1 - Nuclear Sciences and Applications - IAEA

4 MAISONNIER
various economies. Depending on the degree and rate of levelling out of this distribution
as well as on the extent of success in enhancing the efficiency of energy end use
worldwide, the total energy needs could increase enormously.
Whatever the quantity of energy which will be necessary, there will more and
more be the requirement of quality: energy must be produced in a manner that is not
only economically but also environmentally acceptable, even if what is and will be
environmentally acceptable is a moving target difficult to define. Every source of
energy has its own economic, health and environmental costs and risks. Reliance on
fossil fuels, apart from problems linked with global or local availability, carries the
risk of global warming (the greenhouse effect) and acidification, which is perceived
with increasing acuteness both in public opinion and at governmental level. A possible
large scale use of the renewable energy sources (sunlight, biomass, etc.) depends
on local conditions and seems to be confronted with high costs and substantial
environmental consequences. Nuclear power from fission reactors is facing three
main concerns: safety and accidental radioactive releases, waste disposal and nonproliferation.
The degree of concern in these three areas will most probably be lower
in the case of nuclear power from future fusion reactors, for which, however, it is
too early to tell whether eventually they will be economically competitive.
As to the question "When will the first fusion power plant be built?", Academician
Velikhov reported that Artsimovich once gave the sibylline but probably sound
reply: "When there is great need for it." Against the background of recent
experiences, the need for the development of a diversity of widely accessible long
term energy sources which show promise of being not only technologically feasible
but also acceptable from the economic, safety, environmental and non-proliferation
points of view is being perceived more and more acutely. It can be objectively
argued, I think, that fusion has the potential of becoming one of these sources.
The technological problems associated with deuterium-tritium fusion reactors,,
which will have to breed their own fuel (tritium) in a lithium blanket surrounding the
reacting plasma, have gradually been revealed by the many conceptual reactor
designs produced within the world fusion community over more than a decade. These
studies have also evidenced that the achievement of the potential environmental and
safety advantages of fusion will not materialize automatically but will depend to a
large measure on designs specifically tailored to this end, in which the use of low
activation materials could play an important role. The studies have also shown how
economic competitiveness will depend on attaining plasma and engineering performances
such as high beta, high wall loading and ease of maintenance — performances
which are not yet assured.
However, there are fundamental reasons why future fusion reactors have the
potential to reach a high degree of passive safety and to have only a moderate impact
on the environment:
— The reacting chamber of a fusion plant will contain only that quantity of fuel
which is required for immediate use (a few seconds). The energy content of the
fuel will therefore be very small and the amount of energy which will be sus-