Uranium Definition and 155 Threads

  1. 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...
  2. 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?
  3. 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?
  4. 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...
  5. S

    Calculating the Isotope Ratio of Uranium 235 and 238 4.5 Billion Years Ago

    Homework Statement Current share of Uranium isotope on Earth is 99.28% (##^{238}U##) and 0.72% (##^{235}U##), half-life times are ##7.04\cdot 10^8 years## (##^{235}U##) and ##4.468\cdot 10^9 years## (##^{238}U##). Calculate the ratio between the isotopes ##4.5\cdot 10^9 years## ago...
  6. E

    Shooting blocks of Uranium from planet to planet

    This idea stems from the Pascal B nuclear test, which placed a 900kg steel plate over a shaft in where a nuclear explosive was detonated: http://en.wikipedia.org/wiki/Operation_Plumbbob#Propulsion_of_steel_plate_cap The plate shot up at an estimated 66km/s, or 6x escape velocity. Say you...
  7. H

    Uranium isotopes percentage 4.5 billion years ago

    Homework Statement Please help me solve this problem... Given T(1/2) of U-235 = 7.04x10^8 yrs (0.7%) T(1/2) 0f U-238 = 4.468x10^9 yrs (99.3%) Calculate percentage of U-235 & U-238 at the time of creation of earth(~4.5 billion years ago) Homework Equations N(t) = No e^(-λt) The...
  8. D

    Reprocessed Uranium: Why Isn't US Doing This?

    How come this isn't done in the United States yet? Is it all political or is there a real reason we have not done this? I believe we started a facility to do this prior to Three Mile Island's accident, but I think we abandoned it ?
  9. K

    Electric Potential Problem Involving Uranium Atom

    Hi Everybody, I am currently battling with the fourth and final question of my A Level physics work for this week. The problem has been driving me crazy, as I seemed to have completed all of the relevant steps, and I find the right answer only with negative exponents, which isn’t much help at...
  10. G

    Why is Uranium 235 Unstable & Nuclear Fission Explained

    Hello. I have some questions regarding Uranium 235 and its instability. Whenever you hear about nuclear reactions, you almost always hear Uranium 235 linked with it as being quite suitable for splitting because it is unstable (At least I do). I have been vaguely exploring nuclear...
  11. D

    Energy required to fully ionize Uranium

    1. What is the maximum wavelength of light required to fully ionised Uranium to U92+, i.e. strip it of all electrons and leaving a bare nucleus? For simplicity, only consider direct ionisation and neglect non-linear effects. Attempt at solution Ok, so the electron structure of the...
  12. K

    They used to use uranium glaze to color pottery and other objects

    Before nuclear elements had any practical applications, they were used as an orange coloring glaze for pottery and various other objects. Please correct me if I'm mistaken, but wouldn't this coloring glaze be highly radioactive?
  13. I

    Why do nuclei like Uranium and Thorium have such long half lives?

    Why is it that those atoms, with atomic numbers of 90 and 92 have much, much longer half lives than atoms like Radon, Radium, and Polonium? I do realize that atoms with even atomic numbers are more stable than ones with odd numbers, so it makes sense why atoms like astatine, actinium, and...
  14. C

    Effusion Question about Uranium enrichening

    Homework Statement A gas with equal number densities of uranium hexafluoride (UF6) molecules containing two isotopes of uranium, atomic masses 235amu and 238amu, is passed through a porous membrane containing very small holes. Use Graham's Law of Effusion to calculate: How many successive...
  15. D

    Can Thorium Outperform Uranium in Energy Production Per Kilogram?

    In a reactor using Th232 as a fertile material to breed fissile U233, what is the amount of energy released per kg Th232 compared to a reactor using about 20% enriched uranium?
  16. Aaronvan

    Can one purchase depleted uranium?

    I'd like a small sphere of DU to illustrate mass, i.e. compare it to an equivalent (mass or radius) sphere of aluminum (say). I understand DU is used in airliners and yachts and it is safe so long as it is not aerosolized or particles are inhaled. Are small samples of DU available commercially?
  17. C

    What is the optimal level of uranium enrichment for different purposes?

    Forgive me if this question has been asked before or is a FAQ. Can somebody tell me to what percentage uranium has to be enriched in order to build a bomb? Believe me, I'm not trying to build one! I'm just trying to inject some physics into the current Israel/Iran debate. (Let's confine...
  18. C

    Why is Americum more expensive than Uranium?

    The cost of Americum: Cost, pure: $1500 per g (1,5 million USD per Kg) Cost, bulk: per 100g The cost of Uranium: US $ 51,5/lb (at 25.07.2011) or 11,3 cents per gram (natural uranium in the form of the unrefined oxide U3O8). Why is Uranium so much cheaper?
  19. O

    From Uranium isotope to thorium isotope

    I need to complete the following sentence. If I think that electron capture or alpha decay does not occur in my decay process, I have to type a '0' (zero) in the appropriate box: Converting an atom of the isotope Uranium (238-92) into an atom of thorium can be accomplished if an electron...
  20. S

    Uranium Nitride Synthesis Breakthrough

    There have been some recent announcements in the news about the synthesis of Uranium Nitride. One announcement from Los Alamos National Labs mentions the use of photolysis to achieve the desired material...
  21. D

    Uranium Sheets: Home Methods & Industrial Process

    sheets of uranium!? Hello everyone. I was wondering if getting a metal or a piece of radioactive material such as uranium, it could be flatten by ''home methods'' to be as thin a sheet or sheets. If it can't maked by home methods, please point me as its industrial process. Thank you all ;P
  22. N

    An alpha particle is fired at a uranium atom

    Homework Statement "If an alpha particle is fired straight at the nucleus of an uranium atom (q = 92e), at a velocity of 5 x 10^5 m/s, how close will it get to the uranium nucleus? Homework Equations Ek = (mv^2)/2 Ee = (kq1q2)/d The Attempt at a Solution Since the alpha particle and...
  23. K

    How much energy does the nuclear fission in one uranium atom give?

    Does it give a lot or is nuclear fission only powerful when you have a large quantity?
  24. C

    Neutron Absorption of Lead Nuclei compared to Uranium Nuclei

    I have had a question that I cannot get an answer for. I recently had an exam for energy in the nucleus which included a question about why lead nuclei would be inadequate for use as a moderator in a reactor. When I got the answer for the question, it stated that the lead nuclei reflect neutrons...
  25. Z

    Extracting Uranium from seawater

    So, I recently came upon a SA article "How long will the world's uranium supplies last?" (http://www.scientificamerican.com/article.cfm?id=how-long-will-global-uranium-deposits-last), and one of the paragraphs talked about: "Two technologies could greatly extend the uranium supply itself...
  26. M

    Acceleration of an electron held at 1m from the nucleus of an Uranium atom.

    Homework Statement An electron is held fixed at a distance of 1 m from the nucleus of a uranium atom (Z = 92). If the electron is then released, what is the magnitude of its initial acceleration? Homework Equations I am not sure which kinematic equation that I should use...
  27. N

    Why Do Uranium Electron Configurations Differ?

    Homework Statement Electron Configuration of Uranium The Attempt at a Solution [Rn]7s^2 5f^4 But online it says [Rn] 5f^3 6d^1 7s^2 Someone explain why please. Thank you. :)
  28. nukeman

    Producing Uranium for Peaceful vs Weapon Use: Explained

    Hey guys, Can someone explain to me, in a physics/scientific way, the keys differences on what it takes to produce uranium for a nuclear reactor, compared to producing uranium for a Nuclear weapon? Also, when you have the 2 finished products (reactor grade uranium vs weapons grade...
  29. S

    Energy of an electron in a uranium atom

    using special relativity m = m0/(1-v^2/c^2) on an electron orbiting with a speed of 2.01 * 10^8 m/s in an atom,estimate the percentage corrections to the n=1 energy in a uranium (Z=92) atom. so to find the energy I first need the reduced mass, u, for En = u*(9e9)^2*e^4*Z^2/2(h bar)^2*n^2. How...
  30. B

    Explosion at Isfahan Uranium Conversion Facility

    On 28th November there were reports of a large explosion in the Iranian city of Isfahan, home to the Isfahan Uranium Conversion Facility. link - via Haaretz - The BBC claim that Iran is building a plant at the nuclear research facility to convert yellowcake into three forms...
  31. D

    Nuclear Fission of 1g of Uranium 235

    Homework Statement What is the amount of energy released when 1g of uranium 235 undergoes fission? Fission of uranium is: uranium + n -> Ba + Kr +12n. Homework Equations E=Δmc^2 The Attempt at a Solution I found the mass of the reactants to be 236.05256u and the products to be...
  32. M

    Charge and Mass of Singly Ionized Uranium

    Homework Statement Before entering a mass spectrometer, ions pass through a velocity selector consisting of parallel plates separated by 1.9 mm and having a potential difference of 120 V. The magnetic field between the plates is 0.42 T. The magnetic field in the mass spectrometer is 1.2 T...
  33. D

    How Is Energy Calculated in Uranium 235 Fission?

    Homework Statement Another mode in which uranium 235 can undergo fission is U + n -> Te + Zr +n. Calculate the energy change when 1g of uranium 235 undergoes fission in this way. The masses are U=235.04u. n=1.0087u. Te=134.92u. Zr=99.92u. Homework Equations The Attempt at a...
  34. D

    Ease of chain reaction for enriched uranium

    Critical mass is over 50kg so let's say I have 2 halves of a sphere of the isotope U-235, each weighing 30 kg. I drop one onto the other so that they form a supercritical sphere. No doubt a chain reaction would begin, but I assume it would produce energy on the level of a nuclear reactor rather...
  35. P

    Understanding Decay and Half-Life of Uranium

    Homework Statement I'm not sure if whether mass changes when atoms decay. Does emitting alpha/beta/gamma cause the atoms to lose mass? I don't know :confused:Homework Equations Uranium-235 has a half life of 7.35x10^5 years and uranium 238 has a half life of 4.5x10^6 years. Compare the two...
  36. D

    News Is Depleted Uranium Ammunition Safe or Harmful?

    In war, the advantages of Depleted Uranium munitions help the United States stomp other countries into the ground. The United States and its NATO allies maintain that Depleted Uranium dust (a by-product) doesn't cause cancer and birth defects, however, 136 countries are citing other research...
  37. A

    How does neutron absorption turn uranium into plutonium?

    I keep reading that when a U-238 atom absorbs a neutron it turns into Pu-239. How does that happen? If I'm not mistaken Pu-239 is U-238 plus 2 protons and 2 electrons and minus 2 neutrons. When U-238 absorbs the neutron and becomes U-239 I can see that it can turn into Pu-239 if 2 neutrons decay...
  38. E

    Cause of Bump in Uranium Gamma Spectrum

    Homework Statement What is the cause for the bump in the lower energies of this spectrum: http://en.wikipedia.org/wiki/File:Gammaspektrum_Uranerz.jpg The Attempt at a Solution Is it just normal Compton? I'm doubting that because that is very asymmetric. I can't find anything in any textbook I...
  39. J

    Why are fission uranium bombs more used than fusion hydrogen bombs?

    I keeps seeing news about iran making uranium and everybody is using nuclear fission bombs instead of nuclear fusion. Hydrogen bombs are much more powerful because they use fusion, but still all countries that have nuclear weapons use uranium fission bombs, Why? What advantage does fission...
  40. O

    Uranium and Springs: Same Interatomic Distance & Stiffness?

    Homework Statement Chemically, the atoms of these two isotopes behave in essentially identical ways, since the number of protons (92) is identical and the clouds of 92 electrons are nearly identical. The interatomic distance, and the effective "stiffness" of the interatomic bond, both depend...
  41. K

    Move over uranium here comes Thorium

    http://www.wired.com/magazine/2009/12/ff_new_nukes/2/ came across this. I was interested in hearing counter arguments to the approach...
  42. N

    Unraveling the Mysteries of Uranium: Nuclear Energy Explained

    Hi there, first time poster. I'm trying to settle a dispute which is kind of stupid... Now I realize this question might seem dumb but I was wondering why exactly we use Uranium (Uranium-235 to be more exact) in Nuclear power plants? From what I understand, in very basic terms, nuclear...
  43. C

    Adiabatic Process of uranium fission bomb

    Homework Statement The fireball of a uranium fission bomb consists of a sphere of radius = 15m and temperature 300,000K shortly after detonation. Assuming that the expansion is adiabatic and that the fireball remains spherical, estimate the radius of the ball when the temperature is 3000K...
  44. S

    Calculating the mass of consumed Uranium 235

    Homework Statement A typical nuclear fission power plant produces about 3.36 GW of electrical power. Assume that the plant has an overall efficiency of 44.6% and that each fission event produces 250 MeV of thermal energy. Calculate the mass of 235U consumed each day. Answer in units...
  45. D

    Minimum critical mass with natural uranium

    I wanted to know what is the minimum critical mass of natural uranium (99.28% U-238) when moderated by beryllium and light water, when in a optimumally designed lattice. As can be seen in this article (google Plutonium Production Using Natural Uranium) criticality is attained at about 10 tons of...
  46. B

    Uranium Fuels that are denser and cheaper to manufacture than uranium dioxide

    The title is the question. Cheers.
  47. L

    Slow Neutron Fission in Uranium 235: Exploring the Why

    Here's a question. Why does slow neutron is most likely to cause a nuclear fission in Uranium 235, compare to a fast neutron?
  48. M

    Can Laser Beam Increase Alpha-Decay of Uranium?

    Hello. I would ask you can a powerful laser beam increase probability of nuclear alpha-decay of uranium. And can we light chain reaction of nuclear alpha-decay of enriched uranium with a mass much less then critical mass by a laser?
  49. L

    Water and Uranium-235 Reactivity in W88 Secondary: Safety Concerns Explained

    (I apologize in advance if this is in the wrong section of the forum) I found an article online describing the safety concerns of the W88 thermonuclear warhead. Apparently, water can turn the uranium-235 coating of the W88's secondary into a "runaway boiling hot water reactor" (not sure what...
  50. J

    Thermodynamics of Converting uranyl nitrate to uranium oxide

    I would like to know if it is important to consider thermodynamic factors such as the Gibbs Free Energy to design a research project to convert uranyl nitrate to uranium oxide?
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