in demand for fissile material?

5. What are the plans for disposing of the spent submarine fuels held in store at Sellafield?

Trade and Industry Ministers

1. What is the probability that THORP will operate according to plan, given NIREX's problems in establishing a national repository for intermediate level wastes, BNFL's problems in meeting discharge regulations, and foreign customers' problems in taking back separated plutonium and nuclear wastes? What are the financial implications of THORP operating at reduced throughputs, or of its closure?

2. In the event that THORP does not operate according to plan, what contingency plans are being developed for managing spent fuels that have been delivered, or are due to be delivered, to Sellafield for reprocessing. Which policy alternatives are being discussed with British and foreign utilities, and what are their advantages and disadvantages?

3. What options are being developed, and which practical means devised, for disposing of Britain's large stockpile of separated civil plutonium?

4. What representations have been made to MoD to enable excess plutonium in the military inventory to be brought under international safeguards? What has been its response, and what reasons provided?

Foreign and Commonwealth Office Ministers

1. Has the value of the FMCT to arms control and disarmament been seriously underestimated and underrepresented? If so, why and in which ways? What steps can the British government take to rekindle enthusiasm for this measure?

2. What are the estimated additional costs to the UK of verifying an FMCT, and how do they compare with the costs that would be incurred in military and other budgets if no FMCT were negotiated?

3. What initiatives can and should the government take to help overcome the deadlock on negotiation of a Fissile Material Cut-Off Treaty? Which concessions could Britain give to the non-aligned movement in response to its calls for the establishment of an Ad Hoc Committee on Disarmament before it will engage in FMCT negotiations?

4. What discussions have taken place with MoD on the declaration of excess military stocks? What constructive stance can Britain take internationally in regard to the development of an 'excess stocks regime', inside or outside the framework of the FMCT?

Notes:

Note 1: Unless otherwise mentioned, all statistics quoted in this paper are drawn from David Albright, Frans Berkhout and William Walker, SIPRI, Plutonium and Highly Enriched Uranium: World Inventories, Capabilities and Policies 1996 (Oxford University Press: Oxford, 1997). Back.

Note 2: The best discussion of this Agreement is contained in John Simpson, The Independent Nuclear Deterrent: The US, Britain and the Military Atom (Macmillan: London, 1986). Back.

Note 3: Highly-Enriched Uranium (HEU) is defined as uranium containing over 20% of a fissile isotope Uranium-235, and is often referred to as weapon-grade uranium. Back.

Note 4: Urenco is the Anglo-Dutch-German joint enrichment company that operates centrifuge plants at Capenhurst, Almelo (Holland) and Gronau (Germany). Urenco only supplies low-enriched uranium fuels for power reactors. Back.

Note 5: In the US, unlike in the UK, the production of weapon-grade materials and warheads was vertically integrated under the auspices of the Department of Energy. In the UK, the Ministry of Defence managed warhead design and production but acquired fissile materials from other agencies. Back.

Note 6: The central estimate of 5.8 tonnes used in submarines is based upon the assumption that 65 reactor cores have been manufactured, each containing 90 kg of HEU on average. Submarine spent fuels have not been reprocessed in Britain - most are stored at Sellafield. Back.

Note 7: For an up-to-date assessment of the numbers of warheads in the British arsenal, see Malcolm Chalmers, 'British Nuclear Weapons Policy: The Next Steps', Special ISIS Report No. 1, May 1997, pp. 12-13. Back.

Note 8: Weapon-grade, fuel-grade and reactor-grade plutonium are defined as containing less than 7 per cent, 7 to 18 per cent, and over 18 per cent of the isotope 240Pu respectively. Back.

Note 9: In Magnox reactors, it is customary for one-sixth of uranium fuel in the reactor core to be discharged and replaced annually. The first discharge in a power reactor's operating life therefore has been submitted to a comparatively brief period of neutron irradiation (a low burnup), so that it contains low proportions of the even-numbered isotopes of plutonium. Back.

Note 10: This is the quantity announced by the US Department of Energy in January 1996. Back.

Note 11: Supergrade plutonium is defined as containing less than 3 per cent of 240Pu. Back.

Note 12: This assumes an average of 3.5 kilograms of plutonium per warhead, and 500 kilograms in the production pipeline and in strategic reserve. Back.

Note 13: Tritium is used to increase the neutron flux in fission bombs or primaries of thermonuclear weapons, with the objective of increasing the proportion of atoms that is fissioned and thus reducing the amount of fissile material required for a given yield. Back.

Note 14: In the civil sector, HEU is only used in research reactors, mainly to produce isotopes for medical and research purposes. No thermal power reactors operating in the world today use HEU fuels. From 1962 to 1971, the Demonstration Fast Reactor at Dounreay was fuelled with HEU containing some 7.5 tonnes of 235U. The total consumption of HEU was probably less than one tonne as discharged fuels were reprocessed and the extracted HEU rapidly recycled. Back.

Note 15: NRC Report to Congress on the Disposition of Highly Enriched Uranium Previously Exported from the US, Nuclear Regulatory Commission, Washington DC, January 1993. Back.

Note 16: The UKAEA's involvement in production activities ended in 1971 when BNFL was formed to take charge on a 'commercial basis' of its fuel-cycle operations, and nuclear power stations were transferred to the CEGB and SSEB. Back.

Note 17: On the margins, there have been some modest departures from this policy in the 1990s. Part of the Scottish privatised nuclear utility's fuel will be stored at Sellafield over the long term rather than reprocessed. Nuclear Electric has also not committed itself to the reprocessing of spent fuel from the Sizewell B light-water reactor. This reactor was deliberately constructed with large spent fuel storage capacity so that the utility would not be tied to reprocessing. Due to cost-cutting in the 1960s, AGRs were constructed with little storage capacity on site, weakening their bargaining position vis-à-vis BNFL. Back.

Note 18: 'Annual plutonium figures for 1995/96', Department of Trade and Industry, 18 July 1996. Back.

Note 19: A new 'head-end plant' at which oxide fuels were disassembled and dissolved was added to the B204 plant which had already ceased reprocessing Magnox fuels. The resulting chemical solution was passed through one solvent extraction cycle in B204 before being fed into B205. The accident occurred in the head-end plant. Back.

Note 20: Proportionately larger amounts of plutonium would be separated from foreign fuel because LWRs have higher burnups than AGRs. Back.

Note 21: The government's stated position is that nuclear wastes can be returned to foreign contractors as high-level waste, the amounts being increased through 'substitution' to compensate for radioactivity left in the UK in low- and intermediate-level wastes, provided that a disposal site for intermediate-level wastes (ILW) can be 'established by the time BNFL is contractually obliged to return the wastes (i.e. 25 years after they are generated)'. With the abandonment of the site at Sellafield, establishing an ILW repository within this timeframe will be difficult, perhaps even impossible. Reprocessing could still continue if foreign contractors were prepared to take back ILW in addition to HLW. This seems unlikely in the cases of the two largest foreign customers, Germany and Japan. The ability to move any nuclear waste to and from sites in Germany is now heavily constrained by public opposition; and in Japan there is not even any formal recognition of intermediate-level waste as a category separate from high-level or low-level waste. Even if a site could be found, and facilities built, permission would be hard to gain in the current anti-nuclear climate in Japan. Back.

Note 22: Although details are skimpy, it appears that the calculations of total tritium releases were correct, but the proportions going to the atmosphere or into the sea were miscalculated. Back.

Note 23: This is just a beginning. The true excesses after START II is implemented may be closer to 1500 tonnes out of a total US and Russian military inventory of some 1900 tonnes. Back.

Note 24: See National Academy of Sciences, Committee on International Security and Arms Control, Management and Disposition of Excess Weapons Plutonium (National Academy Press: Washington, DC, 1994), p. 34. Back.

Note 25: Responsibility for overseeing Britain's involvement in international safeguards rests with the Department of Trade and Industry. The British representative on the IAEA Board of Governors is a DTI official. Back.

Note 26: Article 77a, Euratom Treaty. Back.

Note 27: If Britain or France held fissile materials outside safeguards that had no relevance to 'defence requirements', they might be considered to be breaching their obligations under the Euratom Treaty. Back.

Note 28: The INFCIRC numbers of the voluntary offer agreements are 263 (UK, September 1976), 288 (US, August 1976), 290 (France, July 1978), 327 (USSR/Russia, February 1985) and 369 (China, September 1988). The British and French agreements are trilateral with the IAEA and Euratom. Back.

Note 29: Although this is formally the approach, a rather different practise has developed for the UK. Sites which may be considered for safeguards are identified to the IAEA. The UK will accept the IAEA's designation of facilities on those sites providing that they are not being used for defence purposes. Back.

Note 30: Although Australia and the US are Parties to the Hexapartite Safeguards Project, it has no implications for safeguarding on their territories as they operate no centrifuge enrichment plants. It is worth considering whether Russia, which possesses the world's largest centrifuge enrichment capacity (outside safeguards), and China which is acquiring a centrifuge facility from Russia (under IAEA safeguards), might be brought into the Hexapartite Safeguards Project. Back.

Note 31: This agreement (INFCIRC/125) is an INFCIRC/66-type agreement which was standard before the NPT came into force. These agreements were usually tied to the supply and usage of particular facilities or materials and contained follow-on clauses which required materials to be safeguarded wherever they were transferred. Because the B205 facility where Japanese Magnox fuels have been reprocessed has also been used for defence purposes, and because the IAEA has not designated the THORP process area, elaborate substitution has been practised to maintain an equivalent quantity of Japanese plutonium under safeguards during reprocessing. This has involved substitution of British plutonium contained either in spent fuels or in separated form. Hence the submission of 'store 9' at Sellafield, which contains separated plutonium, to IAEA inspection. Back.

Note 32: 'UK Statement on GOV/2914, Implementation of Programme 93+2 Measures in the United Kingdom', Special Meeting of the Board of Governors, IAEA, Vienna, 15-16 May 1997. Back.

Note 33: The nine countries involved in the discussions have been China, France, Germany, Japan, Russia, Switzerland, Belgium, the UK and US. Representatives of the nine government agreed an ad referendum text ('Guidelines for the Management of Plutonium') on a common approach to the publication of information on plutonium in the first half of 1997. However, there is still disagreement amongst governments on whether transparency should extend to plutonium contained in irradiated fuel, and there is controversy over whether, or to which extent, the IAEA should become involved in verifying information published by governments. This is problematic in regard to the NWS in which a small minority of facilities are designated for safeguarding by the IAEA. The talks in Vienna ended with the agreement on this text, and remaining difficulties will have to be ironed out in informal contacts between governments. Back.

Note 34: Ironically, the balance between supply and demand was maintained much more precisely in Britain's military than in its civil market for fissile materials. Back.

Note 35: On the issue of transparency, it should be noted that accurate reckonings are essential to the protection of health and the environment, especially when sites come to be decommissioned. Accurate accounting therefore serves both security and welfare interests. Back.

Note 36: This was the sixth of a ten-point programme 'that a Labour government would have taken to New York' to the 1995 NPT Extension Conference. See Robin Cook, 'Bombs away', New Statesman and Society, 14 April 1995. Back.

Note 37: The importance of such histories, and of maintaining past records, has been demonstrated by the IAEA's experience of bringing South Africa under full-scope safeguards, and thereby verifying its disarmament. Back.

Note 38: An FMCT was one of Robin Cook's ten-point programme put forward at the same time. "Rapid progress should be made on President Clinton's proposal for a multilateral convention prohibiting the production of highly enriched uranium or plutonium for nuclear weapons purposes or outside international safeguards." See Robin Cook, New Statesman and Society, op. cit. Back.

Note 39: This stance has been partly encouraged by perceptions that the NWS wriggled off the disarmament hook during both the NPT Extension Conference and the CTBT negotiations. Back.

Note 40: The proposal is that the NWS (and possibly the US and Russia initially) would negotiate a treaty outside the FMCT framework that would address issues concerning the transparency and verification of excess stocks of fissile material. See Albright, Berkhout and Walker, op. cit., chapter 15, pp. 434-437. Back.