Nuclear Reactions – Fission, Fusion and Transmutation Atoms: Nuclear Interactions

Artificial Radioactivity 1919 – Ernest Rutherford bombarded nitrogen gas with alpha particles – some of the nitrogen gas was converted to oxygen Transmutation – conversion of one element into another 14 7 4 2 17 8 1 He + N → O + H

Artificial Radioactivity The development of particle accelerators helped with the creation of many synthetic atoms – many of them radioactive 1934 – Irene and Frederic Joliot-Curie created the first synthetic radioisotope by bombarding aluminum atoms with alpha particles 27 13 4 2 30 15 1 Al + He → P + n target nucleus projectile particle product nucleus ejected particle

Nuclear-Bombardment Reactions Nuclear-bombardment is the bombarding of a projectile particle into a target nucleus with hopes of producing a product nucleus, which might be a new isotope. 246 + = 254 + 4 246 + = 254 + 4(1) 12 ? 246 96 12 6 254 102 1 Cm + → No + 4 n ? C 96 + = 102 + 0 6 ?

Extending the Periodic Table Since 1940, around 26 transuranium elements, elements greater than 92, have been produced Created using accelerators known as cyclotrons

Extending the Periodic Table 1940-1961, Glenn Seaborg, with help from his coworkers at UC-Berkeley, helped to create elements 94-103 – none of these elements occur naturally Examples of names: Americium, Berkelium, Californium Naming of elements is now overseen by the IUPAC – International Union of Pure and Applied Chemistry Names are now assigned by atomic number: element 115 is ununpentium, 118 is ununoctium, until given proper names

Nuclear Fission Nuclear Fission involves the splitting of an atom either by bombardment or a spontaneous process 1938 (Dec 22) – first discovered in Germany by Otto Hahn and Fritz Strassmann 1939 (Jan 13) – explained by Lise Meitner (originally worked with Hahn and Strassmann on the fission reaction before fleeing to Sweden because she was Jewish) and her nephew Otto Frisch Produces large amounts of energy

Nuclear Fission Possible results of nuclear fission Images are of a nuclear chain reaction (those found in weapons and nuclear reactors)

Nuclear Power Plant The concept of nuclear fission being used for energy comes from the development of atomic weapons. Nuclear Fission reactors and uranium enrichment (breeder) reactors showed proof that the energy from fission reactions could be converted to electricity. The first nuclear reactor to produce electricity was the small experimental breeder reactor in Idaho in 1951 – it produced enough electricity to power 4 200W light bulbs.

Nuclear Power Plant

Nuclear Power Plant

Nuclear Fusion Nuclear fission separates nuclei, whereas nuclear fusion involves forcing two small nuclei together. The amount of energy of a fusion reaction is between 3 and 10 times greater than a fission reaction.

Nuclear Fusion The sun is an example of nuclear fusion. The amount of energy from the fusion of 1 gram of H is equal to 6.2 x 108 kJ or the burning of 5000 gallons of gasoline. 1 4 2 +1 4 H → He + 2 e + energy 1

Nuclear Fusion Research has been going on for five decades trying to harness nuclear fusion as a power source. The major difficulties have been trying to maintain the high temperatures required to sustain fusion.