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First contact made with melted nuclear fuel at Fukushima plant

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Re: First contact made with melted nuclear fuel at Fukushima plant

#211
post #210

Earlier quoted context omitted.

That paper has some wording that is hard to understand, so I think this might be what's causing you trouble. The quote you make from the paper is not the only reason. They give 5 reasons. - The exposure rates are significantly lower that Chernobyl (earlier in the paper they explain that in previous studies there is a correlation between exposure and cancer rates -- because the thyroid problem rates here are high whil…

My main beef is how in parralel to the pure data and experiments, there’s all this commentary going back to other events (Chernobyl) or expected results (“ours models would predict") to seed the ideas that some of these data is just non significant. To draw a bad analogy, if we had a plane crash and had to study how 5% survived, we wouldn’t be saying ‘previous crashes had everyone dead, we should not pay too much att…

Well, to be fair, the paper you picked did no experimentation. It's a review paper. Not only that, it's a review paper whose express purpose was to put forth the idea that the high thyroid rates in Fukushima prefecture are likely not due to the disaster (they say as much in the conclusion). It is very possible that it suffers from confirmation bias (I don't know enough about the topic to comment one way or another). If you look on any topic, you will find review papers like this.

If I understand your comment, though, I think you still suffer from misunderstanding the paper. The paper states that the data is consistent with our models. It's not consistent with the idea that the thyroid problems are caused by the disaster. As the paper states, we do not know what the thyroid problem rate was before the disaster because we did not screen people in the same way or at the same rate. The equipment being used now is much better at detecting thyroid problems. Other places using this equipment (for example South Korea) are also finding high rates of thyroid problems. When doing screening in other prefectures, they are also finding high rates of thyroid problems. Discovery of thyroid problems are on the rise all over the world. (All this according to the paper -- I haven't the foggiest clue if it is true).

In other words, the paper is explicitly saying that while the rates are high, it is likely that the high rates are due to a variety of other causes. They go to a considerable amount of effort to document in detail what these are. You seem to be fixed on the idea that the high rates are especially unusual or outside the boundaries of what we would expect if there were not a disaster. This entire paper was written to dispute that point of view. It is not the case that they are simply ignoring it. I think the biggest thing to understand is that they claim that there are places in the world where the rates are higher, which didn't have a nuclear disaster. Since the data does not match that of areas that did have nuclear disasters, but does match that which did not have nuclear disaster, they conclude that the thyroid problems are likely to have been caused by something other than the disaster.

If you dispute that, it's entirely up to you. Like I said, I have no idea if it is true or not -- I'm just telling you what they wrote. Generally, I don't like review papers like this because of the problem with confirmation bias. People start with the conclusion they want to have and then find evidence to support it. You can always find that kind of evidence. It's not even a well written paper... but I didn't choose it ;-)

I think the best way to learn more about whether or not these researchers know what they are talking about is to read the citations that they make. They make a lot of claims about detection rates of thyroid problems, the rate at which these turn in to cancers, etc. If they are wrong that the current rates can be explained by non-disaster causes (or if they are wrong that data does not support a disaster cause), then you should be able to find the problem in those citations. Remember, it's a review paper! They are only gathering data from other papers and putting it together.

I suppose if I'm particularly uncharitable, if the authors of the paper are lazy, then I'd ask you to be at least reach their bar. If the data is rife with swaths of oddities, then write a review paper that points it out. Provide citations that show current data does not match our models. I bet you don't even need to do that. I bet there is at least 1 group of researchers in the entire world who has at least tried to write such a paper. Find it and we can have a much, much better conversation.

Re: First contact made with melted nuclear fuel at Fukushima plant

#212

Earlier quoted context omitted.

Obviously it couldn’t melt through to China but AFAIK the way Czernobyl played out was that they had to somehow stop it from melting down to a flooded basement due to the fear of a long lasting series of hydrogen explosions that could have been truly disastrous for the region, if not Europe. Thus I think that the true worst case has so far never happened: A reactor without any of the modern safeguards (such as boroni…

The sad part is that the whole anti-nuclear politics often prevent building new and way safer reactors, yet they also don't manage to force shutdown all the dangers ones.

> new and way safer reactors

actually the problem was never the reactor itself. chernobyl never failed because the reactor was totally unsafe. It wasn't the newest, but humans could've prevented anything. fukushima wasn't the unsafest reactor as well. however it got hit by a wave it couldn't stand and after that humans missmanaged everything to safely shut it off.

do you see a common denominator? the problem is that money is always involved even when you can build these things for cheap, however money and humans will make reactors unsafe, not the design of the reactor. at some point somebody wants to save money and most often this money saving practice will then be extremly disastorous.

I'm not saying that nuclear is bad per se, of course the waste is bad, but is it worse than coal? I'm not sure. however as long as humans control or have control over these things they will always be unsafe in a certain way.

Re: First contact made with melted nuclear fuel at Fukushima plant

#213
post #15

It took 10 years to even get a robot that could get close to the fuel... and people still ask if nuclear might not be as bad as coal! The truth is that accidents like this can never be cleaned up or salvaged. It's time to move away from nuclear, as other countries have already figured out. Fortunately for us in the US, the last nuclear plant under construction today will likely be cancelled, as the last two were. The…

>The truth is that accidents like this can never be cleaned up or salvaged. It's time to move away from nuclear, as other countries have already figured out. France per-capita CO2 emission is 1/3 the US rate and 1/2 the German rate. This is due to their heavy focus on nuclear power for electricity production. The data shows we should be moving to nuclear rather than away from it. As far as "never" being able to clean…

> Do you really believe that with a reasonable research effort we won't understand how to reprocess nuclear waste and/or accident debris within 50 years? We couldn't even fly until a little more than 100 years ago.

This probably requires a new kind of physics to be discovered and eventually applied. It's absolutely not clear how this should work.

Fluid Dynamics is Newtonian physics, Bernoulli equation already exists since the 17th century.

Re: First contact made with melted nuclear fuel at Fukushima plant

#214
post #212

Earlier quoted context omitted.

The sad part is that the whole anti-nuclear politics often prevent building new and way safer reactors, yet they also don't manage to force shutdown all the dangers ones.

> new and way safer reactors actually the problem was never the reactor itself. chernobyl never failed because the reactor was totally unsafe. It wasn't the newest, but humans could've prevented anything. fukushima wasn't the unsafest reactor as well. however it got hit by a wave it couldn't stand and after that humans missmanaged everything to safely shut it off. do you see a common denominator? the problem is that…

That's somewhat my point as well. There's no perfect world, there will be human errors and there will be natural disasters, but the point with newer reactor designs, is that they have design decisions in them that account for such issues, we have learned from the past, so that even a meltdown can be contained relatively well.

Re: First contact made with melted nuclear fuel at Fukushima plant

#215

Earlier quoted context omitted.

Part of that problem is that water is actually a decent moderator and neutron reflector, so it helps a lot in keeping a chain reaction with lots of energy output going. Some of the energy also goes into splitting water into hydrogen and oxygen. The hydrogen can then collect in some corner of the building until it reaches an concentration where it explodes rather easily. The explosion can then damage the building, rui…

> Moral of the story? Keep your box of boronic sand nice and dry. See also: "For every three units of energy produced by the reactor core of a U.S. nuclear power plants, two units are discharged to the environment as waste heat. Nuclear plants are built on the shores of lakes, rivers, and oceans because these bodies provide the large quantities of cooling water needed to handle the waste heat discharge." [0] [0] http…

Pretty much every energy source has a lot of waste heat produced.

Solar panels get hot, gas turbines have hot exhausts, coal plants have cooling towers etc.

They all approximate a heat engine, and they must theoretically give off heat to the cold reservoir

Re: First contact made with melted nuclear fuel at Fukushima plant

#216

Earlier quoted context omitted.

> Moral of the story? Keep your box of boronic sand nice and dry. See also: "For every three units of energy produced by the reactor core of a U.S. nuclear power plants, two units are discharged to the environment as waste heat. Nuclear plants are built on the shores of lakes, rivers, and oceans because these bodies provide the large quantities of cooling water needed to handle the waste heat discharge." [0] [0] http…

Pretty much every energy source has a lot of waste heat produced. Solar panels get hot, gas turbines have hot exhausts, coal plants have cooling towers etc. They all approximate a heat engine, and they must theoretically give off heat to the cold reservoir

> They all approximate a heat engine

For each of those energy sources mentioned, what would happen if the generating station were to be completely inundated with water?

Re: First contact made with melted nuclear fuel at Fukushima plant

#217
post #66

Earlier quoted context omitted.

What we have right now are three options : fossil fuels, renewable sources like wind/solar/hydro, or nuclear. Fossil fuels kill millions a year related to pollution, and does make whole areas unlivable. About 16% of all fracking oil in the US gets spilled in nature every year[1], on top of crap like Flint. Coal is responsible for 80% of energy-generated related air pollution, worldwide[2]. They are not a good solutio…

> on top of crap like Flint Flint's water contamination has absolutely nothing to do with energy production of any kind. It was caused by the city still having lead water pipes. Edit: > About 16% of all fracking oil in the US gets spilled in nature every year[1] > [1] https://www.bbc.com/news/science-environment-39032748 That isn't at all what that article says. It says 16% of wells suffer a spill each year. The indu…

I'm not american, seems like I mixed up Flint with some other american city that made the news up here for having water catching fire and shit like that.

And indeed, I misread, it's not 16% total spillage but 16% of them spilling at all. This one doesn't really change much to my point that having one in six fracking points spilling out is extremely damaging.

Re: First contact made with melted nuclear fuel at Fukushima plant

#218

Earlier quoted context omitted.

> Those costs are entirely political. This is simply not true. There has been tremendous ongoing incompetence and mismanagement in the reactor construction process in recent years. You may blame regulation -- that's the goto excuse for pronuclear people to avoid coming to unpleasant conclusions -- but the problem is that reactors are complicated things, and reactors with safety systems are even more complicated thing…

> Experience builds up rapidly as the same damned thing is built and installed over and over. Nuclear doesn't have that. Do you think this is the reason the US Navy doesn’t seem to have major problems getting nuclear power plants built and installed in submarines and aircraft carriers? It’s interesting how civilian power companies have had a bunch of high profile failures in this area but as far as I can tell new war…

What's the power output of those I imagine much smaller reactors, compared to ones meant to power entire regions and millions of consumers? What did they cost to build? What risks are there, compared to regular reactors?

Re: First contact made with melted nuclear fuel at Fukushima plant

#219
post #212

Earlier quoted context omitted.

> new and way safer reactors actually the problem was never the reactor itself. chernobyl never failed because the reactor was totally unsafe. It wasn't the newest, but humans could've prevented anything. fukushima wasn't the unsafest reactor as well. however it got hit by a wave it couldn't stand and after that humans missmanaged everything to safely shut it off. do you see a common denominator? the problem is that…

That's somewhat my point as well. There's no perfect world, there will be human errors and there will be natural disasters, but the point with newer reactor designs, is that they have design decisions in them that account for such issues, we have learned from the past, so that even a meltdown can be contained relatively well.

well depends, even the safest system can have a bug. especially the more complex a system gets. I mean look at all the software bugs. I wouldn't count on human technology on catastrophic failures and sadly most humans make errors in situations that we can't control.

Re: First contact made with melted nuclear fuel at Fukushima plant

#220

Earlier quoted context omitted.

I also find it interesting that the "China Syndrome"[2] speculation is pretty much completely debunked. That term was never meant to be taken literally, in the movie where it originates it is presented as a fanciful exaggeration meant to emphasize the seriousness of the risk. The actual plot concerns the risk of groundwater contamination following a nuclear accident, not a planet-piercing tunnel.

But is there a material that humans could build that would sink into Earth like that, for a few kilometers say, either due to melting its way down or gravity or density?

I really don't know. I've never thought of it as anything other than a colorful metaphor and don't know enough physics or chemistry to speculate.
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