Intelligent Energy

Safe nuclear: Let the thorium debate begin

Posting in Cancer

Reactors based on thorium, not uranium, can solve nuclear power's waste and weapons problems, say some experts. No they can't, say others. Mark Halper's latest report from the thorium trail.

So. You've been hearing a bit about this thorium stuff, and how it augurs a safe nuclear future, have you? Certainly you have if you've been paying attention to my energy blog here on SmartPlanet, where I started banging the thorium drum last summer, and have written several accounts since then. Earlier this week, I told you about a thorium reactor that India plans to build.

Oh no it isn't. Arjun Makhijani.

For those of you new to this, and for a quick review: Thorium is a substance that could replace uranium as a nuclear fuel because, its supporters say, it does not yield nasty, weapons-grade waste the way uranium does. And its waste lasts for only a few hundred years, not the tens of thousands associated with uranium. It can work in conventional, water-cooled reactors. But when combined with alternative reactor designs, like a "molten salt" or "liquid fluoride" reactor, it offers even more advantages including greater efficiency, Flibe Energy claims. The U.S built a molten salt reactor in the 1960s at Oak Ridge National Laboratory, but the Nixon administration halted thorium development in favor of more weapons-prone uranium.

But is it really all that good? If it is, why aren't we doing it? What's the catch? These are all great questions that the thorium camp knows it must invite and answer before the thorium ship sails. Last week they were certainly on the mind of one detractor - Arjun Makhijani, president of the Institute of Energy and Environmental Research and an ardent believer in solar power - who took to the national airwaves in the U.S. to rattle the thorium dreamers.

Oh yes it is. Richard Martin.

In a 20-minute segment on a National Public Radio show hosted by NPR's Ira Flatow, Makhijani grilled one of thorium's most visible supporters, author Richard Martin, who has just written a book called SuperFuel, due out in June from Palgrave MacMillan. You can read the full transcript of their debate, and also listen to it, via the link in the previous sentence. Here's a taster:

Makhijani does not believe that thorium is a panacea to the waste and weapons proliferation challenges of nuclear.

"It doesn't solve the proliferation problem," he tells Flatow, noting that thorium reactors yield uranium 233, which can be used to make weapons.

"It doesn't solve the waste problem, either. So every nuclear reactor, no matter what type, creates fission products, which are highly radioactive materials, some short-lived, some long-lived, to make energy.

"With the present reactors, we create about a ton per reactor, per year. If you have a more efficient reactor, at least you will create half a ton, probably eight-tenths of a ton, nine-tenths of a ton. This is highly radioactive waste. If you look at Oak Ridge's current evaluation, they say you have to condition this waste, you have to convert the fluorides, and then you have to have a deep geologic repository."

He also notes that the waste includes long lasting technetium-99, among other radioactive elements, which poses cancer risks when used medically.

Martin retorts,

"When we talk about the waste, one of the things that skeptics of the liquid fuel thorium reactor ignore is the fact that because the core is a liquid, you can continually process waste, even from existing conventional reactors into forms that are much smaller in terms of volume, and the radioactivity drops off much, much quicker. We're talking about a few hundred years as opposed to tens of thousands of years.

So to say that thorium reactors, like any other reactor, will create waste that needs to be handled and stored, et cetera, is true, but the volume, we're talking tenths of a percent of the comparable volume from a conventional reactor. And not only that, but we've got all that waste from our existing nuclear reactor fleet, just sitting around, and we've got no plan for it.

And so we're talking about building a reactor that can process that into forms that are much, much easier to deal with."

The SuperFuel author also says it's highly unlikely that uranium 233 would end up in the hands of bomb-making terrorist. He notes that in a liquid thorium reactor,

"There's no point at which you can divert material. There's no material sitting in a warehouse somewhere, getting ready to be put in the reactor and so on. And to be able to obtain that material, you would have to somehow breach the reactor, shut it down, separate out the fissionable material and get away with it.

"And as I say in 'SuperFuel,' the book, good luck with that. But the other point is that even if you did manage to do that, the uranium-233 is contaminated with yet another isotope, U-232, which is one of the nastiest substances in the universe, and it makes handling and processing and separating out the U-233 virtually impossible, even for a sophisticated nuclear power lab, much less for a rogue nation, or terrorist group or someone of that ilk."

Makhijani counters by citing a Princeton University paper that says there are easy enough ways to bypass handling the uranium 232, to get to the uranium 233 for weapons making purposes. He also plugs another form of "nuclear" power: Solar energy. The sun emits heat from its own ongoing fusion of hydrogen isotopes.

"I have a favorite molten salt reactor," Makhijani says. "My reactor is free. It's in the sky, 93 million miles away. You can store its energy in molten salt. It is being done today. You can generate electricity for 24 hours a day....

"I don't know why - I'm still trying to understand why photovoltaics are still so expensive in this country. But you know Germany - I was at a seminar yesterday at the Heinrich Boll Foundation about the Germany decision to get out of nuclear. They're going to have a completely renewable system maybe by the time thorium reactors become commercial."

The thorium debate is just beginning - or re-beginning, given its decades-old history. Watch for more discussion from me over the next several weeks, as I continue my journey along the thorium trail, examining its tremendous potential and airing other views, writing from London, Chicago, and other stops. I'll even include criticism from another alternative nuclear camp: Those companies that are developing what's called fast neutron reactors, such as what Bill Gates' TerraPower is doing, and what San Diego's General Atomics is also working on.

Feel free to weigh in with comments below, or write to me through the email link.

Photos: Makhijani from TidesMomentum via Flickr. Martin from superfuelbook.com.

More alternative nuclear on SmartPlanet:

And a handy guide to alternative nuclear:

Mark Halper

Contributing Editor

Mark Halper has written for TIME, Fortune, Financial Times, the UK's Independent on Sunday, Forbes, New York Times, Wired, Variety and The Guardian. He is based in Bristol, U.K. Follow him on Twitter. Disclosure