[Jabberwalker]

Yup. CANDUS can burn Thorium:

http://www.nuclearfaq.ca/brat_fuel.htm


Thorium Fuel Cycles

There has long been an attraction for fuel cycles using thorium as a thermal breeder of fissile material (U-233). Thorium is three times as abundant as uranium in the earth’s crust, and U-233 is valuable as a fissile material due to its high value of fission neutrons produced per thermal neutron absorbed (eta).

Existing CANDU reactors can operate on thorium fuel cycles, with comparable fuel-cycle costs to the natural-uranium cycle and with improved uranium utilization. While ultimate efficiency is achieved with a self-sufficient cycle that relies only on bred U-233, economical once-through thorium (OTT) cycles can greatly extend uranium resources.

Several options have been identified for the use of OTT in CANDU reactors (Milgram, 1984), and on-power refuelling is the key to successful exploitation of this material. Two general approaches have emerged: the "mixed-core" approach, and the "mixed-fuel-bundle" approach (Boczar, 1998).

In the "mixed-core" approach, a number of "driver" channels provide the flux requirements for a fewer number of "breeding" channels filled with thorium-oxide fuel. This is the conventional CANDU-OTT strategy, and has the potential to be competitive, in terms of resource utilization and economics, with both natural-uranium and SEU fuel cycles (Milgram, 1982; Dastur, 1995). Complex fuel management is required to handle the different characteristics and residence times of the two fuel types.

In the "mixed-fuel-bundle" approach, thorium oxide is contained in the central elements of a fuel bundle, and SEU is contained in the outer elements. Although uranium utilization and thorium irradiation are not as good as in the "mixed-core" approach, uranium utilization is improved over the natural-uranium cycle (but not SEU), with comparable costs. Fuel management is much simpler than in the "mixed-core" approach, and refuelling rates are about a third of that required with natural uranium (Chan, 1998).

An extension of the CANDU-OTT cycle is the "direct self-recycle" of the thorium elements bearing U-233, into new "mixed-bundles" containing fresh SEU elements. This is an excellent example of a proliferation-resistant fuel-recycle option (Boczar, 1999).

In the long term, the CANDU reactor is synergistic with fast-breeder reactors (FBRs), where a few expensive FBRs could supply the fissile requirement of cheaper, high-conversion-ratio CANDU reactors, operating on the thorium cycle.

Thorium fuel cycles have additional benefits beyond uranium resource extension. Both the thermal conductivity and melting point of thorium oxide are higher than that of uranium oxide (by 50% and 340ºC, respectively). Thorium oxide is chemically very stable, does not oxidize, and creates fewer minor actinides than uranium. Even with the existence of economical uranium fuel cycles, thorium can be used to simultaneously extend resources and create a "mine" of safeguarded U-233 for future exploitation

[DrCaleb]

Jabberwalker Jabberwalker:

I still wonder if the ideal fusion reactor is about the size of a star, with a safe operating distance of about 93 million miles and all that we have to do is figure out an efficient way to harvest the output.

We need to use ours more often.

[DrCaleb]

Khar Khar:

DrCaleb DrCaleb:

Zipperfish Zipperfish:

Woefully ignorant I'm afraid--which is why I liked the article so much. it's the first one that explained the challenges of the thorium reactors. I'm a thermodynamics guy.

It's one of the few articles I've read that didn't have a bright future for Thorium. Too expensive, too many waste products . . . not hopeful. If you wanted to create weapons grade Uranium, it looks like the way to go.

Most of the information I've read said the exact opposite - that Thorium reactors didn't produce weapons, and that the by-products were relatively stable compared to Uranium waste.

<snip>

I'm actually surprised to see this contribution in the Bulletin of the Atomic Scientists. It was kind of funny to see it had made it onto Canadaka, since I had to listen to someone complain about it for an hour yesterday (during which my eyes crossed and I started thinking about hockey). My physicist friend had a conniption reading this article, in part because Alvarez is making mostly a policy and financial argument to stop research. While he might be able to make some excellent points of the finances and policy of thorium research and how much effort we have put into it (and that part of the article is definitely sound), condemning it as a failed panacea as a result of the financial cost seems foolhardy to me. Ongoing research into new technologies shouldn't end because that technology doesn't yet exist. The potentials of thorium production are worth the costs in my view, and apparently that of two dozen or so countries engaged in the research.

His arguments kind of fall apart when you notice that most of his analysis rests of U-233 being a dangerous resource that could be proliferated, all while also stating it's incredibly hard to extract and is a financial liability (with a large cost to even extract it) once it is done so. In a normal reactor using thorium you don't extract it, you simply use it within the reactor proper where it is consumed. Further, such dangerous substances exist already; using proper containment protocols and mechanisms for situations when it is extracted makes sense. Even then, other experts have stated that it is not a resource you could get bomb-making resources out of, making it a boon for non-proliferation. Even if it could be proliferated, it doesn't seem as efficient as is possible with other nuclear fuel sources... but that's just my less than knowledgeable view.

Finally, other organizations, like CERN, continue to support and push for greater use of thorium. Thorium research is far from dead, but it was nice to see another perspective in the forum of costs and perceived dangers. Personally, I still see thorium as the future.

My thoughts anyways.

I posted the article because I know we've had discussions about Thorium as fuel before, and like your friend, this article threw me for a loop. It discounted pretty much everything I have learnt about Thorium as a nuclear fuel. I thought it would be a great discussion! As Winnipegger points out, India is having great success with Thorium as a nuclear fuel, and so apparently is China.

So why would the BAS be so on it? Are they basing their critique solely on the failed US attempts at harnessing it? I too noticed that they don't include any recent advancements in reactor design, like molten salt vs pressurized deuterium as a coolant.

[DrCaleb]

N_Fiddledog N_Fiddledog:

DrCaleb DrCaleb:

It's like arguing with a special needs person sometimes.

Please, tell me more about how you abhor ad hominem attacks.

And that actually is one.

'Abhor' is such a strong word. 'Dislike' is closer. But it also happens to be true.

There is a 'special friend' house for special needs adults near my place. I speak with them often, and like you, they can be very reasonable people at times. But, like you, they get focused on one idea that they just can't let go of.

Like when I tell one gent that when his dog craps on my lawn, he has to clean it up. And he freaks out, saying it wasn't his dog (on the end of the leash he's holding) that I just watched crap on my lawn, or he says he didn't make the dog crap on my lawn, or it was some other dog that left that fresh steaming turd on my lawn - so he doesn't have to clean it up. Or he wants me to prove that it's my lawn. Or he just has a tantrum and storms off.

As Khar points out, safe responsible use of nuclear, biologic and chemical weapons isn't "anti-" anything. Except anti-irresponsible.

Now, feel free to insist your dog did not just crap on the lawn.

[Jabberwalker]

India is having great success with Thorium

The Indians are doing it with a knock-off of our CANDU. We could have Thorium reactors here without too much new engineering. Perhaps the Uranium mining community here in Canada is not so keen, though.

[Khar]

DrCaleb DrCaleb:

I posted the article because I know we've had discussions about Thorium as fuel before, and like your friend, this article threw me for a loop. It discounted pretty much everything I have learnt about Thorium as a nuclear fuel. I thought it would be a great discussion! As Winnipegger points out, India is having great success with Thorium as a nuclear fuel, and so apparently is China.

So why would the BAS be so on it? Are they basing their critique solely on the failed US attempts at harnessing it? I too noticed that they don't include any recent advancements in reactor design, like molten salt vs pressurized deuterium as a coolant.

Oh, I hope you didn't think I was judging you badly or anything, it was just a funny coincidence that I got to hear about it twice. I agree it's an interesting article, just a surprising one to see BAS run. I think it kind of runs along the policy line that is growing a bit more prominent in the USA and a few other states that the sheer cost of this research is too much for what is potentially viewed as a gamble on technology, yeah. Frustration from a lack of broadly sought after tangible thorium technology everyone was dreaming of has probably soured the view of some. I personally agree with you guys on the viability of the technology, though. Especially given Canada and Europe are still gung-ho for researching and using it, alongside India and China, as mentioned by others.

It might also just be Alvarez specifically. For all his involvement, he wasn't involved in anything technical, and isn't capable of speaking about such developments; he worked as a government appointee in related fields, but his credentials and background extend only to policy, and I bet that's why this article is so policy-based. As an aside, I read some of his other articles on the internet, and they are largely the same going back several years, with the same contentions and issues. I'm guessing this was more or less a repeat of his old stuff, but in a new, more trafficked periodical.

[N_Fiddledog]

DrCaleb DrCaleb:

'Abhor' is such a strong word. 'Dislike' is closer. But it also happens to be true.

There is a 'special friend' house for special needs adults near my place. I speak with them often, and like you, they can be very reasonable people at times. But, like you, they get focused on one idea that they just can't let go of.

Like when I tell one gent that when his dog craps on my lawn, he has to clean it up. And he freaks out, saying it wasn't his dog (on the end of the leash he's holding) that I just watched crap on my lawn, or he says he didn't make the dog crap on my lawn, or it was some other dog that left that fresh steaming turd on my lawn - so he doesn't have to clean it up. Or he wants me to prove that it's my lawn. Or he just has a tantrum and storms off.

As Khar points out, safe responsible use of nuclear, biologic and chemical weapons isn't "anti-" anything. Except anti-irresponsible.

Now, feel free to insist your dog did not just crap on the lawn.

Look, I was going to leave this alone. I'd like to, but you won't let me. It's you who's like a dog with a bone, and won't leave it alone.

My only point is there are two sides to this, and both sides appear to have a bias.

These guys you linked to appear to have an anti-nuclear bias. I base this on two things.

1. They say they do. Now if after that they say they have good reason for it, well good for them, but I don't care here. It doesn't damage my point. There is a bias. They say there's a bias. They say they want to explain the negative side of nuclear. Good for them.

2. The stories in the current issue reek of anti-nuclear bias. They are not just examinations of the nuclear issue. I linked to the top five. Here's just the titles.

* America, awash in nuclear weapons materials

* Battlefield weapons and missile defense: Worrisome developments in nuclear South Asia

* Breeder reactors: A possible connection between metal corrosion and sodium leaks

* Are medical radioisotopes contributing to global nuclear insecurity?

* Treasure-island cleanup exposes navy's mishandling its nuclear-past

Those are the first five. I claim they illustrate an anti-nuclear bias as such.

You claim they don't because they claim to have taken up the mantle of an organization from 1945 that claims to have created the atomic bomb. I say even if true so what? It does not prove they do not now have the bias they say they do.

I say because their articles emphasize the negative aspects of nuclear energy, and because they themselves state they are "about threats to the survival and development of humanity from nuclear weapons" that's what we know for sure. So if we assume there is a pro and anti nuke side they are on the anti. If there is a pro and anti thorium side the article suggests they are on the anti.

My point was I enjoyed the article, but I want to hear from the other side. So what? What's your problem.

That somebody would like to hear from the other side has put you into some sort of crazed spin where you launch ad hominem slurs while you accuse others of doing it, and refuse to acknowledge the black and white evidence of a harmless fact. And why do you seem to take it as a some sort of personal insult that somebody dares to suggest your source may be something other than the purified truth from God's personal lips anyway? Why can't you just let it go? They represent the anti-nuke side, so what?

[PublicAnimalNo9]

Jabberwalker Jabberwalker:

India is having great success with Thorium

The Indians are doing it with a knock-off of our CANDU. We could have Thorium reactors here without too much new engineering. Perhaps the Uranium mining community here in Canada is not so keen, though.

That wouldn't be surprising considering we are one of the world's largest uranium producers.

[Jabberwalker]

It's like trying to sell a plug-in electric car in Leduc.

[DrCaleb]

Khar Khar:

Oh, I hope you didn't think I was judging you badly or anything, it was just a funny coincidence that I got to hear about it twice.

Not even a little. And it was good to hear an informed opinion from someone with more knowledge than I.