Welcome back to the thorium trail, the long and winding road to an altogether different and safer way of generating nuclear power by using thorium instead of uranium as fuel.

Last week we stopped in the U.S., where the thorium debate took to the national airwaves. We also ventured to India, to have a look at a thorium reactor that's rising there .

Today, we pull into the UK, where we note that the government's Department of Energy and Climate Change (DECC, the UK equivalent of the U.S. DOE) has spotted thorium on its radar, and is looking into it.

First, my standard review for newcomers, because the parade of interested travelers on this road is growing all the time:

Thorium should replace uranium 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 and others claim. The U.S built a thorium 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.

Second, a note of realism: To say that the British government is contemplating thorium is indeed true. But to be clear, any decision to back or approve thorium, or any commercial deployment of it in Britain, is probably a way off.

Nevertheless, it is well worth noting that thorium has indeed entered the discussion at DECC.

I know this firsthand because three weeks ago I participated in a Parliamentary committee meeting on thorium nuclear power, where one of the speakers was from DECC.

In a carefully crafted, equivocal, on the one hand but on the other presentation entitled Future Nuclear Power and the UK Energy Supply - Can Thorium Play a Role?, DECC senior scientific advisor Rob Arnold described, in impressive detail, the pros and cons of thorium. To paraphrase his own answer to the question he posed: "yes, but, well ... maybe."

Thorium fans, take heart: I did not hear "no."

Thorium, Arnold, said, "can provide many attractive traits," including, in his own words, "potentially more efficient closed-cycle fuel breeding, potentially lower long-term radiotoxicity of wastes, and potentially a more stable matrix for geological disposal of wastes." (Fuel breeding is the creation of more fuel from fuel already burned).

The extent of these benefits depend on the type of reactor in which thorium is deployed, he said.

However, Arnold pointed out that the thorium fuel cycle can require uranium to kick start it. Thus, thorium reactors do not eliminate uranium from the picture. (Thorium supporters are quick to note, thought, that the uranium starter amount is a very small amount, and it supports a highly beneficial thorium process).

He also noted that while a potentially safe process known as ADSR (accelerator driven system reactors, which do not sustain a chain reaction, and are under development) could also support a thorium reaction, the same technology could apply to uranium reactors and make them safer.

Thus, he said, one challenge for thorium is that the nuclear industry may prefer to apply safety, efficiency and breeding improvements to the existing, proven, uranium value chain, which would be less expensive than applying it to a new fuel type, thorium. An underlying challenge for any nuclear initiative - conventional or alternative - is that someone has to provide the billions of dollars required to build any new, large reactor. While government subsidies could play a role, ultimately, industry and private investors have to pony up.

And don't forget that the conventional industry has already been spending to add "passive cooling" features to its new water cooled uranium reactors that do not rely on outside power for cooling in the event of an emergency, such as what happened at the Fukushima plant in Japan, where a tsunami knocked out a diesel generator that was driving the cooling system, leading to meltdowns. The Big 3 conventional nuclear manufacturers - Westinghouse, Areva, and GEH - are all in the passive cooling business.

But, on the other hand (I warned you about equivocal), Arnold repeated that thorium could indeed reduce the amount of plutonium and other undesirable "actinides" in nuclear waste, could provide "fuel security" (there is a lot of thorium in the world), and could run with greater efficiency and "fuel burn-up" than uranium.

Going back and forth, though, he cautioned that these benefits are "speculative."

Arnold was doing his job - he is part of a DECC unit that is evaluating thorium, and that evaluation is so far inconclusive.

Enough equivocation. During the committee's question time, I asked him how truly interested DECC is in backing thorium, especially now that a German joint venture has backed out of plans to build two of eight new nuclear reactors that the British government has approved , and on which it is counting as part of the UK's energy future.

With the conventional nuclear industry delivering such a blow to the government's nuclear vision, doesn't that create an opening for an alternative nuclear approach?

Arnold's answer won't surprise you. Thorium, he said, is part of a "keep your options open" approach.

Baroness Bryony Worthington, a member of the House of Lords who organized the meeting as head of the All Party Parliamentary Group on thorium, explained that "There's going to be a crucial point over the summer where the government as a whole thinks about developing a nuclear strategy - they don't have one at the moment - which will give us that long term view."

Baroness Worthington supports thorium, and is a member of Labour, the opposition party to the coalition of Tories and Liberal Democrats in power. She is also a patron to the Weinberg Foundation, a London-based group formed last September to promote molten salt thorium technology and to honor Dr. Alvin Weinberg, the American scientist who developed Oak Ridge's thorium reactor in the 1960s.

I'll be meeting the Baroness a little further down the road, as we both take the thorium trail to Chicago in a couple of weeks, where I'll stop at the Thorium Energy Alliance Conference. Stay tuned for an account of our upcoming conversation, and for more of my reports from the thorium trail.

In fact after Chicago, I'll be going to Pittsburgh, where I hope to talk to Westinghouse about their interest in thorium. I've asked for an interview with the company's CEO, but so far nothing back. Big Nuclear has been curiously silent on the subject of thorium. Neither Westinghouse, Areva nor GEH would speak to me when I wrote my recent Kachan & Co. report on alternative nuclear technologies.

They're still elusive. They have a uranium value chain to protect. But as countries like China and India start ramping up thorium, it seems that the industry incumbents might want to give it consideration.

Okay, time to pack up and head to the next stop on this trail. See you there.

Photos: Cameron and Davey/Chu from DECC via Flickr. Worthington from parliament.uk

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This post was originally published on Smartplanet.com