How does deuterium interacts with neutrons?

Discussion in 'Physics & Math' started by StMartin, Apr 10, 2008.

  1. StMartin Registered Senior Member

    Messages:
    225
    How does deuterium interacts with neutrons? I sow in nuclear power plants is used heavy water, and it says because the heavy water interacts with neutrons? Is it mechanically stopping them, or there is some other kind of interaction?
    btw- how neutrons in deuterium stick together, how they are attracted, since they don't have any electrical charge?
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Zephyr Humans are ONE Registered Senior Member

    Messages:
    3,371
    There are four fundamental physical forces: gravity, electromagnetism, the strong nuclear force and the weak nuclear force. I think one of the last two explains how the nucleus of an atom sticks together despite the fact that protons repel each other electrically.

    http://en.wikipedia.org/wiki/Nuclear_force
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. zephir Banned Banned

    Messages:
    390
    This can be a quite complex behavior. For example, you can use the mercury droplets model for its understanding. You can imagine, the neutrons are tiny droplets and the deuterium atom nuclei are these large ones. This is because the matter of atom nuclei is behaving like extremely dense fluid and the surface tension effects are heavily pronounced here.

    Whenever such droplets collide, the result will depend on the mutual speed. If the speed is considerably low or the neutrons are falling under small angle to sample, the neutrons can bounce from atom nuclei due the weak nuclear interaction and deBroglie wave interference. If the neutrons will be of "proper" intermediate speed, both droplets will merge, thus creating a larger metastable droplet, which will decay less or more readily due the repulsive forces of weak isospin charge. We can expect a sort of inverse beta decay here due the temporal excess of neutrons, which is violating the ideal 1:2 proton-neutron ratio for nuclides.


    Please Register or Log in to view the hidden image!

    Please Register or Log in to view the hidden image!

    Please Register or Log in to view the hidden image!



    If the neutrons will be too fast, the spallation of droplets will occur quite quickly instead of fusion. But at the extreme mutual speed somewhat strange behavior will occur: the asymptotically free quarks inside of droplets will behave like solid spheres inside of Newton cradle: the impact of neutrons from one side will release the second neutron from the opposite side of deuterium nuclei, the atom nuclei will remain intact miraculously and so called elastic scattering of neutrons will occur.

    This is the reason, why the cross-section of neutrons strongly depends on their energy and why the neutron must be "moderated", before they can be used for nuclear fission. At the case of deuterium the energy of neutrons must be quite high to achieve it, because the deuterium nuclei is lightweight and the neutrons will transfer its momentum into it. This is the reason, why the lightweight atoms can serve as an effective moderators, considering the neutrons aren't absorbed by them too much.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.

Share This Page