Sellafield, in West Cumbria, is responsible for the production of the nuclear materials for nuclear weapons, including plutonium, tritium and Highly Enriched Uranium (HEU). Large stocks of military plutonium are held in special vaults at the site, though no plutonium for use in nuclear weapons is currently being produced. In the past plutonium was produced at Sellafield through the reprocessing of spent nuclear fuel from the nuclear reactors at Calderhall and Chapelcross.
Currently, the main activity at Sellafield is recycling used fuel from nuclear power stations worldwide. The site also houses a series of plants which treat wastes and convert them into forms which can be disposed of safely. In October 1994, Secretary O'Leary signed a memorandum authorizing consideration of shipment of 183,000 gallons of nitric acid containing slightly enriched uranium from the Hanford PUREX plant to the Magnox Fuel Reprocessing Plant at Sellafield.
Also in 1997, Nirex, the radioactive waste management company, abandoned plans to construct a Rock Characterisation Facility (RCF) for ILW deep underground near the Sellafield reprocessing complex, after the Environment Secretary rejected an appeal by Nirex against the 1994 refusal by Cumbria County Council to grant planning approval. Nirex had spent an estimated £200 million in preliminary drilling and scientific studies, but the Minister found scientific uncertainties and technical deficiencies in the company's case. AEA Technology was a member of the consortium that won a £140 million contract to build an ILW encapsulation plant at Sellafield.
Windscale Piles 1 & 2
The independent British weapons program began in 1946, with the first priority being to produce plutonium in reactors (known then as atomic piles). The technology of the time meant that the quickest route to an operating reactor was to build reactors which used natural uranium as fuel, graphite as the moderator and which were cooled by air. Accordingly, in 1946 work began at the former Royal Ordnance factory at Sellafield to build two reactors, on a site renamed as Windscale, to produce plutonium for the UK weapons program. Pile No. 1 began operating in October 1950, Pile No. 2 started up 8 months later and plutonium for the first British bomb was available in March 1952.
Windscale Pile No. 1 caught fire on Thursday 10 October 1957. Fuel melted, the fuel cans burst, uranium ignited and fission products were released into cooling ducts and ejected out of the cooling chimneys. Only after heroic efforts by the operating staff, risking a worse disaster by flooding the reactor with large volumes of water, was the fire put out on Friday 11 October 1957. The main radionuclide of concern in the releases from the fire was iodine-131. Steps were taken to ban milk for 200 square miles around Windscale, limiting the health consequences of the accident. Along with Three Mile Island and Chernobyl, the Windscale fire achieved notoriety as one of the three nuclear disasters which opponents of nuclear power cite as evidence that nuclear power is too risky. While the Windscale fire was a serious nuclear accident, the reactor was not large by modern standards, and the radionuclide releases at Chernobyl were 1,000 times higher.
In September 1997, the UKAEA awarded its largest decommissioning contract to date. A consortium led by British Nuclear Fuels Limited (BNFL) won the contract to dismantle and remove for treatment and storage the core of Pile One at Windscale. The eight-year program of work, valued at £54 million, involves the remote dismantling of the core using four heavy duty manipulators which will penetrate through the roof of the core's biological shield. The Pile, a stack of some 2,000 tonnes of graphite blocks, has been in a state of safe care and maintenance since the October 1957 fire. Its core contains an estimated 15 tonnes of damaged fuel. Pile Two, which was unaffected by the Fire and which was defuelled at the time, will be put on a care and maintenance regime.
Calder Hall (CH) Magnox reactors
Sellafield is home to the world's first industrial scale nuclear power station, Calder Hall. The four Calder Hall (CH) Magnox reactors, with a total output of 194 MW, entered service between October 1956 and May 1959. Calder Hall was opened by the Queen in October 1956. Its primary function was to manufacture plutonium for nuclear weapons but it was also the first nuclear reactor anywhere in the world to generate commercial electricity. These carbon-dioxide cooled reactors, identical to the Chapelcross reactors, produced both weapons grade plutonium and electricity. In 1996 the power station was granted a ten-year operating extension by the NII following a Periodic Safety Review.
Calder Hall closed on 31 March 2003. Calder Hall was initially scheduled for closure between 2006-2008. Following an accident at Chapelcross in July 2001, two of the four Calder Hall reactors, similar in design to those at Chapelcross, were shut down to allow defueling related tests to be carried ou. The remaining two Calder reactors were also shut down by the end of 2001. Reactor 1 was returned to power in July 2002. In Jue 2002 BNFL announced they would close down the Calder Hall Nuclear power plants, and by August 2002 three of the four reactors were closed down. The early closure resulted from the cost of preventing radiation-induced graphite shrinkage in the chargepans used to guide the highly-radioactive fuel rods into place. BNFL's announcement followed an economic review of the operation of its whole magnox reactor fleet. The review concluded that continued operation of the larger magnox stations has a sound economic basis but that Calder Hall and Chapelcross, with their relatively low output but high overheads, had become loss-making. The reactors will be defuelled and subsequently decommissioned.
Thermal Oxide Reprocessing Plant (THORP)
In August 1997, the Nuclear Installations Inspectorate granted British Nuclear Fuels Limited (BNFL) the Consent to Operate its Thermal Oxide Reprocessing Plant (THORP) at Sellafield. THORP, which has been operating since March 1994, has reprocessed well over 800 tonnes of fuel. THORP recovers usable uranium and plutonium from spent nuclear fuel. The main process areas are the fuel receipt and storage area, the head end plant where the fuel contents are separated out from the cladding, and the chemical plants where the uranium and plutonium are separated out from the waste products. BNFL plans to achieve a throughput of 900 tonnes by Thorp's fifth year and reprocess in all 7,000 tonnes of spent fuel in the first ten years, making at least £500 million profit after accounting for all decommissioning and capital costs. THORP is expected to reprocess 14,000 tonnes of spent fuel in its first 20 years of operations and in the order of 100 tonnes of plutonium will be recovered during this time. The exact quantity of plutonium will be dependent on the type of fuel and the level of irradiation in the reactor the fuel originates from. The company has over 15 years' worth of orders, valued at £12 billions, two thirds from overseas as well as the new AGR spent fuel contract.
MOX Demonstration Facility [MDF]
A data falsification incident at BNFL's MOX Demonstration Facility in 1999 led to an investigation by the Health and Safety Executive and a loss of customer confidence in BNFL. The MDF plant was closed in 1999, when it was discovered that a number of employees had falsified quality control data on fuel consignments. In March 2002 British Nuclear Fuels was granted a license to re-commission a MOX demonstration facility at Sellafield. It will operate as a support facility to the new MOX plant.
Sellafield MOX Plant
The MOX Plant at Sellafield is valued by BNFL at a cost of around £460 million. Its purpose is to manufacture a mixed oxide fuel for use in nuclear power stations. The fuel would be made from uranium and plutonium material separated from spent fuel which is reprocessed mainly at the THORP plant at Sellafield.
With the end of the Cold War there are now stockpiles of surplus ex-military plutonium from decommissioned warheads. A study by the US National Academy of Sciences identified two possible ways of reducing the amount of surplus plutonium taken from nuclear weapons in the US and former Soviet Union. One is to convert the plutonium into glass and then bury it deep underground. The other is to convert it into fuel for power reactors. When plutonium dioxide is mixed with uranium dioxide to form a mixed oxide (MOX) fuel, it can be burnt in the conventional nuclear power reactors. A demonstration MOX manufacturing facility at Sellafield began operating in October 1993. The construction of the Sellafield MOX Plant began in April 1994, and was projected to cost some £300 million. With a 120 ton production capacity, it was expected to commence operations in 1998. The Sellafield MOX Plant was designed to fabricate new fuel with depleted, natural or recycled uranium and plutonium which is recovered from used nuclear fuel when it is reprocessed in THORP.
Before the plant can start operations it needs to pass a test of justification required by European law: the benefits of a practice involving ionising radiation need to outweigh any environmental or other detriments. BNFL applied to the Environment Agency in November 1996 for approval to operate the plant. The Environment Agency, after two rounds of public consultations, concluded its consideration in October 1998. The issue was referred to the Secretary of State for the Environment, Transport and the Regions and the Minister of Agriculture, Fisheries and Food in November 1998 because of their statutory responsibility to consider requests that had been made to them to decide the application themselves. The Government's provisional view, in a consultation paper published in June 1999, was that full operation of BNFL's MOX Plant would be justified, but a final decision would depend on the outcome of further consultation on the economic assessment of the practice and on the market for MOX fuel. BNFL submitted a revised economic case in 2001.
Ministerial responsibilities have changed during this period. In 1999 the Food Safety Act established the Food Standards Agency and amended the Radioactive Substances Act 1993. And in June 2001, the Department for the Environment, Transport and the Regions (DETR) was reorganised with responsibility for environmental protection passing to the new Department for Environment, Food and Rural Affairs (DEFRA). As a result justification decisions that would have been taken jointly by the Secretary of State for the Environment, Transport and the Regions and the Minister of Agriculture are now taken jointly by the Secretary of State for Environment, Food and Rural Affairs and the Secretary of State for Health.
The Arthur D Little Ltd (ADL) report, published for consultation 27 July 2001, said that the MOX plant, if allowed to go into operation, would give a financial benefit with a "net present value" of over £200m to the UK over its lifetime. The first stage of active plutonium commissioning of the plant commenced on 21 December 2001. The process involves introducing plutonium bearing material in order to start testing the plant and equipment as a precursor to MOX fuel manufacture.
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