Fission & fusion: a view from Sirius, by Bertrand Barré, ENS president

All too often, a very destructive controversy simmers between the proponents of fusion and the advocates of fission who, seen from Sirius,¹ are both parts of the same community, the nuclear energy specialists.

Fusion zealots claim that ‘their’ energy source is so much cleaner (meaning cleaner than fission, of course), non-proliferating, safer, and more plentiful. Some of them go as far as suggesting that ITER will, indeed, see the light of day as a reactor (as the ‘R’ in the acronym implies), and some also even dare attribute levels of cost competitiveness to the first fusion reactor^.2 Fission fanatics, on the other hand, deride fusion as an eternal dream – saying that its readiness for the market is perpetually delayed. Both sides claim that they should be the sole recipients of the very limited R&D budgets.

Let me first address this last point. It is a fact that, by far, the biggest chunk of the Euratom Framework Programme’s budget was, and still is, devoted to fusion R&D. But this chunk constitutes the bulk of the European money spent on fusion, though (fortunately) fission R&D relies only marginally on EU funding. Furthermore, in the present EU environment, any Euro lost by fusion is very unlikely to be redirected toward fission R&D! This considered, we do constitute a community.

We are a community also because, let's face it, we share the same opponents. As long as fusion seemed very, very remote – both in time and space – some ‘anti-nuke’ spokespeople used to say: “we're not against nuclear energy; we're just against this dirty fission power". Recently, because of the possibility of siting ITER in Europe, we hear (or read in the press): “we're all for fusion, but we're against this dirty ITER, with all that tritium and those activation products". And this is not a purely European phenomenon – similar declarations also appear in the Japanese newspapers.

Like it or not, fusion R&D needs the general nuclear background supplied today by lively fission programmes. If – heaven forbid – mankind were to phase out nuclear power for fear of radioactivity, fusion would stand as much chance of survival as a snowflake in hell. (And the demise of fusion would be but a drop in the ocean of problems mankind would face in solving its ‘development-versus-environment dilemma’ without the help of nuclear power.) On the other hand, the very existence of active R&D on fusion provides nuclear power with a prospect of millennial sustainability, which makes it worth its trouble.

Fission advocates should say, in essence: “Fusion is still a scientific and technical challenge which needs to be very thoroughly addressed, but the prospect of turning the vast reserves of lithium in the earth’s crust into energy sources is worth the effort.” And fusion proponents should acknowledge that, when we have mastered the physics and basic technology of fusion, we shall be happy to turn to fission specialists to engineer an efficient power reactor around our plasma core, to design our specific tritium breeding cycle and to properly manage our radioactive waste, as well as to help establish our Safety Analysis Report and Environmental Impact Assessment.

All in all, the European fission community has strongly supported ITER; we should at least expect the fusion community not to undermine nuclear power when it faces tough opposition in several European countries.

Personally, I do not picture fusion as a successor to fission, no more than oil is a successor to coal. Whenever it is that fusion does go commercial (don't ask me when), oil as well as gas production will be on the decline. Mark my words: I am not speaking about the ultimate exhaustion of these resources; I am only predicting an irreversible decline in production which might last very long. Even if a reasonably optimistic view of the growth potential of renewable energy sources is taken, I am convinced that, in the future, we shall be only too happy to have two forms of nuclear energy to use simultaneously: breeder fission and fusion. As I see it, fission and fusion are two sides of the same ‘nuclear coin’.

¹An expression from the French writer Voltaire, which means: seen from afar, from a broader perspective.
²At this early stage, fusion’s competitiveness is a question unfair to ask and dishonest to answer.