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Ocean Floor Disposal
Ocean floor disposal is a method of sequestering radioactive waste in ocean floor sediment where it is unlikely to be disturbed either geologically or by human activity. Several methods of depositing material in the ocean floor have been proposed, including encasing it in concrete and as the United Kingdom has previously done, dropping it in torpedoes designed to increase the depth of penetration into the ocean floor, or depositing containers in shafts drilled with techniques similar to those used in oil exploration. Ocean floor sediment is saturated with water, but since there is no water table per se and the water does not flow through it the migration of dissolved waste is limited to the rate at which it can diffuse through dense clay. This is slow enough that it could potentially take millions of years for waste to diffuse through several tens of meters of sediment so that by the time it reaches open ocean it would be highly dilute and decayed. Large regions of the ocean flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, 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 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, so requires cooling and shielding. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide (MOX) fuels. The residual 4% is minor actinides and fission products the latter of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Zone
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, 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 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, so requires cooling and shielding. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide (MOX) fuels. The residual 4% is minor actinides and fission products the latter of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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''. Basic concepts Nuclear power relies on fissionable material that can sustain a chain reaction with neutrons. Examples of such materials include uranium and plutonium. Most nuclear reactors use a moderator to lower the kinetic energy of the neutrons and increase the probability that fission will occur. This allows reactors to use material with far lower c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Isolation Pilot Plant
The Waste Isolation Pilot Plant, or WIPP, is the world's third deep geological repository (after Germany's Repository for radioactive waste Morsleben and the Schacht Asse II salt mine) licensed to store transuranic radioactive waste for 10,000 years. The storage rooms at the WIPP are 2,150 feet (660 m) underground in a salt formation of the Delaware Basin. The waste is from the research and production of United States nuclear weapons only. The plant started operation in 1999, and the project is estimated to cost $19 billion in total. It is located approximately east of Carlsbad, New Mexico, in eastern Eddy County, in an area known as the southeastern New Mexico nuclear corridor, which also includes the National Enrichment Facility near Eunice, New Mexico, the Waste Control Specialists low-level waste disposal facility just over the state line near Andrews, Texas, and the International Isotopes, Inc. facility to be built near Eunice, New Mexico. Various mishaps at the pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yucca Mountain Nuclear Waste Repository
The Yucca Mountain Nuclear Waste Repository, as designated by the Nuclear Waste Policy Act amendments of 1987, is a proposed deep geological repository storage facility within Yucca Mountain for spent nuclear fuel and other high-level radioactive waste in the United States. The site is on federal land adjacent to the Nevada Test Site in Nye County, Nevada, about northwest of the Las Vegas Valley. The project was approved in 2002 by the 107th United States Congress, but the 112th Congress ended federal funding for the site via amendment to the Department of Defense and Full-Year Continuing Appropriations Act, passed on April 14, 2011, during the Obama Administration. The project has encountered many difficulties and was highly contested by the public, the Western Shoshone peoples, and many politicians. The project also faces strong state and regional opposition. The Government Accountability Office stated that the closure was for political, not technical or safety reasons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Borehole Disposal
Deep borehole disposal (DBD) 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 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 in 2014 a proposal for a first experimental borehole was 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.Conca, James."DOE Tries To Change The Rules On Nuclear Waste Disposal" ''Forbes'' (January 21, 2016). The upper two miles of the borehole would be filled with pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Disposal Of Radioactive Waste
From 1946 through 1993, thirteen countries used ocean disposal or ocean dumping as a method to dispose of nuclear/radioactive waste with an approximation of 200,000 tons sourcing mainly from the medical, research and nuclear industry. The waste materials included both liquids and solids housed in various containers, as well as reactor vessels, with and without spent or damaged nuclear fuel.IAETECDOC-1105 “Inventory of radioactive waste disposals at sea” August 1999retrieved 2011-12-4 Since 1993, ocean disposal has been banned by international treaties. ( London Convention (1972), Basel Convention, MARPOL 73/78). There has only been the disposal of low level radioactive waste (LLW) thus far in terms of ocean dumping as high level waste has been strictly prohibited. " Ocean floor disposal" (or sub-seabed disposal)—a more deliberate method of delivering radioactive waste to the ocean floor and depositing it into the seabed—was studied by the United Kingdom and Sweden, but nev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizontal Drillhole Disposal
Deep horizontal drillhole disposal is the concept of disposing of high-level radioactive waste from a nuclear reactor in deep horizontal boreholes instead of in more traditional deep geological repositories that are excavated like mines. The design concept is intended to improve upon the vertical borehole concept developed by Sandia National Laboratories, by utilizing modern advancements in directional drilling technology as well as using isotopic methods to measure the affinity a host rock has for isolation. American demonstration A series of tests of the disposal technology were carried out privately in November 2018 and then publicly in January 2019. The test demonstrated emplacement of a test-canister in a horizontal drillhole, and retrieval of the same canister. There was no actual high-level waste used in this test. Details Horizontal drillhole disposal describes proposals to drill over one kilometer vertically, and two kilometers horizontally in the earth’s crust, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convention On The Prevention Of Marine Pollution By Dumping Of Wastes And Other Matter
The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972, commonly called the "London Convention" or "LC '72" and also abbreviated as Marine Dumping, is an agreement to control pollution of the sea by dumping and to encourage regional agreements supplementary to the convention. It covers the deliberate disposal at sea of wastes or other matter from vessels, aircraft, and platforms. It does not cover discharges from land-based sources such as pipes and outfalls, wastes generated incidental to normal operation of vessels, or placement of materials for purposes other than mere disposal, providing such disposal is not contrary to aims of the convention. It entered into force in 1975. As of September 2016, there were 89 Parties to the convention. Background The convention was called for by the United Nations Conference on the Human Environment (June 1972, Stockholm), the treaty was drafted at the Intergovernmental Conference on the Convention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Floor
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of the ocean is very deep, where the seabed is known as the abyssal plain. Seafloor spreading creates mid-ocean ridges along the center line of major ocean basins, where the seabed is slightly shallower than the surrounding abyssal plain. From the abyssal plain, the seabed slopes upward toward the continents and becomes, in order from deep to shallow, the continental rise, slope, and shelf. The depth within the seabed itself, such as the depth down through a sediment core, is known as the “depth below seafloor.” The ecological environment of the seabed and the deepest waters are collectively known, as a habitat for creatures, as the “benthos.” Most of the seabed throughout the world's oceans is covered in layers of marine sediments ... [...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 ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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