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Thursday, March 30, 2023
Dr. Brown: Latest fusion ‘breakthrough’ more hype than sound science
Dr. William Brown. File Photo

Several decades ago, long before there was any sense of urgency and angst about burning fossil fuels and climate change, scientists began to explore the feasibility of harnessing the way the sun fuses hydrogen nuclei to form helium nuclei as way to create abundant “clean” energy with little or no harmful radiation.

Now every step of the way toward nuclear fusion is heralded and hyped by the media and research groups. The recent media blitz, fuelled by the climate crisis, was no different.

Progress in fusion research in the United States and Europe has been agonizingly slow because it takes extremely high temperatures and, in some engineering designs, extreme pressures, to force like-charged hydrogen nuclei to form helium nuclei and create more energy than was required to trigger fusion and sustain the process.  

In the case of the sun, those conditions are met naturally by the enormous gravitational forces and temperatures (10 million degrees Celsius) found in the solar core, where fusion takes place.

But recreating anything like those conditions on Earth presents major design, material and engineering challenges, to say nothing of the need for continuous funding from governments better known for thinking short-term. 

Solving those challenges has been an incremental process for two of the major players, ITER (the International Thermonuclear Experimental Reactor, an international consortium of 35 countries including the EU, U.K., U.S., China, Canada and Japan and based in France), and in the United States, the NIF (National Ignition Facility, based in California). 

Each uses the same nuclear fuel comprised of the two heavy hydrogen isotopes, deuterium (one proton combined with one neutron in the nucleus) and tritium (one proton and two neutrons). 

The principle of both designs is to contain a few milligrams of the nuclear fuel comprised of heavy hydrogen (deuterium and tritium) and heat it high enough that hydrogen nuclei become separated from their electrons to form a highly ionized plasma.

Heated high enough, the hydrogen nuclei will combine to form helium nuclei, losing a tiny bit of mass in the process and creating a huge amount of energy.

Remember Einstein’s simplest, most powerful equation, E=mc2? What that equation states so simply is that for a tiny bit of mass lost, a huge amount of energy is created – i.e., the mc2 where m is mass and c the speed of light squared. 

In the NIF fusion device, a few milligrams of nuclear fuel contained within a pencil eraser-sized metal cylinder is briefly heated by 192 gigantic, highly focused lasers to the 3 million degrees centigrade needed to strip the deuterium and tritium hydrogen atoms of their electrons and create the highly ionized plasma conditions necessary for the helium nuclei to fuse and release an enormous amount energy briefly in a one-time shot.

The recent media hype was about the fact that, for the first time, more energy was generated – very briefly – than was needed to fire the lasers which require an enormous amount of electrical energy.

That was a “first” for any fusion device so far, but a long way from a commercial device that must run – not in single brief shots but repeatedly to sustain fusion long enough to create useful energy. 

This was a one-shot deal and there was no provision for capturing the energy as might be done with a water jacket where the heat could be converted into steam.

From the reports, there were no plans to do so. The fact is the NIF facility was not designed to create a practical fusion.

Fusion for creating efficient practical power is probably several decades away because many challenging engineering problems remain.

If anything, the ITER device in France is a better proposition because it doesn’t depend on costly, unreliable one-shot lasers that require far too much power off the grid with no prospect of solving that problem anytime soon. It was yet another example of a grandstanding event but certainly not good science. 

Fusion is needed because climate change is reaching the tipping point beyond which unusually severe weather, including storms, floods, fires, air and water pollution, will become common place. Fusion is probably the best answer to providing cheap sustainable electrical energy, which should free the world from fossil fuels – we hope.

In the interim, why not nuclear fission devices? The technology is mature and Canada has the talent and experience to make it work.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.

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