A Breakthrough in Nuclear Fusion: What It Means and Why It Matters

Nuclear fusion is the process of combining two light atomic nuclei into a heavier one, releasing a huge amount of energy in the process. It is the same reaction that powers the sun and other stars, and it has long been considered a potential source of clean, safe and abundant energy for humanity. However, achieving nuclear fusion on Earth has been a formidable challenge, requiring extremely high temperatures and pressures to overcome the natural repulsion between positively charged nuclei. For decades, scientists have been working on various methods and devices to create and sustain the conditions needed for fusion, but none have been able to produce more energy than they consume.

That is, until now.

On December 8, 2022, a team of researchers at the Lawrence Livermore National Laboratory (LLNL) in California announced a historic milestone: they had achieved the first controlled fusion experiment in history to reach ignition, also known as scientific energy breakeven. This means that the fusion reaction produced more energy than the laser energy used to drive it. The experiment was conducted at the National Ignition Facility (NIF), the world’s largest and most powerful laser system, which can deliver 1.8 megajoules of ultraviolet laser light to a tiny capsule of deuterium and tritium, two isotopes of hydrogen. The laser beams compress and heat the capsule to create a plasma, a hot and dense state of matter where the nuclei can fuse. The fusion reaction releases helium nuclei and neutrons, which carry most of the energy.

The LLNL team reported that their experiment generated 1.35 megajoules of fusion energy output, exceeding the 1.3 megajoules of laser energy input by 4%. This is a remarkable achievement, considering that previous experiments at NIF had only reached about 3% of the laser energy input. The team attributed their success to several improvements in the design and execution of the experiment, such as using a diamond capsule to hold the fuel, increasing the laser power and precision, and optimizing the timing and shape of the laser pulses.

The LLNL team’s breakthrough has been hailed as a major step forward in the quest for nuclear fusion as a viable energy source. Nuclear fusion has many advantages over other forms of energy production, such as:

• Abundant and renewable fuel: Deuterium can be extracted from seawater, while tritium can be produced from lithium, which is also abundant in nature. A few grams of these fuels can produce as much energy as several tons of coal or oil.
• No greenhouse gas emissions: Nuclear fusion does not produce carbon dioxide or other harmful substances that contribute to global warming and pollution.
• No long-lived radioactive waste: Nuclear fusion produces only helium and neutrons, which do not pose a significant environmental or health risk. The materials used in the fusion reactor may become activated by the neutrons, but they can be recycled or reused within 100 years.
• No risk of meltdown or proliferation: Nuclear fusion does not involve fissile materials like uranium or plutonium, which can be used for nuclear weapons or cause catastrophic accidents. The fusion reaction is self-limiting and stops as soon as the fuel or plasma is depleted.

However, despite these benefits, nuclear fusion still faces many challenges before it can become a commercially viable and widely available energy source. Some of these challenges include:

• Scaling up: The LLNL team’s experiment was conducted on a very small scale, with a capsule of fuel about the size of a peppercorn. To produce enough energy for practical purposes, fusion reactors will need to operate at much larger scales and higher power levels, which will require more advanced technology and engineering.
• Sustaining the reaction: The LLNL team’s experiment lasted only about 100 trillionths of a second, which is too short to harness the energy output. To generate electricity from fusion, reactors will need to maintain a steady-state plasma for minutes or hours, which will require more efficient heating and confinement methods.
• Extracting the energy: The LLNL team’s experiment measured the fusion energy output by detecting the neutrons emitted by the reaction. To convert this energy into electricity, reactors will need to devise ways to capture and transfer the heat from the neutrons to a working fluid, such as water or gas, which can then drive turbines or generators.
• Reducing the cost: The LLNL team’s experiment was conducted at NIF, which cost about $5 billion to build and operates at about $500 million per year. To make fusion energy economically competitive with other sources, reactors will need to reduce the cost of construction and operation while increasing the efficiency and reliability of performance.

These challenges are not insurmountable, but they will require sustained research and development efforts from scientists, engineers and policymakers around the world. The LLNL team’s breakthrough has shown that nuclear fusion is not only possible but achievable within our lifetime. It has also inspired and motivated other fusion projects and initiatives, such as ITER, a multinational collaboration to build the world’s largest fusion reactor in France, which aims to demonstrate 10 times more fusion power output than input by 2035. Nuclear fusion has the potential to revolutionize the energy landscape and address some of the most pressing issues facing humanity today. It is a vision worth pursuing and a goal worth achieving.