Fusion Energy

Written by Aanya Deshpande

Overview

Clean, virtually limitless energy is possible using nuclear fusion. Nuclear fusion is a reaction where two or more atomic nuclei combine to form one, releasing energy in the process. One example of fusion is the sun. In the core of the Sun, hydrogen is being converted into helium, which converts the sun’s mass into energy.

How It Works

In a fusion reaction, two nuclei merge to form a single heavier nucleus, releasing energy because the total mass of the resulting nucleus is less than the mass of the two original nuclei. The mass that is leftover from the reaction becomes energy.

Fusion Power Plants

There would be two main ingredients for a fusion reaction: Deuterium (abundant in seawater) and Tritium (made from lithium, which is also abundant in nature). For fusion to take place matter has to be heated up so that it becomes plasma. In the future, power plants would most likely do this in two ways: magnetic confinement or inertial confinement.

Magnetic Confinement

In magnetic confinement systems, superconducting electromagnets are used to contain the plasma fuel. A powerful electric current is induced in the Deuterium/Tritium plasma, therefore increasing temperature. Auxiliary systems such as microwaves, radio waves or accelerated particles can also help heat the plasma. In the process, temperatures of several hundred million degrees centigrade are achieved, making fusion reactions possible.

Inertial Confinement

Inertial confinement uses pulses from powerful lasers to heat the surface of a Deuterium/Tritium fuel pellet. This causes the pellet to implode, making the fuel hot enough to fuse.

Current Experiments

Currently, experiments cost more energy than they produce with fusion.

Magnetic Confinement - Tokamak

A tokamak is a device that uses a powerful magnetic field to confine plasma in the shape of a torus.

Experiments:

- ITER

- T - 15

- STOR - M

Magnetic Confinement - Stellarator

A stellarator is a plasma device that relies primarily on external magnets to confine a plasma. Experiments:

- WENDELSTEIN

- HSX

- LHD

Inertial Confinement - Laser

Laser fusion is a method of initiating nuclear fusion reactions through heating, and compressing, fuel targets in the form of pellets containing deuterium and tritium.

Experiments:

- NIF

- HiPER

Inertial Confinement - Z-/X-pinch

The Z-pinch is a type of plasma confinement system that uses an electric current in the plasma to generate a magnetic field that compresses a pellet.

Experiments:

- Z-MACHINE

- QIANGGUANG

Safety

The fusion process is safe. Fusion is a self-limiting process, which means that if you cannot control the reaction, the machine switches itself off.

Environmental Safety

Fusion is among the most environmentally friendly sources of energy. There are no CO2 or other harmful atmospheric emissions from the fusion process, which means that fusion does not contribute to greenhouse gas emissions or global warming. Fusion also has no long lived nuclear waste

Resources

https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions

https://www.iaea.org/newscenter/news/nuclear-fusion-basics

Written by Aanya Deshpande from MEDILOQUY