https://www.forbes.com/sites/jamesconca/2018/01/24/can-we-ma...
And at any rate, the article claims that
> The small size and large surface area-to-volume ratio of NuScale’s reactor core, that sits below ground in a super seismic-resistant heat sink, allows natural processes to cool it indefinitely in the case of complete power blackout.
Of course, the surface that allows efficient cooling here is the same surface that allows neutrons to escape, so my hunch is that it has poor neutron economy. (And of course, heat escaping through it will not turn turbines.)
> 2) refueling of this reactor does not require the nuclear plant to shut down.
That is very nice when you're trying to breed plutonium, the natural uranium fuel assemblies only have to irradiated a few weeks and then you would already need to shut the reactor down. When you can switch during operation, than there's less downtime.
So in total I guess it's a pretty inefficient reactor that's perhaps a nice addition to your weapons program.
Disclaimer: I'm of course one of the anti-nuclear types HN always tells me are only anti-nuclear because we don't understand these things.
That is very nice when you're trying to breed plutonium, the natural uranium fuel assemblies only have to irradiated a few weeks and then you would already need to shut the reactor down. When you can switch during operation, than there's less downtime.
So in total I guess it's a pretty inefficient reactor that's perhaps a nice addition to your weapons program.
This is incorrect. The NuScale reactor is not an online-refueling design like the CANDU (which is indeed easily adapted for breeding high grade plutonium simply by adjusting irradation time). It is an offline-refueling design like every other operating PWR. See this NuScale presentation about refueling operations:
https://www.nrc.gov/docs/ML1515/ML15159A311.pdf
The reactor has to be completely shut down for more than a week during refueling (slide 13). The plant can stay online because a plant contains a minimum of 4 reactor modules:
https://www.nuscalepower.com/about-us/faq
So by staggering refueling times, the plant can continuously generate at least 75% of rated output.
The problem that I was trying to show is that people try to answer a question "can a chernobyl(-like) event ever happen again?" which one simply _can't answer_. Not in a "science" way, since to answer this question you need to predict the existence (not probability!) of a literal _punctual_ event which depends on a gazillion factors outside your control (i.e. this is not simply computing a MTBF).
It's a bit like how the Airbus A380 can't crash like the Hindenburg airship did.
In the same way that I'm sure the victims of the next Airbus crash will be happy to know that "it didn't crash like the Hindenburg did".
An Airbus that loses an engine and has to immediately land has objectively failed; however, acting like that’s equivalent to a plane homing into a skyscraper and exploding is not helpful.
More people die every single year from radiation in coal than have died in the entire history of nuclear power. Replacing all coal with nuclear would save more lives and health than fighting nuclear ever could, even in theory.
And delaying coal to nuclear under the banner of "wind and solar maybe one day can help a bit" has blood on its hands.
Every year coal is still here, instead of nuclear, is 100 years of death. If building powerplants (of any type) were instant, and solar were one year away, then we should STILL replace all coal with nuclear TODAY, to minimize harm. (in a spherical chickens in a vacuum sort of way)
And not only do we not have enough solar, we don't even have a plan for energy storage for solar and wind. We have ideas, not a plan.
So solar&wind replacing coal&nuclear is further away than fusion power, by multiples.
But... we all know that it takes a lot longer to build a nuclear plant (on the order of 10-20 years) than it does to build (large) solar or wind farms (on the order of 1-5 years).
So.... yeah, if it was magically possible to replace all coal with nuclear right now, that would be a net improvement in terms of carbon output and general pollution.
But we live in the real world, and that is not possible, so I'm not sure what point you are trying to make, to be honest.
I'm pretty sure that enough solar/wind + storage can be built to replace a significant percentage (30%? 50%?) of the remaining coal plants, before the first new nuclear plant's plans and siting are even finalized, let alone before a new nuclear plant is fully operational.
And it's going to be a lot cheaper, too.
Who should we blame in 10-20 from now if people still are burning coal, oil and gas? Who will take responsibility for the inaction?
Perhaps. But 10-20 years ago, solar/wind/storage was a lot more expensive and a lot less efficient. The situation is quite different now.
> Who should we blame in 10-20 from now if people still are burning coal, oil and gas? Who will take responsibility for the inaction?
Realistically, there will probably still be knuckleheads who will be burning coal, oil and gas in 10-20 years from now. But hopefully they will be a very small minority.
The main thing that gives me hope is that it is now so much cheaper to build/run renewables than fossil fuel plants, that the latter will be phased out sooner rather than later, just for economic reasons. Those 6 out of touch old people on the supreme court are trying to delay things - and their actions will have very bad consequences for all of us - but the trend is clear.
Germany is the largest country in EU. If they are still burning coal, oil and gas in order to supply energy when the wind is low, what will we say about this "very small minority". Investors are putting a lot of money today on fossil fuel power plants that has several decades in estimated life-spans. We can wish and hope that some future technology will prove them wrong, just like climate change denials can wish and hope that scientists are all wrong.
This lead me just back to my original question. Who should we blame in 10-20 if people still are burning coal, oil and gas? If future tech won't save us, who can we blame for making this gamble and using the planet as collateral?
Because of the red tape the mob has strung up. China builds these in two years [1]. France does it in five [2].
[1] https://interestingengineering.com/china-moves-toward-nuclea...
[2] https://lemielleux.com/how-long-does-it-take-france-to-build...
South Korea is also very capable at building these quickly, though I've heard concerns raised about their safety (grain of salt, I have no opinion myself).
Also, the plan described there is an addition to take steam from an ALREADY EXISTING nuclear power plant.
- Nuclear is safer than coal: science (true or not, it's not the point)
- We need to go all the way nuclear: politics. There's a million other things to consider, many of them don't even each into the realm of what is falsifiable (e.g international relations, fuel availability, who knows). _Even_ if nuclear was literally the safest method ever, it is literally still politics whether to use nuclear or not; after all, we sacrifice safety for convenience _many_ times, and good luck defining "convenience" in a scientific way.
Another example:
- Vaccines are safe and effective (scientific; true or not is not the point)
- Vaccines are safe enough compared to the risk of catching the disease itself ("social" sciences; caveat emptor)
- We should force everyone to vaccinate (politics). It does not matter if vaccines are safe, or not. It is still a political topic, not scientific. There are things like ethics, social vs individual rights, etc. that are hardly quantifiable much less scientific.
You can scientificly say something is safe compared to something else, or define safe in some way (less then 1 in X chance of something happening statistically). But there is no such thing as 100% absolute safety. Even an injection with saline is not safe in the absolute.
E.g. if there is a 1 in a trillion chance of a side effect, you will never see it, because there arent a trillion people on earth.
Individuals who are anti nuclear have reasons, explicitly stated, that are misinformed.
Being anti nuclear because Chernobyl is in fact like being anti airplane because Hindenburg.
The criticism is actually (in this analogy) that they claim the hydrogen in a 747 will catch fire. "It's not hydrogen, it's just filled with oxygen and nitrogen" is met with "then what if that spontaneously combusts?!".
But in a way you make a good point. "I don't want to have a rational discussion or learn anything" is indeed the anti nuclear stance. "I don't want the truth, i just want to be right" is political.
The other things you mention are not really even known to anti nuclear people.
Wanting to be right despite facts or ignorance is almost the definition of politics.
People say they're anti nuclear because they want to spare us radiation and death, but when you tell them nuclear would reduce both then they just scream louder.
You can be factually wrong in politics. When your stated and internal reasons don't align with what your actions will accomplish, then that's wrong.
I’m as pro-nuclear as they come, but this is simply not true. No people die from radiation from coal.
When coal is burned, all the uranium daughters accumulated by disintegration—radium, radon, polonium—are also released. The United Nations Scientific Committee on the Effects of Atomic Radiation evaluates the radiation exposure to the population from this source.2 Per gigawattyear (GWe-yr) of electrical energy produced by coal, using the current mix of technology throughout the world, the population exposure is estimated to be about 0.8 lethal cancers per plant-year distributed over the affected population. Table 7.2 summarizes these data. With 400 GWe of coal-fired power plants in the world, this amounts to some 320 deaths per year
The relevant wikipedia quote is
One of the organizations for establishing recommendations on radiation protection guidelines internationally, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) that previously supported the LNT model, no longer supports the model for very low radiation doses.
Projections of the absolute number of cancer cases in a population have less and less information value and can be increasingly misleading at lower and lower doses. As a matter of general practice, the Committee does not use the risks inferred from studies of populations following radiation exposure at moderate and high doses to project absolute numbers of radiation-induced cancers following exposure at low and very low doses.
[2] https://www.unscear.org/docs/publications/2012/UNSCEAR_2012_...
It also means that a "new chernobyl" can happen at any power station, be it hydro, coal, solar, etc.
WTF? Chernobyl will NEVER happen exactly the same way again, that much is obvious since
a) it was already a pretty rare event to begin with,
b) the event is likely referenced during the training of every nuclear operator _worldwide_, making an exact repeat of the human errors involved even more unlikely than it was to begin with,
c) steps were taken to avoid this exact situation to happen _even on the other chernobyl reactors themselves_.
I thought it quite obvious that no one would be worried about a exact repeat of Chernobyl like if you hit the "replay" button on YouTube. (But if you believe this is what people have in mind when they ask "can chernobyl happen again" then please do tell). Therefore the only remaining interpretation is "can a chernobyl[-like] event happen again" -- a category which would roughly map to "major historic nuclear accident, the kind of which it is still talked about several decades after on a non-nuclear discussion forum like HN".
Most assuredly, non-nuclear accidents, no matter how large, won't fit this category. But I have been wrong in the past, maybe people would call a dam breakup "a chernobyl" these days?
Modern reactors all have a containment shell made of concrete and steel that is capable of keeping the melted down uranium core inside it, if the worst possible event would happen. Had Chernobyl had this, the incident might have destroyed the reactor and even killed some employees, but that would have been the end of it, and the world would never even have heard about the incident.
There are also plenty of other security improvements since that ancient design, but the containment shell alone makes what I would call "chernobyl happening again" just about impossible.
https://en.wikipedia.org/wiki/Containment_building
Biggest dam accident is arguably worse than Chernobyl: https://en.wikipedia.org/wiki/1975_Banqiao_Dam_failure
If the original argument was "the exact same thing that happened at Chernobyl will happen again", then that's meaningless and irrelevant, because... who cares? What people actually care about is whether a nuclear disaster could happen again, one that kills a bunch of people and makes a significant area of land uninhabitable for some long period of time.
If you think that's "moving the goalposts", then I don't think you're here to have a good-faith discussion about why people are worried about nuclear energy.
Having said that, I do believe that a significant accidental nuclear disaster is much much much less likely now than in Chernobyl's time. But that doesn't mean it's impossible, or that we shouldn't think about or be worried about it. And also consider that's "accidental": we also need to consider the possibility of terrorist- or state-level attacks, which may be harder to protect against.
Chernobyl lacked many security features that are standard on all modern reactors. The biggest flaw was it had no containment structure. That's the steel & concrete dome which, if the worst happens, keeps the melted uranium contained within it.
That alone would have made the Chernobyl disaster just a bad local industrial accident, and that's the main thing I mean when I say it can't happen again. Though it's far from the only security improvement modern reactors have over Chernobyl.
> But that doesn't mean it's impossible
This is the "you never know!" argument. The good and bad part of it is the same: It is always true! Any thinkable disaster, can conceivably happen, and maybe you "should" be worried about it.
Of course, applied consistently, it would lead to total paralysis. This is no way to rationally approach risk.
Its still kind of a bad question,because we can't rule out dinosaurs attacking the power plant. Maybe the question should be,is there a less than 1 in a million chance of a level 7 event happening when using a modern nuclear plant design in the next 100 years?
Clearly, the nuclear energy in power plants is far more dangerous than those other forms. This is devolving into a silly discussion.
There is a serious discussion to be had about the trade-off in nuclear energy between cost and safety, and whether it's worthwhile.
That also points at one issue. All the now >50 year old reactors should have been replaced with newer versions at some point. Just think about what kind of electronics there is in those things. This didn't happen anywhere. Not in Germany and not in France.
Seems like an issue with how humans think in general. "It's not an issue now, so why worry about it?"
These sorts of creeping disasters never seem to be addressed by any society in a timely fashion.
A solid fuel rod just needs the right disruption, and you have a meltdown. It's inherent to solid fuel designs because they are ... solid.
https://en.wikipedia.org/wiki/Timeline_of_the_Fukushima_Daii...
I look at that timeline and all the active systems that are necessary in solid fuel rod. LFTR doesn't need those to cool, it is a somewhat self-regulating design. There's no high-pressure steam to worry about regulating.
Additionally LFTR:
1) breeds its fuel from Thorium, a low radioactivity element, so some stockpile of heavily radioactive stuff isn't hanging around.
2) "burns" most/all of its fuel, so there isn't some stockpile of bad waste that can get washed away.
I'm not sure if pebble bed type stuff or other schemes could have similar guarantees, and it's not like an underwater LFTR wouldn't have lots of strange elements leaking, but there are so many failure events in that fukushima timeline that IMO a LFTR design would have simply shut down and no big deal.
http://www.chernobylgallery.com/chernobyl-disaster/timeline/
Again, all those pressure events and active cooling system failure points.
LFTR is generally an unproven design, but it has so many good features that I view it as the starting point of next gen nuclear. I think its scalability is the key to nuclear's relevance in the future to compete economically with mature solar/wind/battery.
To get back to your point about the politics: the current nuclear industry... the lobbyists, the regulators, the "culture" ... is gravitationally bound with the solid fuel rod design. A clean slate is needed, and wind/solar sweeping away the economically unviable and inherently dangerous old designs and their political structures is probably doing nuclear a favor in the long run.