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Comment by epistasis | Hacker News Reader

I think you are right, that the power of science fiction has clouded people's judgement of what the future will really be like.

Today, I don't think we can consider nuclear a good or modern energy system when compared to something like solar or wind. Nuclear is used as a heat source to boil water and power a turbine, and throws away half of its thermal energy as waste. disposing of that waste heat is becoming so difficult that reactors in France power down in hot days. This is not some sort of super futuristic power source!!

While small modular reactors are the only near term hope for nuclear, I think that fission is not a good fit for terrestrial power. And fusion is no better until we have direct conversion or some other massive tech leap.

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Good point about heat waste disposal. That's why you almost always see nuclear reactors along lakes/rivers/oceans, which is bad for other reasons as we saw with Fukushima, and all of that hot water being released wreaks havoc with riparian/marine ecosystems. Nuclear has downsides beyond the most obvious one, that of the risk of fallout.

> I think that fission is not a good fit for terrestrial power.

Heh, it's even worse off-planet. If you think dumping the waste heat is hard when you have access to an atmosphere/large bodies of water, wait until you try it when you don't!! ;)

Palo Verde uses cooling ponds filled with grey water. Per Wikipedia, it’s the largest generation plant in the US. It’s not an impossible problem.

Around 2008-2010, ORNL published a paper describing how the cheap electricity and waste heat from a nuclear plant could be used to capture carbon from the air and create carbon neutral fuels for transportation. So again, if we were looking at a holistic picture, we could definitely improve the overall climate situation with nuclear.

How is there "waste heat" in a power plant that is designed to produce heat?

Thermodynamics!

> The efficiency of the Rankine cycle is limited on the cold side by the lower practical temperature of the working fluid.

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

> The efficiency of even the best heat engines is low; usually below 50% and often far below. So the energy lost to the environment by heat engines is a major waste of energy resources. Since a large fraction of the fuels produced worldwide go to powering heat engines, perhaps up to half of the useful energy produced worldwide is wasted in engine inefficiency, although modern cogeneration, combined cycle and energy recycling schemes are beginning to use this heat for other purposes.

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

... the power plant is designed to produce electricity, not to produce heat. If it was designed to produce heat then it wouldn't need the turbines.

The heat is waste. For the same power generation, you want to minimize the amount of waste heat as much as possible.

Solar and wind are still not good at providing a baseline load, especially in winter where the power consumption is higher. France slows down some reactors during heat waves due to environmental regulations not allowing power plants to heat the river past a certain threshold, not because disposing excess heat is inherently difficult.

Why is baseline supply an issue? The only power supplies that are needed in a system are dispatchable aka peak. If your peaker plants can handle the entire load then you don't need any other type of power. You may want to have supplies that are cheaper and/or greener, but you don't need them.

So until Nuclear plants can provide dispatchable power, they're competing against the much cheaper solar/wind power, not against natural gas or batteries where the cost disadvantage isn't as bad. Nuclear theoretically could be dispatchable, but current designs aren't.

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