Which of the following is used to
enrichment of uranium ?
1) ClF3
2) ICl
3) IF7
4) F2
Answers
Answer : F2
Explanation:
Uranium enrichment is a process that is necessary to create an effective nuclear fuel out of mined uranium by increasing the percentage of uranium-235 which undergoes fission with thermal neutrons. Although many reactors require enriched uranium fuel, the Canadian-designed CANDU, the British Magnox reactor and the proposed Molten salt reactor can use natural uranium as their fuel.[2]
Nuclear fuel is mined from naturally occurring uranium ore deposits, and then isolated through chemical reactions and separation processes. These chemical processes used to separate the uranium from the ore are not to be confused with the physical and chemical processes used to enrich the uranium. In its isolated form, the uranium is known as yellowcake and has the chemical formula U3O8. However, naturally occurring uranium does not have a high enough concentration of 235U at only about 0.72% with the remainder being 238U.[3] Due to the fact that uranium-238 is fissionable and not fissile, the concentration of uranium-235 must be increased before it can be effectively used as a nuclear fuel. The purpose of uranium enrichment is to increase the percentage of the uranium-235 isotope with respect to others, with a necessary percentage of around 4% for light water reactors. Enrichment requires uranium to be in a gaseous form, and the simplest way to achieve this is to convert it to a different chemical known as uranium hexafluoride. Uranium needs to be in a gaseous form for enrichment due to the varying chemical and physical properties the different isotopes (U-235 and U-238) have. These differences are most easily utilized and manipulated when uranium is in gaseous form.
The process of changing uranium oxide concentrate to uranium hexafluoride takes place at a conversion plant, the first step for uranium after it leaves a mine. The main conversion process used in Canada, France and Russia is known as the 'wet process' and involves multiple chemical conversion stages. Firstly, the uranium oxide concentrate is dissolved in nitric acid (HNO3), which creates uranyl nitrate (UO2(NO3)2). This uranyl nitrate is then purified, evaporated and finally thermally decomposed to form uranium trioxide powder (UO3). After which there are two kiln processes wherein the UO3 is converted to UO2, then reacted with hydrogen fluoride (HF), to produce uranium tetrafluoride (UF4). Finally the UF4 is fed into a fluidized bed reactor and reacted with gaseous fluorine to produce UF6. After the conversion process, the UF6 needs to be further refined due to the presence of impurities.[4]
Gaseous Diffusion
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For many years the main process was gaseous diffusion. In order to physically separate the uranium the yellowcake uranium was first chemically transformed into uranium hexafluoride (UF6). This chemical is in its solid form under normal conditions, but transforms into a gas if the temperature is raised slightly or the pressure is lowered.[3] Since the 235UF6 molecules are slightly lighter than the 238UF6 molecules, they move more quickly as a gas through diffusion. Thus if uranium hexafluoride is passed through a very long pipe, the gas that emerges at the far end of the pipe will have a slightly higher percentage of 235U. However, the pipe must be extremely long as the lighter 235UF6 diffuses only 0.43% faster than 238UF6.[3] Because of this, the method of gaseous diffusion is not widely used anymore. plz mark as the brainest
Answer:
The correct answer of this question is F2.
Explanation:
Given - Enrichment of uranium.
To Find - Write which of the following is used to enrichment of uranium ?
F2 is used to enrichment of uranium .
Uranium enrichment is a procedure that increases the fraction of uranium-235 that undergoes thermal neutron fission in mined uranium, allowing it to be used as a nuclear fuel.
The goal of uranium enrichment is to raise the proportion of uranium-235 isotope in comparison to other isotopes, with a need of roughly 4% for light water reactors. Enrichment needs uranium to be in a gaseous state, which may be accomplished by converting it to uranium hexa fluoride, a distinct chemical. Because the various isotopes (U-235 and U-238) have distinct chemical and physical characteristics, uranium must be in a gaseous state for enrichment.
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