Nuclear Chemistry Part II “The discovery of nuclear reactions need not bring about the destruction of mankind any more than the discovery of matches” -Albert Einstein

More Nuclear Reactions  A. Nuclear Fission – the splitting of a nucleus into smaller fragments (the splitting is caused by bombarding the nucleus with neutrons ). This process releases enormous amounts of energy. A nuclear chain reaction is a reaction in which the material that starts the reaction (neutron) is also one of the products and can be used to start another reaction.

B. Fission  chain reaction - self-propagating reaction  critical mass - mass required to sustain a chain reaction

C. Nuclear Power  Nuclear Reactors use controlled – fission chain reactions to produce energy or radioactive nuclides.

C. Nuclear Power  a. shielding – radiation absorbing material that is used to decrease exposure to radiation.

C. Nuclear Power  b. fuel – uranium is most often used

C. Nuclear Power  c. control rods – neutron absorbing rods that help control the reaction by limiting the number of free neutrons

Steam C. Nuclear Power e. coolant – water acts as a coolant and transports heat between the reaction and the steam turbines to produce electric current

C. Nuclear Power

 Nuclear Power Plants produce a great deal of energy, the current problems with nuclear power plants include environmental requirements, safety of operation, plant construction costs, and storage and disposal of spent fuel and radioactive waste.

D. Atomic Bomb  chemical explosion is used to form a critical mass of 235 U or 239 Pu  fission develops into an uncontrolled chain reaction

FusionFusion  A. combining of two nuclei to form one nucleus of larger mass, usually very small atoms of hydrogen and helium are used.  B. thermonuclear reaction – requires temp of 40,000,000 K to sustain  1 g of fusion fuel = 20 tons of coal

FusionFusion  C. Sun/Stars – four hydrogen nuclei combine at extremely high temperatures and pressures to form a helium nucleus – this is a fusion reaction.

B. Fusion  Hydrogen Bomb- uncontrolled fusion reactions of hydrogen are the source of energy for the hydrogen bomb. Hydrogen bombs generate a great deal more of energy then an atomic bomb.

B. Fusion  Fusion as a Source of Energy: Fusion reactions generate a great deal more energy and their products are less harmful then fission reactions.  Research is being done to try to use fusion instead of fission, there are a few problems: the temperature required is so high no known material can withstand the temperature.

A. Nuclear Power  Fusion Reactors (not yet sustainable)

A. Nuclear Power  Fusion Reactors (not yet sustainable) Tokamak Fusion Test Reactor Princeton University National Spherical Torus Experiment