Japan Fukushima nuclear thread
Discussion
mcdjl said:
Welshbeef said:
So what's the solution ?
Can they use robots to remove the reactive bits and ship to selefield?
They'll have to be careful if they do. The noise on the camera image is being caused by the radiation. It will cause noise in any electronic component (which will be worse the smaller it is). Depending on what the component is you'll get different effects. Camera = bad image motor controller =random movement etc. Until it just dies that is. And then you've got a dead, radioactive robot on top of the pile. Can they use robots to remove the reactive bits and ship to selefield?
Welshbeef said:
So do they simply need to create a vast concrete dome and seal it up for a thousand years job done?
Not really - remote vehicles is the obvious way to investigate and try to clear things. But those sort of dose rates are not necessarily 'unusual' inside a reactor core with lots of fission products and fuel - although I'm not sure its something you actually make a habit of measuring!I can't speculate on that hole and what it might be/what caused it.
Regarding sealing it for 100 years: both too long and not long enough! But that aside, more tricky than Chernobyl as they have 3, maybe 4 reactors they need to investigate and stabilise - the one 'good' thing about the Chernobyl accident was it was one reactor... and the one at the end of the block so access less complicated than it might have been (but still not easy).
If they can remove fuel elements, even damaged ones, that would reduce dose rates. The 'next step' at Chernobyl is to get the NSC functional and start to dismantle the sarcophagus and remains of the reactor: 31 years after the accident for comparison.
llewop said:
Welshbeef said:
So do they simply need to create a vast concrete dome and seal it up for a thousand years job done?
Not really - remote vehicles is the obvious way to investigate and try to clear things. But those sort of dose rates are not necessarily 'unusual' inside a reactor core with lots of fission products and fuel - although I'm not sure its something you actually make a habit of measuring!I can't speculate on that hole and what it might be/what caused it.
Regarding sealing it for 100 years: both too long and not long enough! But that aside, more tricky than Chernobyl as they have 3, maybe 4 reactors they need to investigate and stabilise - the one 'good' thing about the Chernobyl accident was it was one reactor... and the one at the end of the block so access less complicated than it might have been (but still not easy).
If they can remove fuel elements, even damaged ones, that would reduce dose rates. The 'next step' at Chernobyl is to get the NSC functional and start to dismantle the sarcophagus and remains of the reactor: 31 years after the accident for comparison.
davepoth said:
Digby said:
"Radiation level at Fukushima reactor highest since 2011 disaster"
"Feb 3, 2017: The new radiation level, described by some experts as “unimaginable,”
http://enenews.com/record-high-radiation-levels-at...
Well yes, if you measure the radiation inside the containment vessel, you'd expect quite a lot of it. That's normal. What's not normal is the 2m wide hole in the containment vessel. "Uruguay Syndrome" anyone?"Feb 3, 2017: The new radiation level, described by some experts as “unimaginable,”
http://enenews.com/record-high-radiation-levels-at...
saaby93 said:
With a photo like that, are they worried that with such high levels it might explode?
holes, feather merchants and outright liars like Arnie Gundersen or Helen Caldicott who will tell you Fukushima is a portal to Hades and old Nick himself is about to emerge.Welshbeef said:
How long would it take for all the fuel to be used up/how many months or years?
I cannot imagine a nuclear plant is fuelled once every decade or few decades
Most water cooled reactors will have a refuelling cycle every 12-18 months, some fuel elements will be replaced and others will be shuffled around inside to avoid hot spots and get even usage of fuel. How long a fuel element lasts before it's ready for reprocessing depends on the reactor type, but solid fuel is generally ready for reprocessing once ~1% of the actual fissile is used up, which is why solid fuel sucks from an efficiency perspective and why so-called High Level Waste isn't waste at all, it's mostly still fuel.I cannot imagine a nuclear plant is fuelled once every decade or few decades
Edited by hidetheelephants on Saturday 4th February 16:48
hidetheelephants said:
Most water cooled reactors will have a refuelling cycle every 12-18 months, some fuel elements will be replaced and others will be shuffled around inside to avoid hot spots and get even usage of fuel. How long a fuel element lasts before it's ready for reprocessing depends on the reactor type, but solid fuel is generally ready for reprocessing once ~1% of the actual fissile is used up, which is why solid fuel sucks from an efficiency perspective and why so-called High Level Waste isn't waste at all, it's mostly still fuel.
But this disaster happened in 2011 how can thee be any reaction ongoing now 6 years later? Surely it's now in half life territory?how is it possible for reactivity to increase 6 years later when no more fuel added to the reaction?Edited by hidetheelephants on Saturday 4th February 16:48
Welshbeef said:
But this disaster happened in 2011 how can thee be any reaction ongoing now 6 years later? Surely it's now in half life territory?how is it possible for reactivity to increase 6 years later when no more fuel added to the reaction?
It is unlikely that there has been any further reaction since the early stages of the accident - indeed, it's far from clear that there has been any further reaction since the earthquake caused a reactor trip, indeed, it's doesn't seem particularly likely as the core geometry is important for reactivity. All the damage, including melted reactor vessel bottom head, and melted grates can be adequately explained by radioactive decay heat (which is substantial in the early phase of the accident). The high radiation readings in the current story are a reflection of deeper exploration into the containment structure. Previous attempts to access the containment structure, have been from the top. The most recent attempt is via a fuel pool transfer channel, through which the robot was able to get access to the containment below the reactor (which is where the fuel would have been expected to have escaped to). It is not surprising that radiation levels at this location are substantially higher than elsewhere.
Welshbeef said:
But this disaster happened in 2011 how can thee be any reaction ongoing now 6 years later? Surely it's now in half life territory?how is it possible for reactivity to increase 6 years later when no more fuel added to the reaction?
Fission stopped the second the Tepco Homers pressed the stop button and the control rods were fully inserted, which happened pretty much as the earthquake hit; the shenanigans that followed had nothing to do with fission and everything to do with having a lot of decay heat and no means of getting rid of it fast enough once the power to run the cooling water circulation pumps disappeared when the wave destroyed the fuel supply for the emergency generators.TL;DR - no reaction occurred after the earthquake.
Is there an estimate for total cost yet? I guess not as they don't actually really know full extent and therefore the effort needed to neutralise it. What's total cost up to now been so far?
It's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
It's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
Gandahar said:
Is there an estimate for total cost yet? I guess not as they don't actually really know full extent and therefore the effort needed to neutralise it. What's total cost up to now been so far?
It's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
Which bit? The hysterical knee-jerk response of shutting down safe and functioning reactors has cost upwards of $25bn a year since 2011 in extra gas, oil and coal imports.It's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
MartG said:
And the simple economic fact that the remaining fuel is actually quite valuable
No it's not!The economics of reprocessing spent fuel is negative compared to just making new fuel from enriched uranium. Having to extract the uranium from bits of melted plant will cost vastly more than it's worth.
Gandahar said:
Is there an estimate for total cost yet? I guess not as they don't actually really know full extent and therefore the effort needed to neutralise it. What's total cost up to now been so far?
It's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
£151billion is the latest estimateIt's surprising not more is heard about it, are the Japanese typically low key? If this was in the USA updates would have been far more pressed for.
https://eandt.theiet.org/content/articles/2016/12/...
Reactors designed for submarines are best used for submarines.
Talksteer said:
No it's not!
The economics of reprocessing spent fuel is negative compared to just making new fuel from enriched uranium. Having to extract the uranium from bits of melted plant will cost vastly more than it's worth.
Too simplistic. Include the cost of storage/security of spent fuel - which still has 96% of its energy potential available - and it isn't clear. HMG has been scratching its head for decades over this calculation.The economics of reprocessing spent fuel is negative compared to just making new fuel from enriched uranium. Having to extract the uranium from bits of melted plant will cost vastly more than it's worth.
eldar said:
Talksteer said:
No it's not!
The economics of reprocessing spent fuel is negative compared to just making new fuel from enriched uranium. Having to extract the uranium from bits of melted plant will cost vastly more than it's worth.
Too simplistic. Include the cost of storage/security of spent fuel - which still has 96% of its energy potential available - and it isn't clear. HMG has been scratching its head for decades over this calculation.The economics of reprocessing spent fuel is negative compared to just making new fuel from enriched uranium. Having to extract the uranium from bits of melted plant will cost vastly more than it's worth.
I don't think there's any comparison to be drawn between the well-defined costs of reprocessing fuel that's still in its cladding and the completely undefined costs of extracting and processing corium that's welded to the core support assembly. More adventurous MSR advocates have claimed that with appropriate reactor design it will be possible to simply reduce spent solid fuel(and by corollary also difficult waste like corium) to salts and consume them without any further treatment.
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