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Radioactive Waste
Radioactive waste is a type of hazardous waste that contains radioactive material. It is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, nuclear decommissioning, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment. Radioactive waste is broadly classified into 3 categories: low-level waste (LLW), such as paper, rags, tools, clothing, which contain small amounts of mostly short-lived radioactivity; intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding; and high-level waste (HLW), which is highly radioactive and hot due to decay heat, thus requiring cooling and shielding. Spent nuclear fuel can be processed in nuclear reprocessing plants. One third of the total amount have already been reprocessed. With nuclear reprocessing 96% of the spent fue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TINT Radioactive Wastes' Barrel
In color theory, a tint is a mixture of a color with white, which increases lightness, while a shade is a mixture with black, which increases darkness. A tone is produced either by mixing a color with gray, or by both tinting and shading. Mixing a color with any neutral color (black, gray, and white) reduces the chroma, or colorfulness, while the perceived hue can be affected slightly (see Abney effect and Bezold-Brücke shift). In the graphic arts, especially printmaking and drawing, "tone" has a different meaning, referring to areas of continuous color, produced by various means, as opposed to the linear marks made by an engraved or drawn line. In common language, the term ''shade'' can be generalized to encompass any varieties of a particular color, whether technically they are shades, tints, tones, or slightly different hues. Meanwhile, the term ''tint'' can be generalized to refer to any lighter or darker variation of a color (e.g. " tinted windows"). Wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strontium-90
Strontium-90 () is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.79 years. It undergoes β− decay into yttrium-90, with a decay energy of 0.546 MeV. Strontium-90 has applications in medicine and industry and is an isotope of concern in fallout from nuclear weapons, nuclear weapons testing, and nuclear accidents. Radioactivity Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90Sr is a radiation hazard. 90Sr undergoes β− decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90Y, which in turn undergoes β− decay with a half-life of 64 hours and a decay energy of 2.28 MeV distributed to an electron, an antineutrino, and 90Zr (zirconium), which is stable. Note that 90Sr/Y is almost a pure beta particle source; the gamma photon emission from the decay of 90Y is so infrequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered ''radioactive''. Three of the most common types of decay are Alpha decay, alpha, Beta decay, beta, and Gamma ray, gamma decay. The weak force is the Fundamental interactions, mechanism that is responsible for beta decay, while the other two are governed by the electromagnetic force, electromagnetic and nuclear forces. Radioactive decay is a randomness, random process at the level of single atoms. According to quantum mechanics, quantum theory, it is impossible to predict when a particular atom will decay, regardless of how long the atom has existed. However, for a significant number of identical atoms, the overall decay rate can be expressed as a decay constant or as a half-life. The half-lives of radioactive atoms have a huge range: f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radionuclides
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons to release it as a conversion electron; or used to create and emit a new particle (alpha particle or beta particle) from the nucleus. During those processes, the radionuclide is said to undergo radioactive decay. These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for a collection of atoms of a single nucl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Atomic Energy Agency
The International Atomic Energy Agency (IAEA) is an intergovernmental organization that seeks to promote the peaceful use of nuclear technology, nuclear energy and to inhibit its use for any military purpose, including nuclear weapons. It was established in 1957 as an autonomous international organization; though governed by its own founding treaty, the IAEA Statute, the organization reports to both the United Nations General Assembly, General Assembly and the United Nations Security Council, Security Council of the United Nations, and is headquartered at the United Nations Office at Vienna, UN Office at Vienna, Austria. The IAEA was created in response to growing international concern toward nuclear weapons, especially Cold War (1953–1962), amid rising tensions between the foremost nuclear powers, the United States and the Soviet Union. U.S. president Dwight D. Eisenhower's "Atoms for Peace, Atoms for Peace" speech, which called for the creation of an international organiza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint Convention On The Safety Of Spent Fuel Management And On The Safety Of Radioactive Waste Management
The Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management is a 1997 International Atomic Energy Agency (IAEA) treaty. It is the first treaty to address radioactive waste management on a global scale. Content The states that ratify the Convention agree to be governed by the convention's provisions on the storage of nuclear waste, including transport and the location, design, and operation of storage facilities. The Convention implements meetings of the state parties that review the states' implementation of the convention. The Fourth Review Meeting was held in 2012. A summary report from the meeting, and links to the national reports from the participating countries, is available on the IAEA website. Creation and state parties The convention was concluded in Vienna, Austria, on 29 September 1997 and entered into force on 18 June 2001. It was signed by 42 states. As of March 2025, it has 90 state parties plus the European Atomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Contamination
Radioactive contamination, also called radiological pollution, is the deposition of, or presence of Radioactive decay, radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency (IAEA) definition). Such contamination presents a hazard because the radioactive decay of the contaminants produces ionizing radiation (namely alpha particle, alpha, beta particle, beta, gamma rays and free neutrons). The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable. The sources of radioactive pollution can be classified into two groups: natural and man-made. Follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Transmutation
Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed. A transmutation can be achieved either by nuclear reactions (in which an outside particle reacts with a nucleus) or by radioactive decay, where no outside cause is needed. Natural transmutation by stellar nucleosynthesis in the past created most of the heavier chemical elements in the known existing universe, and continues to take place to this day, creating the vast majority of the most common elements in the universe, including helium, oxygen and carbon. Most stars carry out transmutation through fusion reactions involving hydrogen and helium, while much larger stars are also capable of fusing heavier elements up to iron late in their evolution. Elements heavier than iron, such as gold or lead, are created through elemental transmutations that can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Geological Repository
A deep geological repository is a way of storing hazardous or radioactive waste within a stable geologic environment, typically 200–1,000 m below the surface of the earth. It entails a combination of waste form, waste package, engineered seals and geology that is suited to provide a high level of long-term isolation and containment without future maintenance. This is intended to prevent radioactive dangers. A number of mercury, cyanide and arsenic waste repositories are operating worldwide including Canada ( Giant Mine) and Germany (potash mines in Herfa-Neurode and Zielitz). Radioactive waste storage sites are under construction with the Onkalo in Finland being the most advanced. Principles and background Highly toxic waste that cannot be further recycled must be stored in isolation, to avoid contamination of air, ground and underground water. Deep geological repository is a type of long-term storage that isolates waste in geological structures that are expected to be st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitrification
Vitrification (, via French ') is the full or partial transformation of a substance into a glass, that is to say, a non- crystalline or amorphous solid. Glasses differ from liquids structurally and glasses possess a higher degree of connectivity with the same Hausdorff dimensionality of bonds as crystals: dimH = 3. In the production of ceramics, vitrification is responsible for their impermeability to water. Vitrification is usually achieved by heating materials until they liquify, then cooling the liquid, often rapidly, so that it passes through the glass transition to form a glassy solid. Certain chemical reactions also result in glasses. In terms of chemistry, vitrification is characteristic for amorphous materials or disordered systems and occurs when bonding between elementary particles (atoms, molecules, forming blocks) becomes higher than a certain threshold value. Thermal fluctuations break the bonds; therefore, the lower the temperature, the higher the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PUREX
PUREX (plutonium uranium reduction extraction) is a chemical method used to purify fuel for nuclear reactors or nuclear weapons. It is based on liquid–liquid extraction ion-exchange. PUREX is the '' de facto'' standard aqueous nuclear reprocessing method for the recovery of uranium and plutonium from used nuclear fuel (spent nuclear fuel, or irradiated nuclear fuel). It is also the standard process used in industrial scale operations. PUREX is applied to spent nuclear fuel, which consists primarily of very high atomic-weight ( actinoid or "actinide") elements (e.g. uranium, plutonium, americium) along with smaller amounts of material composed of lighter atoms, notably the fission products produced by reactor operation. The actinoid elements in this case consist primarily of the unconsumed remains of the original fuel (typically U-235, U-238, and/or Pu-239). Chemical process The fuel is first dissolved in nitric acid at a concentration around 7 M. Solids are remo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Decay
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus). The parent nucleus transforms or "decays" into a daughter product, with a mass number that is reduced by four and an atomic number that is reduced by two. An alpha particle is identical to the nucleus of a helium-4 atom, which consists of two protons and two neutrons. It has a charge of and a mass of , and is represented as ^_\alpha. For example, uranium-238 undergoes alpha decay to form thorium-234. While alpha particles have a charge , this is not usually shown because a nuclear equation describes a nuclear reaction without considering the electrons – a convention that does not imply that the nuclei necessarily occur in neutral atoms. Alpha decay typically occurs in the heaviest nuclides. Theoretically, it can occur only in nuclei somewhat heavier than nickel (element 28), where the overall binding energy per nucleon is no longer a maximum a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
