which, shared between 6 billion people, is 7 kWh per day per person.
(There’s currently 369 GW of nuclear reactors, so this figure corresponds
to a 4-fold increase in nuclear power over today’s levels.) I conclude that
ocean extraction of uranium would turn today’s once-through reactors into
a “sustainable” option – assuming that the uranium reactors can cover the
energy cost of the ocean extraction process.

Fast breeder reactors, using uranium from the oceans

If fast reactors are 60 times more efficient, the same extraction of ocean
uranium could deliver 420 kWh per day per person. At last, a sustainable
figure that beats current consumption! – but only with the joint help of two
technologies that are respectively scarcely-developed and unfashionable:
ocean extraction of uranium, and fast breeder reactors.