FAQs: Reprocessing and Sellafield

Sellafield pipeline

What goes on at Sellafield?

Sellafield is the site of various nuclear facilities which include two operating reprocessing plants and the Sellafield MOX fuel fabrication plant, but there are no longer any operating nuclear power stations on the site.

In December 1945 the British cabinet took the decision to build, at Sellafield (originally known as Windscale), the Windscale piles to produce plutonium for Britain's bomb. Since then the Sellafield skyline has been dominated by these two tall chimney-like structures. In October 1957 the uranium fuel in one of the reactors caught fire, causing the release of large amounts of radioactive iodine, and other radioactive materials into the atmosphere. This was undoubtedly one of the world's worst nuclear accidents, which led to some 2 million litres of milk from an area of more than 500 square kilometres being poured away into rivers and the sea. The two reactors were closed down. The United Kingdom Atomic Energy Authority is currently attempting to plan how these two reactors will be decommissioned.

Sellafield was also the site of a prototype Advanced Gas-cooled reactor, which shut down in 1981. The Windscale AGR, as it is known is currently being decommissioned by the UKAEA .

The Calder Hall Magnox nuclear power station, also at Sellafield, was the world's first nuclear power station, opened by the Queen on 17th October 1956. Despite the "Atoms for Peace" spin at the time, it was optimised to produce plutonium for Britain's nuclear weapons for much of its life. It was eventually closed down in 2003.

Sellafield also has two operating reprocessing plants - the Magnox reprocessing plant, (sometimes called B205) and the Thermal Oxide Reprocessing Plant (THORP). Also on the site is the Sellafield MOX fuel fabrication plant, which has yet to produce any MOX (plutonium) fuel.

There are also various waste stores on the site, including 21 tanks which contain liquid High Level Waste (known as B215). This highly radioactive waste generates its own heat, so has to be constantly cooled. Should the cooling system fail, the waste in the tanks would boil, releasing radioactivity into the atmosphere.

There are also various waste processing plants on the site, including the Enhanced Actinide Removal Plant (EARP) which processes liquid waste to remove some of the most radioactive substances before discharging it into the Irish Sea.

What is a reprocessing plant?

A nuclear fuel reprocessing plant is a chemical plant, which separates plutonium and unused uranium from spent nuclear waste fuel. Because its raw material is intensely radioactive, all operations must be carried out by remote control, behind heavy shielding. Firstly the cladding around the spent fuel element is stripped off (this becomes intermediate-level waste) and then the bare fuel rod is dropped into a vat of nitric acid which dissolves it ready for reprocessing. This nitric acid solution is then treated with various solvents to separate out plutonium and unused uranium, leaving behind highly radioactive liquid waste which is transferred to storage tanks.

The uranium metal fuel used in Magnox reactors and the uranium oxide fuel used in most other reactor types have to be treated slightly differently, which is why there are two different reprocessing plants at Sellafield.

The original reason for separating the unused uranium from spent nuclear waste fuel was so that it could be re-used. Some reprocessed uranium from the Magnox programme has been used in the past to manufacture fuel for AGRs, but this is currently uneconomic, so the separated uranium is simply stockpiled. Plutonium was separated so that it could be used to fuel a new kind of reactor, called a fast breeder reactor. But these reactors had enormous technical and economic problems, many caused by the fact that liquid metal is used as the primary coolant - usually sodium. Sodium reacts enthusiastically with water, and liquid sodium can explode on contact with air. The UK built a prototype fast reactor at Dounreay in the north of Scotland, but this has now closed down.

Consequently, this means that Britain no longer has a use for the plutonium and uranium separated during reprocessing. Some countries now use plutonium, mixed with uranium oxide (known as mixed oxide or MOX fuel) to partly fuel some of their conventional nuclear reactors, but Britain has never done this. This means that reprocessing is almost completely pointless.

Does spent fuel have to be reprocessed?

No. It can simply be dry-stored in a warehouse-type building and kept cool usually by natural convection. In fact around 70-80 percent of spent nuclear waste fuel arisings throughout the world are stored rather than reprocessed. There is no reprocessing carried out by the civil nuclear industry in the United States, for example.

The nuclear industry has long argued that Magnox spent fuel must be reprocessed because once the magnesium alloy cladding of the fuel has become wet it reacts chemically with water causing corrosion and degradation. In fact the only dry store ever built in the UK stores Magnox spent fuel next to the Wylfa nuclear power station. More recently BNFL has argued that it would not be economic to introduce dry storage at this late stage in the life-cycle. Nevertheless BNFL has looked at non-reprocessing options, which might be technically feasible. These include dry storage .

In 1988 and 1991 the old Central Electricity Generating Board (which then operated nuclear stations in England and Wales) and Scottish Nuclear put forward detailed plans for large dry store vaults at their Heysham and Torness stations respectively. In 1994, following a public inquiry the Inquiry Reporter found no reason to oppose Scottish Nuclear's dry store at Torness. However, neither of the Heysham or Torness dry stores were built. But British Energy has called for an end to its reprocessing contracts. A BE spokesman stated that "We simply do not believe in reprocessing because of its huge costs and we want to renegotiate this contract". It said reprocessing "has left us with a service we don't need, for a product we don't want, and at a price we cannot afford".

What will happen to all the plutonium at Sellafield?

On 31st December 2001, there were over 60 tonnes of UK separated civil plutonium stockpiled mostly at Sellafield. This stockpile could climb to over 100 tonnes by about 2012. There have recently been suggestions that at least some of this plutonium should be treated as nuclear waste.

There was also almost 17 tonnes of plutonium at Sellafield owned by BNFL's foreign customers. This could grow to 37 tonnes by 2012. These overseas electricity companies will need to decide what they want to do with their plutonium. Some companies may decide to ask BNFL to covert it into MOX fuel in the Sellafield MOX Plant.

When will reprocessing at Sellafield end?

The Magnox Reprocessing Plant (B205) was built in 1964 to reprocess spent nuclear waste fuel from Britain's Magnox stations and two Magnox stations sold to Japan and Italy. BNFL has announced that B205 will close around the end of 2012 .

The Thermal Oxide Reprocessing Plant (THORP) opened in 1994. It has contracts to reprocess spent nuclear waste fuel for British Energy and foreign utilities in Japan, Germany, Switzerland, the Netherlands, Spain, Italy and Sweden. It was originally expected that THORP would reprocess around 7,000 tonnes of spent nuclear waste fuel in its first ten years of operation - the so-called "baseload contracts". But by 31st March 2004 it had reprocessed only a little over 5,000 tonnes. The plant has a few post-baseload contracts from British Energy and German utilities, but there are rumours the plant will close by 2010 at the latest.

What is the environmental impact of reprocessing?

Sellafield discharges around 8 million litres of radioactive liquids into the Irish Sea every day . Radioactivity is measured in Becquerels (Bq) - the standard international unit of radioactivity. One becquerel is one radioactive disintegration per second. Radioactive discharges tend to be Terabecquerels (TBq) (1,000,000,000,000 or 1012 becquerels) .

Sellafield discharges around 86,500 TBq into the Irish Sea every year . Much of this is radioactive hydrogen or tritium, so discharges are often given excluding tritium. But this should not be taken to suggest that tritium is harmless.

The Radioactive Waste Management Advisory Committee gives indicative discharges from Sellafield when both reprocessing plants are working at high throughput rates . Total discharges, excluding tritium, are given as:-

Magnox: 132 Terabecquerels (TBq)
THORP: 9 TBq
Other Plant: 33TBq


This compares to discharges of around 0.1-2 TBq for an operating nuclear station. Radioactivity from Sellafield can be found as far away as the Arctic. It concentrates in fish, shellfish, seaweed and other marine animals and plants. Plutonium discharged from Sellafield was expected to remain locked in the sediments at the bottom of the Irish Sea, but there is now evidence that these sediments are being re-mobilised. Radioactivity can also be detected in seaspray and it can move inland up rivers by a process known as tidal inundation.

There are higher levels of childhood leukaemia around Sellafield than the national average, particularly in a village called Seascale. Following a scientific/medical expert enquiry, the official response to this excess of cancers was that radiation doses, projected from Sellafield's known releases and from measured radioactive contamination in the area, would be far too low to account for the excess cancer incidence, and therefore that the cause must be some factor other than radiation. On the other hand the occurrence of a highly pronounced increase in leukaemia in the immediate vicinity of the UK's (and Europe's) largest radioactive polluter seems too much of a coincidence. Surely a more likely explanation is that the models used to estimate the risks of Sellafield's discharges are incorrect. This view is reinforced by the observation of other excess leukaemias near other nuclear establishments particularly Dounreay, in Caithness, Scotland .

What about discharges into the atmosphere?

Radioactive discharges into the atmosphere from Sellafield are dominated by the inert gas, Krypton-85. 101,000 TBq of Krypton-85 were discharged from Sellafield in 2002. Because Krypton does not react chemically it travels right around the globe raising radioactivity levels in the atmosphere everywhere.

Operating nuclear power stations can release large quantities of another inert gas - Argon-41 - which can result in relatively high radiation doses to people living near the stations. Dungeness A, for example, released 1,200TBq of Argon-41, and Sizewell A released 1,850TBq in 2002. Emissions of gaseous tritium from the Chapelcross Magnox station near Dumfries are also important. Chapelcross manufactures tritium for use in the UK's nuclear weapons. In 2002 Chapelcross released 763 TBq of tritium into the atmosphere.

Aren't we going to need a few nuclear power stations to help reduce greenhouse gas emissions?

Advocates of nuclear power, aware of its unpopularity and the unsolved problems, nevertheless hold it up as a low carbon option. But we would be crazy to try solving one environmental problem (climate change) by making another one worse - we still have absolutely no idea what we are going to do with the nuclear waste we have already created, so making more would be stupid. As well as being dangerous nuclear power has proved unreliable and expensive - it is still unable to compete without huge subsidies. The threat of terrorism only compounds the risks. Nuclear power advocates say that we must expand its use despite the problems because renewable energy is unable to deliver on a large scale, or that it cannot develop fast enough.

A recent report from Greenpeace on just one renewable technology - offshore wind - shows that it could provide 30% of the European Union's electricity by 2020 . And there is a whole range of other renewable technologies available to us - solar energy, tidal and wave energy, biomass, and onshore wind. Combined with better energy efficiency these technologies offer an immediate, clean safe and effective answer to both climate change and energy security.

What's the government doing about nuclear waste?

The UK nuclear industry has been producing nuclear waste since the 1950s, but it has yet to come up with a way of dealing with it. There have been a string of failed attempts to come up with a deep underground "disposal" site for nuclear waste since 1976 . The most recent attempt was made by the nuclear industry's waste disposal body, Nirex, which wanted to build a dump beneath the Sellafield nuclear facility. But this was refused planning permission in 1997. The Government launched its latest attempt to find a solution to this intractable problem in 2001 by launching a consultation process . It has also established a new independent Committee on Radioactive Waste Management (CoRWM). CoRWM will review all options for nuclear waste management, not just "deep disposal" and is expected to make recommendations to the Government by the end of 2005.