Solving Nuclear Waste: Accelerator Driven Transmutation Reactor
A first-of-a-kind reactor system has been set up in Belgium by coupling a subcritical assembly with a particle accelerator. The work is a major step in a program to research advanced waste management.
The equipment, known as Guinevere, is a demonstration model that supports the project for a larger version that will be called Myrrha (Multipurpose Hybrid Research Reactor for High-tech Applications). It was assembled by France's National Centre for Scientific Research and is managed by the Belgian Nuclear Research Centre (SCK-CEN) at Mol, about 50 kilometres east of Antwerp. The overall project is supported by 12 other European laboratories and the European Commission.
Nuclear terminology classifies an item of equipment as in a critical state if the chain fission reaction is self-sustaining and each reaction leads on average to one more. The term supercritical means the number of fissions is increasing, while subcritical means it is decreasing and will therefore dwindle to nothing. _World Nuclear News
Dangerous radioactive isotopes with long half-lives can be transmuted to elements with much shorter half-lives, using spallation neutrons. Spallation neutrons are generated when a beam of protons is accelerated into a spallation target. Neutrons, lacking a charge, do not have to overcome the "coulomb barrier", and can be much more readily incorporated into atomic nuclei to transmute one isotope into another.
(Clarification: In the early stages of this research, neutrons will be generated via Deuterium - Tritium collisions. Later iterations of the project will use the proton beam - spallation target method.)
Myrrha will be able to produce radioisotopes and doped silicon, but its research functions would be particularly well suited to investigating transmutation. This is when certain radioactive isotopes with long half lives are made to 'catch' a neutron and thereby change into a different isotope that will decay more quickly to a stable form with no radioactivity. If achievable on an industrial scale, transmutation could greatly simplify the permanent geologic disposal of radioactive waste. Myrrha can also be used to test the feasibility of lead fast reactor technology and is seen as complimentary to the Jules Horowitz Reactor, a thermal spectrum reactor under construction in Cadarache, France.
The total cost of Myrrha has been put at €960 million ($1.2 billion), with 40% of this coming from the Belgian government. SCK-CEN is looking to set up an international consortium to ensure additional financing and has completed a memorandum of understanding with the Chinese Academy of Sciences focusing on Myrrha. _World Nuclear News
While this European (and soon, Chinese) research is quite preliminary in terms of real world application to the nuclear waste problem, it should produce a great deal of data which will assist in designing future, waste-burning nuclear reactors.
Parenthetically, transmutation by the addition of a neutron is supposed to be behind the "cold fusion" or low energy nuclear reaction (LENR) efforts of a number of startup energy companies -- including Andrea Rossi's Leonardo Corporation, Defkalion of Greece, and Brillouin Energy. The methods being used by these startups for converting protons into neutrons is far from clear at this point.
In addition, sub-critical accelerator driven nuclear reactor designs have also been proposed for the use of thorium 232, an abundant fuel which is fertile rather than fissile -- it must be fed neutrons for conversion to fissile U 233, which spontaneously splits into smaller nuclei and more neutrons.
Labels: nuclear energy, transmutation
posted by al fin at 7:50 am
5 Comments:
I don't think any of the LENR folks understand what exactly is going on, they just know it works, and isn't chemical. A lot of people are screaming "scam!" over Rossi in particular, but that mostly seems to be reaction to testing and demonstrating methods, which call into question what he's doing, not that LENR itself is wrong.
There are several theories on what exactly is going on, but no one has been able to verify much.
I agree that it is remarkable how many reputable scientists have reported excess energy associated with LENRs.
Will the phenomenon ever be commercially viable? Probably, sooner or later. It may have to wait for atomically precise nano-assemblers to achieve reliable mass production.
Rossi does not inspire confidence.
"radioactive isotopes with long half lives are made to 'catch' a neutron and thereby change into a different isotope that will decay more quickly to a stable form with no radioactivity"
This is what normal reactors do too. Changing all that nasty old uranium which has been lying in the soil for 4 billion years killing people (& their predecessors) if the Linear No Threshold theory is anything to go by, into nice safe reactor waste which, because of its short half life/high radioactivity is less radioactive than the ground it was mined from in a few centuries.
The anti-nuclear movement should be rally grateful for this side effect of nuclear power ;-)
Yes. But try telling them that.
http://technologygateway.nasa.gov/media/CC/lenr/lenr.html
NASA just released this video confirmation of LENR.
BTW, note that using a linear accelerator to irradiate Mercury - can create GOLD!
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