New Submersion Method Being Considered for Fukushima Debris Cleanup (japantimes.co.jp) 70
AmiMoJo writes: The operator of the Fukushima No. 1 nuclear power plant, which suffered core meltdowns in 2011, is considering a new submersion method for removing radioactive fuel debris that would wholly encase a reactor building in a water-filled, tank-like structure, a source close to the company said earlier this month. Conceptual breakthroughs with the method, whose advantages include using water's ability to interrupt radiation and thereby provide a safer working environment, have made it a promising candidate for the cleanup of the defunct nuclear plant, according to the source close to Tokyo Electric Power Company Holdings (Tepco). But with no proven track record in the nuclear field, investigations are ongoing into future technological issues and costs, among other contingencies. The source said it could "require advanced technology to stop water leaking out and become a huge construction project."
Were it to go ahead, the process from building to actual debris removal would be lengthy and would likely affect total decommissioning costs, currently pegged at about $57.45 billion. In the aftermath of the March 2011 Great East Japan Earthquake and tsunami, nuclear fuel cooling processes failed at the Fukushima plant's reactors 1 through 3, causing the fuel to melt and re-solidify into radioactive debris mixed with concrete, metal and other materials present in the reactors. Debris removal is the operator's most challenging issue in the Fukushima plant cleanup. Some 880 tons of the radioactive waste material is estimated to have been created by the nuclear meltdown across the three reactors. The new submersion method, which is currently expected to be applied to the No. 3 reactor, would involve building a strong, pressure-resistant structure, much like a ship's hull or a plane's body, completely encapsulating the reactor, including underground. The structure could then be filled with water, and removal work would take place from the top.
Were it to go ahead, the process from building to actual debris removal would be lengthy and would likely affect total decommissioning costs, currently pegged at about $57.45 billion. In the aftermath of the March 2011 Great East Japan Earthquake and tsunami, nuclear fuel cooling processes failed at the Fukushima plant's reactors 1 through 3, causing the fuel to melt and re-solidify into radioactive debris mixed with concrete, metal and other materials present in the reactors. Debris removal is the operator's most challenging issue in the Fukushima plant cleanup. Some 880 tons of the radioactive waste material is estimated to have been created by the nuclear meltdown across the three reactors. The new submersion method, which is currently expected to be applied to the No. 3 reactor, would involve building a strong, pressure-resistant structure, much like a ship's hull or a plane's body, completely encapsulating the reactor, including underground. The structure could then be filled with water, and removal work would take place from the top.
immersing nuclear debris in water? (Score:2)
Without knowing the specifics of the reactor, I can't say for certain that this is a dumb idea...
That said, most reactors are designed to not actually fission without water...which would mean one of the side-effects of adding water to the damaged reactors is to get the fission reactions going again.
Which won't produce a bomb, but will irradiate the people working in or near the places that U-235 is immersed in water.
Assuming they're not complete idiots, and that the tech-writers aren't completely clueles
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A boost to the Japanese film industry; perhaps they can get Denis Villeneuve to direct Godzilla 2049.
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At the very least it seems like it will create lots of contaminated water thT then has to be got rid of. Tell me they won't dump that in the ocean.
Tell me why they should not dump that in the ocean. Tritium is a naturally occurring isotope, we'd be unable to detect if they were dumping it in the ocean. Not unless the concentration of the tritium was incredibly high, in which case they could likely sell it for making the glowing paint used for emergency exit signs and gun sights.
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is tritium the only thing that will get added to the water ?
Well that's what is difficult to remove, has raised concerns in the past, and has the chemical abbreviation of "T". I see I almost certainly misinterpreted a typo in the comment as a concern over tritium. Anything that is not tritium is nearly trivial to remove, that is likely one of many reasons why they plan to flood part of the site in an effort to aid cleanup. In the fine article it mentions that the water would protect the workers from radiation, which is certainly advantageous. In the past the cle
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Well, it's the only thing that is still part of water.
That said, there are going to be fission byproducts included.
So, some helium, various mildly radioactive metals, smaller (ranging from waaaay smaller to slightly smaller) amounts of pretty much everything on the periodic table between helium and thorium.
Realistically, it's not all that big a deal if they're not completely clueless (and I've seen only one thing that the Japanese did that would fit the definition of "completely clueless" - 7 December 1
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Tell me why they should not dump that in the ocean. Tritium is a naturally occurring isotope, we'd be unable to detect if they were dumping it in the ocean.
The same can be said for lead (206, 207, 208).
"The ocean is big" is not an argument for dumping toxic shit into the ocean, for fuck's sake.
That out of the way, we're not talking about tritium. We're talking about fuel debris, which means decay chain products.
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"The ocean is big" is not an argument for dumping toxic shit into the ocean, for fuck's sake.
That's true, but we are dealing with diminishing returns. Spending billions to sequester a few milligrams of radioactive isotopes is silly.
We would be better off if those billions were used to clean up coal mine tailings or erect wind turbines.
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"Tell me why we shouldn't..." is a ridiculous thing to say. Any person should be able to come up with a hundred reasons we shouldn't.
That isn't to say I don't realize the reality of the situation (Fukushima is disposing of their tritiated water in the ocean already- but over several decades to keep the concentration in the releases very low)
Because there is no practical way to
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Fukushima is disposing of their tritiated water in the ocean already- but over several decades
The slow release is for political reasons. There is no health issue or scientific reason.
Tritium is produced naturally when cosmic rays strike nitrogen in the atmosphere. Most of it ends up in the ocean. The Pacific Ocean contains about 2 kg, and a full release from Fukushima would only be a fraction of that.
Tritium has a half-life of 12 years. It decays by low energy beta emission. It does not bioaccumulate.
The money spent on Fukushima should be invested elsewhere.
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The slow release is for political reasons. There is no health issue or scientific reason.
Flatly untrue.
Tritium is produced naturally when cosmic rays strike nitrogen in the atmosphere. Most of it ends up in the ocean. The Pacific Ocean contains about 2 kg, and a full release from Fukushima would only be a fraction of that.
Not this argument again.
A full release of Fukushima distributed across the entire ocean would of course be nothing. But that's not how it works.
Tritiated water is dangerous. Tritium is a beta emitter, and the one place where it is dangerous, is inside of your body- and inside the bodies of things that live in that water.
Tritium has a half-life of 12 years. It decays by low energy beta emission. It does not bioaccumulate.
It doesn't need to.
It's capable of doing plenty of damage as it passes through, particularly if you have elevated the local environments concentration of it enough.
There is
Re: immersing nuclear debris in water? (Score:2)
I thought about an ocean dump. Lets say they've dealt with that concern somehow. What about radioactive material leeching into the ground water?
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There are somewhere around a quintillion tons of water in the oceans of the world. Adding a few million tons of radioactive water (containing a few thousand tons of actual radioisotopes) to the ocean won't even be noticed...
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Which won't produce a bomb, but will irradiate the people working in or near the places that U-235 is immersed in water.
That's not how radiation works. In fact it's the exact opposite of the effect water has. Water is incredibly dense and very effective at stopping gamma radiation which is ... one of the reasons why fuel rods are handled under water in the first place.
Re:immersing nuclear debris in water? (Score:4, Insightful)
The post you replied to was referring to the ability of water to moderate (reduce the energy of) neutron radiation, which can potentially increase the rate of a fission reaction (by increasing the effective cross-section).
It's a valid concern, but such an obvious one that it is hard to imagine that it would not have been considered.
Re: immersing nuclear debris in water? (Score:1)
Maybe....maybe there is no way to safely remove, dispose of the reactor so, a controlled reaction to eventually make the core inert? Thus full immersion in water?
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It takes some distance for water to moderate neutron flux. In a reactor where most of the fissile material is at the bottom of the containment tank the water won't do much but provide cooling and protection to stuff and people at the top of the water column.
It's an intriguing concept, making the busted reactor effectively a holding pool, but I think engineering and operation of such a thing would be difficult. You'd have to circulate and cool the water and it'd have to be treated like primary water since it
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Compared to doing it in air though it seems like a much better solution. The dry approach still needs massive filters and radiation mitigation, and you have the challenge of equipment constantly breaking down due to radiation.
The challenge would seem to be to make the "pool" as small as practical... which is quite a lot of work. Just oversizing it means a whole lot of things become harder.
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Some substances react better with slow/thermal neutrons.
Some substances react better with fast neutrons.
So slowing the neutrons may make them less reactive, depending on what else is there.
Misunderstanding the fast/slow neutron reaction difference is why Castle Bravo [wikipedia.org] was a much bigger bang than expected. The designers knew that Li-6 reacted with thermal neutrons, but they didn't know that the more plentiful Li-7 reacted energetically with fast neutrons, producing even more neutrons in the process.
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Protip: Look at the situation there before doing baseless speculation. Hint: The cores are flooded with... water.
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A rather small amount of boron will keep the water from promoting fission reactions.
Of course they will build new reactors. (Score:1)
From the fine article...
While the extensive cleanup goes on in Fukushima, the government said on Aug. 24 that it is considering the construction of the next generation of nuclear plants amid an increasingly fraught energy supply environment and the countryâ(TM)s dependency on imported natural resources.
They are "considering" construction of next generation nuclear plants? What's the alternative? Building previous generation nuclear power plants? Continuing to import energy?
Japan is going to have to build nuclear power plants. It's that or see their economy turn to shit. Nuclear power is the worst option to produce energy, except for all the others. There's no good option here, just the least bad.
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The alternative is offshore wind. Japan has plenty of it.
The only problem is that Japanese companies are way behind on the tech, and the government doesn't want to be buying thousands of foreign made windmills.
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The alternative is offshore wind. Japan has plenty of it.
I read an article recently on a website called "Slashdot", perhaps you've heard of it, that offshore wind power costs more than nuclear power. Apparently the cost difference can be quite large. Therefore using wind power would be included in the options that turn their economy to shit.
Is is possible for future developments to bring down the costs of offshore wind power? Sure. Just like future developments can bring down the costs of nuclear power. Right now and for the foreseeable future nuclear power
Re:Of course they will build new reactors. (Score:4, Interesting)
Offshore wind auctions in the UK recently came in at £27/MWh, zero subsidies.
New nuclear is around £130/MWh, plus the usual staggering subsidies.
Hitachi, the company that builds Japanese nuclear plants, declined to take up the contract in the UK. Apparently £130/MWh plus subsidies wasn't enough.
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Shallow water vs very deep water.
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Shallow water vs very deep water.
Which becomes irrelevant given modern floating designs.
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No, that is entirely the problem; modern floating designs cost 30-50% more. Getting that premium down to 10% is what is needed.
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Offshore wind auctions in the UK recently came in at ã27/MWh, zero subsidies.
But that's the prices in UK, what are the prices in Japan?
I expect offshore wind energy costs to come down in Japan as they gain experience with building windmills off shore. I also expect Japan to see nuclear energy costs come down as they gain experience building new nuclear power plants. Given the inherently intermittent nature of wind power Japan will have to build nuclear power plants to keep the lights on.
Do you believe that development of low cost grid scale energy storage will aid in adoption of o
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We should be developing it because we’ll need it eventually
The future may be fusion or MSRs. But anyone who believes we should be building more pressurized LWRs is delusional.
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Okay then, call me delusional.
PWRs are a relatively mature technology and so can offer low costs as it won't be some first of a kind design. It will be safe and reliable, because PWRs have a history of being safe and reliable. That makes this a low risk technology that has a high probability of being profitable for many decades.
Fusion has not yet shown to be even close to something that can provide more power out than power in. That makes this a dead end for any energy production for anyone in the energy
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PWRs are a relatively mature technology
That is the problem. PWRs have been one financial debacle after another. Vogtle, Hinkley, and Summer all had massive cost overruns and decades of delay, and since the technology is mature, there is no reason to believe that "Next time will be different."
and so can offer low costs
Yes, you are delusional. You have repeated this reality-denying nonsense over and over. The last time this came up, I challenged you to name a single nuke built in any Western country in the past 30 years that has been successful.
You failed to do so. Instead
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The last time this came up, I challenged you to name a single nuke built in any Western country in the past 30 years that has been successful.
For one you'll need to define your terms. What defines "successful"? What is a "Western country"? There's over 400 civil nuclear power reactors in the world right now and you can't find one that is "successful' in a "Western country" built in the last 30 years? Why must it be in the last 30 years? Why must it be in a "Western country" when the people constructing the power plants are often international amalgamations operating all over the world. If a country isn't "Western" enough then how does that
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What defines "successful"?
Produces power at a reasonable price. Let's say 10 cents/kwh, retail.
What is a "Western country"?
USA, Canada, EU.
you can't find one that is "successful' in a "Western country" built in the last 30 years?
No, I can't. Neither can you. Because there aren't any.
Why must it be in the last 30 years?
Because we are talking about whether NEW nukes make sense. That they may have made sense half a century ago is irrelevant.
Why must it be in a "Western country"
Because America and the EU aren't going to adopt Chinese political and legal systems.
toss out the experience they built in the last 30 years with a first of a kind reactor.
Bullcrap. NONE of the recent debacles are "first of a kind" reactors. They are all standardized designs. Vogtle and Summer are AP1000s. Hinkley is an EPR.
Standa
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But itâ(TM)s harder to rationalize why the Chinese and Russians cant manage to make nuclear economical.
What are you talking about? Russia and China are building plenty of civil nuclear power reactors. China has something like two dozen under construction now, with many more planned. Russia has been building civil power plants on land and on floating platforms, for themselves and for export to their allies. They made it economical.
In places like Australia the cost of a new nuclear power plant is effectively infinite because the government banned any new construction. There's no demonstrating nuclear powe
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China has half a dozen new nuclear plants [world-nuclear.org] under construction, each with multiple reactors. Russia has.. two? They're expanding nuclear capacity, certainly - but Chinese solar and wind is growing much faster, because it's so cheap.
Look at the numbers [wikipedia.org]. While nuclear generation has gone up 5x since 2008, wind and solar PV generation have gone up 31x and 1,717x - from almost nothing to 727 TWh/year, double nuclear's 366 TWh. And annual generation is still growing at 15%, triple nuclear growth of 5%. The Chinese
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wind and solar PV generation have gone up 31x and 1,717x - from almost nothing to 727 TWh/year
Right, "from almost nothing". It's easy to show big gains when starting with something so small.
The Chinese clearly feel renewables are better value
That's not true. Because if it were so clear then they'd build no nuclear power at all.
They are "clearly" not taking chances on which will prove to be the best option. They are developing all the top options, pitting them against each other in competition. In time they will likely find a few of those options will fail, and perhaps find new options to try in the future.
unsubsidised solar is $31-42/MWh LCoE to nuclear's $129-198/MWh - a quarter the price
How do those numbers look at local midnig
Re: Of course they will build new reactors. (Score:2)
It's easy to show big gains when starting with something so small.
Not so easy to grow that much when there was no manufacturing capacity or economies of scale yet. But the point was that they've got double the generation and triple the growth - adding six times more TWh than nuclear, and the gap is only widening.
That's not true. Because if it were so clear then they'd build no nuclear power at all.
It's clearly true, because they're building vastly more renewable generation than nuclear. They're still building nuclear as well because as I said, nuclear is also an important part of the generation mix.
How do those numbers look at local midnight?
Wind is just as cheap, and typically generates most at nigh
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Nuclear alone is not enough
Who is claiming it is? We have the claim from the nuclear power opponents that renewable energy sources with grid-scale energy storage will provide reliable and low cost energy. We have government studies showing we will need nuclear power, and we have sky high energy costs all over the world proving these studies correct.
I'd love to see you actually cite one of those studies, for a change. As I said, your unsupported claims are not worth much these days.
I've cited plenty of studies on Slashdot in the past. I'd like to see studies showing renewable energy can provide reliable and low cost energy for once. Here's a video discussing stud
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we have sky high energy costs all over the world proving these studies correct
It may have escaped your notice, but those sky high costs are all from fossil fuels. Not renewables, which have been remarkably stable, so I'd say that's not "proof" but evidence against.
As I think I have made clear, I'm not against the use of nuclear power where it makes sense. I'm more concerned with your false claims that "solar can't compete on price", which you have not only failed to back up, but are glossing over all the evidence presented against.
We are going to need nuclear power and the data from the studies on renewable energy prove it, people need only look closely at the data.
Since you mentioned Australia, that's a great example
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It may have escaped your notice, but those sky high costs are all from fossil fuels. Not renewables, which have been remarkably stable, so I'd say that's not "proof" but evidence against.
I did notice that something like 80% of all energy (not just electricity) we produce is from fossil fuels. If renewable energy were cheaper than fossil fuels then we would not see any growth in fossil fuel use. Fossil fuels are nearly universally hated because of the CO2 emissions and pollution. People tolerate fossil fuels because they are low cost and reliable.
Utilities would not be building coal power plants if renewable energy were cheaper and a direct substitute. Renewable energy is not a direct su
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I like nuclear. I want it to be a big part of our power mix. But at some point, if t
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The alternative is offshore wind. Japan has plenty of it.
I read an article recently on a website called "Slashdot", perhaps you've heard of it, that offshore wind power costs more than nuclear power.
You must be one of the nuclear fanatics. Most shameless liars known to man.
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You must be one of the nuclear fanatics. Most shameless liars known to man.
Am I going to need to start attaching warning to your posts in nuclear threads too? It is a known fact that you anti nuclear types are known to make up facts and figures on the spot and alter information to spread your FUD. Two of the biggest spreaders of FUD on slashdot have warning attached to their accounts.
Do you need one too?
Re:Of course they will build new reactors. (Score:4, Informative)
It would seem the only thing they really have going for them, emissions-wise, is population decline. By 2060, their workforce population under the age of 65 is set to crater [wikipedia.org] to less than it was in 1920, and half of what it was in 2010. Bye bye Japan, it was nice knowing you.
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Japans CO2 emissions are equal to their 1990 emissions, 30% down from their peak.
Japan's population at 125million is slightly higher than their 1990 123million, but only 1.5% lower than their peak.
There's more to emissions than building windfarms and culling the population.
The Question No One Asks (Score:1)
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It was cheaper, because it was closer to the water. Same with the emergency generators. Placing them on a hill would have been more expensive. Of course they would have then been able to prevent 3 (!) core melts, but the nuclear assholes do not care about doing the engineering right. They care about raking in as much money as possible at the start and hope that somebody else will have to pay for the cleanup.
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"Next time will be different."
Cooling for 5 years (Score:2)
What I find weird about the Fukushima design is the need to "cool down" the fuel for 5 years before disposal.
If something needs to be cooled for 5 years, it means it's full of energy and the process should be more efficient with the fuel rather than waste it like that.
I've heard that Uranium processes only take advantage of 1% of the fuel, while Thorium's percentage is much higher.
We shouldn't waste fuel like that. We should use efficient processes.
They've endangered us ALL! (Score:1)