nuclear fission

Examples of nuclear fission in the following topics:

• Nuclear Fission

  • Nuclear fission occurs when an atom splits into two or more smaller atoms, most often the as the result of neutron bombardment.
  • Nuclear fission is a process by which the nucleus of an atom is split into two or more smaller nuclei, known as fission products.
  • The strong nuclear force is the force between two or more nucleons.
  • While nuclear fission can occur without this neutron bombardment, in what would be termed spontaneous fission, this is a rare occurrence; most fission reactions, especially those utilized for energy and weaponry, occur via neutron bombardment.
  • In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process.

• Nuclear Reactors

  • The energy released from nuclear fission can be harnessed to make electricity with a nuclear reactor.
  • When a large, fissile atomic nucleus such as uranium-235 or plutonium-239 absorbs a neutron, it may undergo nuclear fission.
  • Nuclear reactors generally have automatic and manual systems to shut the fission reaction down if unsafe conditions are detected.
  • Just as many conventional thermal power stations generate electricity by harnessing the thermal energy released from burning fossil fuels, nuclear power plants convert the energy released from nuclear fission.
  • A possible nuclear fission chain reaction.

• The Atomic Bomb

  • Atomic bombs are nuclear weapons that use the energetic output of nuclear fission to produce massive explosions.
  • Atomic bombs are nuclear weapons that use the energetic output of nuclear fission to produce massive explosions.
  • Atomic bombs are made up of a fissile element, such as uranium, that is enriched in the isotope that can sustain a fission nuclear chain reaction.
  • Fission can be self-sustaining because it produces more neutrons with the speed required to cause new fissions.
  • In fission weapons, a mass of fissile material, either enriched uranium or plutonium, is assembled into a supercritical mass—the amount of material needed to start an exponentially growing nuclear chain reaction.

• The Hydrogen Bomb

  • The hydrogen bomb is a nuclear weapon that uses a mixture of fission and fusion to produce a massive explosion.
  • A thermonuclear weapon is a nuclear weapon designed to use the heat generated by a fission bomb to compress a nuclear fusion stage.
  • After this, the secondary explosive is compressed by X-rays coming from the nuclear fission of the primary explosive.
  • The only two nuclear weapons that have been used were both fission-based.
  • The nuclear fusion releases neutrons much faster than a fission reaction, and these neutrons then bombard the remaining fissile fuel, causing it to undergo fission much more rapidly.

• Present Sources of Energy

  • Present sources of energy include fossil fuels, various types of renewable energy, and nuclear power.
  • As of December 2009, the world had 436 nuclear reactors.
  • Since commercial nuclear energy began in the mid 1950's, 2008 was the first year that no new nuclear power plant was connected to the grid, although two were connected in 2009.
  • Annual generation of nuclear power has been on a slight downward trend since 2007, decreasing 1.8% in 2009 with nuclear power still meeting 13–14% of the world's electricity demand.
  • Nuclear (fission) power stations, excluding the contribution from naval nuclear fission reactors, provided about 5.7% of the world's energy and 13% of the world's electricity in 2012.

• Fusion Reactors

  • A fusion reactor is designed to use the thermal energy from nuclear fusion to produce electricity.
  • Fusion power is the power generated by nuclear fusion processes.
  • This is similar to the process used in fossil fuel and nuclear fission power stations.
  • Above this atomic mass, energy will generally be released by nuclear fission reactions; below this mass, energy will be released by fusion.
  • According to the Lawson criterion, the easiest and most immediately promising nuclear reaction for fusion power is:

• Nuclear Binding Energy and Mass Defect

  • This energy—available as nuclear energy—can be used to produce nuclear power or build nuclear weapons.
  • Nuclear binding energy is also used to determine whether fission or fusion will be a favorable process.
  • Elements heavier than iron-56 will generally release energy upon fission, as the lighter elements produced contain greater nuclear binding energy.
  • As such, there is a peak at iron-56 on the nuclear binding energy curve.
  • Calculate the mass defect and nuclear binding energy of an atom

• Isotopes in Medicine

  • Nuclear medicine is a medical specialty that involves the application of radioactive substances to diagnose or treat disease.
  • In nuclear medicine procedures, radionuclides are combined with other elements to form chemical compounds.
  • This property of radiopharmaceuticals allows nuclear medicine the ability to image the extent of a disease process in the body.
  • In nuclear medical imaging, radiopharmaceuticals are taken internally, either intravenously or orally.
  • The radiopharmaceuticals used in nuclear medicine therapy emit ionizing radiation that travels only a short distance.

• Nuclear Stability

  • An isotope's nuclear stability depends on the balance of electric and nuclear forces between its protons and neutrons and their arrangement.
  • In nuclear physics, stability of an atom's nucleus depends on the number of protons and neutrons it contains.
  • This force is offset by the nuclear force, which attracts protons and neutrons.
  • This is because, for any constant number of protons, the difference between nuclear force and electrostatic repulsion of protons increases with increasing neutron count.

• Nuclear Fusion

  • Nuclear fusion is the process by which two or more atomic nuclei join together to form a single heavier nucleus and large amounts of energy.
  • Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse," to form a single heavier nucleus.
  • This force, called the strong nuclear force, overcomes electric repulsion in a very close range.
  • At nucleus radii distances, the attractive nuclear force is stronger than the repulsive electrostatic force.
  • Describe the electrostatic and strong nuclear forces and how they act to oppose or promote a fusion reaction