Ultra Safe Nuclear • Hacker News Board

Re: Ultra Safe Nuclear

#191

Post by Klinky » Thu, Sep 17, 2020, 9:20 PM UTC

yongjik wrote: post #123

xibalba wrote: post #3

Assuming nuclear truly can be ultra safe, how do you convince a public that has seen Chernobyl, Three Mile Island, and Fukushima to get on board? Particularly when the "competition" (solar, wind, etc) has such a strong tailwind.

Ever heard of Kessennuma [1]? You probably don't remember the name. When the 2011 Tohoku Earthquake hit, an oil tank ruptured, caught fire, and burnt for four days. According to [2], 1,152 people were killed, with additional 214 missing. That's a similar level as Fukushima's expected casualties, probably more. But nobody talks about Kessennuma, and nobody brings it up as an evidence that fossil fuels are an inherentl…

Is the point you're trying to make that nuclear and fossil fuels can both be dangerous during a natural disaster? I don't think anyone will dispute this.

Re: Ultra Safe Nuclear

#192

Post by OliverJones » Thu, Sep 17, 2020, 9:20 PM UTC

mehmeta wrote: post #169

What would be the ballpark cost for this reactor producing 5MWe?

It would be great to know the capital and ongoing maintenance cost per MWe of load, and the lifecycle cost per gWh. This product is pitched at remote sites, so presumably the costs aren't low enough (yet?) for places where power grid connection is an option.

Re: Ultra Safe Nuclear

#193

Post by wazoox » Thu, Sep 17, 2020, 9:21 PM UTC

ceilingcorner wrote: post #60

I find it a little odd that a site called Hacker News is so bullish on nuclear power. Could there be anything less hacker than a centralized, exclusively government owned and operated source of power? No thanks. I’d rather put more resources into solar, wind, and other sources of power that don’t depend on the government to not explode and irradiate the immediate area for hundreds of years.

Centralisation is more efficient. Centralisation is good. Because of centralisation and interconnection (power grid is a network) we only need to have power generation capacity equivalent to less than a third of the total power of all electrically powered machinery.

If every household had to produce its own power, we would need either to carefully plan our usage, or to have as much production capacity as our peak usage, so globally we'd have 3 times as much production capacity as we have nowadays. That would amount to a tremendous waste or resources, an awful misallocation... It would be absolutely anti-ecological.

The more you're using unpredictable energy sources such as wind and solar, the more you need backup power (batteries, gas, coal, nuclear, etc). Case in point: in the EU, there has been virtually no wind at all for two weeks (except in Denmark). So we burn coal and gas, massively.

Germany has a power generation capacity 68% larger than France for roughly the same number of TWh produced annually, because it needs backup production capacity for all its windmills and PV solar. What's the result? Electricity is 58% more expensive in Germany than in France.

Re: Ultra Safe Nuclear

#194

Post by rtx » Thu, Sep 17, 2020, 9:21 PM UTC

jka wrote: post #24

grawprog wrote: post #8

So why has nuclear waste become a thing that's not mentioned anymore? It was a pretty big thing in the 90's, now it seems to get brushed under the rug for all this 'safe' nuclear power marketing. It's mot just meltdowns and containment breaches that are a problem with nuclear power. None of the renewable alternatives produce radioactive waste that needs to be stored and dealt with. https://en.m.wikipedia.org/wiki/Rad…

I don't know, and I have been wondering whether much of the evident pro-nuclear lobbying recently (it seems apparent on many threads here related to energy generation) might be due to the nuclear industry being in serious threat of becoming obsolete. I've harped on about this many times before, but the levelized cost of energy[1] for renewables like solar and wind power is substantially cheaper than nuclear power now…

>it seems apparent on many threads here related to energy generation

It might be due to informed people reaching the same conclusion.

Re: Ultra Safe Nuclear

#195

Post by Klinky » Thu, Sep 17, 2020, 9:23 PM UTC

rurounijones wrote: post #103

xibalba wrote: post #3

Assuming nuclear truly can be ultra safe, how do you convince a public that has seen Chernobyl, Three Mile Island, and Fukushima to get on board? Particularly when the "competition" (solar, wind, etc) has such a strong tailwind.

The US Navy has been successfully operating Nuclear Reactors without incident for decades in the harshest environments on earth [1] It can be done safely. https://www.mofa.go.jp/region/n-america/us/security/fact0604...

Apples to oranges. Reactor designs are completely different. They are basically set it and forget it designs that then require extremely costly refueling and refurbishment.

Edit: I was wrong, the Ultra Safe Nuclear plan is somewhat similar. My comparison was with typical power grid reactor designs, not disposable reactors like what's being proposed.

Re: Ultra Safe Nuclear

#196

Post by theptip » Thu, Sep 17, 2020, 9:25 PM UTC

manfredo wrote: post #17

grawprog wrote: post #8

So why has nuclear waste become a thing that's not mentioned anymore? It was a pretty big thing in the 90's, now it seems to get brushed under the rug for all this 'safe' nuclear power marketing. It's mot just meltdowns and containment breaches that are a problem with nuclear power. None of the renewable alternatives produce radioactive waste that needs to be stored and dealt with. https://en.m.wikipedia.org/wiki/Rad…

Because it's not a problem. There's actually very little of it. It occupies a volume the footprint of a football field and 10 yards high [1]. Storing it is pretty foolproof: bury it in an area with no aquifer. The main risk of contamination is getting into the groundwater. If there's no groundwater the risk of contamination is eliminated even if the containers decay over time. And lastly, it doesn't make sense to bur…

One point that's commonly missed in the lay discussions is that the stuff with a really long half-life (e.g. uranium/plutonium) is not that radioactive/harmful; by definition if it takes you 100k years for 50% of your unstable nuclei to decay, the emission rate per second is very low.

In contrast, the really nasty stuff has a very short half-life, and emits radiation at a very high rate for a very short duration. These can be more like 10s of years half-life. The counterpoint is that they become mostly non-radioactive in 100s of years, not 100s of millenia.

The actual environmental risks from long-half-life radioactive substances are pretty minimal as far as I can see.

The US makes this problem a lot worse than it needs to be by declining to reprocess nuclear fuel (I believe on proliferation concerns). Reprocessing is done in Europe, China, and Russia. You can separate the uranium & plutonium in spent fuel rods from the shorter-lived and much more nasty fission products, reuse the uranium, do something safe with the potentially weapons-grade plutonium, and then handle / store the separated fission products in a shorter-term facility.

The design goals of Yucca Mountain were assuming that you need to keep nuclear fuel safe for 100k years; that's an intensely challenging design constraint. If we just need to keep something safe for 100s of years it becomes much more tractable.

See https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/r... for some further reading.

Re: Ultra Safe Nuclear

#197

Post by jacobr1 » Thu, Sep 17, 2020, 9:28 PM UTC

hairytrog wrote: post #189

simonebrunozzi wrote: post #179

Earlier quoted context omitted.

> which you can't really do because of Xenon poisoning Can you clarify this part? You mean that channging the power level of the reactor would cause Xenon poisoning?

I highly recommend HBO's Chernobyl. Explains a lot this stuff. Basically, as a nuclear reactor operates, it is turning the Uranium into lots of other stuff. One component of this other stuff is Xenon-135, which absorbs neutrons and basically gets in the way of nuclear reactions. This is not an issue if you keep the reactor on because there are enough neutrons to keep things going and overcome the Xenon absorption. Bu…

Ah, the the molten salt loop is like a flywheel?

Re: Ultra Safe Nuclear

#198

Post by cmehdy » Thu, Sep 17, 2020, 9:29 PM UTC

epistasis wrote: post #184

cmehdy wrote: post #168

Earlier quoted context omitted.

I'm not even sure what fight you're trying to pick here, because I'm all for renewables and energy. It's painfully obvious that no, renewables alone do not have the ability to cover at a low-CO2 footprint and continuous usage the energy needs that we currently have and that are, even with reduction of consumption in richer countries, bound to grow on the whole as population follows the models that indicate about 9 bi…

My "fight" is that you have now made two plainly false claims: 1) physics precudes renewables from providing our energy needs. This is just a silly claim. There are no such "physics" and if you think that "energy density" stops this from happening, you clearly haven't run any numbers. 2) Renewables aren't reducing carbon output. This is also incredibly bizarre. > You might want to re-assess why is it that you are see…

I'm making the claim because it is painfully obvious that unless you're making calculations about spherical cows there's nowhere near enough resources, surface, and specifically predictability to have renewables be more than marginal for a long time. And at all times, due to unpredictability, there is no chance at all that the source is controllable. Therefore, unless and until we have much much MUCH better ways to store energy (which would be absolutely fantastic), we cannot count on renewables alone.

As for the second thing I did not claim that, I said that renewables have a CO2 footprint that isn't negligible due to their construction and maintenance (and again, I'm all for renewables - I'm just not lying to myself about renewables solving all the worlds problems)

And I don't understand what you're on about when it comes to energy density. If you haven't understood the following you're just deluding yourself: the quantity of materials (i.e. what comes into making a solar panel or windmill or a power plant) and the volume of the transformation sources (i.e. how much space you need for your windmills and solar panels and nuclear power plants) AND the possibility to leverage the energy (i.e. where you can put your mills, panels, or plants) are all overwhelmingly in favour of nuclear.

So we should absolutely turn towards renewables, but if you think for one minute that the oil+gas+coal could be dropped for solar panels and mills without actually being carried by the sheer energy output of nuclear, you haven't quite taken a look at the numbers enough.

Re: Ultra Safe Nuclear

#199

Post by sixstringtheory » Thu, Sep 17, 2020, 9:29 PM UTC

ceilingcorner wrote: post #78

evgen wrote: post #70

Earlier quoted context omitted.

I think the site is bullish on nuclear power because it is overwhelmingly populated by reasonably educated people who are capable of performing risk analysis and understand cost/benefit tradeoffs. If you are looking for a herd of scared sheep who will parrot back whatever propaganda is being pushed by Greenpeace today I think you will have better luck over at Reddit.

That doesn’t really address my comment, at all. These sort of strawman accusations of parroting propaganda are so bizarre. I don’t think I’ve read a single article or book by Greenpeace in my life. I genuinely have no idea what you are referring to.

Your original comment also commits some logical fallacies.

You’re focusing on the label applied to the supposed users of HN, which is ad hominem. Then you employ a no true scotsman to tell them that they aren’t really hackers because they espouse a position that you deem non-hacker.

Re: Ultra Safe Nuclear

#200

Post by TeMPOraL » Thu, Sep 17, 2020, 9:30 PM UTC

ceilingcorner wrote: post #60

I find it a little odd that a site called Hacker News is so bullish on nuclear power. Could there be anything less hacker than a centralized, exclusively government owned and operated source of power? No thanks. I’d rather put more resources into solar, wind, and other sources of power that don’t depend on the government to not explode and irradiate the immediate area for hundreds of years.

You seem to harbor an assumption that decentralized = hacker, centralized = not hacker. It's only true to a limited extent.

Hackers tend to like things they can get their hands on individually, and decentralized stuff is usually much easier to get into and do something interesting with. But a part of being a hacker is also thinking rationally. That leads one to recognize the drawbacks of decentralization and benefits of centralization. And not all hackers are anarchists.

On top of that, education and rational thought leads one to look at the math and physics behind the energy and climate problems, and that's a straight path to becoming a nuclear supporter.