Thermal Oxide Reprocessing Plant

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THORP is the abbreviation for Thermal Oxide Reprocessing Plant and denotes the newer of the two nuclear fuel reprocessing plants located in Sellafield , Great Britain . The name expresses that oxidic fuel elements from thermal reactors, i.e. from light water reactors , are processed there.

Procedure

The plant was designed for a capacity of up to 1200 tons of uranium per year ( depending on burnup ); this throughput has not yet been achieved in any year. By March 2005 a total of around 5670 t had been processed.

The reprocessing takes place according to the PUREX process with the following individual steps:

  • Reception and storage of fuel assemblies
  • Fuel element dismantling and dissolution in nitric acid
  • Separation of the fission products from the reusable materials uranium / plutonium
  • Separation of uranium and plutonium
  • Final purification of uranium and plutonium and conversion to UO 3 or PuO 2
  • Waste treatment and storage

The liquid, highly radioactive waste is vitrified in the WVP ( Windscale Vitrification Plant ).

In the Sellafield MOX Plant (SMP), another building complex in Sellafield, the reprocessed plutonium oxide was processed into fresh MOX fuel elements for light water reactors. The SMP was closed in 2011, a few months after the Fukushima nuclear disaster .

history

The first reprocessing plant in Sellafield had a purely military objective: since the 1950s, the weapons plutonium produced in the two Windscale reactors has been separated there afterwards for use in nuclear weapons for further processing. In 1964, the B205 plant for fuel elements of the British Magnox reactors and later EGR reactors was put into operation. From 1969 to 1973 another plant was also in operation, which was intended for light water reactors abroad that were not (yet) in operation in Great Britain . However, the project failed in 1973 due to a serious accident .

Construction of the THORP facility began in 1983 and was completed in January 1992. In contrast to the older B205 plant, which was intended for the fuel elements of British reactors that could not be stored for long, THORP was built for British and foreign customers for purely commercial reasons.

At the end of 1994, however, the two German energy groups RWE and Bayernwerk terminated contracts that had already been concluded for the reprocessing of their fuel elements in Thorp. The purchase agreement with the French plant in La Hague was not extended. They justified both steps with cost disadvantages ("Uranium is cheap on the world market, reprocessing is very expensive"). In Thorp, this termination meant that refurbishment orders totaling 550 tons were dropped, around 20 percent of Thorp orders for the years 2004 to 2014. The Thorp managers had originally calculated that they would be able to make a profit from 2004 onwards.

The red-green coalition (1998-2005) was fundamentally against reprocessing ("plutonium economy"); it urged the nuclear companies to forego it.

Since a political decision - the atomic consensus of summer 2000, implemented in an amendment to the Atomic Energy Act in 2002 - Germany has stopped supplying spent fuel elements for reprocessing since mid-2005 and has taken back all waste. The MOX fuel elements that are still being procured by individual nuclear power plant operators originate from contracts concluded before this decision.

The MOX fuel assembly plant (which is not part of THORP) was closed in 2011, a few months after the Fukushima nuclear disaster .

On April 19, 2005, it was noticed on the THORP premises that around 90,000 liters of plutonium- containing liquid had leaked over the course of several months . Operating personnel first noticed in August 2004 that more liquid was entering the system than was coming out again; the leak remained undetected until 2005. Apparently no radioactivity was released into the environment; the accident was classified as INES 3. In January 2007 Thorp received approval to go back into operation.

On November 9, 2018, nuclear fuel was processed for the last time due to declining demand. The plant is to be used as a tank farm in the future.

Individual evidence

  1. ↑ a b spiegel.de August 3, 2011: Great Britain closes the fuel element factory
  2. ↑ spiegel.de January 30, 1995: Turning away from the processing
  3. ^ Spiegel.de February 1, 1999: Chaos with the Chancellor
  4. ↑ More details in the English Wikipedia or here: Thermal Oxide Reprocessing Plant (THORP) leak investigation and consent to restart
  5. ↑ www.iwr.de November 20, 2018: Sellafield nuclear facility: end and restart at the same time

literature

Ch. Küppers / M. Sailer: MOX-Wirtschaft or the civilian use of plutonium , an IPPNW publication

Coordinates: 54 ° 24 ′ 56 ″  N , 3 ° 30 ′ 6 ″  W.