Urenco, BNGSL and a mountain of uranium waste
Close to Ellesmere Port on the Mersey Estuary, Capenhurst has supplied enriched uranium for the UK nuclear industry and weapons since 1952. While much of the site is being decommissioned, commercial uranium enrichment is planned to continue until 2035, and nuclear waste will be stored there until at least the middle of the 22nd century.
The site is shared between British Nuclear Group Sellafield Ltd, a subsidiary of BNFL (British Nuclear Fuels Ltd.), and Urenco UK ltd. The two sides of the site work very closely together with joint emergency procedures and routes of waste disposal. In fact, as with much of the nuclear industry, the actual relationship is opaque and confusing, as BNFL owns one third stake of Urenco, and the future plants for both sites are clearly intertwined.
The BNGSL side of the site is involved with decommissioning the obsolete historical parts of the site, overseen by the Nuclear Decommissioning Authority. The current plan for the site is to demolish most of the buildings, but leave part of the 1950s uranium diffusion plant for the storage of 60,000 tonnes of depleted uranium from Chapelcross and the Magnox reprocessing plant at Sellafield
The depleted uranium is stored in the form of uranium hexafluoride (or ‘hex’ as it is known in the industry), a material which is not only radioactive and chemically toxic, but also reacts with the water vapour in the air and is highly corrosive. Even by the standards of the nuclear industry this is considered an extremely difficult and dangerous material, so a deconversion plant will be constructed to convert 40,000 tonnes of hex back into a more stable oxide form at a cost of around £170 million.
As all uranium contains some traces of U235, the isotope burned in power stations, and as there are no safe ways to dispose of the waste, it will be stored until 2150 in the hope that the byzantine economics of the nuclear industry will make it profitable to re-enrich for fuel at some point. Even though costs for the decommissioning the last part of the site, and for the disposal of the waste have not been factored in, the lifecycle costs from 2006 to 2150 are projected to be over £2 billion.
In its naturally occurring form, uranium ore is made up of three isotopes: U234, U235 and U238. They behave in the same way chemically, but their radiological properties are different. U238 makes up more than 99% of naturally occurring uranium, and is less radioactive than the fissionable U235, which is used in power stations and nuclear weapons. To isolate the U235 the uranium is spun in centrifuges where the different weights of the molecules cause them to separate. For reactor fuel, the concentration of U235 needs to be about 3%-4% (for weapons the concentration required is about 90% U235), so most of the uranium ore discarded as waste - called 'depleted uranium' (DU). For reactor grade uranium, about 7kg of DU is produced for every kilogram of fissionable material. The amount of waste produced, along with its density and other properties have lead to some countries using it in conventional weaponry - such as armour piercing tank shells, with serious environmental and health ramifications.
Urenco is a British, Dutch and German uranium enrichment venture, set up in 1971 to challenge the US dominance in civil nuclear technology. Enrichment is done through spinning the hex (heated up to form a gas) in a series of connected centrifuges to separate the U235 from the U238. Urenco claims to have a 23% stake in the global market for enriched uranium. It was also the employer of A. Q. Khan, the 'father' of the Pakistani nuclear weapons program, who used designs stolen from Urenco to build the Pakistani bomb, and subsequently exported them to Iran, North Korea and Lybia through a clandestine global network.
- 1940 Built as Capenhurst Royal Ordinance Factory
- 1952 Uranium Enrichment Diffusion Plant for Nuclear Weapons
- 1961 Enrichment for Nuclear Power begins
- 1971 Urenco founded
- 1982 Diffusion plant closes, but centrifuge enrichment continues
- 1992 Site split. Urenco takes over enrichment operations BNFL begin decommissioning rest of site
- 1995 BNFL begin storage of waste
- 2005 BNGSL set up as a subsidiary of BNFL & takes over all operations
- 2007 Urenco separative capacity increased to 3500 tonnes
- 2020 Uranium Hex deconversion plant planned to be built
- 2035 Urenco plan to cease enrichment and begin decomissioning
- 2120 BGNSL plan to store Depleted Uranium on site until this date
- 2153 Urenco plan to store Depleted Uranium on site until this date
- post-2153 Uranium's half life is 4.5 billion years. There are no plans after this date. Disposal of the DU stored on site, and decommissioning of radioactive buildings and equipment have not been costed.
The Urenco Capenhurst site can work with around 3500 tonnes of uranium at any one time, and while the enriched uranium is sold on as nuclear fuel, much of the depleted uranium byproduct is stored on site, still in its hexaflouride form. Health and Safety Executive (HSE) have set an upper limit of 70,000 tonnes of hex that can be stored on site, so much of the uranium hexaflouride is exported Russia for further re-enrichment. This is in violation of Russian law, as much of this waste remains there. According to Greenpeace Russia, storage of hex often does not meet even Russian safety standards. Greenpeace states that Urenco exported 59,328 tonnes there between 1996 and 2003, of which 13,676 tonnes of this was in 2002-2003. As the capacity in Capenhurst has risen since then, it seems likely that more recent figures are higher.
Urenco are keen to dispel typical impressions of the nuclear industry, and retain an active PR machine. They have edited their Wikipedia page to state that "Urenco has has always been open regarding A. Q. Khan", and they try particularly hard to show themselves as having good environmental credentials. They trumpet the fact that every department in the company has a recycling coordinator, and that when they had to move a pond to enlarge their hex storage, they handled the wildlife with care. With no apparent sense of irony, they also point out that an earth mound constructed specifically to absorb radiation from the store was specially planted to increase biodiversity!
The plans for the Urenco site are for enrichment to continue there until 2035, and for storage of depleted uranium until 2120, and it seems likely that it will be converted from hex to an oxide form in BNGFL's deconversion plant, or another facility. These plans depend upon Urenco being able to decommission and clean up most of the site by 2040, and run non-nuclear commercial activities alongside the storage. The HSE has expressed concern that this may be unrealistic, that the site may be hiding unknown contamination from before Urenco took it over in 1993, and that Urenco will be unable to pay for storage, security and the preservation of knowledge to dispose of the waste in the most safe way. In its most recent report on the HSE stated that Urenco had not set aside a segregated fund for this purpose, in contravention of Government policy.
Waste is released into the air through an incinerator on the BNGSL site, leaving a radioactive ash, and releasing uranium and some of its daughter products into the atmosphere. There are also a number of vents on both sites which expel gasses. On the BNGSL site there are no limits to how much gas can be vented, only a need to follow 'best practicable measures' to reduce the amount. Urenco only have annual limits to radioactive gas emissions and a requirement to notify the Environment Agency if their quarterly emissions go over certain levels. However, it is known that day-to-day emissions can be much higher than the average.
Solid radioactive waste is sent to the Drigg landfill site near Sellafield, and to nearby landfill site at Clifton Marsh. Lancaster County Council Website describes Clifton Marsh as a "municipal waste disposal facility including green waste composting and woodchip processing", and mentions that it is situated in the Ribble Estuary Sites of Special Scientific Interest consultation area. Dumping of waste at Clifton Marsh is euphemistically labeled 'controlled burial', but the sole safeguards are that the waste must be packaged in bags, buried 1.5 meters deep, and guarded until it is buried.
The Capenhurst site releases radioactive liquid discharge into the Rivacre brook which runs for about 1/3 mile from the site before traveling through the town of Ellesmere Port and the Rivacre Valley Country Park (pictured right) into the Mersey Estuary, an International Committee on Wetlands Ramsar special protection area. Again there is an annual limit & quarterly notification levels are set for the site. Samples are regularly taken of the level of radioactivity in the brook. In 1999 the radioactivity of the sediment at the discharge point rose as high as 10,000 Becquerels/kilogram (Bq/kg); the average of the figures for the period 1993 to 2005 was 6007 Bq/kg. The algae 1.5 km downstream in Ellesmere Port showed radioactivity levels of 810 Bq/kg in 1999, with the average figure over the same period being 221 Bq/kg.
At the last review of the limits for radioactive discharge from the site, the Environment Agency did no detailed calculations of the risks to surrounding populations as its initial figures for the radiation dose to the 'critical group' (a hypothetical group of children playing some way downstream in the brook) was lower than 20 microSilverts/year (μSv/y). The Environment Agency's initial figure was 18 μSv, and this presumed that the hypothetical children would not live close enough to the site to receive a direct dose of radiation, and would not receive a radiation dose from consuming local food. The Food Standards Agency's 'possible' upper limit for exposure was 30μSv/y through food pathways, and Health Protection Agency measurements in 2006 gave figures for direct radiation exposure (i.e. simply from proximity to the site) of less than 10 to 80μSv/y. Traces of uranium are routinely found in grasses and cow pats in the surrounding farms. The Environment Agency justified their decision by referring to a need to "move away from very simple, unrealistic and cautious assumptions in radiological assessments i.e. avoiding gross pessimism". In other words, they do not think it appropriate to assess danger to the public from Capenhurst on the basis of a worst case scenario.
Khan wondered freely through the Almelo building, even in areas he did not have access too, took documents home and commissioned photographs of parts. He probably copied many of the designs when supposedly translating them from German into Dutch as he was seen taking copious notes in Urdu. Despite all this, when his photographer colleague tried to express concern to the management of FDO and Urenco, there was no response. In 1977, two years after the Dutch secret service had contacted FDO to warn them about Khan's activities, they exported instrumentation originally designed for Urenco to him in Pakistan. With a flair for circumventing restrictions intended to stop the spread of nuclear technology, Khan was able to build nuclear warheads for Pakistan, using uranium enriched in Urenco centrifuges.
There is much speculation about the degree of authorisation he had from the Pakistani state, but throughout the 1990s and early 2000s he put together a complex network of contacts, and used them to export nuclear technology to other countries. As a result of his activities the enrichment plants in North Korea and Iran both use the Urenco designs from Almelo (pictured), as did the Libyan nuclear program until it was suspended in 2003. The Iraqi nuclear program under Saddam Hussein also used Urenco designed centrifuges, though they may have obtained them from another source as Khan is known to have approached them in early 1991. While the United States expressed great moral outrage when the story of Khan's activities broke in 2003, it is clear that they had been aware of Khan's activities for a number of years, but had regularly turned a blind eye to Pakistan's nuclear program for reasons of geopolitics, both in the 1980s during the Soviet Afghan war, and after the 9/11 attacks in 2001.
Environment agency consultation on BNGSL Capenhurst:
HSE review of Urenco Capenhurst decommissioning strategy:
Greenpeace Russia site on Uranium Hexaflouride imports:
The Atlantic 2 part article on A.Q. Khan:
Campaign Against Depleted Uranium