Thermal Oxide Reprocessing Plant
THORP is the abbreviation for Thermal Oxide Reprocessing Plant and refers to the newer of the two in Sellafield, UK reprocessing plants for nuclear fuel. The name expresses that there oxide fuel from thermal reactors, that is, from light-water reactors, to be worked up.
Method
The plant was designed for a capacity of up to 1200 tonnes of uranium per year ( abbrandabhängig ); this flow but was not yet reached in any year. By March 2005 a total of approximately 5670 tonnes processed.
The reprocessing is based on the PUREX process with the following individual steps:
- Fuel element receiving and storage
- Fuel element decomposition and dissolution in nitric acid
- Separating the cleavage products of the reusable substances uranium / plutonium
- Separation of uranium and plutonium
- Cleaning of uranium and plutonium and conversion to UO3 or PuO2
- Waste treatment and storage
The liquid high-level radioactive waste will be vitrified in the plant WVP ( Windscale Vitrification Plant).
In the Sellafield MOX Plant ( SMP), another building complex at Sellafield, the reclaimed plutonium was processed into fresh MOX fuel for light water reactors. The SMP was in 2011, a few months after the nuclear disaster in Fukushima, closed.
History
The first reprocessing plant in Sellafield had a purely military objective: Since the 1950s, produced in the two Windscale reactors weapons - grade plutonium was separated there in follow-up for use in nuclear weapons for further processing. In 1964 the plant was taken for B205 fuel the British Magnox reactors and later AGR reactors in operation. 1969-1973 was also another plant in operation, which was intended for the UK (yet) standing in operating light water reactors abroad. The project failed, however, in 1973 a serious accident.
The construction of the THORP plant began in 1983 and was completed in January 1992. In contrast to the older system B205, which was planned for the not long storable fuel British reactors, THORP was built for purely commercial considerations for British and foreign customers.
End of 1994, but announced the two German energy companies RWE and Bavaria work already completed contracts to reprocess their fuel in Thorp. The purchase agreement with the French plant at La Hague was not renewed. They justified both steps with cost disadvantages ( "Uranium is cheap to have on the world market, the reprocessing is very expensive "). In Thorp accounted for by this notice refurbishment orders with a total of 550 tonnes, about 20 percent of Thorp - orders for the years 2004 to 2014. Thorp The managers had originally calculated to be able to make the year 2004 a profit.
The red-green coalition (1998-2005) was basically against the reprocessing ( " plutonium economy "); it urged the nuclear companies to renounce it.
Germany has been delivering a political decision - nuclear consensus from the summer of 2000, implemented in 2002 in an amendment to the Atomic Energy Act - since mid- 2005, no more spent fuel for reprocessing and takes back all waste. The MOX fuel, which are of individual nuclear operators continued to receive date from contracts concluded before that decision.
The MOX fuel fabrication plant (but not one of THORP ) in 2011, a few months after the nuclear disaster in Fukushima, closed.
On 19 April 2005 has been noted on the THORP premises that the course of several months, about 90,000 liters of plutonium - containing liquid had leaked. Operator had first noticed in August 2004 that more liquid went into the plant as came out again; the leak remained undetected until 2005. It got supposedly no radioactivity into the environment; the accident was classified as INES 3. In January 2007, Thorp received permission to go back into service.