Topic: Thorium power, how is it going in the US? - page 8. (Read 11262 times)

I understand that you have some kind of anxiety problem and want to manage it by controlling the facts you are exposed to but you really should really find a more productive way to deal with it.

A therapist could help you out with the anxiety and a physics textbook could rectify the deficiencies in your understanding of how nuclear reactions work.

That is bullshit.

The situation is so completely different than what happens in a traditional reactor that it's deceptive to use the same word to describe it.

First of all the reactor couldn't operate at full power with no cooling for more than a very short period of time because of physics. High temperatures shut down the fission reaction.

Even if there was fracture in the reactor vessle or associated piping you wouldn't get an explosion, fire, uncontrolled criticiality resulting in a "China Syndrome", or massive release of airborne radioactivitiy

There would be a mess on the floor which would cool and freeze into an inert solid.

nit-picking aside the definition still holds true, that is the reactor is operating on close or above peak output with the cooling inoperable. Once that situation occurs and you can't do anything about it you'll have a meltdown.

What's melting is vital parts of the reactor itself not the fuel. That could be gas for all I care.


I am speaking of current state of the art, since this is about technology even beyond that I think that is only fair. I doubt this article was about a state of the art powerplant.
Yes there will always be some danger associated with it, but till I see an example to the contrary I maintain my opinion that nuclear power is more dangerous.

The safest commonly used power source is hydropower and while it still is harmful to the ecosystem it has the least impact on human civilization.

Please explain what a "meltdown" means in the context of a liquid fueled reactor?

Read the Wikipedia article; it covers most of the basics: http://en.wikipedia.org/wiki/LFTR. Take particular note of the "Safety" section. There are no high pressures in this design, nor flammable metals which generate explosive hydrogen gas when they get hot enough (zirconium).

There was a test reactor that was successfully built and operated from 1964-1969, based on a set of ideas that had been floating around the Manhatten Project engineers since 1945. All the possible show-stoppng engineering challenges were solved during that set of experiments.

The LFTR design can burn a wide variety of fuels, or even a mixture of them. It could be started on waste from existing reactors, or on uranium recovered from dismantled nuclear reactors, or on the same mined and enriched natural uranium that power existing reactors. It can also burn plutonium. It could take all the waste that's building up around existing plants, recover more energy from it, and convert into something that only requires 300 years of long term storage instead of 10000.

The only reason this technology didn't take off in the 1960s is because of politics. There is no engineering or technological reason this shouldn't have been done 40 years ago.

http://www.youtube.com/watch?v=bbyr7jZOllI

Great post.  Too bad the world of nuclear moves so slowly, Thorium would have been/would be/will be a great stepping stone from fission/fossil fuel to fusion and solar (solar includes wind, tidal and hydro for me since they are all cycles powered by the sun)

The politicians don't care, as long as they get money to campaign from industries.  If one were to do a kickstarter for a project like this all the funds would end up being spent in Washington DC and Ottawa.  Countries like Iran should have taken on the Thorium dream instead of Uranium, they could take over in energy technology because they would be building a whole system from scratch.


Which conventional power is safe?  Greenhouse emissions aside, I just heard a story about cows being exposed to the exhaust from Coal fired generators can get cancer.  Then when human's eat the cow cancer antibodies and protein (which are not destroyed by cooking) they cause problems.  Anyone who thinks there is such a thing as "safe" power is dreaming.

My problem is that the people on wikipedia claim that meltdown is impossible, and that is simply not true.
It's the usual thing with some fanatic proponents, especially in nuclear power... claim one thing and once you research it it turns out to be an exaggeration.

This is probably safer than the reactors running in current powerplants, but nowhere as safe as conventional power.

The main problem with any reactor imo is that is has to run as hot as possible in order to archive higher Carnot Efficiency. So they are constructed to the limits of what the material can withstand. With conventional power you have a limit on the temperature you are able to generate in the first place, not so with nuclear power. It needs a technology which is able to withstand such high temperatures to be able to leverage the higher efficiency in the first place. Steam is not it. Thermoacoustic devices might do it for example.

Excelent post. When I've made more BTC, I'll send you a tip

Would the starter uranium be required for testing during the design/construction of the reactor, or could we do it all from theroy?

Yes it will require red tape unless you plan to buy enriched uranium or weapons grade plutonium from some illegal arms dealer.

The natural istope of thorium isn't fissionable.  It is however "fertile" which means it can by neutron capture become an unstable fissionable isotope.  



The Th-232 is easy to acquire.  Just dig some out of the ground.   You don't even need enrichment.   The "n" in the equation is deceptively simple but the cross section of an atom is very small so most neutrons simply "miss" and you need a LOT of neutrons (like quadrillions per second) and the only source which is sustainable and cost effective is enriched uranium or plutonium.

A thorium reactor doesn't fission thorium.  It "builds" uranium (which it fissions very similar to a uranium thermal reactor) from Thorium as needed in real time.  However it needs a critical mass of uranium/plutonium to act as a "spark plug" and produce enough "n" in the equation above to produce a sustainable chain reaction. That fissionable critical mass produces enough neutrons to convert some small % of the Thorium fuel to Uranium and those Uranium converts more of the Thorium to Uranium. 

So once "started" the reactor is self sustaining but you need that "spark plug".  Without it you simply have a cold inert reactor.


Honestly Thorium reactors are the only nuclear power which makes any sense.   The waste is less toxic, has shorter half lives, and proliferation resistant  (waste is "contaminated with a high % of U232).   The fuel is cheaper, more abundant, and doesn't require expensive (and polluting) enrichment.  The fuel cycle is more efficient which means less mining is necessary per unit of energy.  The reactors are safer, requires less refueling, and suffers less neutron embrittlement.   The fuel also has some nice physical properties, higher melting point, non-oxodizing, and better thermal conductivity, which make it safer in an "loss of coolant accident".

So given all that why did we use a uranium fuel cycle .... Simple, you can't build bombs with thorium.  The sad thing is the uranium legacy was for nothing.   After the DOD co-opted the DOE nuclear program and steered (forced ?) development away from Thorium and towards weapon friendly Uanium  it become obvious that power reactors would never be able to produce the quantity of weapons grade material necessary.  So we built dedicated "bomb reactors" optimized for the production of weapons grade plutonium.   The rest of the world copied the US model since the R&D, designs, and expertise already existed and Thorium being theoretical and untested got sidelined for 60 years.  

Do you think we have the tech sorted today DeathAndTaxes, or that it wouldn't be a problem to develop it?

Why would they need the red tape at all being that there a very different thing to build, in the same way that a remote control car doesn't need a driving license?

Wouldn't it just be worth doing anyway? It's not like anyones got to know, it's not like trying to build a uranium power station, which would be near impossible to do in secret and have many more complexities and take up a lot more space.

Although I guess KickStarter would make it so much more transparent.

True although stopping active fission is relatively easy.  The harder to solve problem is decay heat.  Modern reactor designs employ passively safe measures which are designed to keep reactor cool (dissipate decay heat) without the need for pumps and/or electrical power.

Thoruim reactors however don't require many concessions to safety, like building a huge dome around them, because they can't explode/vent dangerously, or containing uranium carefully, because they don't contain any uranium and much of the earth is made of thorium so it's quite safe.

If they worked in the same way uranium nuclear reactors do there would be no point at all.

I severely doubt this is any safer from the meltdown problem than other designs.

Since the "primer source" is nothing but some highly radioactive material all that has to happen for a meltdown scenario is that the mechanism regulating the link between it and the reactor to lock up. It's exactly the same problem.

LOLZ.  The tech isn't the problem.  The red tape would strangle your kickstarter project in it's craddle.

Hell approval for construction of the next conventional nuclear reactor has taken .... 17.5 years and final approval hasn't even been given yet.  The company has broken ground but if final approval is denied or delayed another decade they are just building a multi-billion foundation for nothing.  Well maybe they can use it for the first exahash bitcoin farm in 2042.

Just to put this into perspective this is an existing nuclear utility with 40 years experience building a modern safe reactor (AP1000 over a dozen under construction in China) which is an evolutionary upgrade from an existing designs (with millions of operating hours and no serious events) at an existing nuclear power site (which already has two operating reactors and was originally approved to have eight).  Throw in the fact that the utility, the powerplant and the new reactor proposal has nearly unanimous support of the local community.    That ultra-conservative baby step has taken almost two decades.

Clean - Totally
Safe - Although not edible.
Recycles - Can make harmful nuclear by-products safe.
Small - Could be pint glass sized for 600MW.
Fuel lasts a long time.
Fuel is Abundant.
Produces much more power.
etc...

Unfortunatly $1.8 billion for the first reactor.

Obama is on board, he hopes 5 years. China love this too. China and the US are even working together, although I don't know to what extent.

If this will have the usual pace of a snail pulling the tortoise, is anyone up for a KickStarter project? With crowdsourcing as well, we could outpace their efforts.