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Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

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Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#151

Post by eric-hu »

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power.

Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nuclear power statistics haven't factored in a major waste storage incident because one hasn't happened yet. Until we've witnessed multiple lifecycles of nuclear fuel consumption to full waste breakdown, the safety stats could still swing against nuclear power. Maybe all it'd take is a terrorist incident involving nuclear waste. From what I understand, breeder reactors can vastly reduce the quantity of a power plant's waste and produce waste with a much shorter half life. This isn't widely implemented or shared because that technology can also be used to produce weapons grade material. I think humanity will be ready if/when we can sort out our differences without violence and greed/corruption are no longer problems for most large orgs.

Additionally, renewables seem to have better scalability today than they did in the 90's when I formed my initial opinions. Right now, the worst case situation with a renewable power source is probably a large dam bursting. That's certainly possible due to corruption or terrorism too. If the three gorges dam suddenly burst, that could take out most of Shanghai. For most other renewables, the potential worst case is much milder though.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#152

Post by cel1ne »

eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

Isn't there also the issue of fuel-reserves (uranium etc.) actually not lasting more than about 50-100 years?

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#153

Post by eric-hu »

cel1ne wrote: post #152
eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

Isn't there also the issue of fuel-reserves (uranium etc.) actually not lasting more than about 50-100 years?

Yeah, that's an issue too, though again, breeder reactors could extend that number significantly. But the countries that possess that tech don't want to use it widely or share it. Not sure if the former is due to cost or lack of expertise. The latter is definitely due to distrust in humanity.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#154

Post by gizmo »

eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

I agree that renewables are a very good alternative to nuclear power, but in practice moving away from nuclear means doubling down on coal. The problems with nuclear are political, but the alternatives to nuclear power are mired in political conflict as well.

As for your dam bursting scenario, something like that actually happened in the 70s when the Banqiao Dam burst. Nearly 200.000 people died. Fukushima had 0 radiation deaths.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#155

Post by littlestymaar »

eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

> Maybe all it'd take is a terrorist incident involving nuclear waste.

There are so many radiologic sources out there, used for many purposes (medicine, gammagraphy), very dangerous[1] but taken with much less care than nuclear wastes from the nuclear power industry. Stuff like this [2] happen all the time …

[1] https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident [2] (in French) https://www.asn.fr/Controler/Actualites-du-controle/Avis-d-i...

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#156

Post by nihonde »

themodelplumber wrote: post #132
nielsbot wrote: post #50

Earlier quoted context omitted.

That's basically what they say at the end of the article: “I’ve been a robotic engineer for 30 years, and we’ve never faced anything as hard as this,” said Shinji Kawatsuma, director of research and development at the center. “This is a divine mission for Japan’s robot engineers.”

> This is a divine mission for Japan’s robot engineers That is so cool. I'd love to see some kind of "lessons learned" summary from the robotics people.

I saw a good documentary on NHK about the effort to enlist high schoolers and college students who might be able to think outside the box regarding this mission. My impression is that, no matter what happens in Fukushima, Japan is going to have a deep bench of robotics engineers in the coming decades.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#157

Post by [deleted] »

smallnamespace wrote: post #94
lovemenot wrote: post #75

Earlier quoted context omitted.

>> And that's with incompetence and neglect. Yes, and rightly so. Engineers must design around human fallibility. They don't get to blame human error and claim the whole system is otherwise perfectly safe. Either the system is safe under conditions of human fallibility, or it is unsafe. >> There's just no good reason for either Chernobyl or Fukushima Of course there is reason. Humans are part of the system and a rela…

How do engineers design around the propensity of politicians to kick the can down the road?

[deleted]

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#158

Post by littlestymaar »

jenga22 wrote: post #105

I wonder what they do once the robot sees the uranium? I mean the robot itself is now heavily contaminated. Do they just leave the robot down there? Or do they somehow decontaminate it so they can use it again?

> I wonder what they do once the robot sees the uranium? I mean the robot itself is now heavily contaminated.

Contamination isn't as dramatic as you'd think, it's mostly superficial : you have radioactive dust sticking on the robot, and you "just" need to wash it thoroughly to remove the contamination.

People usually have a wrong vision of radioactive contamination : they think being exposed to radiations makes you radioactive in return. In fact, it doesn't : being exposed to a radioactive material (which means you get struck by gamma rays, alpha and/or beta particles) doesn't make you radioactive. You can get contaminated with radioactive dust (which is a real problem if you ingest or inhale it, since it's hard to wash there) but you don't become radioactive yourself.

The mistake didn't appear out of nowhere though : things exposed to neutrons becomes radioactive (they become activated) and neutrons are emitted by nuclear fission, which occur in a exploding atomic bomb or a working nuclear plant. But when the plant shuts down, the chain reaction stops and so does the neutron emission. All that remain is radioactivity, as fission products keep decaying.

That being said, in practice I'm not sure the electronics in the robot is in a good enough shape to be used again …

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#159

Post by lovemenot »

smallnamespace wrote: post #94
lovemenot wrote: post #75

Earlier quoted context omitted.

>> And that's with incompetence and neglect. Yes, and rightly so. Engineers must design around human fallibility. They don't get to blame human error and claim the whole system is otherwise perfectly safe. Either the system is safe under conditions of human fallibility, or it is unsafe. >> There's just no good reason for either Chernobyl or Fukushima Of course there is reason. Humans are part of the system and a rela…

How do engineers design around the propensity of politicians to kick the can down the road?

Not every project is the right project for you right now. Select well.

Politicians' influence wanes, while engineers' waxes.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#160

Post by cptskippy »

gizmo wrote: post #154
eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

I agree that renewables are a very good alternative to nuclear power, but in practice moving away from nuclear means doubling down on coal. The problems with nuclear are political, but the alternatives to nuclear power are mired in political conflict as well. As for your dam bursting scenario, something like that actually happened in the 70s when the Banqiao Dam burst. Nearly 200.000 people died. Fukushima had 0 radi…

> Fukushima had 0 radiation deaths.

I think making that statement or even the comparison to other types of disasters is a little disingenuous. With most disasters they happen and then they're over in very short order. A nuclear disaster is very slow to unfold and the deaths from radiation related illnesses are not yet fully realized for quite some time.

The Chernobyl disaster is still unfolding and even with the latest containment, NSC, having been installed. It will take hundreds of years before we're done with it.

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