Fusion Energy

What is fusion energy?

Nuclear fusion occurs when one or more lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. This reaction happens in nature: it is the process that powers stars like the Sun, and because of fusion’s net energy generation, life on the Earth is possible.

What are fusion energy’s benefits?

Fusion energy provides distinct advantages as a net-zero, firm energy source:

1. Zero Carbon Emissions: Unlike fossil fuels, fusion energy emits no greenhouse gases during the fusion process. By transitioning to fusion power, we can significantly reduce our carbon footprint, preserve natural resources, and foster a cleaner environment for future generations.
2. Abundant Fuel Supply: Fusion fuel sources, such as deuterium and tritium, can be extracted from seawater and are virtually inexhaustible. With an ample supply of fuel, fusion energy offers long-term energy security and relief from concerns over resource scarcity.
3. Safety and Waste Reduction: Fusion is self-limiting, making it inherently safe. Moreover, fusion machines are being tailored to not generate high level radioactive waste, making fusion a responsible and sustainable energy option.
4. Minimal Land Requirements: Fusion offers higher energy output per land used with no significant space requirements for fuel or waste.
5. Less Transmission Expansion: Fusion’s smaller footprint increases the suitability of locating plants near demand centers, thus reducing the expansion of long-distance transmission systems.

What are the different approaches to tapping into fusion energy?

There are many different approaches to harnessing the power of fusion energy – and CATF encourages advancement of all approaches that offer promise. Here are some of the most prominent approaches:

1. Magnetic Confinement Fusion (MCF): The most prominent fusion research approach, MCF involves using powerful magnetic fields to confine and heat the plasma to the extreme temperatures required for fusion. Projects such as ITER and SPARC (a compact fusion machine being developed by MIT and Commonwealth Fusion Systems) aim to achieve sustained fusion reactions and pave the way for commercial-scale fusion power plants.
2. Magnetized Target Fusion (MTF): Developed in the 1970’s by the U.S. Naval Reactors program, MTF relies on an imploding cylindrical metal liner that compresses a preheated and magnetized plasma configuration until thermonuclear conditions are achieved.
3. Inertial Confinement Fusion (ICF): In ICF, high-energy lasers or particle beams compress and heat small fuel pellets to induce fusion. This approach, exemplified by the National Ignition Facility (NIF) in the United States, seeks to replicate the conditions found in the core of stars. While ICF faces technical challenges, progress is being made in achieving ignition and sustained fusion reactions.
4. Field Reverse Configuration: Field reversed configurations, as well as related field-reversed mirrors, offer compact toroids with little or no toroidal magnetic field. This approach is characterized by high beta plasmas and their macroscopic stability.
5. Other Fusion Categories: Magnetic or electric pinches, inertial electrostatic confinement, muon-catalyzed fusion and other forms of low-power fusion also exist, often at earlier stages of development when compared to more familiar categories.

What is the difference between nuclear fusion and nuclear fission?

Fusion and fission are different ways to convert energy into something useful, like heat or electricity. Both have the power to generate zero-carbon energy.

Energy is defined as the ability to do work. The categories of potential energy include kinetic, electrical, magnetic, nuclear, and gravitational. For each category, scientists have formulas to describe them. Fusion and fission both convert energy from atoms, but in opposite ways.

Fusion brings small nuclei so close that together that they fuse. Nuclei must be near enough that they can feel each other’s nuclear force. For fusion to occur, reacting nuclei must be very close to each other, within 10^-10– 10^-15 (a thousand trillionth) meter of one another. This is the same process that powers stars. The stars exploit their own gravity to create plasma conditions in their central regions where net fusion energy is generated. On Earth, fusion energy machines rely on other categories of energy to create similar conditions.

Fission breaks atoms apart, splitting up big nuclei into smaller ones. A neutron hits a larger atom, forcing it to split into two smaller atoms—also known as fission products. Additional neutrons are also released that can initiate a chain reaction. Energy is released when each atom splits.

Does nuclear fusion produce waste?

Fusion does produce waste. However, efforts are underway to minimize, circularize, or eliminate waste from the fusion energy cycle as much as possible. Most of the concepts being developed include materials affected by tritium. Tritium is a low beta energy emitter and low risk when outside the human body. As an isotope of hydrogen, it is highly mobile and can displace hydrogen in a range of organic compounds that can be inhaled or ingested (see Boyer, 2009). Tritium occurs naturally in the environment in very low concentrations and it was widely dispersed into the atmosphere during weapons testing in the 1950’s and 1960’s. Accordingly, tritium release limits to the environment are stringent. As it is short-lived, tritiated waste will be 99% decayed within 82 years.

Also, reduced activation materials will result in low-level radioactive waste after 100 years of operation shutdown. Fusion–tailored Reduced Activation Ferritic Martensitic steels like EUROFER97 and F82H have been produced with this objective.

Is nuclear fusion safe?

Yes, fusion energy can be safely commercialized. Fusion is self-limiting, meaning the machine generating it turns off as soon as it is not in control – making it inherently safe. This characteristic results from the dependable physics of magnetically confined plasma. Additionally, fusion energy machines create their fuel as they operate, so unlike fossil and fission plants, no large stockpile of fuel exists on site. They are designed in a way that does not produce highly radioactive, long-lived nuclear waste.