Nuclear Fusion: Is it as Safe as We Think?November 4, 2013 | Print |
HAVANA TIMES — It seems to me that we are not sufficiently aware of the risks surrounding a new, emerging technology. Producing energy through the fusion of light nuclei (such as deuterium and tritium, which are heavy, radioactive isotopes of hydrogen) is the dream of many physicists and technologists.
This is the process which takes place inside the sun, the stars and hydrogen bombs. The aim is to “domesticate” the thermonuclear reaction so that, on the one hand, it does not produce an explosion (like the 50-megaton hydrogen bomb detonated by the Soviets in the Arctic in 1961), and, on the other, the process stabilizes at a temperature in which the atomic nuclei can fuse and generate energy.
No fusion thermonuclear plant yet exists.
Existing complexes are fission plants. I am referring to those that work on uranium and plutonium (like the Chernobyl and Fukushima nuclear power plants).
Since I was a child, I, the son of electrical engineers and physics lovers, have been hearing that we will “soon” see the first fusion reactor. I’ve read stories about complex Tokamak machines that use a magnetic field to control the ultra-hot plasma where the thermonuclear reaction is supposed to take place, and about reactors that heat up and weld radioactive isotopes with lasers.
In the 80s, there were even those who claimed they could achieve “cold fusion”, something which turned out to be a hoax.
I was about to get bored from the long wait (I’ve had plenty of people tell me that the “sun on earth” is just “around the corner”) when, this past October 18, Cuba’s Granma newspaper published an article quoting a BBC piece (Paul Rincon’s “Nuclear fusion milestone passed at US lab”) which reported that, under strictly controlled conditions and using 192 lasers, scientists at California’s National Ignition Facility managed to have a hydrogen pellet produce more energy by nuclear fusion than that supplied by the lasers.
That is to say, for the first time in history, controlled fusion has become a fact. It’s been proven: a facility that produces energy through the fusion of hydrogen nuclei can be constructed.
Of course, we’re not talking about a functioning thermonuclear plant, but about the possibility, in principle, of building one in the future.
In this connection, Granma repeats what has become a commonplace for those who write (or read) about the study of nuclear fusion:
“They call it ‘The Holy Grail’ of energy, for it is clean, cheaper and practically inexhaustible…for it can meet the world’s energy needs without the threat of nuclear proliferation or environmental damage. [While] fission produces highly destructive and long-lasting residues that are difficult to eliminate, the residue produced by fusion is helium, a harmless and economically valuable gas.”
From this, we get the idea that fusion is so good that, in addition to solving humanity’s energy problems once and for all, it can be used to produce helium, a gas with which balloons at sweet-fifteen birthday parties can be filled up. It all sounds very clean and safe.
I feel, however, that we are (once again) giving in to dangerous hyperbole. Nuclear fusion produces neutrons.
Neutrons, as their name indicates, are neutral particles. As such, it isn’t hard for them to interact with positively-charged atomic nuclei. Neutronic radiation, thus, is capable of transforming a given nucleus into a heavier isotope, which tends to be radioactive.
This leads us to the problem of “the first wall”: any nuclear fusion facilities must be fitted with an internal container made up by a “first wall” that faces the space where the reaction takes place.
This wall will be exposed to neutronic radiation. It won’t take long for it to become radioactive and begin to erode. In time, it will have to be replaced by another wall if the fusion reactor is to remain in operation.
Where will the discarded containers end up? These “first walls” will be loaded with radioactivity. As fusion technology develops, this can become a problem.
Scientists may claim that the levels of radioactivity produced are low and the risks minor when compared to the advantages of this energy generating technology. But they said the same thing when fission reactors started to be used, and we know what happened later. I wonder if scientists have any concrete proposal in this regard.