Chapter 10 Fission and Fusion

Fission The splitting of an atomic nucleus into smaller parts. Huge amounts of energy can be produced from a very small amount of mass. Larger atoms are used for fission.

Figure 7 Converting Mass into Energy When fission takes place, about 0.1% of the mass is lost and is converted into energy.

Figure 7 Mass-Energy Equation E = mc 2 E represents energy m represents mass c represents the speed of light (3.0 x 10 8 m/s) Huge amount of energy from a very little amount of mass. This equation is used for nuclear reactions…not chemical reactions

Fission…energy 1 kg of Uranium-235 is equivalent to the chemical energy produced by burning 17,000 kg of coal First atomic bomb = 1945 –Used 5 kg of Pu-239 –Explosion = 18,600 tons of TNT

Figure 7 Fission Chain Reaction When fission occurs a chain reaction happens (one fission results in many more to follow).

Figure 7 Fission Products The products produced from fission: Energy (make electrical energy) Radioactive waste

Fusion What it is: –Combining the nuclei (plural for nucleus) from 2 atoms to form a larger nucleus…nucleosynthesis –During fusion a very small amount of mass is converted into energy. –Requires extremely high temperatures (10,000,000 o C)

Figure 7 Fusion continued… Some day it may provide efficient and clean energy but there are some issues. Problems: Hard to get temps high enough Need to be able to contain plasma

Figure 7 Fusion Example of fusion = sun Combining H atoms to form He Temperature is about 10,000,000 o C

Figure 7 Fusion Fusion of lighter elements (smaller than Fe) RELEASE energy Why? because there is LESS OPPOSING FORCE…less protons in each nuclei trying push away from each other. Fusion of elements heavier than Fe ABSORB energy.

Fusion: A thimbleful of liquid heavy- hydrogen fuel could produce as much energy as 20 tons of coal. Or, more realistically, one pick-up truck full of deuterium = 21,000 rail car loads of coal or 10 million barrels of oil. Clearly, with seawater as our energy source, our energy problems would be over forever! Clearly, with seawater as our energy source, our energy problems would be over forever!