Minor actinide

The minor actinides are the actinide elements in used nuclear fuel other than uranium and plutonium, which are termed the major actinides. The minor actinides include neptunium (element 93), americium (element 95), curium (element 96), berkelium (element 97), californium (element 98), einsteinium (element 99), and fermium (element 100).[2] The most important isotopes in spent nuclear fuel are neptunium-237, americium-241, americium-243, curium-242 through -248, and californium-249 through -252.

Plutonium and the minor actinides will be responsible for the bulk of the radiotoxicity and heat generation of used nuclear fuel in the medium term (300 to 20,000 years in the future).[3]

The plutonium from a power reactor tends to have a greater amount of Pu-241 than the plutonium generated by the lower burnup operations designed to create weapons-grade plutonium. Because the reactor-grade plutonium contains so much Pu-241 the presence of americium-241 makes the plutonium less suitable for making a nuclear weapon. The ingrowth of americium in plutonium is one of the methods for identifying the origin of an unknown sample of plutonium and the time since it was last separated chemically from the americium.

Americium is commonly used in industry as both an alpha particle and as a low photon energy gamma radiation source. For instance it is used in many smoke detectors. Americium can be formed by neutron capture of Pu-239 and Pu-240 forming Pu-241 which then beta decays to Am-241.[4] In general, as the energy of the neutrons increases, the ratio of the fission cross section to the neutron capture cross section changes in favour of fission. Hence if MOX is used in a thermal reactor such as a boiling water reactor (BWR) or pressurized water reactor (PWR) then more americium can be expected in the used fuel than that from a fast neutron reactor.[5]

Some of the minor actinides have been found in fallout from bomb tests. See Actinides in the environment for details.

Transuranics in LWR spent fuel (burnup 55 GWdth/T) and mean neutron consumption via fission [6]
Isotope Fraction DLWR Dfast Dsuperthermal
Np-237 0.0539 1.12 -0.59 -0.46
Pu-238 0.0364 0.17 -1.36 -0.13
Pu-239 0.451 -0.67 -1.46 -1.07
Pu-240 0.206 0.44 -0.96 0.14
Pu-241 0.121 -0.56 -1.24 -0.86
Pu-242 0.0813 1.76 -0.44 1.12
Am-241 0.0242 1.12 -0.62 -0.54
Am-242m 0.000088 0.15 -1.36 -1.53
Am-243 0.0179 0.82 -0.60 0.21
Cm-243 0.00011 -1.90 -2.13 -1.63
Cm-244 0.00765 -0.15 -1.39 -0.48
Cm-245 0.000638 -1.48 -2.51 -1.37
Weighted sum -0.03 -1.16 -0.51
Negative numbers mean net neutron producer
Sasahara
Transmutation flow between 238Pu and 244Cm in LWR.[1]
Fission percentage is 100 minus shown percentages.
Total rate of transmutation varies greatly by nuclide.
245Cm–248Cm are long-lived with negligible decay.

References

  1. ^ Sasahara, Akihiro; Matsumura, Tetsuo; Nicolaou, Giorgos; Papaioannou, Dimitri (April 2004). "Neutron and Gamma Ray Source Evaluation of LWR High Burn-up UO2 and MOX Spent Fuels". Journal of Nuclear Science and Technology. 41 (4): 448–456. doi:10.3327/jnst.41.448. Archived from the original on 2010-11-19.
  2. ^ Moyer, Bruce A. (2009). Ion Exchange and Solvent Extraction: A Series of Advances, Volume 19. CRC Press. p. 120. ISBN 9781420059700.
  3. ^ Stacey, Weston M. (2007). Nuclear Reactor Physics. John Wiley & Sons. p. 240. ISBN 9783527406791.
  4. ^ Raj, Gurdeep (2008). Advanced Inorganic Chemistry Vol-1, 31st ed. Krishna Prakashan Media. p. 356. ISBN 9788187224037.
  5. ^ Berthou, V.; et al. (2003). "Transmutation characteristics in thermal and fast neutron spectra: application to americium" (PDF). Journal of Nuclear Materials. 320: 156–162. Bibcode:2003JNuM..320..156B. doi:10.1016/S0022-3115(03)00183-1.
  6. ^ Etienne Parent (2003). "Nuclear Fuel Cycles for Mid-Century Deployment" (PDF). MIT. p. 104. Archived from the original (PDF) on 2009-02-25.
ASTRID (reactor)

ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) is a 600 MW sodium-cooled fast breeder reactor (Generation IV) project, proposed by the Commissariat à l'énergie atomique (CEA). It is proposed to be built on the Marcoule Nuclear Site in France. It is the successor of the three French fast reactors Rapsodie, Phénix and Superphénix. A final decision on construction is to be made in 2019.

The main goals of ASTRID are the multi-recycling of plutonium, aiming at preserving natural uranium resources, minor actinide transmutation, aiming at reducing nuclear waste, and an enhanced safety comparable to Generation III reactors, such as the EPR. It is envisaged as a 600 MW industrial prototype connected to the grid. A commercial series of 1500 MW SFR reactors is planned to be deployed around 2050.As of 2012, the project involves 500 people, with almost half among industrial partners. Those include Électricité de France, Areva, Alstom Power Systems, Comex Nucléaire, Jacobs France, Toshiba and Bouygues Construction.In 2014 Japan agreed to cooperate in developing the emergency reactor cooling system, and in a few other areas. As of 2016, France was seeking the full involvement of Japan in ASTRID development. In November 2018 France informed Japan it will halt joint development.If a decision is made to proceed with construction, ASTRID is expected to start operating in the 2030s.

Americium

Americium is a synthetic radioactive chemical element with the symbol Am and atomic number 95. It is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas.Americium was first produced in 1944 by the group of Glenn T. Seaborg from Berkeley, California, at the Metallurgical Laboratory of the University of Chicago, a part of the Manhattan Project. Although it is the third element in the transuranic series, it was discovered fourth, after the heavier curium. The discovery was kept secret and only released to the public in November 1945. Most americium is produced by uranium or plutonium being bombarded with neutrons in nuclear reactors – one tonne of spent nuclear fuel contains about 100 grams of americium. It is widely used in commercial ionization chamber smoke detectors, as well as in neutron sources and industrial gauges. Several unusual applications, such as nuclear batteries or fuel for space ships with nuclear propulsion, have been proposed for the isotope 242mAm, but they are as yet hindered by the scarcity and high price of this nuclear isomer.

Americium is a relatively soft radioactive metal with silvery appearance. Its common isotopes are 241Am and 243Am. In chemical compounds, americium usually assumes the oxidation state +3, especially in solutions. Several other oxidation states are known, which range from +2 to +7 and can be identified by their characteristic optical absorption spectra. The crystal lattice of solid americium and its compounds contain small intrinsic radiogenic defects, due to metamictization induced by self-irradiation with alpha particles, which accumulates with time; this can cause a drift of some material properties over time, more noticeable in older samples.

Charles Madic

Charles Madic (August 8, 1942 – March 1, 2008) was a French scientist working on the reprocessing of radioactive material.

Deep borehole disposal

Deep borehole disposal is the concept of disposing high-level radioactive waste from nuclear reactors in extremely deep boreholes instead of in more traditional deep geological repositories that are excavated like mines. Deep borehole disposal seeks to place the waste as much as five kilometres (3.1 mi) beneath the surface of the Earth and relies primarily on the thickness of the natural geological barrier to safely isolate the waste from the biosphere for a very long period of time so that it should not pose a threat to humans and the environment. The concept was originally developed in the 1970s, but recently a proposal for a first experimental borehole has been proposed by a consortium headed by Sandia National Laboratories.The waste would be put into the lower mile of such a hole, within crystalline rock to isolate it from the environment. The upper two miles of the borehole would be filled with protective layers including asphalt, bentonite, concrete and crushed rock that are expected to protect the environment during geologic time, and the hole would be lined with steel casing.A pair of proposed test boreholes in the United States were cancelled due to public opposition and lack of funding in 2016 and 2017.

Integral fast reactor

The integral fast reactor (IFR, originally advanced liquid-metal reactor) is a design for a nuclear reactor using fast neutrons and no neutron moderator (a "fast" reactor). IFR would breed more fuel and is distinguished by a nuclear fuel cycle that uses reprocessing via electrorefining at the reactor site.

IFR development began in 1984 and the U.S. Department of Energy built a prototype, the Experimental Breeder Reactor II. On April 3, 1986, two tests demonstrated the inherent safety of the IFR concept. These tests simulated accidents involving loss of coolant flow. Even with its normal shutdown devices disabled, the reactor shut itself down safely without overheating anywhere in the system. The IFR project was canceled by the US Congress in 1994, three years before completion.The proposed Generation IV Sodium-Cooled Fast Reactor is its closest surviving fast breeder reactor design. Other countries have also designed and operated fast reactors.

S-PRISM (from SuperPRISM), also called PRISM (Power Reactor Innovative Small Module), is the name of a nuclear power plant design by GE Hitachi Nuclear Energy (GEH) based on the Integral Fast Reactor.

Integrated Nuclear Fuel Cycle Information System

Integrated Nuclear Fuel Cycle Information System (iNFCIS) is a set of databases related to the nuclear fuel cycle maintained by the International Atomic Energy Agency (IAEA). The main objective of iNFCIS is to provide information on all aspects of nuclear fuel cycle to various researchers, analysts, energy planners, academicians, students and the general public. Presently iNFCIS includes several modules. iNFCIS requires free registration for on-line access.

MADB

Madb or MADB can refer to:

Mythology

Medb, an Irish legendary figure in Proto-Indo-European religion, also called Queen MaeveScience and medicine

madB, a protein-encoding gene in Phycomyces blakesleeanus

Mandibuloacral dysplasia with type B lipodystrophy, a type of Laminopathy

Carboxybiotin decarboxylase, an enzymeAcronyms for databases

Minor actinide property database Integrated Nuclear Fuel Cycle Information System#Modules

Magyar agár database

Microarray database

Message Addressing Database, for WS-Addressing

Material Acquisition Database

National Security and Nuclear Diplomacy

National Security and Nuclear Diplomacy is the memoir of Hassan Rouhani, the first secretary of Iran's Supreme National Security Council who was also in charge of Iran's nuclear case under President Mohammad Khatami as tensions began to escalate over Iran's nuclear program. About two years after this book was first published in 2011, its author was elected as President of Iran on 15 June 2013. In this book, he has focused on Iran's nuclear program and challenges created by the Western countries, especially the United States and three European countries of France, Germany and United Kingdom, during 678 days (from October 6, 2003 to August 15, 2005) when he and his team were handling Iran's nuclear case. The history of Iran's nuclear technology and the process of achieving complete nuclear fuel cycle are major topics of the book.

This is the first book written by a high-ranking Iranian official who was once leading Iran's nuclear negotiating team. Other memoirs have been also published on Iran's nuclear case including by Mohamed ElBaradei (former Director-General of IAEA), Joschka Fischer (former German foreign minister), Jack Straw (former British foreign secretary), and Hossein Mousavian (a former member of Iran's nuclear negotiating team).

Nuclear fuel cycle

The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in the back end, which are necessary to safely manage, contain, and either reprocess or dispose of spent nuclear fuel. If spent fuel is not reprocessed, the fuel cycle is referred to as an open fuel cycle (or a once-through fuel cycle); if the spent fuel is reprocessed, it is referred to as a closed fuel cycle.

Radioactive waste

Radioactive waste is waste that contains radioactive material. Radioactive waste is usually a by-product of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine. Radioactive waste is hazardous to most forms of life and the environment, and is regulated by government agencies in order to protect human health and the environment.

Radioactivity naturally decays over time, so radioactive waste has to be isolated and confined in appropriate disposal facilities for a sufficient period until it no longer poses a threat. The time radioactive waste must be stored for depends on the type of waste and radioactive isotopes. Current approaches to managing radioactive waste have been segregation and storage for short-lived waste, near-surface disposal for low and some intermediate level waste, and deep burial or partitioning / transmutation for the high-level waste.

A summary of the amounts of radioactive waste and management approaches for most developed countries are presented and reviewed periodically as part of the International Atomic Energy Agency (IAEA) Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management.

Sodium-cooled fast reactor

A sodium-cooled fast reactor is a fast neutron reactor cooled by liquid sodium.

The acronym SFR particularly refers to two Generation IV reactor proposals, one based on existing LMFR technology using MOX fuel, the other based on the metal-fueled integral fast reactor.

Several sodium-cooled fast reactors have been built, some still in operation, and others are in planning or under construction.

Spent nuclear fuel

Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant). It is no longer useful in sustaining a nuclear reaction in an ordinary thermal reactor and depending on its point along the nuclear fuel cycle, it may have considerably different isotopic constituents.

Transuranium element

The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements.

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