1 / 13

Two Fun Things to do with Nuclei

Two Fun Things to do with Nuclei. By: Mark Burns Charlie Piggott Ken Howlett. Nuclear Fission.

devaki
Download Presentation

Two Fun Things to do with Nuclei

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Two Fun Things to do with Nuclei By: Mark Burns Charlie Piggott Ken Howlett

  2. Nuclear Fission • Nuclear fission occurs when a neutron is absorbed by the nucleus of an atom (typically Uranium-235) and the imbalance between protons and neutrons causes it to split into two lighter atoms. When splitting, the atom released gamma radiation and heat energy in large quantities. Some of the mass is converted into energy, and the relationship can be found with the formula “e=mc²”.

  3. How Nuclear Fission is Used in Atomic Bombs • A fission reaction that is left uncontrolled with a large enough critical mass (fissionable material), it causes a large release on energy and is used as a weapon in the form of an atomic bomb. When, on average, a neutron from one split Uranium atom hits more that one other Uranium atom, the Uranium is said to be “supercritical.” A supercritical mass will continuously heat up as the fission continues. Weapons-grade Uranium is preferably kept at a very high supercritical stage, so all of the atoms will split very quickly (a microsecond.) Artist’s < Rendering

  4. How Nuclear Fission is Used in Nuclear Power Plants • The Uranium used in nuclear power plants is formed into pellets and placed within rods, which are made into bundles. The bundles are now placed in a coolant (water.) The uranium that is undergoing fission is kept at a state of slightly supercritical (which means that on average, one neutron released during fission will hit another nucleus, and that an unsupervised uranium mass will eventually overheat.)

  5. How Nuclear Fission is Used in Nuclear Power Plants II • The rate of nuclear fission is controlled by control rods, which are made up of materials that absorb neutrons. Fewer control rods in a bundle will increase the rate of fission and the output of energy. The gamma and heat energy released in the nuclear decay heats the water around the bundles and turns it to steam, which turns the turbine, which turns the generator to generate electricity.

  6. Using Nuclear Fission Safely • To prevent overheating, the uranium bundles are usually submerged in water. • To protect the turbine from coming into contact with radioactive water, the steam from the water surrounding the uranium bundles is sometimes used to heat water in another pipe, which turns the turbine. • Sometimes, carbon dioxide gas or liquid sodium or potassium is used to cool the uranium bundles instead of water. These cool the uranium bundles better, so the reactor can be run at a higher temperature than with a water coolant.

  7. Using Nuclear Power Safely II • The uranium bundles and the coolant are housed within a radiation shield, which is usually a wall of concrete. This is housed within a steel vessel, which also houses the core and maintenance equipment. This vessel is in turn surrounded by another concrete building that can withstand the impact of a jet plane. All of these structures are designed to prevent any radiation from leaking out into inhabited areas.

  8. When Things Go Awry • In 1986 at the Chernobyl nuclear plant about 80 miles of Kiev (in the Ukraine), safety measures were ignored. The plant workers lost control of the nuclear reaction and eventually there was an explosion which killed 30 people and released radiation that contaminated all land in a 20 mile radius. 135,000 were evacuated.

  9. When Things Go Awry II • In 1979, the water pumps at the reactor of the Three Mile Island reactor stopped pumping water. Without water, the uranium bundle overheated. Radioactive gasses were released. Although this may sound bad, each person that was affected by the radioactive gas received less radiation than a person gets from an X-ray.

  10. Nuclear Fusion • Nuclear fusion occurs when two isotopes of hydrogen (tritium and deuterium) are bound together at high pressure and heat. This causes the hydrogen atoms to fuse into helium, but losing some of its mass to energy. • Fusion can only be achieved when the matter being fused is in the plasma state of matter, because other forms of matter would just become plasma if subjected to the same heat.

  11. How Nuclear Fusion Works in Hydrogen Bombs • Ingredients for “hydrogen bombs”: 1 part tritium (a trillion molecules or so) 1 part deuterium (a trillion molecules or so) 5 parts atomic bombs 1 part uranium casing Shake well Artists Rendering>

  12. Why Nuclear Fusion Isn’t Used in Power Plants • Nuclear fusion is not normally used in power plants because its just not efficient enough. • A nuclear fusion power plant can, however, produce 1 million watts of electricity. (full scale plant of course) • One very hard thing about fusion power is it would be very hard to contain, but if contained, would be transferred from heat to electricity much like fission plants. • A 1000 MW generator would yield a yearly consumption of 150 kg of deuterium and 400 kg of lithium.

  13. Bibliography • http://www.fastload.org/nu/Nuclear_chain_reaction.html • http://science.howstuffworks.com/nuclear-power.htm • http://www.iclei.org/EFACTS/FISSION.HTM • http://www.iclei.org/EFACTS/FISSION.HM

More Related