[webdevatlurk]

I have no idea if molten salt reactors are as awesome as this website represents them to be, but I thought the following point was interesting:

"light water reactors can use only about 4% of their available energy."

They're comparing with 1960s reactors designs, so maybe more modern water reactors are more efficient. But, it's still amazing to me that there's that much more energy that we could potentially harness from the fuel.

[DennisP]

It's because light water reactors use thermal (i.e. slowed down) neutrons, which can only fission U235, and that's 0.7% of natural uranium. We enrich the fuel to at least 2% U235 and that's mainly what the reactor can use.

The reactor also gets about a third of its energy by fissioning plutonium, which is formed when U238 absorbs a neutron.

Without reprocessing, a light water reactor can't even fission all the U235, because some of the waste products of fission reactions are strong neutron absorbers. (If you're in France you can reprocess the waste to remove the fission products.)

Molten salt reactors remove most of the fission products continuously. Some MSRs, like Terrestrial Energy's, are still thermal reactors using uranium, so they're about as efficient as France.

Some MSR designs use fast neutrons, which are able to fission more plutonium along with other transuranics and U238. Others use thorium fuel, which can be completely fissioned by thermal neutrons. (First thorium absorbs a neutron and becomes U233, then that fissions. Heavier non-fissile isotopes aren't created in the first place.)

[comicjk]

Currently the fuel is very inexpensive - a tiny fraction of the total cost of the electricity produced. Most of the cost is the initial capital, and most of the ongoing cost is the (highly specialized) labor. A new reactor design that saves fuel is not really what the industry needs.

[lightgreen]

According to Wikipedia current uranium reserves will last for 135 years. It would be 13 years if we increase energy production in nuclear plants 10 times to replace coal and gas.

So even if fuel is inexpensive now, it can become expensive quite quickly.

https://en.m.wikipedia.org/wiki/Peak_uranium

[thrower123]

I believe Peak Oil was supposed to happen a dozen times now; we keep finding more when it becomes worthwhile to do additional exploration, and extraction technology keeps improving. Maybe uranium is different, but I would believe it when I see it.

[mikekchar]

As per wikipedia: "Peak oil is the theorized point in time when the maximum rate of extraction of petroleum is reached". You can still discover new sources of petroleum after "Peak Oil", but the idea is that you will never find enough to increase the maximum extraction rate.

What we see as consumers is conflated by the fact that there are self-imposed limits on extraction by OPEC designed to raise prices. Due to various political situations, those limits have been slowly removed. When you see predictions of "Peak Oil", often they are based on existing production and not maximum production (and hence are nonsense).

I'm not aware of any literature that attempts to speculate on current maximum production capacity. Probably it exists, but I certainly can't find it. Whether we have hit "Peak Oil" already, or whether it will come in the future, I don't know. A lot of that kind of stuff is politically very sensitive and oil companies/OPEC are understandably reluctant to be straight forward with the data.

Finite resources eventually run out. When you don't know how much you have, it's tempting to assume that because you are finding more, you will continue to find more. There is no real guarantee of that. It's a risky strategy.

[imtringued]

EROI has been driven down with every single year. One day it will take more energy to extract it than the energy we receive from it but we won't run out.

[nickik]

As with all of these 'Peak' this simply wrong. I don't know how many more times we have to go threw this cycle before we can stop with these peaks.

[mmt]

What about the ongoing cost of waste and eventual cost of decommissioning? Are those affected by quantity of fuel used (or, more specifically, by Transatomic's design)?

[foxyv]

When a reactor is built in the US, the operator will start paying into an account for waste disposal. This is included in the cost of energy production. Since high level waste quantities are pretty low for nuclear reactors (About 27 tons a year)[1] disposal of fuel isn't the largest issue.

Decommissioning on the other hand is remarkably expensive because of secondary nuclear waste like contaminated reactor vessels and concrete make up 99% of the nuclear waste.

[1] http://www.world-nuclear.org/information-library/nuclear-fue...