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Wasn't Gates teaming up with the Chinese a few years back to look into thorium energy?

It seems like he's one of the few people setting up money dedicated to basic research in energy.

We know how to build reactors that burn nearly all nuclear waste but Democrats killed that program because they were too ignorant to understand that the design required passive safety and even succeeded in testing a worse-than-Fukushima scenario The ONLY valid concern they had was proliferation risk, and as the Russians have proven at Beloyarsk, a once through design without reprocessing still burns 70% of the fuel (you can then reprocess it at a secure site), MUCH higher than the 5% at best for current reactors and typically .7-1%. Integral Fast Reactors cost quite a bit more to build, but you more than make up for that with fuel efficiency.

There also has been renewed interest in stuff like LFTR and the like (I'm more a fan of Terrestrial's Uranium version - single fluid 30 year run before recycling - this was also proposed for the MSRE). The anti-nuclear people complain that leaves long lived actinides, but you can separate these and add them back into the fuel for the next 30 year run. The anti-nuclear folk then complain that you still have some highly radioactive fission materials, and I say yeah - and the worst of them decay to background radiation levels in 300 years, not millions. I'm also very curious about the skunk-works version of fusion. Tokamak design was never realistic and far too expensive.

Some nuclear plants can be ramped up and down ...

Some designs provide automatic load-following - from this MSR PDF:

... as the reactor temperature rises, the reactivity decreases. The reactor thus automatically reduces its activity if it overheats. Conversely, if more power is required of the reactor, more heat is drawn out. The returning colder salt increases reactivity and power levels resulting in automatic load following.

MSRs can also be manually throttled quickly due to the absence of the neutron poison problem.

That coal should be left in the ground, and not foolishly burned for energy. It is criminal to turn such a valuable concentrated carbon resource into ash, particulate, and CO2 and disperse it into our environment. Incidentally, there is more than 10 times the energy recoverable from the traces of uranium and thorium within the coal, than from combusting the coal itself. Of course, that isn't available if we mix the ash into sidewalks and roads, and such. (and it still contains some of the other nasties which didn't make it into our air or water already.)

The point is that there will never be "enough" coal if we continue using it as an energy source. It might last for a while, but conservation is still not sustainable. Conservation will only drive up prices for energy and preclude using it for energy intensive processes like recycling. Even producing the steel, concrete, and rare earths necessary for renewables is highly energy intensive and entirely dependent upon heat from fossil fuels today. Those renewables are also exposed to the elements and need to be recycled every decade or two. We are already reverting to burning trees, and it is only going to get worse until more people accept that nuclear power.

Anyway the crucial point is that nuclear provides reliable energy 24/7 through severe weather or natural disasters and with a minimal environmental footprint. They are among the most robust structures in existence, and molten salt reactors would be even more resistant to damage. (Granted, the transmission infrastructure is still vulnerable, and that is another reason why it should be minimized.) Even coal and natural gas plants can be taken off line by severe weather. During the recent polar vortex, it was nuclear which kept the lights on in New England.

So the small amount of waste (from a commercial reactor that doesn't exist yet) stored today needs to be stored until 2313 to be safe

Okay, world installed generation capacity 2010 5,067 gigawatts Let's replace it all with LFTRs.

Let's pick a hypothetical 1Gw LFTR design, most of the LFTR folks think there would be no advantage to scale larger.

5,067 of these LFTRs produce (5067*0.17) ~861 tons of waste per year requiring 300 year storage.

So with no increase in LFTRs from the 2008 power capacity, as much as (861*300)~258,300 tons of waste would be stored in this single (hypothetical) depot, which represents the waste of 300 years' total world electricity generation. Using density of lead (arbitrary) I get ~ 729,700 cubic feet, or a an array of foot-cubes 855 feet square. Or ~38 American football fields, that is if there is no stacking of these cubes. It all could fit into Yucca Mountain with room for a few more thousand years' worth to spare. That is, IF it was necessary to store it long. But really only ~300 years.

The world's nuclear waste in Yucca Mountain with LOTS of room to spare.

On second thought, let's reserve Yucca Mountain for tourism and grab 40 football fields at random.

There's also the mounting pile of lower level nuclear waste that exists regardless of primary fuel type. Don't get me wrong, it's a better option than 10000 years and bigger piles, but "only ~300 years" is deliberately deceptive.

I reserve my deliberate deceptions for less important topics than Thorium.

One of the reasons I sing the praises of Kirk Sorensen's two fluid LFTR idea is that there is really no practical life-limit envisioned for the fluoride salts themselves. Even the Hastelloy-N plumbing is potentially recyclable. While others like David LeBlanc are pursuing interesting variations such as the Denatured MSR which delays processing as might be desired in a small reactor, I believe Sorensen has decided to pursue the 'endgame' and produce the most useful and logical embodiment to the concept. His active processing column is (in my opinion as a layman) a best-fit for the scale of 1GW reactors that could power our world.

I do not completely believe the Chinese Thorium time window feint. I think there might be tactics in play to dupe world investors into thinking that Thorium energy is on the really slow boat from China, so they have plenty of time to lollygag and burn more coal. Then (I think) one day, sooner rather than later, it will be suddenly announced there is a working prototype and the Chinese firms are looking for capital.

Regardless of the Chinese effort (they really NEED this technology as do we) I'd rather see some US investors in play to build this thing that we have invested developed.

Well, unless our reactors are so efficient they can burn everything beyond iron on the periodic table we'll never hit 100% energy extraction, and I'm pretty sure the "million times the specific energy of coal" is referring to the total theoretical nuclear energy present.

There will never be a reactor that can burn anything below thorium, as the closest elements that could be fissile are unstable and decay too fast, while elements further down are too stable to fission.

And the energy density of nuclear fuel is not theoretical. Combustion of one metric ton of coal gives 8.136 MWh of thermal energy, while fission of one metric ton of fissile fuel yields 22800000 MWh of thermal energy, or roughly 2.8 million times more energy.

Still given the abundance of thorium and uranium I won't challenge your wildly speculative 30B year figure, except to point out that *extraction* is the real problem as they both tend to to be extremely diffuse. If we have to pulverize a ton of granite to chemically extract 50T of coal-equivalent nuclear fuel then we'll have a whole new ecological (and possibly economic) problem on our hands, especially if energy consumption has climbed to 1000x current levels.

The numbers are back of the envelope calculations done by Alvin Weinberg, co-inventor of the Pressurized Water Reactor and Director of Oak Ridge National Labs. It's from a paper called "Energy as an ultimate raw material" which was published in 1959. The 30B number is actually based on just the amount of extractable thorium available in the earths crust, when projecting for a population of 7 billion at western levels of energy consumption. You can find the paper here: http://www.the-weinberg-foundation.org/downloads/Weinberg_EnergyRawMaterial.pdf

Something he brings up in the paper is the mining needed. The numbers he's using assumes 3 grams of uranium and thorium per metric ton of rock. The mining required to provide enough fuel for 40 TW heat (we use ~18 TW today) would then be about 10 million tons of rock a day, which is comparable to the 6 million tons mined a day in for coal and lignite in 1953.

The number for the concentration of nuclear fuel in rocks is quite low though. The crustal average is ~13 grams of uranium and thorium. But it still mean that to supply the entire world today, we would need to mine less rocks than what coal mining 60 years ago did.

This also does not take into account that there exists highly concentrated sources available (monazites with thorium content in whole percents) that will be used first, and vast quantities of less dense sources like granites that still have 25-100 g/ton of thorium.