Nuclear fusion

I read a paper on the subject a couple years ago and the writer said that titanium was necessary for it to be practical. I have done web searches and it seems the logical answer would be mining the moon as that's where the large quantities of titanium are available. If fusion were available do you suppose it would save enough money to defray the enormous cost of lunar mining? Yes it sounds far fetched, however crazy things have paid off in the past.

MA, as far as I know, nuclear fusion has never been harnessed for peaceful uses. Makes a hell of a bomb.

We are missing a tremendous source of cheap, cheap power that is also safe beyond anything current fission plants can provide. That is thorium. Engineers and scientists at the Oak Ridge plant ran a thorium generating plant for 20 yrs w/o incident and they found that it could not do a 3 mile island or Chernobyl because of it's design and the fact that the isotope it uses is incapable of that kind of runaway.

The reason our current type of nuke plant was developed was because thorium waste didn't generate enough plutonium for bombs.

Titanium or palladium is what the electrodes for cold fusion are made from. But having a lot of moon titanium, well, that alone probably won't be enough to make cold fusion a reality anytime soon.

Engineers and scientists at the Oak Ridge plant ran a thorium generating plant for 20 yrs w/o incident and they found that it could not do a 3 mile island or Chernobyl because of it's design and the fact that the isotope it uses is incapable of that kind of runaway. Originally Posted by John Bull

OK, looks like somebody's been believing everything he reads in Wired again. I don't want to turn this into a physics class, but despite the article's claims that thorium will save the human race this just isn't so. Most of what has been in the press about thorium lately has been a load of bunk sponsored by the nuclear power industry in India (for reasons I will detail below).

Myth #1 - Thorium reactors can't melt down or explode.

By design, the fuel cycle in a thorium reactor produces or "breeds" uranium-233. U-233 makes a quite lovely nuclear bomb if one so desires and you have be very careful with a thorium reactor or it could, literally, go "boom". All breeder-type reactors are inherently dangerous in this way. Despite the claims, thorium reactors are perfectly capable of going super-critical and melting down or even just exploding outright. You can make a thorium reactor that runs at sub-critical phase and would have little risk of a true "Chernobyl" type accident, but such a reactor would be so inefficient that its cost would far exceed its usable electrical output.

We no longer allow construction of plutonium breeder reactors for these same reasons. A "sub-critical" plutonium breeder actually came very close to nuclear detonation during an accident in 1966. The resulting explosion and radioactive contamination would have pretty much taken out Detroit, Toledo, and most of the surrounding area. Uranium reactors have (slightly) higher potential for "melt-down" type accidents but I'll take that small extra risk over a full-fledged nuclear detonation any day, thank you.

Myth #2 - Thorium reactors are "cleaner" than uranium.

This is true for thorium itself, but it ignores the problem of waste.

First off, the thorium fuel cycle also produces uranium-232. This is an EXTREMELY dangerous isotope - one of the nastiest that there is - because it produces significantly more radiation than other isotopes in its class. The presence of U-232 in the spent fuel from a thorium plant makes the waste much more dangerous than that from a uranium fuel reactor. Some people consider U-232 to be equivalent to plutonium as a terrorist problem because small amounts can be used to make a very, very nasty "dirty bomb". We currently have no way to process spent fuel from thorium reactors to make it safe enough for transportation to permanent storage facilities because the U-232 is so dangerous.

Second, if you want to make an efficient thorium reactor you need to use what's called a "blanket" design. This requires the use of plutonium - another EXTREMELY dangerous isotope - as part of the fuel assembly. It's claimed that the Pu would be transmuted to other, safer isotopes in a thorium reactor and this is true to some extent. However, in order to eliminate enough Pu in the fuel assemblies to make them reasonably safe you'd have to run the reactor to what's called "burn-out" - meaning that you'd have to let the thing sit there making no electricity for 10-20 years to burn away the Pu before you can go in and reload it. In short, it ain't gonna work like people claim and the waste from your thorium reactor is gonna be some of the nastiest, most dangerous stuff man ever made.

Myth #3 - Thorium can be used in the reactors we already have.

Thorium reactors require very specialized cooling systems. You can't run them with the typical light water systems that you find in uranium reactors - they just don't work with that. Instead you have to use exotic designs like pressurized heavy water or molten salt as the coolant. This makes thorium reactors much, much more expensive to build and, if molten salt is used, significantly more dangerous to operate than uranium light water systems. (Molten salt coolants are explosive on contact with air so even a minor coolant leak becomes a damn serious problem in a real big hurry.)

It is possible to adapt some existing pressurized heavy water reactors (PHWR's) to use thorium in a blanket design. This is, however, extremely frowned upon from a safety viewpoint as PHWR's produce more waste than light water designs. Given how nasty thorium waste is this is the last thing you want to do.

In short, physicists and nuclear engineers pretty much know what they're doing. They don't use thorium for very good reasons outside of certain reactors for research and other specialized needs. It's not the wonder fuel that the magazine articles claim it is.

So why is the press so gung-ho about thorium? Because India is spending big bucks to promote thorium as a fuel.

India has very little uranium, but it has loads of thorium reserves and an extreme need for new electrical generation. The Indians want to both use and sell thorium fuel - something that the rest of the world isn't too thrilled about and has refused to help with. They are now finishing construction of a blanket-design thorium plant at Madras and have seeded thorium into the uranium fuel of some of their PHWR's in other parts of the country. In order to short-circuit the criticism the Indian nuclear power agencies have been papering the planet with news stories about their new miracle fuel.

I, for one, am particularly troubled that a country like India is building a risky reactor design using a fuel system that will produce copious amounts of waste that would be very useful for terrorism and that it is doing so without the cooperation from other countries with significantly more experience and expertise. I'm not knocking the Indians when it comes to brains. They've proven that they're as good as the next guy when it comes to high tech. I'm just not all that comfortable having this reactor go up in a country that routinely changes it's government with a pistol or a bomb instead of an election.

It's possible, with sufficient investment in research and another 20 to 30 of science, that we could someday build thorium reactors that are both safe and efficient enough to justify the cost. I wouldn't hold my breath. Uranium is a far superior and safer fuel given the technology we have now and it's still so dangerous that we're not building any more uranium plants either. And even if we do come up with a decent reactor design for thorium we still have the nasty waste to deal with. As with most "miracles" you read about in the popular press, this one is also too good to be true.

As for cold fusion, well, I'll believe it when I see it powering my water heater. Yes, there's something there. No, it ain't something that's happening any time soon. I'm hoping that my grand-kids see it happen before they die.

Cheers,
Mazo.

Mazomaniac beat me to it. But in addition to your facts being off, so is your history.

http://en.wikipedia.org/wiki/Molten-...tor_Experiment

http://www.cosmosmagazine.com/node/348/

I can't understand TTH, why you would put so much stock in a so-called public encyclopedia that anyone can change at will, and so little in articles in a magazine devoted to new tech. Here is another link to another mag.
And, btw, the references that got me started on the thorium bandwagon came from my local newspaper which, unfortunately, wants payment for links to their articles.

If you want an authoritative source then here's the International Atomic Energy Agency's review of thorium reactor science: http://www-pub.iaea.org/mtcd/publica...e_1450_web.pdf

This booklet effectively summarizes the state of thorium as a potential fuel and assesses both the benefits and drawbacks of using it. It's a pretty well balanced view of the situation - at least as it stood in 2005.

As I said above, and as this report pretty much reiterates, thorium has potential, but we're a long way from it right now. Thorium reactors have been up and running for more than 40 years. Physicists and engineers ain't stupid. If there really was such a great advantage to thorium fuel cycles over uranium we'd have built thorium reactors from the start. There's nothing new about the technology.

The excuse that we built uranium reactors because we needed the plutonium for bombs is also bunk. You can't make Pu-239 in a commercial power reactor. You need specialized breeder systems for that. The US operated a grand total of just 14 plutonium breeders throughout it's entire weapons production program - none of which were used for power production AFAIK. The Russian only had 13 although a couple of those were dual use and are still on line as generating stations. Compare that number to the 400+ commercial reactors in current operation. Nobody had to ignore thorium to make bombs. There was plenty of capacity for making weapons grade material in just the research reactors at Hanford and Savannah River to more than meet our needs.

Like I said, thorium fuel cycles are a good idea and worth exploring. But there are plenty of things worth exploring that turn out to be useless. We need a few decades of research before anybody (except the Indians) is going to be comfortable with thorium fuel.

Cheers,
Mazo.

http://www.cosmosmagazine.com/node/348/

I can't understand TTH, why you would put so much stock in a so-called public encyclopedia that anyone can change at will, and so little in articles in a magazine devoted to new tech. Originally Posted by John Bull

The 8 MWt Experimental molten salt reactor (MSRE), constructed in Oak Ridge National Laboratory (ORNL), USA in the 1960s as part of breeder reactor development programme, is the first and the only thorium-based MSR in the world. The 8 MWt MSRE had a core volume of <2 m3 and operated with a molten fuel cum coolant salt of composition 7LiF/BeF2/ThF4/UF4, at an outlet temperature of 6500C and demonstrated: (i) the chemical compatibility of graphite moderator with fluoride salt, (ii) the removal of Xe and Kr from the fuel (iii) conversion of 232Th to 233U and in situ fission of the latter. The MSRE generated database on the physical, chemical and corrosion properties of molten salts, worked with different fuels, including 235U, 233U and plutonium during 1965–1969 and paved the way for the conceptual design of a molten salt breeder reactor (MSBR) of 1 000 MW(e) in the mid 1970s. The graphite moderated MSBR–1000 was designed for achieving thermal breeding in 232Th –233U fuel cycle (breeding ratio ~1.06) and generation of electricity using a steam cycle. The proposed fuel core had a volume of 48.7 m3 with a molten salt composition of 71.7 mole% Li7F, 16% BeF2, 12% ThF4 and 0.3% UF4 and 233U and Th inventory of ~1 500 kg and 68 100 kg respectively. The MSRE was shutdown in December 1969 and the MSBR–1000 was not constructed.

http://www-pub.iaea.org/mtcd/publica...e_1450_web.pdf

Happier? It was still active five years, not twenty.

It may be imperfect at this time, I'm neither a chemist nor a phyicist but the reports I read in the newspaper looked pretty damned good to me. If there is still work to do, sobeit. But, in my mind, almost anything is better than the nuke plants we have now.

I can't understand why anyone would want one of those in your backyard or within 200 miles of your home. Instead, give me a dirty coal plant any day.

Better yet! Let's have fuel cells in our basements to generate all the power we need for our homes and electric cars etc. No more power outages, unless you forget to fill the tank with hydrogen - assuming you're not using natural gas or propane.

More on the subject:

http://www.slate.com/id/2258112/entry/2258878/

I have to say that I'm on the fence about the cold fusion stuff.

I started out as a physicist and I've been following this thing from the very beginning. I actually met one of the original cold fusion guys at a conference before he got drummed out of the science. He did not seem at all like the crack-pot people later made him out to be. I've also seen the latest data from the Navy's cold fusion labs and there does certainly seem to be something to it.

On the other hand, the skeptics correctly point out that cold fusion would violate one of the most fundamental laws of physics we know of. Not that it would be such a shocker that humans might be wrong about the laws of nature. But I gotta admit that it's a pretty long leap to explain how cold fusion could possible occur without a significant rearrangement in our understanding of the atom and quantum mechanics.

My own opinion is that there's some seriously weird shit that happens at the quantum level that we are still way too dumb to understand. I don't like the skeptical responses based on the premise that if we don't understand something then it can't possibly be true. It may well be that there's a quantum-level effect that explains cold fusion and we simply don't know about it yet. Nothing to do about that but keep studying it.

In the end I would not be surprised at all if cold fusion turns out to be true and someday proves to be a nice little energy source. That said, I'm not going to be filling the safe deposit box with palladium bars waiting for the big move on cold fusion metals. I think bridges in New York City or stock in Arizona gold mines would prove to be a better investment.

Cheers,
Mazo.

I can't understand why anyone would want one of those in your backyard or within 200 miles of your home. Instead, give me a dirty coal plant any day. Originally Posted by John Bull

There's an interesting perspective about nuke vs. chemical that a lot of people don't realize:

If a nuke plant has a problem you know about it right away. Radiation is very easy to detect. Even tiny amounts are easily picked up with cheap equipment that gives you an immediate warning. If something gets loose from a nuke plant you know the second it happens and you can do something about it before people get hurt. The response is almost instantaneous.

On the other hand, if a chemical-fired power plant has a problem it often takes years before anybody figures it out. Coal plants are notorious for pumping lead and mercury into the air and contaminating everything within a fifty-mile radius. Problem is, you have no idea if that coal plant in your back yard is pumping crap into your lungs unless you're willing to spend serious cash and wait three months for the test results to come back. Most problems at chemical-fired plants aren't detected until people in the area have spent years sucking in heavy metals.

I'm no fan of nuclear power as it exists today, but I at least gotta give credit where credit is due. When there have been serious accidents at nuke plants they've been dealt with swiftly and effectively. Accidents at nuke plants are obviously more serious than anything you get out of a coal plant, but at least you know when to run.

Cheers,
Mazo.