Nuclear scientists claim to have achieved a breakthrough in fusion research, with the energy return on energy invested reaching a new high of 154%; the previous record was 70%.
So what is nuclear fusion?
Fusion is the reaction that drives energy production in the sun, and indeed in all the stars in the universe. The basis of fusion is the conversion of mass into energy, very similar to nuclear fission. In fusion, two atomic nuclei fuse to create a new element, giving off some mass as energy in the process. In fission, a nucleus splits to create two new particles and also loses mass, which is released as energy.
It was Albert Einstein who first predicted that mass can be converted into energy, a discovery that led to nuclear weapons and nuclear power. The only problem is that it is extremely difficult to convert mass into energy. In some ways, this is just as well. If it were easy, all matter would quickly turn back into energy and the universe would not exist.
However, producing continuous power from fission is a bit easier than fusion. You need highly radioactive elements in close proximity and an initial trigger to start the reaction. This is what happens in a nuclear reactor. Fuel rods containing enriched uranium generate heat inside the reactors for long periods of time.
Fission, however, also has its problems. First, the uranium has to be mined and enriched. After the reaction is complete, the fuel rods contain large amounts of radioactive material that must be stored safely for several centuries. Nuclear waste is one reason there is a strong anti-nuclear lobby. Nuclear power is a dangerous process with long-term environmental consequences.
Fusion, if it could work, does not share this problem. But melting requires a temperature of at least 1 million Kelvin (almost the same as Celsius at this temperature). Generating such temperatures requires massive amounts of energy and sophisticated engineering design. No material can withstand such temperatures, and the only way to contain a fusion reaction is to suspend it in space, surrounded only by electromagnetic radiation.
What is the new technological advance?
The new results have been achieved at the US National Ignition Facility in California. The facility uses an array of 192 giant X-ray lasers focused on a small cylinder of gold containing deuterium and tritium, which are isotopes of hydrogen. The lasers instantly destroy the gold shell, heat the deuterium/tritium mixture to about 3 million Kelvin, and smash the atoms together, forming a helium atom, releasing a neutron, and generating a packet of energy.
The experiment in California released 3.15 megajoules (MJ), but required 2.05 MJ of laser power to drive the fusion reaction, hence the net energy increase of 54%. But this calculation ignores the 300 MJ needed to heat up the lasers before the experiment could start. If this value is included, the equation is negative.
How excited should we be about this result?
We shouldn’t get the least bit excited about the result. We have known in principle that fusion could be used to generate power, otherwise there would be no sun and no stars. However, reproducing the conditions inside the sun on our small planet is an almost impossible goal. Yes, we can create 5 million Kelvin conditions, and on a small scale, with very sophisticated equipment and a lot of public funding, we can produce fusion reactions.
Scientists in this field are desperate to make any progress because the research is costing billions of dollars. Therefore, advertisements of this nature should be treated with some caution.
The other thing about nuclear energy research is that historically it has been an easy way to subsidize the development of nuclear weapons. The unrevealed agenda of the superpowers in nuclear research has been bigger and better nuclear weapons, not necessarily abundant nuclear power. Tackling the seemingly impossible, at enormous cost to the public purse, has more to do with military strategy than energy policy.
Public research budgets would be better spent on developing renewable energy and energy storage technologies than on nuclear fusion. Seventy years of fusion research have led to the bland result that with a battery of high-powered X-ray lasers and 302.5 MJ of energy, it is possible to generate 3.15 MJ of heat, which still needs to be converted into electrical energy. at a heat to power efficiency of perhaps 35%.
We should use the abundance of energy already on the Earth’s surface in the form of waves, wind and solar energy, without dreaming of bringing us the sun and stars.
