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Enriched uranium
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U with 99.2732–99.2752% natural abundance), uranium-235 (235U, 0.7198–0.7210%), and uranium-234 (234U, 0.0049–0.0059%). 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons.
Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons. Low-enriched uranium (below 20% 235U) is necessary to operate light water reactors, which make up almost 90% of nuclear electricity generation. Highly enriched uranium (above 20% 235U) is used for the cores of many nuclear weapons, as well as compact reactors for naval propulsion and research, as well as breeder reactors. There are about 2,000 tonnes of highly enriched uranium in the world.
Enrichment methods were first developed on a large scale by the Manhattan Project. Its gaseous diffusion method was used in the 1940s and 1950s, when the gas centrifuge method was developed in the Soviet Union, and became widespread.
The 238U remaining after enrichment is known as depleted uranium (DU), and is considerably less radioactive than natural uranium, though still very dense. Depleted uranium is used as a radiation shielding material and for armor-penetrating weapons.
Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable (the CANDU design is a notable exception). Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the uranium ore is mined, it must go through a milling process to extract the uranium from the ore.
This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as "yellowcake", contains roughly 80% uranium whereas the original ore typically contains as little as 0.1% uranium.
This yellowcake is further processed to obtain the desired form of uranium suitable for nuclear fuel production. After the milling process is complete, the uranium must next undergo a process of conversion, "to either uranium dioxide, which can be used as the fuel for those types of reactors that do not require enriched uranium, or into uranium hexafluoride, which can be enriched to produce fuel for the majority of types of reactors". Naturally occurring uranium is made of a mixture of 235U and 238U. The 235U is fissile, meaning it is easily split with neutrons while the remainder is 238U, but in nature, more than 99% of the extracted ore is 238U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of 235U ranging between 3.5% and 4.5% (although a few reactor designs using a graphite or heavy water moderator, such as the RBMK and CANDU, are capable of operating with natural uranium as fuel). There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide.
Reprocessed uranium (RepU) undergoes a series of chemical and physical treatments to extract usable uranium from spent nuclear fuel. RepU is a product of nuclear fuel cycles involving nuclear reprocessing of spent fuel. RepU recovered from light water reactor (LWR) spent fuel typically contains slightly more 235U than natural uranium, and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as CANDU reactors. It also contains the undesirable isotope uranium-236, which undergoes neutron capture, wasting neutrons (and requiring higher 235U enrichment) and creating neptunium-237, which would be one of the more mobile and troublesome radionuclides in deep geological repository disposal of nuclear waste. Reprocessed uranium often carries traces of other transuranic elements and fission products, necessitating careful monitoring and management during fuel fabrication and reactor operation.
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Enriched uranium AI simulator
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Enriched uranium
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U with 99.2732–99.2752% natural abundance), uranium-235 (235U, 0.7198–0.7210%), and uranium-234 (234U, 0.0049–0.0059%). 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons.
Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons. Low-enriched uranium (below 20% 235U) is necessary to operate light water reactors, which make up almost 90% of nuclear electricity generation. Highly enriched uranium (above 20% 235U) is used for the cores of many nuclear weapons, as well as compact reactors for naval propulsion and research, as well as breeder reactors. There are about 2,000 tonnes of highly enriched uranium in the world.
Enrichment methods were first developed on a large scale by the Manhattan Project. Its gaseous diffusion method was used in the 1940s and 1950s, when the gas centrifuge method was developed in the Soviet Union, and became widespread.
The 238U remaining after enrichment is known as depleted uranium (DU), and is considerably less radioactive than natural uranium, though still very dense. Depleted uranium is used as a radiation shielding material and for armor-penetrating weapons.
Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable (the CANDU design is a notable exception). Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the uranium ore is mined, it must go through a milling process to extract the uranium from the ore.
This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as "yellowcake", contains roughly 80% uranium whereas the original ore typically contains as little as 0.1% uranium.
This yellowcake is further processed to obtain the desired form of uranium suitable for nuclear fuel production. After the milling process is complete, the uranium must next undergo a process of conversion, "to either uranium dioxide, which can be used as the fuel for those types of reactors that do not require enriched uranium, or into uranium hexafluoride, which can be enriched to produce fuel for the majority of types of reactors". Naturally occurring uranium is made of a mixture of 235U and 238U. The 235U is fissile, meaning it is easily split with neutrons while the remainder is 238U, but in nature, more than 99% of the extracted ore is 238U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of 235U ranging between 3.5% and 4.5% (although a few reactor designs using a graphite or heavy water moderator, such as the RBMK and CANDU, are capable of operating with natural uranium as fuel). There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide.
Reprocessed uranium (RepU) undergoes a series of chemical and physical treatments to extract usable uranium from spent nuclear fuel. RepU is a product of nuclear fuel cycles involving nuclear reprocessing of spent fuel. RepU recovered from light water reactor (LWR) spent fuel typically contains slightly more 235U than natural uranium, and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as CANDU reactors. It also contains the undesirable isotope uranium-236, which undergoes neutron capture, wasting neutrons (and requiring higher 235U enrichment) and creating neptunium-237, which would be one of the more mobile and troublesome radionuclides in deep geological repository disposal of nuclear waste. Reprocessed uranium often carries traces of other transuranic elements and fission products, necessitating careful monitoring and management during fuel fabrication and reactor operation.