How fission makes power
- A neutron hits uranium-235The nucleus splits in two
- Energy and more neutrons fly outA tiny bit of mass becomes energy
- Those neutrons split more atomsA controlled chain reaction
- The heat boils waterSteam spins a turbine and generator
E = mc²
A very small mass (m) times the speed of light squared (c²) equals a huge amount of energy.
The scale of it
1 pelletof uranium fuel
≈ 1 tonof coal in energy
~1/5of U.S. electricity
24/7steady power, rain or shine
A typical fuel pellet is about the size of a fingertip.
Inside a reactor
Fuel rods
Hold the uranium pellets
Moderator
Usually water; slows neutrons so fission continues
Control rods
Absorb neutrons to speed up or slow down the reaction
Containment
Thick steel and concrete around the reactor
Sources: U.S. Department of Energy; U.S. Energy Information Administration; Nuclear Energy Institute
Remember
Fission turns a little mass into a lot of energy; control rods and engineering keep it steady and safe.
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Answer key
- What happens in nuclear fission?A heavy nucleus splitsFission splits a heavy nucleus such as uranium-235.
- Which equation links mass and energy?E = mc²Einstein's E = mc².
- What do control rods do?Absorb neutrons to control the reactionThey soak up neutrons to slow or stop the chain reaction.
- Roughly how much U.S. electricity comes from nuclear power?About one-fifthAbout 19 to 20 percent.
- What turns the reactor's heat into electricity?Steam spinning a turbine and generatorHeat makes steam; steam turns the turbine.