Fukushima Daiichi nuclear disaster

[Tankus]

There's been a 5.3 in the Fukushima prefecture today.......TEPCO are reporting no radiation spike or any other iregularities.
Those damaged storage ponds are still loaded . .....Must have been a real shit your bricks time for the workers onsite when it hit.

 

[elbows]

Well they probably got rather used to earthquakes in the first year after the disaster as there were plenty back then, but I'm somewhat out of date in regards to how frequently they've been happening in more recent times.

Other recent news is they finally got round to noticing that part of the structure of the reactor 1 & 2 stack/chimney (that was used for venting highly radioactive substances) is damaged, presumably by the original earthquake that caused the tsunami.

 

[Dr Jon]

The Crisis at Fukushima 4 Demands a Global Take-Over

 

[elbows]

The Crisis at Fukushima 4 Demands a Global Take-Over

Laying it on a bit thick there to say the least. Tell me in what way the quantity of debris in the pool is troubling, or how Arnie Gundersen knows the fuel rods are 'bent, damaged and embrittled to the point of crumbling'. Given that Arnie thought that railings on the refuelling bridge were actually exposed fuel racks, and never loudly admitted his massive error when it became clear, I don't think I'll be taking his word on that one.

The mission to remove the fuel rods from that pool is not trivial. Stuff might go wrong. But I highly doubt the odds resemble what these fear mongers promote, in just the same way that the building hasn't fallen over.

I also note a lack of detail about exactly what is wrong with the current plan to remove the fuel rods, or quite how the international community can improve the plan.

For those that are interested, here is the document which shows the timetable for debris and fuel removal, including details of the debris itself. If everything stays on schedule then fuel removal will indeed begin in mid-november.

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130826_07-e.pdf

 

[yardbird]

I've just heard on the bbc that there is more leaking of "highly toxic radioactive water" and also that the access by people to there homes in the area has been increased from one to three years,

 

[Tankus]

Surely 4 is relatively the easier fix , its the slumped cores from the other reactors that's the major cause of concern , and that cesuim is still being produced.?

 

[elbows]

I've just heard on the bbc that there is more leaking of "highly toxic radioactive water" and also that the access by people to there homes in the area has been increased from one to three years,

There have certainly been numerous further leaks since we last talked about it on this thread. Some of them were caused by very stupid human errors, and the latest was due to heavier than expected rain.

As for residents returning home, I think the authorities have always been bullshitting about this, stating very optimistic timescales in order to give people hope. So the fact this has slipped from March 2014 to sometime in 2017 is no surprise.

 

[TopCat]

The operation to play a crazy game of fiddle sticks is about to get under way. They have to lift out the fuel rod assemblies out of the cooling pool and put each one in a canister without dropping any on the floor or letting them touch. If they fuck it up and drop a rod then it will catch fire apparently and preclude the removal of any more, with the possibility of them all going up being present. http://tinyurl.com/l8lgten

 

[TopCat]

What happened to the proposal to freeze the ground (using a ice super hero?) to create an ice barrier to hold the radioactive water back from the ocean?

 

[elbows]

The ground freezing thing is still under consideration, but it will take them ages and they will do some smaller-scale experiments using the technique first. And its not quite as simple as holding water back from the ocean, its more to try to stop groundwater entering the reactor basements.

As for the fuel rod assembly removal, the reality is not quite the same as the way it is often characterised. Things could go wrong, but its really not as precarious as often suggested. For example the fuel rods remain underwater, they are being moved from one part of the pool to another part of the reactor that is underwater. And they are not using random dodgy equipment to move them, they have rebuilt the sort of equipment that is normally in place at reactors for this purpose.

For example see the photos in this document which show a new green refuelling bridge (just scroll past the first few pages):

http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130925_04-j.pdf

 

[TopCat]

The pool is full of debris and is really high up. The boron wafers in the fuel rods have degraded. It's fiddle sticks I tell thee!

 

[elbows]

Its not full of debris anymore, they've spent the last month or two removing that stuff.

Some of the fuel rods having potentially degraded is the main risk, and so I shall be watching with interest. Not that it sounds like they will be providing a realtime running commentary for this operation though, there are already signs they will be vague about dates with the excuse of 'security'. And there are a lot of fuel bundles, so it will drag on for a long time.

 

[TopCat]

1330 fuel rods to be removed. The debris has not all been removed. It's in and amongst the rods.

 

[camouflage]

I had wondered if all the ceasium in the Pacific now might actually give the fishies a rest from mankinds relentless war againt them, in a Chernobyl Park kind of way, (the glowing green-belt). Turns out no, trade-able levels for radioactive material in fish have just been pushed up by a few thousand times instead (an extra 8 deaths per seventy years or something, there's an article somewhere). We'll all be glowing by the decades end and the war on those bastard upstart fish (they hate our freedoms apparently) will carry on without any let-up whatsoever.

 

[MikeMcc]

Just a reminder (again) about relative risk:

http://xkcd.com/radiation/

Just imagine the dilution in the Pacific...

 

[Tankus]

But its not all diluted is it. !

Put it in the food chain and that pyramid gets reversed with us on the small end

 

[elbows]

They are very close to starting the fuel removal from reactor 4 fuel pool now, as most of the certification is in place and in recent days one of the transportation casks had made it into the reactor 4 building.

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_131113_12-e.pdf

The operation will take about a year due to the silly amount of fuel rod bundles that are in that pool.

I believe TEPCO have recently acknowledged that they know about 3 damaged fuel bundles in the pool. But these are not bundles that were damaged in the disaster, they were damaged in other incidents 10 and 25 years ago.

Meanwhile for geeks interested in the exact details of the disaster, damage to containment, leakage points etc, something interesting has been detected using a boat in the torus room of reactor 1. They have found water gushing from the point where one of the vent pipes from the drywell connects to the torus (suppression chamber).

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_131113_11-e.pdf

Analysis of reactor 1 core melt potential has always been worse than the other reactors for several reasons, including the length of time that reactor went without water injection, the smaller size of various parts of that reactor, and the extra decay heat that stemmed from this reactor running out of water within hours of being shut down. Radiation levels in the torus room are much higher at this reactor than the others. And there are several reasons why vent pipes are an obvious potential failure point. Also I am only speculating at this point, but some core melt analysis documents for this kind of reactor do suggest that if molten corium was able to eat into the steel shell of the drywell, the point where the floor/wall of this shell meets the vent pipe is a good candidate. Also I don't know the position of the reactor pedestal opening (which molten corium could splash though if it falls out of the reactor vessel) is for reactor 1, but one potential location matches the south-east direction that the leaking vent pipe just happens to be in.

 

[elbows]

Apparently they have confirmed that fuel removal will start on Monday. They will be doing the fuel bundles that have never been used first (these are easier to deal with and technically don't even require water shielding, e.g. they removed two of these in the past for inspection using a crude crane setup that I've posted video of in the past).

http://www.japantimes.co.jp/news/20...day/#at_pco=tcb-1.0&at_tot=8&at_ab=-&at_pos=0

 

[elbows]

There is some video showing parts of the fuel removal operation which started this week.

An empty transport cask is moved into the pool, then one of the unused fuel bundles is moved into the cask.



Following on from what I said in a previous post about some damaged fuel that has been in the pool since well before the tsunami, it has now been revealed that there are actually 80 damaged fuel bundles spread across all four reactor spent fuel pools, with the bulk of them in reactor 1 pool. Again these are fuel bundles that were known to be damaged long before the disaster, and the bulk of them seem to be in reactor 1 pool because that was the first reactor that was built and there were probably deficits in the fuel manufacturing process at that point in the history of nuclear power. So this is an interesting example of longstanding fuel issues that have gone undealt with, and largely unreported in public, over many decades, and only come out now because they finally have to empty these pools as a result of the disaster.

http://ex-skf.blogspot.co.uk/2013/11/fukushima-i-nuke-plant-tepco-admits.html

 

[equationgirl]

Its not full of debris anymore, they've spent the last month or two removing that stuff.

Some of the fuel rods having potentially degraded is the main risk, and so I shall be watching with interest. Not that it sounds like they will be providing a realtime running commentary for this operation though, there are already signs they will be vague about dates with the excuse of 'security'. And there are a lot of fuel bundles, so it will drag on for a long time.

This could be years of work to decommission the fuel rods, never mind anything else. Look how long the decommissioning has been going on at UK sites like Dounreay and Sellafield.

 

[Tankus]

Where are putting it...? More short term ,high risk, above ground , vunerable, on site storage?

Another temporary temporary 'arrangement' ?? With the can being kicked down to some 'other' Governments risk/cost.

 

[elbows]

Where are putting it...? More short term ,high risk, above ground , vunerable, on site storage?

Another temporary temporary 'arrangement' ?? With the can being kicked down to some 'other' Governments risk/cost.

Well as I'm sure you are well aware, temporary arrangements are pretty much the story of used nuclear fuel everywhere, nuclear business as usual.

I have to strongly dispute the idea that all fuel pools are high risk though. As I've long been saying, the risk of nuclear energy disasters is not high, otherwise we would have seen more disasters over the last 40+ years. Its the stakes that are high - i.e. a low risk of something going wrong, but very severe consequences on the rare occasions that something does go wrong. It is pathetic and unacceptable that so few medium and long-term measures to deal with nuclear fuel have been entertained so far.

They are moving the fuel to the common fuel pool, which is at ground level on the site. That pool avoided catastrophic disaster during the tsunami, earthquake and power cut nightmares on site, so it would be foolish to suggest there is a very high risk of something going wrong at that pool in future. This in no way means I am pro nuclear power or at all happy with the way humanity has failed to deal with spent nuclear fuel or intends to deal with it in future. But I don't believe in hyping the threat, especially since there are so many greater risks present at the Fukushima site, including the fuel pools that are perched on high at damaged reactor buildings at Fukushima.

 

[Mr.Bishie]

This could be years of work to decommission the fuel rods, never mind anything else. Look how long the decommissioning has been going on at UK sites like Dounreay and Sellafield.

40 years, according to an article in the Guardian today!

 

[The Pale King]

These updates are really appreciated, elbows. Even if it does make me nervous when an alert pops up...

 

[elbows]

This could be years of work to decommission the fuel rods, never mind anything else. Look how long the decommissioning has been going on at UK sites like Dounreay and Sellafield.

I'm not entirely sure that the term decommission is appropriate for fuel rods themselves. Reactors and sites are decommissioned over long periods of time as you point out.

But when it comes to the spent fuel, the approach has generally been to leave them in fuel pools at reactor sites for ages. As pools have become full, some of the older fuel bundles have been moved to dry cask storage, again usually on-site. Since the heat the fuel gives off decreases over time, its possible to move fuel from pools to dry casks in time periods such as 5 years after the fuel was last used. But again in practice its often been done much more slowly than that, and operators have often favoured refitting their spent fuel pools to cram more fuel in. In the case of Fukushima, I expect the common spent fuel pool was built later on in order to deal with the individual reactor pools filling up, but I believe they also have some dry cask storage on-site too.

Some countries, such as the UK and France indulged in a lot of fuel reprocessing instead, but this agenda has obviously hit various snags at times and still leaves plenty of radioactive waste.

Certainly when it ones to decommissioning the reactors at Fukushima and removing the melted fuel from the broken reactors, they have talked about 40 year timescales. But this is considered optimistic by many, due to a large number of complications. Decommissioning a reactor that didn't melt down is tedious, decommissioning one with fuel that has escaped the reactor pressure vessel due to core meltdown is uncharted territory that requires technologies and solutions that are presently unavailable.

There is also a lot of other radioactive material, e.g. debris currently stored in containers, at the Fukushima site. Whether this and the spent fuel ever gets moved elsewhere may depend on whether they ever manage to decommission the reactors and remove the melted fuel. If they fail to do that, perhaps they may as well keep a lot of radioactive shit at the site indefinitely.

 

[equationgirl]

Wasn't sure if decommission was strictly the right word, but thought it better than 'remove' for example, because I doubt it's a simple case of removal, if you see what I mean.

 

[Tankus]

whats the bet it becomes a site of choice for all the other stored "temp " holding ponds in Japan ......

if its shitted up ...whats a bit more shit !!!

 

[elbows]

Wasn't sure if decommission was strictly the right word, but thought it better than 'remove' for example, because I doubt it's a simple case of removal, if you see what I mean.

Well I guess its fair enough to describe the process as the decommissioning of the fuel pool, rather than the fuel.

whats the bet it becomes a site of choice for all the other stored "temp " holding ponds in Japan ......

if its shitted up ...whats a bit more shit !!!

It has crossed my mind. Probably a few issues with this though, such as conditions on site, transportation across damaged infrastructure, future tsunami risk. And I haven't looked at whether Japan has any long term spent fuel storage plans (in most countries such plans have been put on hold). Anyway I guess it will be a long time before this comes up.

Assuming they eventually, over the next 5-ish years, manage to remove the fuel from all of the reactor pools, we might also hear more about 'plan b' for dealing with the melted fuel in the reactors. They won't want to give up easily on removing it, but it will be so bloody difficult that eventually, with spent fuel pools emptied and decay heat in reactors reduced substantially over time, they may be forced to look at something vaguely similar to Chernobyl. How many more problems they have with the water cooling system and other stuff like rust inside the reactors are factors too.

Anyway it sounds like the first cask of fuel bundles from reactor 4 has now been transferred out of the building and into the common spent fuel pool building. I'm not at all surprised they have managed this, especially since the first fuel bundles they've moved are unused ones that technically don't actually have to be treated in such a sensitive manner.

 

[ChrisD]

http://climateviewer.com/2013/11/24/10-most-radioactive-places-on-earth/

according to this website Fukushima is No. 1 (and could be for some years to come)

 

[elbows]

http://climateviewer.com/2013/11/24/10-most-radioactive-places-on-earth/

according to this website Fukushima is No. 1 (and could be for some years to come)

I have no reason to believe that list is sorted by how radioactive the places on the list are. For example the location numbered 7 had this in its description:

Experts believe that Karachay may be the most radioactive place in the world, and over 400,000 people have been exposed to radiation from the plant as a result of the various serious incidents that have occurred — including fires and deadly dust storms.