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For instance, the use of MOX fuel (239 Pu in a 238 U matrix) is likely to lead to the production of more 241 Am and heavier nuclides than a uranium/thorium based fuel (233 U in a 232 Th matrix). For highly enriched fuels used in marine reactors and research reactors , the isotope inventory will vary based on in-core fuel management and reactor ...
Spent fuel consists of radioactive ceramic, cooled until its short-half-life radioactives have decayed, so its heat-production is negligible. When initially made, the ceramic fuel is also wrapped in sealed tubes of corrosion-resistant zirconium alloy. Therefore, spent fuel is not water-soluble in any conventional sense, and is mechanically sturdy.
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.
The first reprocessing approach is based on the PUREX (Plutonium Uranium Reduction EXtraction) process, which is the standard and mature technology applied worldwide to recover uranium and plutonium from spent nuclear fuel at industrial scale. Following the dissolution of the spent fuel in nitric acid and the removal of uranium and plutonium ...
The radiation hazard from spent nuclear fuel declines as its radioactive components decay, but remains high for many years. For example 10 years after removal from a reactor, the surface dose rate for a typical spent fuel assembly still exceeds 10,000 rem/hour, resulting in a fatal dose in just minutes. [20]
The lifecycle of fuel in the present US system. If put in one place the total inventory of spent nuclear fuel generated by the commercial fleet of power stations in the United States, would stand 7.6 metres (25 ft) tall and be 91 metres (300 ft) on a side, approximately the footprint of one American football field.
Reprocessing of spent nuclear fuel by the PUREX method, first developed in the 1940s to produce plutonium for nuclear weapons, [1] was demonstrated commercially in Belgium to partially re-fuel a LWR in the 1960s. [2] This aqueous chemical process continues to be used commercially to separate reactor grade plutonium (RGPu) for reuse as MOX fuel ...
The high short-term radioactivity of spent nuclear fuel is primarily from fission products with short half-life.The radioactivity in the fission product mixture is mostly due to short-lived isotopes such as 131 I and 140 Ba, after about four months 141 Ce, 95 Zr/ 95 Nb and 89 Sr constitute the largest contributors, while after about two or three years the largest share is taken by 144 Ce/ 144 ...