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La Hague site
The La Hague site is a nuclear fuel reprocessing plant at La Hague on the Cotentin Peninsula in northern France, with the Manche storage centre bordering on it. Operated by Orano, formerly AREVA, and prior to that COGEMA (Compagnie générale des matières atomiques), La Hague has nearly half of the world's light water reactor spent nuclear fuel reprocessing capacity. It has been in operation since 1976, and has a capacity of about 1,700 tonnes per year. It extracts plutonium which is then recycled into MOX fuel at the Marcoule site.
It has treated spent nuclear fuel from France, Japan, Germany, Belgium, Switzerland, Italy, Spain and the Netherlands. It processed 1100 tonnes in 2005. The non-recyclable part of the radioactive waste is eventually sent back to the user nation. Prior to 2015, more than 32,000 tonnes of spent nuclear fuel has been reprocessed, with 70% of that from France, 17% from Germany and 9% from Japan.
Spent nuclear fuel roughly consists of three categories. The largest fraction by far is uranium that was present in the fuel from the start and was not affected by the nuclear reactions. Most of this uranium consists of uranium-238, which has a low radioactivity.
Around 3-4% of the material consists of fission products. These are mostly composed of highly radioactive isotopes, as the fission of uranium has endowed these with too many neutrons to be stable. As with all highly radioactive material, this level of radioactivity decreases relatively rapidly, although storage and shielding is required for at least hundreds of years.
Third, atom species are present which have a larger mass and atomic number than uranium itself. The majority of this so-called transuranic waste consists of plutonium isotopes, although other species are also present, such as americium.
Spent fuel treatment plants seek to separate these three categories into fractions that are as pure as possible. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide MOX fuels.
One of the main method for the separation of spent fuel is the PUREX process, which separates the plutonium and other transuranics from the remainder of the spent fuel. The uranium and plutonium are separated in turn in a series of complex chemical operations. The uranium becomes uranyl nitrate and the plutonium will be converted into plutonium oxide. The latter is used to produce fresh fuel called MOX – mixed oxides of uranium and plutonium, which can be used as fuel in nuclear reactors. The uranium fraction is very low in radioactivity and can be stored in specialized warehouses.
Long-term storage of radioactive waste requires the stabilization of the waste into a form that will neither react nor degrade for extended periods. Decades of research efforts have shown that a viable way to do this is through vitrification. High temperature treated ("calcined") fuel separation fractions are fed into an induction heated furnace with fragmented glass. The resulting glass contains the waste products which are bonded to the glass matrix. The fission products, which make up around 4% of the spent fuel mass, are the ones that are vitrified in this glass, as they cannot be used for any other purpose, and are generally highly radioactive. In practice, because of limits to separation of the three categories, a small amount of transuranic isotopes will be present in this material.
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La Hague site
The La Hague site is a nuclear fuel reprocessing plant at La Hague on the Cotentin Peninsula in northern France, with the Manche storage centre bordering on it. Operated by Orano, formerly AREVA, and prior to that COGEMA (Compagnie générale des matières atomiques), La Hague has nearly half of the world's light water reactor spent nuclear fuel reprocessing capacity. It has been in operation since 1976, and has a capacity of about 1,700 tonnes per year. It extracts plutonium which is then recycled into MOX fuel at the Marcoule site.
It has treated spent nuclear fuel from France, Japan, Germany, Belgium, Switzerland, Italy, Spain and the Netherlands. It processed 1100 tonnes in 2005. The non-recyclable part of the radioactive waste is eventually sent back to the user nation. Prior to 2015, more than 32,000 tonnes of spent nuclear fuel has been reprocessed, with 70% of that from France, 17% from Germany and 9% from Japan.
Spent nuclear fuel roughly consists of three categories. The largest fraction by far is uranium that was present in the fuel from the start and was not affected by the nuclear reactions. Most of this uranium consists of uranium-238, which has a low radioactivity.
Around 3-4% of the material consists of fission products. These are mostly composed of highly radioactive isotopes, as the fission of uranium has endowed these with too many neutrons to be stable. As with all highly radioactive material, this level of radioactivity decreases relatively rapidly, although storage and shielding is required for at least hundreds of years.
Third, atom species are present which have a larger mass and atomic number than uranium itself. The majority of this so-called transuranic waste consists of plutonium isotopes, although other species are also present, such as americium.
Spent fuel treatment plants seek to separate these three categories into fractions that are as pure as possible. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide MOX fuels.
One of the main method for the separation of spent fuel is the PUREX process, which separates the plutonium and other transuranics from the remainder of the spent fuel. The uranium and plutonium are separated in turn in a series of complex chemical operations. The uranium becomes uranyl nitrate and the plutonium will be converted into plutonium oxide. The latter is used to produce fresh fuel called MOX – mixed oxides of uranium and plutonium, which can be used as fuel in nuclear reactors. The uranium fraction is very low in radioactivity and can be stored in specialized warehouses.
Long-term storage of radioactive waste requires the stabilization of the waste into a form that will neither react nor degrade for extended periods. Decades of research efforts have shown that a viable way to do this is through vitrification. High temperature treated ("calcined") fuel separation fractions are fed into an induction heated furnace with fragmented glass. The resulting glass contains the waste products which are bonded to the glass matrix. The fission products, which make up around 4% of the spent fuel mass, are the ones that are vitrified in this glass, as they cannot be used for any other purpose, and are generally highly radioactive. In practice, because of limits to separation of the three categories, a small amount of transuranic isotopes will be present in this material.