Molten Salt Reactors • Hacker News Board

Re: Molten Salt Reactors

#71

Post by martinald » Sat, Jul 13, 2019, 12:06 PM UTC

jillesvangurp wrote: post #50

acidburnNSA wrote: post #38

Earlier quoted context omitted.

Are you suggesting that variable renewables plus batteries will approach prices that are... too cheap to meter? Looking at current cost VRE trends, when variable sources contribute up to 4% of world energy, and surrounded by massive amounts of cheap but high-carbon natural gas, and assuming that the trends will just continue exponentially downward without serious complication, is optimistic. Cost of integration of va…

Yes. Not indefinitely of course but we've seen nothing yet and there's enough in the research pipeline to suggest clear trends over the next two decades in terms of cost improvements, efficiency improvements, cheaper materials, etc. That 4% you mention was less than 1% not so long ago and will be closer to 40% not too long from now. Such is the nature of exponentials. IMHO 5X cost reduction is basically a done deal e…

This is very very optimistic. While the prices of panels are going down the rest of the cost isn't (land, permitting, installation labour, etc). And panels are only a small proportion of the cost now.

There is also only so much more efficient the panels can get per sq m. Right now we are approaching 20% efficiency, so the idea that they are going to get 10* cheaper with complete ease seems to be pushing it.

Regardless solar and wind have a lot of externalities that aren't really priced into these 2c/kWh PPA prices. If you need to build a fleet of natural gas plants that are only operational 10% of the time and therefore cost 50c/kWh to take up the slack from low solar days it needs to be priced in somehow.

Re: Molten Salt Reactors

#72

Post by simion314 » Sat, Jul 13, 2019, 12:44 PM UTC

jillesvangurp wrote: post #32

The elephant in the room with any kind of fission reactor is that they are going to need a lot of security. Even when the fuel and waste product is not weapons grade uranium, it's still highly radioactive and a great source of material for a dirty bomb. Basically anything that goes boom combined with small amounts of radioactive material and a bit of wind is a great way to depopulate e.g. large cities. So, having lot…

You could say the same thing about any airplane, even small planes or drones could be filled with explosives and hit strategic targets like a chemical factory.

You can place the nuclear generators in police stations, military bases, other locations that are already protected, there is no need to have a small nuclear generator in each electronic device like in Fallout.

Re: Molten Salt Reactors

#73

Post by pfdietz » Sat, Jul 13, 2019, 12:46 PM UTC

Tuna-Fish wrote: post #59

Mirioron wrote: post #54

Earlier quoted context omitted.

Aren't roof solar panels very inefficient? They can't track the sun and you can't have good density from them either. Furthermore, they don't work for office buildings and apartment buildings. > Not to dismiss it entirely but arguing cost increases seems a bit far fetched in light of current trends in the market. I think what the parent was saying is that because solar and wind don't reliably produce energy, we will…

> Aren't roof solar panels very inefficient? They can't track the sun We are well past the point where tracking the sun was desirable. The apparatus that allows solar panels to track the sun is now much more expensive, especially when you consider the maintenance costs, than just using more static panels.

Actually, most new utility scale PV in the US southwest is now using single axis tracking systems. The advantage here is that the power curve is flattened over the day, which both makes better use of the inverters and pushes more production into higher value time periods.

Re: Molten Salt Reactors

#74

Post by pfdietz » Sat, Jul 13, 2019, 12:48 PM UTC

jabl wrote: post #57

jillesvangurp wrote: post #50

Earlier quoted context omitted.

Yes. Not indefinitely of course but we've seen nothing yet and there's enough in the research pipeline to suggest clear trends over the next two decades in terms of cost improvements, efficiency improvements, cheaper materials, etc. That 4% you mention was less than 1% not so long ago and will be closer to 40% not too long from now. Such is the nature of exponentials. IMHO 5X cost reduction is basically a done deal e…

> That 4% you mention was less than 1% not so long ago and will be closer to 40% not too long from now. Such is the nature of exponentials. But such is not the nature of the logistic function, which is usually a more accurate model of how technologies penetrate. (yes, in the beginning it looks like an exponential)

There is a final cost decline "baked in" to the curve, though. That's because the lifespan of solar now for calculations is maybe 20 years. Anything more would not make sense as costs are declining so fast. When the tech matures, the final part is extending the lifespan to 40-60 years.

Re: Molten Salt Reactors

#75

Post by pfdietz » Sat, Jul 13, 2019, 12:50 PM UTC

audunw wrote: post #52

Mirioron wrote: post #51

Earlier quoted context omitted.

Renewables have the problem that the larger the portion of your power that's generated through these renewables, the exponentially more storage you need. It's not a linear relationship, because you can have weather that doesn't cooperate for long periods of time, but the power can't go out. Another issue is that solar and wind aren't really suitable everywhere. The further north you go the less economical solar becom…

What’s happening right now is that renewables are being paired with an increasing number of gas power plants. Since gas power can ramp up so quickly they’re a good match until storage can take over. So I think we already have the solution to the problem you’re describing: just pay to maintain a decent amount of the existing gas power plant. If they’re only there for backup, the impact on CO2 emissions will be negligi…

And if people complain about the peakers releasing CO2, they could be converted to use hydrogen. Hydrogen can be produced either from renewables + electrolysis, or from 24/7 plants reforming methane to hydrogen with the carbon sequestered and the hydrogen stored underground for later use.

Re: Molten Salt Reactors

#76

Post by pfdietz » Sat, Jul 13, 2019, 12:53 PM UTC

alex_young wrote: post #36

kragen wrote: post #29

Earlier quoted context omitted.

I don't know enough about storage costs to calculate them well, although several recent low-priced PV power-purchase agreements have included storage components, including the one we're talking about here. I look forward to seeing your calculations!

Perhaps this is hard to calculate because it's unbounded? Typically: Known costs for (anything) Maybe there's something wrong with my math?

I hope you aren't making the assumption that storage = batteries, then arguing because weeks and months of batteries would be needed, it's impossibly expensive.

Re: Molten Salt Reactors

#77

Post by twic » Sat, Jul 13, 2019, 1:10 PM UTC

wffurr wrote: post #64

dgudkov wrote: post #42

Earlier quoted context omitted.

>It couldn't win against coal on a balance sheet It did win against coal on a balance sheet. It's the environmental concerns that stopped nuclear from proliferation, not the economical.

And the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal. This is still well within the realm of economics.

> the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal

It very much did happen for coal. That's what this whole global warming business is about.

Re: Molten Salt Reactors

#78

Post by Symmetry » Sat, Jul 13, 2019, 1:19 PM UTC

pweezy wrote: post #66

> Molten salt fuels were first conceived of in the late 1940s, when people began thinking of nuclear powered airplanes! > The idea was to have very long range bombers in the air at all times I had never heard of this idea, and thought it was super interesting. Imagine aircraft that could stay in the air indefinitely (for some practical purposes), carrying massive loads without fuel being a concern. Similar to nuclear…

In the long run nuclear jets could be really useful for the exploration of planets that don't have free oxygen in the atmosphere like Venus, Saturn, etc.

Re: Molten Salt Reactors

#79

Post by DennisP » Sat, Jul 13, 2019, 1:26 PM UTC

achalhp wrote: post #39

>Tritium production: If lithium is used in the salt, tritium will be produced, Not a disadvantage for all MSRs. Both lithium and beryllium can be avoided. FLiBe is required for efficient MSRs and MSBR. >Mobile fission products It is the only disadvantage common to all molten-salt reactors and all fluid-fuel reactors. Pumps and pipes have to handle a hot radioactive liquid. > Material Degradation Common to all nuclear…

Regarding pumps and pipes, the Moltex design avoids them entirely. Liquid fuel is contained in vertical fuel rods, open at the top to allow escape of gaseous fission products (some of which are strong neutron absorbers). The pipes are mostly immersed in a pool of molten salt coolant.

https://www.moltexenergy.com/

Re: Molten Salt Reactors

#80

Post by jddj » Sat, Jul 13, 2019, 1:36 PM UTC

twic wrote: post #77

wffurr wrote: post #64

Earlier quoted context omitted.

And the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal. This is still well within the realm of economics.

> the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal It very much did happen for coal. That's what this whole global warming business is about.

internalized by regulation would imply that the externalities (eg. Climate change) are effectively factored into the cost of producing power by burning coal due to the cost of complying to imposed regulations.

This still isn't the case in most of the world.