Nobel laureate: Go thorium

October 28th, 2013

Posted by Mark Halper

Carlo Rubbia Geneva THEC13 Reception2

Carlo Rubbia, mixing with delegates at this week’s International Thorium Energy Conference, says thorium has “absolute pre-eminence” over other fuel types, including uranium and fossil fuels.

GENEVA – If nuclear power is to finally overcome public opposition and the post-Fukushima backlash, government and industry must walk away from traditional reactor technology and shift to superior designs that rely on thorium rather than uranium.

So said Nobel Prize winning physicist Carlo Rubbia this morning, addressing the Thorium Energy Conference 2013, held here at the renowned international physics lab CERN.

“In order to be vigorously continued, nuclear power must be profoundly modified,” said Rubbia, a former director general of CERN and the co-winner of the 1984 Nobel Prize in Physics.

Rubbia noted that thorium has “absolute pre-eminence” over all fuels including uranium as well as fossil fuels. He said it must become a staple of nuclear because it leaves less long-lived waste than uranium, is far more plentiful, is resistant to weapons proliferation and has a much higher energy content so that reactors will require less of it (see chart below).


Rubbia called for a shift toward thorium so that nuclear could play a big role as a low-CO2 energy source, a function that the public tends to associate with renewable energies like wind and solar.

“A distinction between renewable and not renewable energy is academic,” said Rubbia, who pointed out that the country most famous for CO2-spewing coal-fired plants, China, could generate the equivalent of its 2007 electricity production – 3.2 trillion kWh – by using an amount of thorium that is just a small percentage of China’s domestic production of rare earth metals. Thorium comes from minerals that also also contain rare earth elements, a class of materials that are vital to the world economy and that China controls.

MonaziteITHEC Geneva2013

Energy’s rock solid future. Thorium occurs naturally in minerals like this chunk of monazite from South Africa’s Steenkampskraal mine, on display at the Geneva conference.

Rubbia told a packed audience of thorium and reactor experts that thorium is probably also a superior fuel for reactors known as breeders, which produce more of their own fuel.

Thorium supporters differ over the best way to deploy the fuel. Speakers and enthusiasts from around the world are gathered here for four days to compare notes and advocate their own approaches.


Rubbia, a particle physicist, prefers a method in which an accelerator coaxes thorium to split by bombarding it with a neutron – a concept known as an “energy amplifier” which he helped conceive.

Unlike uranium, thorium is not “fissile.” It requires a method to kick start it, such as the accelerator approach or another technique that mixes it with an isotope of uranium that releases neutrons that in turn excite thorium.

Scientists and engineers also differ over whether to burn thorium in conventional reactors or in a number of alternatives such as molten salt reactors or pebble bed reactors, the designs for which date back decades. Both run at much higher temperatures than today’s reactors and thus support a more efficient generating cycle. They could also serve as a low-CO2 source of industrial process heat, replacing fossil fuels in operations such as cement and steel making.

Rubbia co-won the 1984 Nobel for work at CERN leading to the discovery of the W and Z bosons, which are related to the weak force, one of the four fundamental forces of nature along with the strong force, gravity and electromagnetism.

He is currently affiliated with the Gran Sasso National Laboratory in Italy as well as the Institute for Advanced Sustainability Studies in Germany. He was recently named a senator for life in Italy, where he previously ran ENEA, an energy and technology development agency where he promoted solar thermal power.

Other speakers followed Rubbia outlining their preferences for thorium and providing updates for thorium reactor initiatives in countries including China, Japan and India. Stay tuned the Weinberg blog for more reports.

Photos are by Mark Halper

EnergySourceJoules Rubbia CERN THEC

The Crown Joule. Thorium has a higher energy content than any other fuel including uranium, even uranium extracted from seawater (sw in the chart), according to this slide from Rubbia’s Geneva presentation.



  1. G.R.L. Cowan says:

    As good as thorium power is, on paper, several of the virtues claimed for it are already, in uranium reactors, off the drawing board and out in the real world. They are depriving fossil fuel vendors and governments of billions in fossil fuel revenue every week, and in the bargain preventing pollution-caused deaths at a rate that — as Kharecha and Hansen recently noted — nets to nearly a thousand a week after theoretical fatalities from Chernobyl, etc., are counted.

    Heavy water reactors already burn unenriched uranium. Like thorium, it is nearly inexhaustible. The uranium price spike of 2007 or thereabouts, although it topped out at less than $4 per barrel-of-petroleum-equivalent, triggered a prospecting effort that has been finding more than 100 million barrels-of-petroleum-equivalent per day. And all varieties of power reactor seem, in practice, to have been perfect in their immunity to involvement in nuclear weapon proliferation, despite lacking this immunity in theory.

    • Monte says:

      GRL I think you miss the point that Thorium, which is way more efficient at producing energy than Uranium….for me the REAL upshot is that it cant be turned into a weapon. :)

    • Bernard55 says:

      Like thorium, it is nearly inexhaustible. That is what you said ! But some studies I read somewhere said that Uranium is not for ever !! Can not remember actually how many years more they were calculating , but it is not much !! it could be something like oil , may be 50 , may be 100 years , or a bit more , but not much more !! If the chineses are actually in south Sudan , it is because they want the uranium that is there !! And that is the cause for thousand of killing and torturing in that region!

  2. James says:

    Monte, please excuse my naivety here, but, why can this not, given time and research, also not be used for weapons and their development??



    • Nick says:

      It can. The way a uranium reactor is utilized to make a bomb is by bombarding uranium with neutrons. The same thing can occur in a thorium reactor. Of course, you have to have the uranium to bombard, so it’s safer to restrict access to uranium, and still be able to generate power using thorium as the source.

  3. Bernard55 says:

    Every thing can be used as a weapon , even water , even air !! Thinking that way we should stop breathing now , since air can easily kill people if you know how to use it !!

  4. saf1 says:

    We really hope this technology comes true ASAP.
    Thorium is the next renewable energy for mankind.
    Totally support laser power systems in developing
    and improving this technology. The world are with you.

  5. 111 says:

    Standard nuclear reactors rely on engineered safety, meaning you have to act on them to keep them safe and unforseen circumstances that prevent you from doing so can always happen.
    Liquid reactors are passively safe. Meaning they’re safe to leave on their own. If a bomb blows a hole in the reactor the stuff that spills out freezes solid. If you loose all the power to your reactor it can shut itself down without human intervention.
    It’s not prone to runaway criticality (like chernobyl) since as it gets hotter fission becomes less likely to happen.

    The heavy water reactor uses about 0.7% of the energy content of uranium before you have to take it out and reprocess it or bury it as nuclear waste. Reprocessing nuclear fuel is very expensive. As is manufacturing solid fuel rcods (you can’t just put mined uranium in a reactor!).
    A liquid reactor by its very nature can continuously reprocess fuel on its own reaching much higher efficency than 0.7%, thus lowering by orders of magnitude the amount of waste generated compared to solid fuel reactors.

    Let’s not forget “waste” is only such if you have no use for it. The nuclear “waste” that comes out of liquid reactors can be easily collected and used if you have applications for it. Solid fuel reactor waste is trapped inside the solid fuel rods and accessing it is not economical, in liquid fuel reactors you can separate the fission products easily and possibly use them for other purpouses.

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