Fission is the splitting of a heavy atom into
Two or more lighter nuclei
Fusion is combining two small nuclei to make a heavier nucleus
Fission and Fusion break the Law of Conservation of Mass!!!
The law says mass (matter) can not be created or destroyed.
However, in these nuclear reactions, a bit of mass IS destroyed, and converted into….
• In fusion and fission, small amounts of mass are converted into huge amounts of energy
• Compared to a gram of natural gas (methane), a gram of material converted to energy in a nuclear reaction gives off one BILLION times more energy
Fission Reactions
Neutron + U-235
A neutron is fired at U-235 and is captured, forming unstable U-236, which then splits up
Fission Reactions
n + U Ba + Kr + 3 n + energy1
023592
14256
9136 0
A neutron bombards a U-235 and it splits into Ba-142, Kr-91 three neutrons and ENERGY
The three neutrons can then go on to start other fission reactions
1
Nuclear Reactors
FUEL
• Must be FISSIONABLE• Controlled chain
reactions• U-233• U-235• Pu-239• Radioactive Waste can
be solid, liquid or gas
CONTROL• Control Rods
(MODERATORS) absorb neutrons
• Control rods made of Cadmium (Cd), Graphite (C), Boron (B)
• COOLANT = Liquid Sodium Na (l) or Heavy Water
• Steel and High Density concrete shield personnel
Thanks to FUSION, we have sunlight!
Hydrogen fuses withHydrogen to makeHelium + energyin stars, like our own sun