What is Uranium: Definition and 152 Discussions

Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.In nature, uranium is found as uranium-238 (99.2739–99.2752%), uranium-235 (0.7198–0.7202%), and a very small amount of uranium-234 (0.0050–0.0059%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth.
Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 is the only naturally occurring fissile isotope, which makes it widely used in nuclear power plants and nuclear weapons. However, because of the tiny amounts found in nature, uranium needs to undergo enrichment so that enough uranium-235 is present. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor. Another fissile isotope, uranium-233, can be produced from natural thorium and is studied for future industrial use in nuclear technology. Uranium-238 has a small probability for spontaneous fission or even induced fission with fast neutrons; uranium-235 and to a lesser degree uranium-233 have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain a sustained nuclear chain reaction. This generates the heat in nuclear power reactors, and produces the fissile material for nuclear weapons. Depleted uranium (238U) is used in kinetic energy penetrators and armor plating. Uranium is used as a colorant in uranium glass, producing lemon yellow to green colors. Uranium glass fluoresces green in ultraviolet light. It was also used for tinting and shading in early photography.
The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the recently discovered planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. Research by Otto Hahn, Lise Meitner, Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used uranium metal and uranium-derived plutonium-239. The security of those weapons is closely monitored. Since around 2000, plutonium obtained by dismantling cold war era bombs is used as fuel for nuclear reactors.The development and deployment of these nuclear reactors continue on a global base. There is increasing interest in these power plants as they are powerful sources of CO2-free energy. In 2019, 440 nuclear power reactors produced 2586 TWh (billion kWh) of CO2-free electricity worldwide, more than the global installations of solar and wind power combined.

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  1. N

    Acceleration of Uranium 238 ion through a potential difference

    I don't understand why the Uranium 238 ions are accelerated I think ##\Delta V = -2000 V## to accelerate since the ion would be accelerated by more postive charges so ## V_i > V_f ##
  2. mark_bose

    Searching for a single and complete resource about nuclear fuels

    Hello, I am looking for a comprehensive resource (paper, book or any kind of document) that contains the most relevant properties of most nuclear fuels. To be more specific, the information i am looking for are thermophysical properties, chemical compatibility with other materials and...
  3. S

    I How bad is this article about uranium glass?

    https://getpocket.com/explore/item/these-people-love-to-collect-radioactive-glass-are-they-nuts It talks about uranium giving off "alpha waves/rays" & "beta waves/rays", and an isotope of U-308. My understanding is that alpha & beta radiation is particle in nature whereas gamma radiation is a...
  4. NewPhysi

    I Nuclear Fission of Uranium-235

    I'm learning about nuclear fission for fun, well based on my research, 82% of the time that uranium-235 absorbs a neutron it will fission, the uranium-235 will briefly turn into an excited uranium-236 and after that, it will split, the other 18% of the time it will just emit radiation and...
  5. O

    B Alpha Particles of Uranium 238

    I have a simple question. Do alpha particles from radiation arc and fall after leaving its source? Are these particles bound by the same gravitational laws as us?
  6. Tristan_Ruel

    I Help getting my Cloud Chamber to work please

    Hello! I'm currently building a cloud chamber, my end goal is to make it powered by Peltier chips but that won't happen until I can make it work with dry ice. I've been able to achieve a supersaturated layer of isopropyl alcohol in the chamber, however, even with very radioactive uranite...
  7. nuclearsneke

    Uranium density in fuel meat/kernel

    Howdy partners! I am currently doing some project on Klt40s neutronic simulation (you might have heard of Akademik Lomonosov, the floating npp). But I have encountered a problem with fuel density. The only info that i got that "uranium density IN FUEL MEAT/KERNEL" is 4.5 g/cm3. The Fuel is...
  8. S

    Calculate the dose rate in a drum of U3O8

    Summary:: Calcul of dose rate. Hello everyone ! I have to calculate the total dose that an operator takes during different tasks in a workshop. . I must not use numerical software, so it's only calculous with the data I have. My question could be considered as stupid but the engineer in...
  9. I

    Explaining Differences in Terbium & Uranium Electron Configs

    Why is terbium's electron configuration [Xe] 6s2 4f9, with no electrons in the d subshell and one extra in the f sub shell, while uranium's electron configuration is [Rn] 7s2 5f3 6d1, with one electron in the d subshell and none extra in the f subshell? Are lanthanum and actinide d block...
  10. pimpypot

    Wood/Glass/Metal Where to Find Uranium Glass Beads/Wands & Safety Protocols

    I cannot find a source of uranium glass beads/wands for art making. It is mentioned online that one can make UV glass with a derivative of uranyl nitrate, UO2(NO3)2 . Does anyone know a source of uranyl nitrate, or raw glass material, and what are the minimum safety protocols, such as...
  11. Marasmusine

    HEU reactors vs. LEU reactors

    Summary:: How do high-enriched uranium reactors compare with low-enriched uranium reactors? Hello, I'm doing some research for a book, and there's some information about fission reactors I just can't find. I am comparing HEU fission reactors with LEU fission reactors ... even ballpark figures...
  12. J

    I Why is Uranium-236 less stable than Uranium-235 and Uranium-238?

    Why is Uranium-236 less stable than Uranium-235 and Uranium-238?
  13. JD_PM

    A How to explain the nuclear radius of Uranium 238 using QM

    I am studying how to determine the nuclear charge radius from direct measurement of the Coulomb energy differences of nuclei. My book says that there is strong evidence which suggests that the nuclear force does not distinguish between protons and neutrons. Thus changing a proton into a...
  14. S

    Rate of emission of alpha particle in uranium decay

    Homework Statement U - 238 is undergoing alpha emission into Th - 234. U - 238 has half – life of 109 years. Calculate the emission rate of alpha when uranium has mass of 10 grams Homework Equations A = λN A = A0 (1/2)n , n = t / half - life The Attempt at a Solution Not sure how to do it but...
  15. Mackenzie Cobb

    Why isn't tungsten used in nuclear reactors?

    Me again, with another potentially ignorant nuclear science question: Why isn't tungsten used to prevent meltdown in nuclear reactors? If tungsten has a higher melting point of tungsten is almost 6200 degrees Fahrenheit, and nuclear meltdown happens when the uranium fuel is some 5200 degrees...
  16. nomadreid

    I Uranium isotopes with m in superscript

    On the page https://en.wikipedia.org/wiki/Isotopes_of_uranium, some of the superscripts have, besides the atomic number, also an "m". For example, besides the usual isotope 234U with spin 0+, there is also the isotope 234mU (with nuclear spin 6-). What is this "m"? While I am at it, what is the...
  17. Delta Force

    Properties of Depleted and Natural Uranium?

    Depleted uranium is often used for applications in which high density is valued, such as counterweights, tank armor, and armor-piercing ammunition. Obviously there are going to be some differences between depleted uranium (defined as having 0.3% or less U-235) and natural uranium (averaging...
  18. N

    How many kg Uranium is needed for 5kW produced?

    Homework Statement Energy released is 5.6MeV, 5kW is produced, Half life = 87.7 years for Uranium Need to find how many kg you need to produced that much power. Homework Equations E = Pt, Q = (mass defect) * 931.5MeV/c^2 The Attempt at a Solution I solved for the energy released to be...
  19. Evanish

    Question about the resources needed in mining

    Hello, I was wondering if the resources needed to extract some amount of a mineral from ore goes up in way proportional to the percentage that mineral makes up of the ore. I'm not sure I'm expressing things clearly so I'll give an example. Let's say you have three ores. The only major...
  20. K

    B Why uranium dioxide is used in nuclear reactors?

    In Wikipedia I read that Uranium-235 is a nuclear is fuel in fission reactors, also that Uranium-235 is split (fission) and energy is revealed. But in some images showing how nuclear reactors work, they show Uranium dioxide as nuclear fuel elements. In Wikipedia, it's written that the oxides...
  21. P

    Radioactive decay of Uranium 238

    Homework Statement Analyzing a rock sample, it is found that it contains 1.58 mg of 238U and 0.342 mg of 206Pb, which is the stable final product of the disintegration of 238U. Assume that all 206Pb found comes from the disintegration of 238U originally contained in sample. How old is this...
  22. B

    I How is the fission of Uranium to Europium possible?

    According to the following website listing the yields of fission products for Uranium and other transuranic isotopes: https://www-nds.iaea.org/sgnucdat/c3.htm The fission product 63-Eu-155 is rare but not impossible. According to my maths, this means there must be another daughter nuclei with...
  23. G

    Uranium deposit -- location techniques question

    I read that one can find Uranium for its gamma radiation hence gamma can travel through even dense and thick stuff, but natural Uranium that hasn't gone through fission doesn't emit gamma correct, so I was reading how they find Uranium reserves underground and it says that they use a alpha...
  24. Strife_Cloud

    Uranium conversion / reprocessing TRU isotopes

    I am doing a study guide for a nuclear chemistry introductory course FINAL EXAM. A few of the questions have me confused because, although they are asked in a multiple-choice format, the prof. has indicated that multiple choices may be correct for given problems and that you must not only choose...
  25. ORF

    I Why uranium glass glows green if it's under UV light?

    Hello Why the uranium glass glows green if it's under UV light? The most accurate thing I have found it's a brief history of uranium glass: somewhere it's said the more uranium oxide you put in the glass, the more intense will be the green light when exposed to UV light. Thank you for your...
  26. Delta Force

    Seeking Information on the Orkney Uranium Deposit

    Apparently there is a major uranium deposit at Orkney in the United Kingdom that might also be very high grade (the article seems to indicate it is 50.2% grade, which would be even higher grade than Canada's deposits). I've found a lot of information on the controversy surrounding potential...
  27. P

    Uranium 235 over Polonium 210 in Nuclear Plants?

    I was researching on radioactive elements and found out that polonium is the most radioactive element and the most radioactive isotope of polonium (out of 33!) is polonium 210. So I was wondering why it isn't used in nuclear plants and bombs. I know that if a slow neutron was to hit uranium 235...
  28. Mrinmoy Naskar

    Why does uranium not have any stable isotopes?

    why uranium does not have any stable isotope?
  29. Metals

    B Understanding Nuclear Bombs: The Physics Behind Their Devastation

    Now I'm familiar with how nuclear fission works to produce thermal energy and alpha/ beta/gamma radiation, but how do they work in the bomb? When is the high energy neutron fired into the uranium-235, and when does the chain reaction producing the heat begin? Why is it that there's a huge...
  30. kiwaho

    How many barns at least for a commercial nuclear reactor?

    The conventional commercial fission reactors use uranium-235 as fuel. Its cross section of (n, fission) reaction at thermal neutron is about 585 barns. My question is: Is there a known threshold of the cross section that makes a nuclear reaction not sustainable if the minimal cross section is...
  31. Adraasa Kynuei

    A question about a uranium enricher plot device in a game

    Hi! I am a big fan of science fiction, military fiction and all sorts of media covering this kind of topic. :smile: So I have played Metal Gear Solid V: The Phantom Pain and in it there is this plot device called metallic archaea that basically enriches uranium quite easily. This invention...
  32. Jeremy Thomson

    Buckyball encased uranium - the smallest possible pebble bed

    Is there a trend in pebble bed reactors towards smaller pebble sizes? The smallest conceivable would be a carbon buckyball encasing a (single?) uranium atom. This Wikipedia article (https://en.wikipedia.org/wiki/Endohedral_fullerene) says two cerium atoms have been encapsulated in a c80...
  33. W

    What to do with Depleted Uranium?

    Found this recently. Anyone know where it came from and what I can or should do with it? Thanks.
  34. harborwolf

    What is this old bottle of 'Uranium' found at my workplace?

    I was wondering if anyone could give me some insight as to what I found at my work the other day. We have old chemicals (some REALLY old) that turn up in random cabinets from time to time, and this time I was a bottle with a mostly-decayed label where the only thing that could be read was...
  35. M

    Kinetic Energy of uranium particles

    Homework Statement A uranium-238 atom can break up into athorium-234 atom and a particle called an alpha particle, α-4. The numbers indicate the inertias of the atoms and the alpha particle in atomic mass units (1 amu = 1.66 × 10^−27 kg). When an uranium atom initially at rest breaks up, the...
  36. D

    Why does U235 fission to U236 18% of the time

    First of all, let me say I'm not a physicist, an undergrad, study physics or have any particular education surrounding physics. I'm actually simply a photographer with a special interest in science - so if possible, keep any answers simple. Right, so I was reading about the fission of U235, and...
  37. J

    Found a bottle of uranium nitrate, safe to be around?

    No, I'm not asking if I *should* handle it, just what my level of concern ought to be in regards to being around this stuff. My physics department hired me to clean up one of the labs they want to start using again. I opened one of the cabinets and saw a pair of small glass stoppered and...
  38. enter

    Is the Lewis structure model enough to fully represent complex molecules?

    I do not know if uranium monoxide exists or not because I can't find anything about it on the internet, but i can make a lewis dot structure of it. Can somebody help about this?
  39. Sir Bro

    How can I calculate sieverts from the activity of depleted uranium?

    Homework Statement So I'm looking at the radiation exposure risk regarding depleted uranium (U-238) and nuclear waste (4.20% U-235, 95.8% U-238). Yes I know these compositions are incorrect; they're close enough to exact for my purposes. The only information I have is the half lives of the...
  40. I

    Effusion in Uranium Enrichment: Calculating Concentration and Number of Repeats

    Homework Statement Naturally occurring uranium contains 0.7% ##\;^{235}U## and 99.3% ##\; ^{238}U## . To enrich it one uses a method based on repeated effusion. a) Consider a step in this process. In a container, which is divided in two parts by a porous plug, one part contains natural uranium...
  41. C

    Fission of Uranium: Why U-235 is Better than U-238

    Why is U-235 better for fission than U-238, i was reading that when a neutron strikes U-235 than it create U-236 which has an even number of nucleons, so it can break apart evenly. When the neutron strikes the uranium it causes it to oscillate and then it breaks apart. Is this like have a...
  42. S

    Nuclear waste and depleted uranium research paper (No math)

    Homework Statement (This isn't a typical problem here so feel free to suggest an alternative forum category or website.) I'm trying to do research for a paper about nuclear waste and depleted uranium storage by the DOD. I have a lot of questions I need to answer before I can get too far into...
  43. P

    Nuclear Physics - Uranium decay chain and Bateman equation

    Homework Statement Calculate the activity of ##^{222}Rn## in an ore sample containing 5g of natural uranium. Homework Equations ##^{238}U## decay chain (to Radon): ##^{238}U\rightarrow^{234}Th\rightarrow^{234}Pa\rightarrow^{234}U\rightarrow^{230}Th\rightarrow^{226}Ra\rightarrow^{222}Ra##...
  44. J

    Uranium & Diamonds: Heat Transfer in Nuclear Reactors

    This article http://www.technologyreview.com/news/530981/new-nuclear-fuel-could-boost-reactors-but-also-safety-worries/ about new fuel rod design with better heat transfer than traditional designs reminded me of how diamonds are being used in electronics...
  45. R

    A question about the Hamiltonian of the fission of Uranium

    so I am taking a quantum mechanics course, we started taking about dispersion. so he the lecturer gave us an example about the fission of uranium by alpha ray... he said that we should place a detector in order to detect the alpha particlee , but the detector can only detect particlees with...
  46. D

    Lightning & Uranium: Evidence of Abundance?

    We say that electrons that are freed when radioactivity of radon ionizes air molecules accelerate in the electric field E produced by thunderclouds and can thus ionize other molecules if E is greater than 3 MV/m, so that more and more free electrons are produced, which leads to lightning when...
  47. Warpspeed13

    Question about Depleted Uranium

    So depleted uranium is mostly U-238 which can't sustain a chain reaction. If you were to compress depleted uranium to a thousand times it's normal density could it then sustain a reaction?
  48. avito009

    Uranium 236: Stability and Decay

    If uranium 238 is more stable than uranium 235 because 3 extra neutrons add to strong force then uranium 236 having 1 extra neutron should have more strong force than uranium 235 so why does it decay so fast and why is it more unstable than uranium 235?
  49. BrainMan

    Conservation of momentum uranium atom problem

    Homework Statement A uranium atom of mass 238 u decays by emitting an alpha particle (the nucleus of a helium atom) of mass 4 u at a speed of 2 x 107 m/s. (Note that "u" is the symbol for atomic mass units and 1 u = 1.67 x 10-27 kg.) What is the recoil speed of the resulting nucleus immediately...