NUCLEAR CHEMISTRY By Mr M

Radiation All elements after bismuth are radioactive All elements after bismuth are radioactive Some others are, but only in certain forms like carbon 14Some others are, but only in certain forms like carbon 14 Being radioactive means that the element is naturally unstable and wants to fall apart into smaller elements and radiationBeing radioactive means that the element is naturally unstable and wants to fall apart into smaller elements and radiation There are three main types of nuclear radiation… There are three main types of nuclear radiation…

Alpha Radiation α or α or Helium nuclei Helium nuclei Can be stopped by a piece of paper or a layer of skin Can be stopped by a piece of paper or a layer of skin Not very dangerous for external contact, must be consumed to do harm Not very dangerous for external contact, must be consumed to do harm

Beta β or β or Electron Electron Can be stopped by a piece of metal or wood beam Can be stopped by a piece of metal or wood beam Can cause damage from external exposure Can cause damage from external exposure

Gamma γ or γ or Piece of the electromagnetic spectrum Piece of the electromagnetic spectrum Takes a few feet of concrete to stop it Takes a few feet of concrete to stop it Will rip through the human body Will rip through the human body

Fission/Fusion Fission = the splitting of an atom Fission = the splitting of an atom Ex. Uranium splits into barium and kryptonEx. Uranium splits into barium and krypton Fusion = the combining of atoms Fusion = the combining of atoms ex. Hydrogen fuse into heliumex. Hydrogen fuse into helium

Nuclear Power Nuclear power plants use fission Nuclear power plants use fission 3% U-235 is needed for a nuclear power plant 3% U-235 is needed for a nuclear power plant 1 0 n U -> 142 Ba + 91 Kr n 1 0 n U -> 142 Ba + 91 Kr n

Schematics

Control rods absorb neutrons Control rods absorb neutrons The heat of the reactions turns water to steam The heat of the reactions turns water to steam The steam turns a turbine which makes the power that goes to your houseThe steam turns a turbine which makes the power that goes to your house

Who uses it?

Is it safe? Used fuel rods must be stored after use Used fuel rods must be stored after use Pu-239 is a radioactive waste productPu-239 is a radioactive waste product It has a half life of 24,000 yearsIt has a half life of 24,000 years Shielding = radiation absorbing material Shielding = radiation absorbing material Moderator = slow down fast neutrons Moderator = slow down fast neutrons Nuclear waste is stored deep under ground Nuclear waste is stored deep under ground

What if something does go wrong? Chernobyl Chernobyl 1985, Chernobyl Ukraine1985, Chernobyl Ukraine Engineers lost control of the plant during a routine test by overriding the plant’s safety mechanisms and withdrew most of the control rods from the reactor coreEngineers lost control of the plant during a routine test by overriding the plant’s safety mechanisms and withdrew most of the control rods from the reactor core The reactor overheated and broke out into a fire, this resulted in an explosion…The reactor overheated and broke out into a fire, this resulted in an explosion…

Chernobyl

Thyroid Cancer The explosion released radioactive iodine The explosion released radioactive iodine KI pills are given out to dilute the amount of radioactive iodine in the body KI pills are given out to dilute the amount of radioactive iodine in the body The beta radiation from the radioactive I initiates thyroid cancer The beta radiation from the radioactive I initiates thyroid cancer

Three Mile Island 1979, Harrisburg Pennsylvania 1979, Harrisburg Pennsylvania Failures in the water based cooling system Failures in the water based cooling system The core heated to over 2200°C The core heated to over 2200°C Half of it meltedHalf of it melted The plant was thirty minutes from complete meltdownThe plant was thirty minutes from complete meltdown

Waste The waste from a nuclear power plant is still radioactive and will be for hundreds of years. The waste from a nuclear power plant is still radioactive and will be for hundreds of years. It can be reused in the newest power plants It can be reused in the newest power plants It can be stored in salt mines It can be stored in salt mines

Fusion Plants 2 H He -> 4 He +2protons 2 H He -> 4 He +2protons Produces almost a million times as much energy as regular exothermic chemical reactions Produces almost a million times as much energy as regular exothermic chemical reactions Requires higher temperatures and confinement Requires higher temperatures and confinement Best source of 3 He is the moon Best source of 3 He is the moon

Harnessing Nuclear Energy: The Bomb Atomic bombs use 97% U-235 Atomic bombs use 97% U-235 This high of a concentration can be detected by flying over a weapon plant This high of a concentration can be detected by flying over a weapon plant Missiles are stored underground or under water Missiles are stored underground or under water

Critical Mass The minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction The minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction 52 kg for U kg for U-235

PET Scans Positron emission tomography Positron emission tomography Nuclear Medicine Nuclear Medicine

Medical Scans MRI = magnetic Resonance Imaging MRI = magnetic Resonance Imaging CAT Scan = Computer Aided Tomography CAT Scan = Computer Aided Tomography

Radon Radon is an elemental gas Radon is an elemental gas It is in the air we breath, but does not react or dissolve well so posses little threat It is in the air we breath, but does not react or dissolve well so posses little threat Radon loses alpha particles which do not go much more than 10 cm Radon loses alpha particles which do not go much more than 10 cm

Daughter Elements Radon decomposes in lead, polonium, and bismuth Radon decomposes in lead, polonium, and bismuth They attach to dust particles and can cause radiation damage to bronchial cells They attach to dust particles and can cause radiation damage to bronchial cells This leads to lung cancerThis leads to lung cancer It is the second leading cause of lung cancerIt is the second leading cause of lung cancer

Other Applications Sterilizing medical equipment Sterilizing medical equipment Dating fossils Dating fossils Teflon pots and pans Teflon pots and pans Smoke detectors Smoke detectors Exit signs Exit signs Radium paint for watches Radium paint for watches