Friday, October 23, 2009

Meanwhile, in the World of Thorium

jons_jakob_berzelius The Thorium Energy Alliance had its first annual conference in Washington earlier this week, so The New York Times decided to take a look at the potential of Thorium as a fuel for nuclear energy plants.

Rajendran Raja, a physicist at Fermilab — the U.S. Department of Energy’s Fermi National Accelerator Laboratory in Batavia, Illinois — said by telephone that the benefit of adding thorium to the fuel mix would be to create much more fuel using existing abundant resources and to reduce waste.

That sounds promising.

This could be done by building a high-intensity proton accelerator with the capacity to produce fast neutrons that could convert nuclear waste, thorium-232 and uranium-238 into fuel, he said.

In case you thought there wasn’t a but:

But to accomplish this, a proton accelerator would need to be 10 times more power-intense than anything that has been produced to date.

And as you can imagine, such an accelerator would need considerable amounts of electricity itself to do the job. The article goes on to say that Fermilab is trying to overcome the issue, but has not quite got there yet.

The Indians are doing without the accelerator:

India has been making advances in the field of thorium-based fuels, working to design and develop a prototype for an atomic reactor using thorium and low-enriched uranium.

Which, if we understand the history of thorium energy is the “traditional” way of leveraging the element. We had hoped the article would be more hopeful itself, but not so much:

[John Boldeman, an Australian specialist in nuclear science and engineering] acknowledged that creating any thorium systems would be a long process that could take decades before finding success.

We suspect countries like Australia and India – which sit on piles of Thorium – as well as Fermilab will find ways to get those decades down to years. Too promising to do otherwise.

See here for much more about thorium – potentials and pitfalls - from the World Nuclear Association. And pay a visit to Kirk Sorenson’s terrific blog about Thorium – and here you thought we were niche.

This is Jons Jakob Berzelius, who identified Thorium as an element in 1828. Why not call it Berzelium? Here’s the thing: Berzelius is Swedish. Hmmm! Thorium, Thorium. Where did he get that name?


Ioannes said...

So what's wrong with the idea of the Carlo Rubbia Energy Amplifier?

Normally subcritical pile with a particle beam to cause neutron spallation off lead to activate Th-232 and turn it into U-233?

Kirk Sorensen said...

Thanks for the shout-out Mark! I'm planning to have some blog posts up soon talking about the TEA Conference and how it went. I think the video from the conference will also be available soon.

Kirk Sorensen said...

Ioannes, there's nothing "wrong" with the Rubbia "Energy Amplifier", but it solves a "problem" that doesn't exist. The EA uses a complicated particle accelerator to create additional neutrons that allow you to run the reactor subcritical. Shut off the beam and the reactor shuts down.

But LFTRs (along with many other kinds of reactors) have strong negative temperature coefficients of reactivity. Shut off heat removal and they shut down anyway. You don't need the complication of a particle accelerator to run the reactor--you can run it critical and have confidence that it can do a safe shutdown. In addition, LFTR has a "freeze plug" that melts from the decay heat of the fission products, and drains the salt into a passively cooled configuration.

A particle accelerator is not needed to unlock the potential of thorium. Just some good salt and good engineering.

Marcel F. Williams said...

A large enough ADS reactor should produce more energy than it consumes. It could also be used to produce uranium 233 by destroying waste plutonium 239, producing more than twice as much fissile uranium 233 as the original fissile plutonium 239.

Robert Hargraves said...

The perceived advantage of Rubbia's ADS reactor is that a criticality accident is not possible, because the core is always slightly subcritical, only being critical when the accelerator is switched on, so if a problem occurs it can be switched off.

But all other license-able designs have intrinsic physical properties that prevent runaway criticality. No control system action is required in the liquid fluid thorium reactor because heated fluid expands out of the moderated core, reducing criticality. The freeze plug is a secondary backup.

Kirk Sorensen said...

I've put up a blog post about the first day of the TEA conference:

Day One Highlights at the TEA Conference