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Encyclopedia > Nuclear reprocessing

Contents

Energy Portal

Nuclear reprocessing separates any usable elements (e.g., uranium and plutonium) from fission products and other materials in spent nuclear reactor fuels. Usually the goal is to recycle the reprocessed uranium or place these elements in new mixed oxide fuel (MOX), but some reprocessing is done to obtain plutonium for weapons. It is the process that partially closes the loop in the nuclear fuel cycle. Image File history File links Portal. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Used nuclear fuel (often called spent nuclear fuel) is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant) to the point that it is no longer useful in sustaining a nuclear reaction. ... Core of a small nuclear reactor used for research. ... Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... Reprocessed uranium (RepU) is the uranium recovered from nuclear fuel reprocessing. ... Mixed oxide, or MOX fuel, is a blend of plutonium and natural uranium or depleted uranium which behaves similarly (though not identically) to the enriched uranium feed for which most nuclear reactors were designed. ... The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. ...


History

The first large-scale nuclear reactors were built during World War II. These reactors were designed for the production of plutonium for use in nuclear weapons. The only reprocessing required, therefore, was the extraction of the plutonium (free of fission-product contamination) from the spent natural uranium fuel. In 1943, several methods were proposed for separating the relatively small quantity of plutonium from the uranium and fission products. The first method selected, a precipitation process called the Bismuth Phosphate process, was developed and tested at the Oak Ridge National Laboratory (ORNL) in the 1943-1945 period to produce quantities of plutonium for evaluation and use in weapons programs. ORNL produced the first macroscopic quantities (grams) of separated plutonium with these processes. Combatants Major Allied powers: United Kingdom Soviet Union United States France Republic of China and others Major Axis powers: Germany Italy Japan and others Commanders Winston Churchill Joseph Stalin Franklin Roosevelt Charles de Gaulle Chiang Kai-Shek Adolf Hitler Benito Mussolini Hirohito Casualties Military dead: 17,000,000 Civilian dead... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Natural uranium (NU) refers to refined uranium with the same isotopic ratios as found in nature. ... General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous reddish white Atomic mass 208. ... Above is a ball-and-stick model of the inorganic hydrogenphosphate anion (HPO42−). Colour coding: P (orange); O (red); H (white). ... A combination of federal, state and private funds is providing $300 million for the construction of 13 facilities on ORNLs new main campus. ... A nuclear fireball lights up the night in a United States nuclear test. ...


The Bismuth Phosphate process was first operated on a large scale at Hanford, Washington, in the latter part of 1944. It was successful for plutonium separation in the emergency situation existing then, but it had a significant weakness: the inability to recover uranium. The first successful solvent extraction process for the recovery of both uranium and plutonium in decontaminated form was developed at ORNL in 1949. It was this process, named PUREX, (see below) which became the current standard method. Hanford was a small agricultural community in Benton County, Washington. ...


In March 1977, fear of nuclear weapons proliferation (especially after India demonstrated nuclear weapons capabilities using reprocessing technology) led President Jimmy Carter to issue a Presidential directive to indefinitely suspend the commercial reprocessing and recycling of plutonium in the U.S. Other nations did not copy the policy and continued to reprocess spent nuclear fuel. For other persons named Jimmy Carter, see Jimmy Carter (disambiguation). ... Presidential directives are a form of executive order issued by the President of the United States with the advice and consent of the National Security Council. ...


However, in March 1999, the U.S. Department of Energy (DOE) signed a contract with a consortium comprised of Duke Energy, COGEMA, and Stone & Webster (DCS) to design and operate a Mixed Oxide (MOX) fuel fabrication facility. Site preparation at the Savannah River Site (South Carolina) began in October of 2005. [1] The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... A consortium is an association of two or more individuals, companies, organisations or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for achieving a common goal. ... Mixed oxide, or MOX fuel, is a blend of plutonium and natural uranium or depleted uranium which behaves similarly (though not identically) to the enriched uranium feed for which most nuclear reactors were designed. ...


The Global Nuclear Energy Partnership, announced by the secretary of the Department of Energy, Samuel Bodman, on February 6, 2006, is a plan to form an international partnership to reprocess spent nuclear fuel in a way that renders the plutonium in it usable for nuclear fuel but not for nuclear weapons. The Global Nuclear Energy Partnership, announced by U.S. Department of Energy secretary Samuel Bodman on February 6, 2006, is a plan to form an international partnership to see spent nuclear fuel reprocessed in a way that renders the plutonium in it usable for nuclear fuel but not for nuclear... Samuel Bodman Samuel Wright Bodman (born 1938) is the United States Secretary of Energy and was previously Deputy Secretary of the U.S. Treasury Department. ... February 6 is the 37th day of the year in the Gregorian Calendar. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Used nuclear fuel (often called spent nuclear fuel) is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant) to the point that it is no longer useful in sustaining a nuclear reaction. ... Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ...


Old Methods which are no longer used

Bismuth phosphate

The bismuth phosphate process is a very old process which adds lots of material to the final highly active waste. It was replaced by solvent extraction processes. The process was designed to extract plutonium from aluminium-clad uranium metal fuel. The fuel was declad by boiling it in caustic soda. After decladding, the uranium metal was dissolved in nitric acid. The plutonium at this point is in the +4 oxidation state. It was then precipitated by the addition of bismuth nitrate and phosphoric acid to form the bismuth phosphate. The plutonium was co-precipitated with this. The supernatant liquid (containing many of the Fission products) was separated from the solid. The precipitate was then dissolved in nitric acid before the addition of an oxidant such as potassium permanganate which converted the plutonium to PuO22+ (Pu VI), then a dichromate salt was added to maintain the plutonium in the +6 oxidation state. The bismuth phosphate was then re-precipitated leaving the plutonium in solution. Then an iron (II) salt such as ferrous sulfate was added and the plutonium re-precipitated again using a bismuth phosphate carrier precipitate. Then lanthanum salts and fluoride were added to create solid lanthanum fluoride which acted as a carrier for the Pu. This was converted to the oxide by the action of a base. The lanthanum plutonium oxide was then collected and extracted with nitric acid to form plutonium nitrate. [2] Waste inside a wheelie bin Waste, rubbish, trash, garbage, or junk is unwanted or undesired material. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... Sodium hydroxide (NaOH), also known as caustic soda or lye in North America, is a caustic metallic base used in industry (mostly as a strong chemical base) in the manufacture of paper, textiles, and detergents. ... The chemical compound nitric acid (HNO3), otherwise known as aqua fortis or spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). ... General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous reddish white Atomic mass 208. ... Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is an inorganic mineral acid having the chemical formula H3PO4. ... The liquid, containing soluble compounds, that is left behind after a mixture is centrifuged or precipitated. ... Fission products are the residues of fission processes. ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... Potassium permanganate is the chemical compound KMnO4. ... Chromates and Dichromates are salts of chromic acid. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ... Fluoride is the ionic form of fluorine. ...


Hexone or Redox

This is a liquid-liquid extraction process which uses methyl isobutyl ketone as the extractant. The extraction is by a solvation mechanism. This process has the disadvantge of requiring the use of a salting out reagent (aluminium nitrate) is required to increase the nitrate concentration in the aqueous phase to obtain a resonable distribution ratio (D value). Also hexone is degraded by concentrated nitric acid. This process has been replaced by PUREX.[3][4] General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... An electrostatic potential map of the nitrate ion. ...


Pu4+ + 4NO3- + 2S --> [Pu(NO3)4S2]


Butex, β,β'-dibutyoxydiethyl ether

A process based on a solvation extraction process using the triether extractant named above. This process has the disadvantge of requiring the use of a salting out reagent (aluminium nitrate) is required to increase the nitrate concentration in the aqueous phase to obtain a reasonable distribution ratio. This process was used at Windscale many years ago. This process has been replaced by PUREX. General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... An electrostatic potential map of the nitrate ion. ... Sellafield aerial view. ...


The current main method which is in use

Main article: PUREX

Overview of PUREX The PUREX process is used to reprocess spent nuclear fuel, in order to extract uranium and plutonium, independent of each other, from the fission products. ...


This process can be used to recover weapon-grade materials from spent nuclear reactor fuel, and as such, its component chemicals are monitored. PUREX is an acronym standing for Plutonium and Uranium Recovery by EXtraction. The PUREX process is a liquid-liquid extraction method used to reprocess spent nuclear fuel, in order to extract uranium and plutonium, independent of each other, from the fission products. The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter. ... Core of a small nuclear reactor used for research. ... Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their solution preferences for two different immiscible liquids, usually water and an organic solvent. ... Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... For the generation of electrical power by fission, see Nuclear power plant An induced nuclear fission event. ...


This is currently the most completely developed and most widely used process in the industry at present.


Possible methods for future use

Aqueous methods

UREX

The PUREX process can be modified to make a UREX (URanium EXtraction) process which could be used to save space inside high level nuclear waste disposal sites, such as Yucca Mountain, by removing the uranium which makes up the vast majority of the mass and volume of used fuel and recycling it as reprocessed uranium. Political Punk band from Victorville, Ca WWW.MYSPACE.COM/NUCLEARWASTEX ... Yucca Mountain Yucca Mountain is a ridge-line in Nye County, Nevada, composed of volcanic material (mostly tuff) ejected from a now-extinct caldera-forming supervolcano. ... Reprocessed uranium (RepU) is the uranium recovered from nuclear fuel reprocessing. ...


The UREX process is a PUREX process which has been modified to prevent the plutonium being extracted. This can be done by adding a plutonium reductant before the first metal extraction step. In the UREX process, ~99.9% of the Uranium and >95% of Technetium are separated from each other and the other fission products and actinides. The key is the addition of acetohydroxamic acid (AHA) to the extraction and scrub sections of the process. The addition of AHA greatly diminishes the extractability of Plutonium and Neptunium, providing greater proliferation resistance than with the plutonium extraction stage of the PUREX process. General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass [98](0) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number neptunium, Np, 93 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery metallic Atomic mass (237) g/mol Electron configuration [Rn] 5f4 6d1 7s2 Electrons per shell 2, 8, 18, 32, 22, 9, 2 Physical properties Phase solid Density (near r. ...


TRUEX

Adding a second extraction agent, octyl(phenyl)-N, N-dibutyl carbamoylmethyl phosphine oxide(CMPO) in combination with tributylphosphate, (TBP), the PUREX process can be turned into the TRUEX (TRansUranic EXtraction) process this is a process which was invented in the USA by Argonne National Laboratory, and is designed to remove the transuranic metals (Am/Cm) from waste. The idea is that by lowering the alpha activity of the waste, the majority of the waste can then be disposed of with greater ease. In common with PUREX this process operates by a solvation mechanism.


DIAMEX

As an alternative to TRUEX, an extraction process using a malondiamide has been devised. The DIAMEX (DIAMideEXtraction) process has the advantage of avoiding the formation of organic waste which contains elements other than Carbon, Hydrogen, Nitrogen, and Oxygen. Such an organic waste can be burned without the formation of acidic gases which could contribute to acid rain. The DIAMEX process is being worked on in Europe by the French CEA. The process is sufficiently mature that an industrial plant could be constructed with the existing knowledge of the process. In common with PUREX this process operates by a solvation mechanism. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... The effects of acid rain in the Jizera Mountains of the Czech Republic Acid rain (or more accurately acid precipitation)[1] occurs when sulfur dioxide and nitrogen oxides are emitted into the atmosphere, undergo chemical transformations and are absorbed by water droplets in clouds. ... World map showing Europe A satellite composite image of Europe Europe is one of the seven traditional continents of the Earth. ... CEA is an abbreviation the may refer to the following: Carcinoembryonic antigen - a tumour marker for colorectal cancer. ...


SANEX

Selective ActiNide EXtraction. As part of the management of minor actinides it has been proposed that the lanthanides and trivalent minor actinides should be removed from the PUREX raffinate by a process such as DIAMEX or TRUEX. In order to allow the actinides such as americium to be either reused in industrial sources or used as fuel the lanthanides must be removed. The lanthanides has large neutron cross sections and hence they would poison a neutron driven nuclear reaction. To date the extraction system for the SANEX process has not been defined, but currently several different research groups are working towards a process. For instance the French CEA is working on a bis-triaiznyl pyridine (BTP) based process. The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... Raffinate is a term in solvent extraction to describe a liquid stream which remains after the extraction with the immisible liquid to remove solutes from the original liquor. ... The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table. ... CEA is an abbreviation the may refer to the following: Carcinoembryonic antigen - a tumour marker for colorectal cancer. ...


References:

  • SANEX-BTP Process Studies
  • SANEX-BTP Process Development
  • Modelling and achievement of a SANEX process

Other systems such as the dithiophosphinic acids are being worked on by some other workers.


UNEX

This is the UNiversal EXtraction process which was developed in Russia and the Czech Republic, it is a process designed to remove all of the most troublesome (Sr, Cs and minor actinides) radioisotopes from the raffinates left after the extraction of uranium and plutonium from used nuclear fuel. [5][6] The chemistry is based upon the interaction of cesium and strontium with poly ethylene oxide (poly ethylene glycol) [7] and a cobalt carborane anion (known as chlorinated cobalt dicarbollide) . The actinides are extracted by CMPO, and the diluent is a polar aromatic such as nitrobenzene. Other dilents such as meta-nitrobenzotrifluoride and phenyl trifluoromethyl sulfone [8]have been suggested as well. The minor actinides are the actinide elements in spent fuel other than uranium and plutonium, these are termed major actinides. ... A radionuclide is an atom with an unstable nucleus. ... Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... General Name, Symbol, Number Caesium, Cs, 55 Series Alkali metals Group, Period, Block 1(IA), 6, s Density, Hardness 1879 kg/m3, 0. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Atomic mass 87. ... The chemical compound ethylene oxide is an important industrial chemical used as an intermediate in the production of ethylene glycol and other chemicals, and as a sterilant for foodstuffs and medical supplies. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... This article or section does not cite its references or sources. ... 3D model of carborane acid, colors: Hydrogen - white, Chlorine - yellow, Boron - green, Carbon - black A carborane is a cluster composed of boron and carbon atoms. ... An anion is an ion with negative charge. ... Categories: Move to Wiktionary | Stub ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... Nitrobenzene, also known as nitrobenzol or oil of mirbane, is a poisonous organic compound with an almond odor and chemical formula C6H5NO2. ... Fluoride is the ionic form of fluorine. ... A sulfone is a chemical compound containing a sulfonyl functional group attached to two carbon atoms. ...


Electrochemical method in aqueous alkali

An exotic method using electrochemistry and ion exchange in ammonium carbonate has been reported.[9] English chemists John Daniell (left) and Michael Faraday (right), both credited to be founders of electrochemistry as known today. ... Ion exchange is a process in which ions are exchanged between a solution and an ion exchanger, an insoluble solid or gel. ... Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride Ammonium is also an old name for the Siwa oasis in western Egypt. ... In inorganic chemistry, a carbonate is a salt of carbonic acid. ...


Non aqueous methods

Pyroprocessing is a generic term for Pyrometallurgy processes. These processes are not currently in significant use worldwide, but they have been researched and developed at Argonne National Laboratory and elsewhere. The principles behind them are well understood, and no significant technical barriers exist to their adoption. The primary economic hurdle to widespread adoption is that reprocessing as a whole is not currently (2005) in favor, and places that do reprocess already have PUREX plants constructed. Consequently, there is little demand for new pyrometalurgical systems, although there could be if the Generation IV reactor programs become reality. Pyrometallurgy uses high temperatures to transform metals and their ores. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Generation IV reactors (Gen IV) are a set of theoretical nuclear reactor designs currently being researched. ...


Pyrometallurgical processing techniques involve several stages: volatilisation, liquid-liquid extraction using immiscible metal-metal phases or metal-salt phases, electrorefining in molten salt, fractional crystallisation, etc. They are generally based on the use of either fused (low-melting point) salts such as chlorides or fluorides (eg LiCl+KCl or LiF+CaF2) or fused metals such as cadmium, bismuth or aluminium. They are most readily applied to metal rather than oxide fuels. Electrowinning (sometimes abbreviated to EW, also known as Electrorefining) the electrodeposition of metals from their ores that have been put in solution or liquefied. ...


Advantages

  • Pyroprocessing can readily be applied to high burn-up fuel and fuel which has had little cooling time, since the operating temperatures are high already.
  • It does not use water. Water is problematic in nuclear chemistry for many reasons. First of all, it tends to serve as a moderator, and accelerate nuclear reactions. Secondly, it is easily contaminated, and not easily cleaned up, and it tends to evaporate, potentially taking Tritium with it. This is not as large an advantage as it might first appear as it is possible to treat normal oxide fuel using a process called Voloxidation [10]which removes 99% of the tritium from used fuel. The tritium can be reovered in the form of a strong solution which might be suitable for use as a supply of tritium for industrial applications.
  • It separates out all actinides, and therefore produces fuel that is heavily spiked with heavy actinides, such as Plutonium (240+), and Curium 242. This does not prevent the fuel from being suitable for reactors, but it makes it hard to manipulate, steal, or make nuclear weapons from. This is generally considered a fairly desirable property. In contrast, the PUREX process can easily produce separated Uranium and Plutonium, and also tends to leave the remaining actinides (like Curium) behind, producing more dangerous nuclear waste.
  • It is somewhat more efficient and considerably more compact than aqueous processing methods, allowing the possibility of on-site reprocessing of reactor wastes. This circumvents various transportation and security issues, allowing the reactor to simply store a small volume (perhaps a few percent of the original volume of the spent fuel) of fission product laced salt on site until decommissioning, when everything could be dealt with at once.
  • Since pyrometalurgy recovers all the actinides, the remaining waste is not nearly as long lived as it would otherwise be. Most of the long term (past a couple hundred years) radioactivity produced by nuclear waste is produced by the actinides. These actinides can (mostly) be consumed by reactors as fuel, so extracting them from the waste and reinserting them into the reactor reduces the long term threat from the waste, and reduces the fuel needs of the reactor.

Disadvantages Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ... The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table with atomic numbers 89 - 103. ...

  • The used salt from pyro processing is not suitable for conversion into a glass in the same way as the raffinate from PUREX processing.

Raffinate is a term in solvent extraction to describe a liquid stream which remains after the extraction with the immisible liquid to remove solutes from the original liquor. ...

PYRO-A

In nuclear engineering, PYRO-A refers to a type of nuclear reprocessing. More specifically, it is a means of separating actinides (elements within the actinide family, generally heavier than U-235) from non-actinides. The principles are quite simple. The spent fuel is placed in an anode basket which is immersed in a molten salt electrolyte. An electrical current is applied, causing the uranium metal (or sometimes oxide, depending on the spent fuel) to plate out on a solid metal cathode while the other actinides (and the rare earths) can be absorbed into a liquid cadmium cathode. Many of the fission products (such as cesium, zirconium and strontium) remain in the salt. [11][12][13] As alternatives to the moltern cadmium electrode it is possible to use a molten bismuth cathode, or a solid aluminium cathode [14] [15]. The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table with atomic numbers 89 - 103. ... Diagram of a zinc anode in a galvanic cell. ... Four styles of household basket. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Atomic mass 112. ... General Name, Symbol, Number Caesium, Cs, 55 Series Alkali metals Group, Period, Block 1(IA), 6, s Density, Hardness 1879 kg/m3, 0. ... General Name, Symbol, Number zirconium, Zr, 40 Chemical series transition metals Group, Period, Block 4, 5, d Appearance silvery white Atomic mass 91. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Atomic mass 87. ... General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous reddish white Atomic mass 208. ...


As an alternative to electrowinning, the wanted metal can be isolated by using a molten alloy of an electropositive metal and a less reactive metal.[16] Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms positive ions (cations) and has metallic bonds. ... Physics In physics, melting is the process of heating a solid substance to a point (called melting point) where it turns liquid. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... An electropositive atom, or element, is one that easily loses electrons. ...


Since the majority of the long term radioactivity, and volume, of spent fuel comes from actinides, removing the actinides produces waste that is more compact, and not nearly as dangerous over the long term. The radioactivity of this waste will then drop to the level of various naturally occurring minerals and ores within a few hundred, rather than thousands, years. Radioactivity may mean: Look up radioactivity in Wiktionary, the free dictionary. ...


The mixed actinides produced by pyrometallic processing can be used again as nuclear fuel, as they are virtually all either fissile, or fertile, though many of these materials would require a fast breeder reactor in order to be burned efficiently. In a thermal neutron spectrum, the concentrations of several heavy actinides (Curium-242 and Plutonium-240) can become quite high, creating fuel that is substantially different from the usual Uranium or mixed oxides (MOX) that most current reactors were designed to use. This article or section should include material from Fissile material In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... Fertile may be used in the following conrtext: Fertility, a term used to describe the ability of people or animals to produce healthy offspring. ... The fast breeder or fast breeder reactor (FBR) is a fast neutron reactor designed to breed fuel by producing more fissile material than it consumes. ... This article does not cite its references or sources. ... General Name, Symbol, Number curium, Cm, 96 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery Atomic mass (247) g/mol Electron configuration [Rn] 5f7 6d1 7s2 Electrons per shell 2, 8, 18, 32, 25, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ...


PYRO-B

Another pyrochemical process, the PYRO-B process, has been developed for the processing and recycling of fuel from a transmuter reactor ( A Fast breeder reactor designed to convert transuranic nuclear waste into fission products ). A typical transmuter fuel is free of uranium and contains recovered transuranics in an inert matrix such as metallic zirconium. In the PYRO-B processing of such fuel, an electrorefining step is used to separate the residual transuranic elements from the fission products and recycle the transuranics to the reactor for fissioning. Newly-generated technetium and iodine are extracted for incorporation into transmutation targets, and the other fission products are sent to waste. The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... The fast breeder or fast breeder reactor (FBR) is a fast neutron reactor designed to breed fuel by producing more fissile material than it consumes. ... In chemistry, transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, the atomic number of Uranium. ... General Name, Symbol, Number zirconium, Zr, 40 Chemical series transition metals Group, Period, Block 4, 5, d Appearance silvery white Atomic mass 91. ... Electrowinning (sometimes abbreviated to EW, also known as Electrorefining) the electrodeposition of metals from their ores that have been put in solution or liquefied. ...


Fluoride volatility

A related process exists in which the uranium is distilled away after conversion to uranium hexafluoride, this is the Fluoride volatility process. General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... Uranium hexafluoride, or UF6, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons. ... This is a method for the removal of elements, which form volatile fluorides, from fused molten fluoride salts. ...


Economics of reprocessing nuclear fuel

The relative economics of reprocessing-waste disposal and interim storage-direct disposal has been the focus of much debate over the past ten years. Many approaches have been used and to a certain extent the approach taken has determined the outcome of the assessment. These studies model the total fuel cycle costs of a reprocessing-recycling system based on thermal recycling of plutonium and compare this to the total costs of an open fuel cycle with direct disposal. The range of results produced by these studies is very wide, but all are agreed that under current (2005) economic conditions the reprocessing-recycle option is the more costly. Face-to-face trading interactions among on the New York Stock Exchange trading floor Economics or oeconomics is the study of human choice behaviour. ...


If reprocessing is undertaken only to reduce the radioactive level of spent fuel it should be taken into account that spent nuclear fuel becomes less radioactive over time. After 40 years its radioactivity drops by 99.9% [17], though it still takes over a thousand years for the level of radioactivity to approach that of natural uranium [18]. However the level of transuranic elements, including plutonium-239, remains high for over 100,000 years, so if not reused as nuclear fuel (the whole point of reprocessing) then those elements need secure disposal because of nuclear proliferation reasons. In chemistry, transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, the atomic number of Uranium. ... World map with nuclear weapons development status represented by color. ...

  • Recycled Nuclear Fuel Cost Calculator designed by the WISE Uranium Project

List of nuclear reprocessing sites

The COGEMA La Hague site is a nuclear fuel reprocessing plant near La Hague on the French Cotentin Peninsula that currently has over half of the worlds light water reactor spent nuclear fuel reprocessing capacity. ... Mayak is the name of a nuclear fuel reprocessing plant between the towns of Kasli and Kyshtym (also transliterated Kishtym or Kishtim) 150 km northwest of Chelyabinsk in Russia. ... THORP, or Thermal Oxide Reprocessing Plant, is a nuclear fuel reprocessing plant at Sellafield in Cumbria, England, operated by BNFL. It processes spent nuclear fuel from nuclear reactors and separates the uranium and plutonium, which can be reused in mixed oxide fuel, from the radioactive wastes, which are treated and... B205 is the name of the magnox nuclear reprocessing plant at Windscale in northern England. ... The Sellafield facility on the Cumbrian coast, United Kingdom Sellafield is the name of a nuclear site, close to the village and railway station of Seascale, operated by the British Nuclear Group, but owned since 1 April 2005 by the Nuclear Decommissioning Authority. ... West Valley Reprocessing Plant is a spent nuclear fuel reprocessing plant at West Valley, New York, USA, was operated successfully from 1966-72. ...

See also

The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. ... The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... A typical SNF shipping cask mounted on a railroad car. ... The Global Nuclear Energy Partnership, announced by U.S. Department of Energy secretary Samuel Bodman on February 6, 2006, is a plan to form an international partnership to see spent nuclear fuel reprocessed in a way that renders the plutonium in it usable for nuclear fuel but not for nuclear... The Megatons to Megawatts Program is the name given the program implementing the 1993 United States-Russia nonproliferation agreement to convert high-enriched uranium taken from dismantled Russian nuclear weapons into low-enriched-uranium for nuclear fuel. ...

References

  • OECD Nuclear Energy Agency, The Economics of the Nuclear Fuel Cycle, Paris, 1994
  • I. Hensing and W Schultz, Economic Comparison of Nuclear Fuel Cycle Options, Energiewirtschaftlichen Instituts, Cologne, 1995.
  • Cogema, Reprocessing-Recycling: the Industrial Stakes, presentation to the Konrad-Adenauer-Stiftung, Bonn, 9 May 1995.
  • OECD Nuclear Energy Agency, Plutonium Fuel: An Assessment, Paris, 1989.
  • National Research Council, "Nuclear Wastes: Technologies for Separation and Transmutation", National Academy Press, Washington D.C. 1996.

External links

  • Processing of Used Nuclear Fuel, World Nuclear Association
  • Reactor-Grade Plutonium and Development of Nuclear Weapons, Analytical Center for Non-proliferation
  • PUREX Process, European Nuclear Society
  • Mixed Oxide Fuel (MOX) - World Nuclear Association
  • MOX production and use - Greenpeace
  • Disposal Options for Surplus Weapons-Usable Plutonium - Congressional Research Service Report for Congress
  • Brief History of Fuel Repreocessing

  Results from FactBites:
 
UK Nuclear Reprocessing Plant (3265 words)
Technically, reprocessing is the chemical treatment of spent reactor fuel to separate the plutonium and uranium from spent fuel rods and from each other, to be used again as fuel (1).
Typically, nuclear reprocessing plants, such as Thorp plant, carry out a chemical operation which separates the elements of the fuel rods; thereby extracting 97% uranium and plutonium which can be utilized again for energy purposes.
After reprocessing, the nuclear waste is then shipped back to the country of origin in a glass form, resulting from a process known as vitrification.
  More results at FactBites »

 
 

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