6.7 Nuclear Power

How nuclear power works

Nuclear power plants generate electricity through nuclear fission, splitting uranium-235 atoms in a controlled chain reaction. This releases heat, which boils water into steam, spinning turbines to generate electricity. Control rods absorb neutrons to regulate the reaction rate, while a moderator (often water) slows neutrons so fission can continue efficiently.

Benefits of nuclear energy

Nuclear power produces no direct CO2 emissions during operation, making it valuable for reducing greenhouse gases. It has a very high energy density (small amounts of fuel produce large amounts of energy) and provides reliable, continuous baseload power unlike intermittent solar or wind.

Risks and drawbacks

Major concerns include radioactive waste disposal, which remains hazardous for thousands of years, high construction costs, and risk of meltdowns (e.g., Chernobyl, Fukushima) if cooling systems fail. Mining uranium also causes habitat destruction and pollution. Public perception and long-term storage of spent fuel remain major barriers to expansion.

Key terms

Nuclear fission

The splitting of large atomic nuclei (like uranium-235), releasing heat energy used to generate electricity.

Control rods

Materials that absorb neutrons to regulate and control the rate of a nuclear chain reaction.

Moderator

A substance (often water) that slows down neutrons so fission reactions can continue efficiently.

Energy density (nuclear)

Nuclear fuel produces a very large amount of energy from a small amount of material compared to fossil fuels.

Nuclear meltdown

A severe reactor failure where the core overheats and melts, potentially releasing radioactive material (e.g., Chernobyl, Fukushima).

Try an AP-style question

What process produces energy in nuclear power plants?

1. Chemical reactions of oil
2. Fission of uranium-235
3. Burning of coal
4. Fusion of hydrogen