Nuclear reprocessing

The nuclear reprocessing is a chemical process aiming to the separation of the potentially reusable elements (the Uranium and the Plutonium, but also actinides minor), of the fission product contained in irradiated nuclear fuel. At the time of the reprocessing, the sheath of the fuel pins is sheared then treated like radioactive waste of average activity with long life while the fission products and certain actinides form waste of high activity.

Historically, the technique of the reprocessing was developed to obtain plutonium necessary for the manufacture of the nuclear weapons. It was also developed within the framework of a programme not led of development of the die to fast neutrons.

In 2007, the reprocessing is used by the civil nuclear industie certain countries in order to separate then to re-use the Plutonium in a mixture of plutonium and uranium oxide (MOX) which can be again used as fuel in a generating engine. In certain countries, the uranium of reprocessing (URT) also been the subject of an D-enrichment (URE) in order to manufacture of new fuel. Lastly, of the research programs and the experimental irradiations are carried out to develop the reprocessing of minor actinides.

The nuclear reprocessing is one stages of the Cycle of nuclear fuel.

Process PUREX

Chemical process PUREX (Plutonium and Uranium Recovery by EXtraction) currently used makes it possible to separate the Plutonium and uranium independently one of the other from the minor actinides and the fission product by a method of extraction liquid-liquid:

elimination of the sheaths (by shearing - dissolution for example);
dissolution of fuel irradiated in nitric acid;
recovery of the insoluble solids;
extraction of uranium and plutonium by a organic Solvent of tributyl-phosphate 30% (TBP) in dodecane;
recovery of the fission products in the nitric acid phase;
extraction of the plutonium of the solution uranium/plutonium by reduction of plutonium;
purification, concentration and chemical conversion of uranium and plutonium.

At the conclusion of this stage, the minor actinides and the fission products are calcined then vitrified within an inert matrix which ensures the physicochemical stability of the parcel of waste. The other matters available are the plutonium (in form metal or oxide), which can be used jointly with uranium depleted in order to manufacture fuel MOX and the uranium, whose enrichment is equal to that of irradiated fuel.

Other processes

Other processes are currently under development: processes in aqueous way (UREX, TRUEX, DIAMEX, SANEX, UNEX, THOREX) as well as pyrometallurgical processes.

Lists of the world sites of nuclear reprocessing

Plant reprocessing of La Hague in France
Plant reprocessing of Sellafield (formerly called Windscale) in the United Kingdom
Complex nuclear power Mayak in Russia
Plant reprocessing of Tokay in Japan
Plant reprocessing of West Valley in the United States (stopped since 1972)

In 2007, a reprocessing plant of Russian military plutonium is in project in the United States.

World capacity of civilian nuclear reprocessing

World capacity of combustible reprocessing

of light water reactors

France, La Hague: 1700 tonnes/an
the United Kingdom, Sellafield (THORP): 900 tonnes/an
Russia, Ozersk (Mayak): 400 tonnes/an
Japan: 14 tonnes/an
Total (approximately): 3000 tonnes/an

Other nuclear fuels

the United Kingdom, Sellafield: 1500 tonnes/an
India: 275 tonnes/an
Total (approximately): 1750 Total tonnes/an

of the capacities: 4750 tonnes/an

Notes and references of the article

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