Thorium backed as a 'future fuel'

http://www.bbc.co.uk/news/science-environment-24638816

by ximeng • 13 years ago

105 36 13 years ago

bbc.co.uk

wil4213• 13 years ago

Key words: "I’m a lawyer not a scientist but in my opinion..."

Sounds like he's not a lawyer but a politician.

arethuza2• 13 years ago

"the former Swedish foreign minister" - right before the bit you quoted.

wil4213• 13 years ago

My point was I dont want to listen to a lawyer or politician. Give me the words of a scientist, preferably a nuclear one.

hygap2• 13 years ago

As far as I was aware the reactors at Fukushima shut down correctly as soon as the earth quake occurred. While the crisis definitely continued I think the reporters portrayal of the reasoning is somewhat misleading. As it insinuates it was the fuel rods inability to control the reaction was the problem, rather than the cooling system's inability to deal with the excess heat generated post shut down.

"When a uranium reactor overheats and the fuel rods can’t contain the chain reaction, as happened at Fukushima, the crisis continues."

mnw21cam3• 13 years ago

Yes, the reactor shut down correctly. However, in a working uranium reactor, there will be large quantities of fission products that are also radioactive and are therefore spontaneously decaying in a long chain towards stable isotopes. Some of the fission products are quite short-lived, so for quite some time after the reactor is shut down they will be generating a lot of heat.

What happened at Fukushima is that the cooling system that needs to keep running for weeks after a shutdown broke. This caused the water in the reaction vessel to boil, uncovering the tops of the fuel rods, which then got so hot that they broke steam into constituent hydrogen and oxygen (which caused the subsequent explosions) and they cracked open, releasing some nasty isotopes into the coolant water. The coolant water with nasties in is what has been leaking out into the environment.

hygap2• 13 years ago

I agree, well expanded. The mechanism seems to be a lot safer in a liquid thorium reactor where the thorium drains away into a safety chamber in the event of a similar disaster.

I just wanted to point out the events the article portrays are incorrect and the writer could have conveyed this message without insinuating there was a meltdown due to the failure of the (wait he says fuel rods not control rods....) O well.

soperj• 13 years ago

There has been some articles indicating that the containment block might have already been compromised prior to the tsunami.

gngeal• 13 years ago

A Swedish guy rooting for thorium? Odin's beard, how surprising!

(Jokes aside, I've been in love with this idea since my high school studies of nuclear engineering. I know a lot of these things didn't pan out eventually, but I still find that sad.)

apendleton• 13 years ago

As has been typical over the last year or so of writing about thorium power in the press, this article glosses over the difference between using thorium in a conventional water-cooled reactor and using thorium in a liquid fuel configuration, which is what lots of thorium advocates want. Many of the benefits (particularly in terms of increased fuel burn, and automatic shutoff in the event of failure) are dependent on the LFTR design, but one could easily read this article and assume they also apply to the MOX design being developed in India; for the most part, they don't. Certainly, you get some of the benefits of thorium fuel in that configuration (more abundant fuel as compared to uranium, for example), but it's an important distinction that needs to be part of the conversation.

jjoonathan• 13 years ago

The Thorium publicity spree is about rebranding nuclear power, not about having a technical discussion. If the only message that gets across is "new thorium reactors are safer than old reactors," it's still a win for everyone involved because this message is a subset of the truth (new reactor designs are safer than old designs in general).

I don't think the public properly appreciates the extent to which nuclear safety mechanisms have improved dramatically over time, not least because a design's safety profile is largely "frozen in" when it is built, so we occasionally see a half-century old "bug" rear its head (Fukushima). The public sees it as evidence against the safety claims of future nuclear plants, even though it is not (quite the opposite: building newer, safer plants lets us retire the old, dangerous ones). Rebranding might get them to take another look.

Actually, I think including as much detail as the parent post did might be a net negative because it muddies the core message. Simplicity and straightforwardness are key.

mcv• 13 years ago

One big thing that always gets mentioned in any Thorium discussion is that originally, Uranium was chosen over Thorium exactly because it is inherently less safe; it can be used to make bombs, which is what all the nuclear powers were really interested in. So Uranium research got lots of government support while Thorium research was dropped.

I'm no nuclear physicist, so I have no idea if Thorium really is inherently safer than Uranium, but if it is, I'm all for it. But if it is indeed safer and cheaper, and old tech that's been ignored for decades, then why aren't there new Thorium reactors popping up all over the place? Or are there? Is anyone still investing in the Uranium/Plutonium cycle?

swashboon2• 13 years ago

Does anyone know if any substantial gains have been made in what I believe is the number one problem with Thorium reactors: that moving liquid salt through the reactor is extreamly corrosive and parts don't last very long (under a year iirc)?

DennisP2• 13 years ago

Oak Ridge was actually pretty successful with Hastelloy-N, which pretty much solved the chemical corrosion issue in the absence of neutrons. There was still some concern about the neutrons causing problems, but Oak Ridge thought they'd figured out how to solve it by adding something extra to the alloy. It hasn't been tested long-term though.

not_that_noob• 13 years ago

See below. It was tested for 9 years and didn't show significant corrosion. The leak happened not in the Hastelloy but in a ceramic seal between the alloy components. An appropriate seal or coating on the seal may be able to fix this issue. Overall, I'd say the containment issue is as you say mostly solved.

Here's the report:http://moltensalt.org/references/static/downloads/pdf/ORNL-T...

known• 13 years ago

The ratio of plutonium needed to seed and convert thorium into fissionable uranium-233 is very high (4:5)

DennisP2• 13 years ago

But you only need it to start the reactor.

Thorium backed as a 'future fuel'

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