Thorium Fission: Overcoming Hurdles to Power

[#Thomas#]

Greetings,

I am curious, what is keeping us from having thorium fission reactors? What are the hurdles that we need to overcome?

 

[Doug Huffman]

Economic. Uranium infrastructure is extant. Technological, molten solid coolant is problematic.

 

[Blackberg]

What else are we going to do with uranium anyways.

 

[boneh3ad]

There's also the political angle. Just as nuclear power was starting to get popular again, Fukushima Daiichi happened, which is a real shame. If I recall, the thorium cycle produces less waste, is more abundant on the planet, and cannot be weaponized (or not very easily), so it has little to no proliferation concerns.

 

[SteamKing]

Greetings,

I am curious, what is keeping us from having thorium fission reactors? What are the hurdles that we need to overcome?

One big obstacle is that thorium itself doesn't fission. Thorium-232 captures a neutron and then decays into U-233, which is capable of fission. However, this decay process involves the emission of gamma radiation, which makes handling irradiated Th-232 material very dangerous.

http://en.wikipedia.org/wiki/Thorium_fuel_cycle

The irradiation of thorium also produces U-232, which is not fissile, but which also produces gamma rays as it decays.

All in all, thorium is not the cheap nuclear fuel which has been portrayed by some.

 

[#Thomas#]

Alright then, 2 more follow up questions:

1) Does it really have to be molten solid coolant? Whats wrong with using thorium with water coolant? And why is liquefied solid coolant such a big problem, I know of at least 1 place where it is in use, the solar tower in spain...

2) How long is the decay of the thorium waste compared to uranium?

 

[Doug Huffman]

Fission byproducts, waste, are a spectrum. A long lived thorium waste product is 232 Pa with a half-life of 32,760 years. But a long half-life makes for a lower specific activity.

Molten coolant is often the solvent for the dissolved fuel.

Coolant other than water will become activated, radioactive, a leak then is a leak of solidifying radioactive material. See the Monju disaster.

 

[#Thomas#]

Ahh, yes, makes sense, to stiffen up is a lot better than to spill around. But what are the problems with implementation? I know that there's a solar tower in spain that uses molten salt to generate power when there is no sunlight, like at night.