Nuclear Production of Hydrogen, Fourth Information Exchange ...

CHANGING THE WORLD WITH HYDROGEN AND NUCLEAR: FROM PAST SUCCESSES TO SHAPING THE FUTURE
Mother Nature provided hydrogen and nuclear, both instrumental to support the development
of life and the advent of man
The universe and supernovae
Hydrogen and nuclear reactions have been at the origin of the universe.
Hydrogen is the simplest atom (made of only one proton and one electron). It was synthetised
first and it is by far the most abundant in the universe.
It is at the origin of the energy of stars that are both energy sources of the universe and factories
of heavier atoms released into the space by supernovae.
Of these heavier atoms, uranium is the heaviest, so that together with hydrogen, the lightest, we
may think they both surround all elements of the universe, including those that constitute the Earth,
ourselves and the items of our daily life. Hydrogen and uranium are this sort of alpha and omega that
Mother Nature invented to energise our universe and to support the development of life.
Since the beginning of life on Earth, our comfort here stems from hydrogen and nuclear and our
ancestors have been enjoying them for long before they understood why. This is an example of what
the French mathematician, physicist and philosopher Blaise Pascal summarised in the 17 th century in
saying, “We always understand more than we know.”
The sun
Our beloved sun that warms up the Earth from above burns hydrogen in a cycle of fusion reactions
that was discovered by Hans Bethe, a German scientist who received the Nobel Prize in physics in
1967 for his understanding of nucleosynthesis in the sun.
The blue planet
Geothermal heat that warms the Earth from underground originates from the radioactive decay of
atoms such as uranium, thorium, radium, potassium… and provides significantly milder conditions
than those that would result from the mere heat balance between the heat flux from the sun and the
heat loss by radiation to the deep black space.
In the 19 th century, the time of the British naturalist Charles Darwin, most people believed that
the age of Earth was about 6 000 years, as estimated by Bishop Ussher in the 17 th century from his
reading of the Bible. In 1862, the physicist William Thomson (who later became Lord Kelvin) published
calculations that fixed the age of Earth at between 20 and 400 million years. He assumed that Earth
had been created as a completely molten ball of rock, and determined the amount of time it took for
the ball to cool at its present temperature. His calculations did not account for the ongoing source in
the form of radioactive decay, which was unknown at the time. Biologists had trouble accepting such
a short age for Earth. After radioactivity was discovered at the end of the 19 th century, Lord Rayleigh
developed the thought that radioactive materials present in the Earth are generating more heat than
is leaking out and that the temperature must be rising. This vision led him to first estimate the age of
the Earth at about 2 billion years. Realities of nature surpass human imagination…
Beyond radioactivity, nuclear energy occurred spontaneously on Earth when sustained fission
reactions developed spontaneously in the uranium mine of Oklo in Gabon in Africa, showing the path
towards fission reactors about 2 billion years ahead.
The evolution of man
Hydrogen in the sun and in the waters of our blue planet, together with nuclear in the sun and in the
soil under our feet provided conditions that were appropriate for the development of life on the Earth
4 billion years ago. Humans arrived after a long chain of evolution of living beings that included
simple and multiple cell organisms, fish, insects, amphibians, reptiles, birds, mammals… with whom
we still share an important part of our genes.
The chain had to survive terrific events such as the fall of a meteorite that caused the end of the
dinosaurs and I wish to share with you a personal thought at this opportunity. At the secondary era
22 NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010