Open letter to Messrs. Charpak, Balibar,
Treiner
August 21, 2010
Jean-Pierre Petit
Former research director at CNRS
plasma physics specialist (still active)
BP 55, 84122 Pertuis
Pertuis, August 21, 2010
To Messrs.
Georges Charpak
, Nobel Prize in Physics
(
Paris Academy of Sciences)
Jacques Treiner
(Pierre and Marie Curie University)
Sébastien Balibar
(École Normale Supérieure)
Enclosure:
the letter from Professor Valentin Smirnov of 2007,
director of the Institute of Nuclear Fusion at the Kurtchatov Institute of High Temperatures in Moscow,
still without a recipient.
Gentlemen,
I have read in the press your positions against the ITER project.
In thirty years, when the failure of the project will be obvious, it will be easy for these people to retire saying "we are sorry, we were wrong," entrusting this baby, now a non-viable monster, after a painful and costly gestation, to the next generations.
Indeed, as you point out, the cost of this project will become so high that it will represent the entire research budget for the next twenty years.
Repeating an image used by the press, simplified so that the general public can understand, it's as if we were promised to put the sun in a pot, but we don't have the pot, and we have postponed this "minor detail" until later, when the feasibility of a fusion capable of producing more energy than it consumes will have been demonstrated, even if only for a few minutes.
One of those who pointed out the problematic aspect of this research on the magical material that should make up this pot was the late Gilles De Gennes, who was extremely skeptical about the possibility of a superconducting magnet being able to withstand a neutron flux as damaging as that.
The JET produced fusion reactions for a time on the order of a second, that's a fact.
It produced 15 megawatts of fusion energy, with a ratio
Q = energy produced / energy injected = 0.65
ITER is expected to produce 500 MW, with a yield higher than one (Q=10), operating for six minutes. Assuming this goal is achieved, what interest would this demonstration have if no solution has been found to prevent a rapid and extremely costly degradation of the essential magnetic confinement system? How could such a generator be profitable if its superconducting magnet had to be replaced every week or every month?
The press has mentioned the issue of the wall and its problematic durability. It is known that this wall is not only subjected to neutron bombardment, emitted during fusion reactions. Also arrive the hydrogen ions corresponding to the "tails of the Maxwell-Boltzmann velocity distributions," in this plasma at 100 million degrees. The fusion plasma is collisional and these collisions tend to establish, around an average thermal velocity, a Gaussian velocity distribution, with slow and fast ions at each end. These latter will cross the magnetic barrier and detach ions from the wall, the "first wall." These will pollute the plasma and cause its cooling by bremsstrahlung, by braking radiation, which increases as the square of the ionic charge involved (a dangerous effect if this first wall is made of tungsten!). This pollution by heavy ions would be inevitable.
A decontamination of the fusion plasma has been planned and is supposed to be ensured along the "grooves" clearly visible at the base of the toroidal chamber, which correspond to a technique called "divertor." Such a system has never been tested on a large scale and nothing guarantees that it will be effective. Another problem.
The decontamination system of ITER ("divertors")
Faced with this emerging controversy, Mr.
Bernard Bigot
, administrator of CEA, tells us:
- If we don't do ITER, by what means will 9 billion humans, in 2070, be able to provide themselves with energy to meet their needs? ... How can we ensure, at the horizon of this century, a sustainable energy for the entire planet? ... If we manage to master the physics, we will find materials capable of withstanding a neutron flux with an energy of 14 million electron volts. ... Abandoning it would be unreasonable. The obstacles will be mastered.
I read that you suggest, along with the simple cancellation of this ITER project, to return to the technique of fast breeder reactors, like Superphénix, and in general to the so-called fourth generation power plants. The technique of fast breeder reactors is a variant of conventional nuclear energy, based on the fission of plutonium 239. Using a coolant fluid such as sodium, which allows more easily the passage of fast neutrons, in contrast to water (pressurized) which stops them. A neutron bombardment is used to transmute a fertile cover of U238, which turns into Pu 239, with a ratio of 1.25, this reactor "producing more plutonium than it consumes."
This option, whose danger has been the subject of criticism, up to the project's cancellation, does not eliminate the question of the activation of structures and the mass production of waste.
I regret that you do not mention, among other possible options, that of
aneutronic fusion
(actually very weakly neutronic, due to secondary reactions, of minor importance), where the most suitable mixture is the combination
Boron
11
- Hydrogen
1
, giving three Helium
4
and ... no neutrons
As long as the ignition temperature of hundreds of millions of degrees had not been reached (in the English JET), the extraction of energy from a deuterium-tritium mixture remained out of reach. The breakthrough achieved with the English JET machine changed the situation in 1991 (first fusion reactions) - 1997 (obtaining a yield Q = 0.64 with 15 MW of power released by the fusion reactions).
In the case of this boron-hydrogen reaction, this ignition temperature is one billion degrees. Now, it turns out, as reported by Professor Malcolm Haines in 2006, that a temperature reaching 3.7 billion degrees was achieved in 2005 in the Sandia Z-machine, designed by Professor Gerold Yonas in the early 1970s, the conduct of these works having later been entrusted to Professor Deeney.
Ion Viscous Heating in a Magnetohydrodynamically Unstable Z Pinch at Over 2 x 10
9
Kelvin
M. G. Haines, P. D. Le Pell, C. A. Coverdale, B. Jones, C. Deeney, and J. P. Apruzese
PHYSICAL REVIEW LETTERS 24 February 2006
download the article
My analysis of this article
A temperature much higher has most likely been achieved as early as 2008 in the ZR machine (the "refurbished" Z-machine where the discharge intensity was increased from 18 to 28 million amperes). Now, the temperature achieved is supposed to increase as the square of this intensity. Thus, a temperature of several nine billion degrees could potentially have been achieved with this new setup. However, as I could see, from the mouth of Matzen and Mac Kee, the two administrative managers of the project, who came to report on its simple technological aspects at the conference on High Pulsed Powers in Vilnius (September 2008), where I...