Cover Schaetzing Limit

(Picture: Randomhouse)

The English edition of Limit, a science fiction novel set in a world in which fusion power is about to overtake traditional gas and oil business, was published in November. The main story unfolds around a conflict between China and the US over the Moon’s Helium-3 (3He) resources which they need as fuel for their fusion power plants. Limit, which was originally published in German in 2009, is very optimistic about the development of fusion power: It is set in the year 2025. In the real world of today, fusion research focuses on tritium and deuterium (D-T) fusion. 3He-D fusion has been considered on a theoretical level.

Franziska Biegalke, an environmental sciences student at Greifswald’s Ernst-Moritz-Arndt University has looked into the relevance of 3He-D fusion for future fusion power plants for her Bachelor’s thesis.

How did you come to choose this topic for your thesis in the first place?

As part of my Bachelor’s course I attended the course “structure of matter” held by Dr. Hans-Stephan Bosch from IPP. I liked his lecture and approached him about doing my Bachelor’s thesis. We needed to find a topic, which I – not being a physicist – could handle and which was related to current scientific activities. We looked into a few options, among them the comparison of 3He-D and D-T fusion. After some reading, I found it really exciting. With the exception of an excursion to Wendelstein 7-X and some chapters in Bosch’s lecture, I had not dealt with fusion before.

Franziska Biegalke

Franziska Biegalke in Greifswald’s harbour (picture: private)

Assuming that D-T fusion is successful. Is there a realistic possibility for 3He-D fusion plants in the far future?

Well, I don’t think so. The main issue is availability. Only traces of 3He are available on Earth – not sufficient to enable any usage. As long as the moon’s 3He resources cannot be exploited in an economical way, 3He-D fusion is not an option in my view. Furthermore, lunar regolith contains little 3He, so that one would have to mine immense amounts of it. I can’t say if that will ever be possible, but surely not in the foreseeable future.

Why is 3He-D fusion under discussion at all? Would it be a better alternative to D-T fusion?

It is often said that 3He-D fusion has the advantage of neutron free fusion reactions, because it produces alpha particles (4He) and protons. In contrast to neutrons, the movement of these charged particles can be controlled by magnetic fields. But, if one looks into the details, it turns out that 3He-D fusion is not completely free of neutrons. This is what I quantified in my thesis. The alpha particles, protons and the deuteron undergo further reactions which do produce parasite neutrons. The reaction yields less neutrons, with a lower energy, but they cannot be neglected.

Will you stay in energy research or even in fusion science?

I have now applied for a master’s course and I really enjoy physics, for instance. I can well imagine to continue in the areas of renewable energies or fusion, maybe with a master’s thesis. But just as I came across 3He-D fusion and found it a surprisingly fascinating topic, it is also likely that a completely different, but evenly fascinating topic will cross my path next.