What Is Enriched Uranium?
Uranium: A rare chemical element found in nature and radioactive. According to the definition of the International Atomic Energy Agency, uranium 235 with an abundance of 3% is low-enriched uranium for nuclear power plant generation, and uranium with an abundance of more than 80% of 235 is highly enriched uranium. Among them, the abundance of more than 90% is called weapon-level high enrichment Uranium, mainly used in the manufacture of nuclear weapons.
- Chinese name
- Enriched uranium
- Foreign name
- Enriched uranium
- Highly enriched uranium
- Mainly used to make nuclear weapons
- uranium
- A rare chemical element
- Uranium: A rare chemical element that exists in nature and is radioactive. According to the definition of the International Atomic Energy Agency, uranium 235 with an abundance of 3% is low-enriched uranium for nuclear power plant generation, and uranium with an abundance of more than 80% of 235 is highly enriched uranium. Among them, the abundance of more than 90% is called weapon-level high enrichment. Uranium, mainly used in the manufacture of nuclear weapons.
Brief introduction of enriched uranium
- Whether it is the peaceful use of nuclear energy or the manufacture of nuclear weapons, enriching uranium is necessary. Therefore, the IAEA hopes to be able to control all uranium enrichment activities in countries around the world to prevent the proliferation of nuclear weapons.
- Enriched uranium can be divided into high-enriched uranium (HEU) (more than 20%), low-enriched uranium (LEU) (2% -20%), and slightly-enriched uranium (SEU) (0.9% -2%) according to the content of uranium 235. ). Uranium-235 content of more than 85% is called weapon-grade enriched uranium, which is directly used to make atomic bombs.
Basic information of enriched uranium
- Uranium is a rare chemical element found in nature and is radioactive. The three isotopes of uranium coexist in natural ore. The content of uranium 235 is very low, only about 0.7%. In order to meet the needs of nuclear weapons and nuclear power, some countries have built uranium enrichment plants, using natural uranium ore as raw materials, and using isotopic separation methods (diffusion method, centrifugation method, laser method, etc.) to separate the three isotopes of natural uranium in order to improve The abundance of uranium 235, refining enriched uranium.
- According to the definition of the International Atomic Energy Agency, uranium 235 with an abundance of 3% is low-enriched uranium for nuclear power plant generation, and uranium with an abundance of more than 80% of 235 is highly enriched uranium. Among them, the abundance of more than 90% is called weapon-level high enrichment. Uranium, mainly used in the manufacture of nuclear weapons. Obtaining uranium is a very complicated series of processes, which need to go through processes such as prospecting, mining, beneficiation, leaching, smelting, refining, etc., and enrichment and separation is the last process, which requires a high level of technology. To obtain 1 kg of weapon-grade uranium 235 requires 200 tons of uranium ore. Because it involves nuclear weapons, uranium enrichment technology is a sensitive technology that the international community strictly prohibits proliferation. In addition to several nuclear powers, Japan, Germany, India, Pakistan, Argentina and other countries have mastered uranium enrichment technology. Refining and enriching uranium usually uses gas centrifugation, and gas centrifuges are the key equipment. Therefore, the United States and other countries usually own the equipment as the standard for judging whether a country conducts nuclear weapons research.
- The current nuclear power plant uses uranium nuclear fuel. There are 12 isotopes of uranium (uranium-226 ~ uranium-240). Among them, uranium-234 does not undergo nuclear fission, uranium-238 does not undergo nuclear fission under normal circumstances, and uranium-235 isotope atoms can easily undergo nuclear fission, or uranium is actually used as a nuclear fuel. 235. However, in the uranium mined from the mine, the content of uranium-235 is very low, accounting for only 0.64%, and most of it is uranium-238, which accounts for 99.2%. This is equivalent to our briquette plant or oil refinery. Most of the briquette produced is silt, and of course it cannot be burned. According to the research results, uranium-235 content in uranium nuclear fuel must reach more than 3% before it can be burned. Therefore, the mined uranium is different from the mined coal blocks that can be used directly as fuel. It needs to undergo purification and enrichment procedures to increase the content of uranium-235 before it can be used as fuel.
Uranium enrichment technology
Existing methods for enriching uranium
- The technology for purifying the enriched uranium-235 content is more complicated, because the various isotopes of the elements are like "twin sisters". They are very similar in both physical and chemical properties, and they have achieved great results by using various physical purification methods or chemical purification methods. Micro, but the price is high. The main methods used today to purify uranium-235 include gas diffusion method, ion exchange method, gas centrifugation method, distillation method, electrolytic method, electromagnetic method, electric current method, etc. Among them, the most mature method is the gas diffusion method, which is used to make the first atomic bomb. The uranium nuclear material is manufactured in this way. For all these purification methods, their technological processes are relatively complicated, the investment in setting up a plant is high, the energy consumed during operation is also high, and the output is low, and the cost of the produced uranium nuclear fuel is high. Therefore, scientists have been looking for new purification methods.
Enriched uranium laser purification
- Laser scientists have suggested that the use of lasers for purification may greatly reduce the cost of producing uranium fuel.
- There are two technical routes for laser-enriched uranium-235: one is called the atomic method, and the other is called the molecular method. The raw materials used in atomic purification are uranium blocks obtained by refining uranium ore. The uranium block was first heated to a high temperature with a furnace to form uranium atomic vapors. The uranium vapors contained the uranium element isotopes uranium-234, uranium-235, and uranium-238 atoms. Then use a laser in the visible range (such as a dye laser pumped with a copper vapor laser) to irradiate this uranium atomic vapor. The output wavelength of the laser is tuned so that it falls in the center of the atomic absorption line of uranium-235, so that it can obtain excitation or ionization alone. Later, other physical methods can be used to separate uranium-235 atoms from the isotope uranium mixture. This technical route is relatively mature and has reached the stage of production and application.
- The molecular method uses raw materials of molecular compounds of uranium (such as uranium hexafluoride). A laser in the mid-infrared band (such as a 16 micron laser) is used to irradiate this compound, and the selected laser wavelength is exactly to excite (or ionize) the molecules of this compound of uranium-235, and then pass the atomic method in front The uranium-235 can be obtained by separating the molecular compound containing uranium-235 from the mixture by physical or chemical methods used in the chemical method, and then chemically decomposing the molecular compound containing uranium-235. This technical route has not yet reached the stage of production, but in terms of development potential, molecular methods are superior to atomic methods. On the one hand, because the raw material used for molecular separation is a molecular compound of uranium, the source of the raw material is relatively abundant; secondly, heating is not required during the separation process, and the atomic method needs to be heated to more than 2000 degrees to make the uranium raw material form vapor. High temperature uranium vapor is highly corrosive. Therefore, the production method of the molecular method is relatively simple, and the production cost is correspondingly low.
Information about enriched uranium
1020% Uranium enrichment Iran announced plans to build 10 uranium plants to produce 20% enriched uranium
- According to Hong Kong s Grand Public Network, Iran s Atomic Energy Agency s President Saleh said that Iran s production of enriched uranium with a purity of 20 percent will begin on February 9, 2010 under the supervision of IAEA inspectors. Salehi also said that Iran can terminate its domestic production if it can obtain uranium with a purity of 20% from overseas. Iran states that it is ready to exchange low-enriched uranium for high-enriched uranium, but hopes to modify the nuclear fuel exchange agreement drafted by the United Nations.
- Iranian President Mahmoud Ahmadinejad asked his Atomic Energy Organization on Sunday to start producing more advanced enriched uranium for Tehran. US Secretary of Defense Robert Gates is disappointed with Iran's response. "If the international community can work together to put pressure on the Iranian government, I believe there is still time for sanctions and pressure to work," Gates said at a press conference during his visit to Italy. Germany has also raised its call for sanctions. Britain also said Iran's new plan violates UN resolutions.
- Iranian media quoted Saleh's statement on the evening of the 7th, saying that Iran plans to build ten new uranium enrichment plants in the next "Iranian Year" (from March 21). His remarks are likely to further strain relations between Iran and Western countries. Iran announced in November 2009 that it plans to build ten new uranium enrichment plants to support its large-scale nuclear expansion. However, Iran has not specified the relevant timing. The West is worried that Iran's nuclear program is aimed at creating a nuclear bomb, but Iran has denied doing so.
Enriched uranium pushes domestic air defense system
- Separately, Iran s official news agency, the Islamic Republic News Agency, quoted a commander of the Iranian Air Force as saying that Iran is about to announce a locally-built air defense system. The performance of this system is on par with Russia's S-300 air defense missile system. Russia's national arms dealer declined to say whether plans to sell the S-300 system to Iran would continue. Although the S-300 system can protect Iran's nuclear facilities from air strikes, selling such a system to Iran is a sensitive issue in Russia's relations with the United States and Israel. The United States and Israel have actively urged Russia not to enter into this transaction. The S-300 air defense missile system can intercept cruise missiles and enemy aircraft. The maximum interception distance is 150 kilometers and the interception speed is greater than 2 kilometers per second.