⚡ Fusion Reactors

What Is Fusion?

Fusion happens when light atomic nuclei join to form a heavier nucleus.

• Mass turns into energy
• This follows E = mc²

Fusion powers stars, including our Sun.

In reactors, we try to copy this process on Earth, in a controlled way, to make clean energy without the problems of fossil fuels or long‑lived nuclear waste.

Fusion vs Fission

Fission (today’s nuclear plants):

• Splits heavy atoms (like uranium)
• Creates more long‑lived radioactive waste

Fusion (future reactors):

• Joins light atoms (like hydrogen forms)
• Produces much less long‑lived waste
• Needs extreme heat and pressure

Both release huge energy, but fusion is safer: the reaction tends to stop by itself if conditions change.

Why Fusion Is Hard

To fuse, positively charged nuclei must get very close, but they repel each other.

We must:

• Heat fuel to over 100 million °C
• Keep it hot and dense long enough

Atoms then move so fast they form plasma, a super‑hot, charged gas. Controlling this wild plasma is the main challenge of fusion reactors.

Fusion Fuel Basics

Common fuels:

• Deuterium (D): heavy hydrogen, found in seawater
• Tritium (T): radioactive hydrogen, made in reactors

The main reaction aimed for:

> D + T → Helium + neutron + lots of energy

Deuterium is almost unlimited. Tritium must be bred inside the reactor using lithium blankets.