Fukushima Daiichi nuclear disaster

[ATOMIC SUPLEX]

I wish someone would produce a clear report on dose and time. "It's like having a chest X ray" - What one in your life? every year? or a year long chest X ray? In comparison to what? One year in the zone? an instant? A couple of hours? A lifetime?

 

[elbows]

Barking_Mad used milliseverts for the yearly carcinogenic dose, so my post was relevant.

Ahh right.

In that case 150 microsieverts x 24 hours x 365 days = 1314000 microsieverts per year = 1314 millisieverts per year = more than 10 times a carcinogenic dose.

In reality you likely wouldnt be exposed to that level 24/7, and there will also be some decay in the radiation level over the course of a year. but even so nobody should be living in an area with readings that high.

 

[elbows]

I wish someone would produce a clear report on dose and time. "It's like having a chest X ray" - What one in your life? every year? or a year long chest X ray? In comparison to what? One year in the zone? an instant? A couple of hours? A lifetime?

There are 2 things going on when the media use these comparisons. They are trying to give people some sense of what the numbers mean. But they also tend to use this stuff to mislead and downplay the problem.

Time is indeed the key factor. Pretty much all the figures we are given for radiation levels at the site and further away are per hour. Pretty much all the figures the media use when comparing to chest x-rays are for a single x-ray. So if they say that such and such a level is equivalent to a single chest x-ray, what this really means is its the equivalent of receiving 1 x-ray per hour.

 

[elbows]

The attempts to create positive headlines that I was complaining about yesterday evening are continuing today, although not quite so bad:

http://www3.nhk.or.jp/daily/english/18_30.html

The Tokyo Electric Power Company, or TEPCO, says radiation readings fell slightly after water was discharged at the No.3 reactor of the Fukushima Daiichi nuclear power plant.

The company's Fukushima office took measurements about 500 meters northwest of the reactor on Friday afternoon.

The firm says that as of 1:50 PM, before the dousing operation began, the level of radiation stood at 3,484 microsieverts per hour, but dropped to 3,339 microsieverts by 2:50 PM, shortly after the operation.

The office cautions that it must closely analyze the small decline before making any judgment.
Friday, March 18, 2011 17:36 +0900 (JST)

OK at least they are using the higher numbers on site now rather than the ones from a location that has levels 10 times lower than that. And they have added a caveat about it being a small decline that needs careful analysis. When I look at the data in detail I still expect to see that this decline is a result of the decay that is taking place anyway, regardless of these spraying activities.

The real good news is that there have been no more massive spikes in any of the levels for several days now.

 

[Barking_Mad]

 

[elbows]

The real good news is that there have been no more massive spikes in any of the levels for several days now.

Spoke too soon. Following data shows that at the area of the plant that has been measuring levels in the 3000-4000 microsievert range in recent days (3-4 millisieverts), around 3.20pm JST the levels started to go back up again. They had fallen as low as 3345 microsieverts but as of 4pm when the data ends, had gone back up to 4485 microsieverts (4.485 millisieverts).

Not sure if this is actually down to a new release, or a change in wind direction affecting what this monitoring point has picked up, but its certainly spoils the nice decay trend that had been apparent for several days.

Data is within this document but its in Japanese.

http://www.meti.go.jp/press/20110318008/20110318008-3.pdf

 

[ATOMIC SUPLEX]

Should I stay or should I go?

 

[elbows]

Should I stay or should I go?

Where abouts are you?

Data on wind and plume prediction models has not been shared in a clear and timely manner, and much uncertainty remains in regards to whats already been released and what could yet happen.

From what I could tell there were signs that Tokyo received some contamination several days ago, and levels have been falling there since.

 

[Crispy]

Please use this thread to talk about the nuclear disaster

This thread is for general Japan earthquake/tsunami discussion

 

[audiotech]

'Japan weighs need to bury nuclear plant.'

Japanese engineers conceded on Friday that burying a crippled nuclear plant in sand and concrete may be the only way to prevent a catastrophic radiation release, the method used to seal huge leakages from Chernobyl in 1986.

http://uk.news.yahoo.com/22/20110318/tts-uk-japan-quake-ca02f96.html

 

[Fuchs66]

What I haven't heard mention of so far is that due to the fact that tonnes of sea water are being used to cool the fuel rods/reactor cores evaporating in the process, surely the affected reactors/fuel rods are slowly being caked with an ever thicker layer of salt which would impede the cooling effect to some extent.

 

[laptop]

What I haven't heard mention of so far is that due to the fact that tonnes of sea water are being used to cool the fuel rods/reactor cores evaporating in the process, surely the affected reactors/fuel rods are slowly being caked with an ever thicker layer of salt which would impede the cooling effect to some extent.

Very likely. And how does the zirconium of the fuel rod cladding react with salt?

Sandpile looks like the only way to go after this... just as soon as they can be sure it won't be an erupting sandpile...

 

[elbows]

Please use this thread to talk about the nuclear disaster

This thread is for general Japan earthquake/tsunami discussion

Thanks for your sterling and time-consuming work in separating the threads.

 

[elbows]

What I haven't heard mention of so far is that due to the fact that tonnes of sea water are being used to cool the fuel rods/reactor cores evaporating in the process, surely the affected reactors/fuel rods are slowly being caked with an ever thicker layer of salt which would impede the cooling effect to some extent.

Its been mentioned a few times in the press, although with more emphasis on what the salt water does to the equipment such as pumps than what it does to the fuel.

There was also at least one story of the threat that re-adding water to a pool that is empty or almost empty of water can bring, although I've forgotten the details right now.

 

[laptop]

There was also at least one story of the threat that re-adding water to a pool that is empty or almost empty of water can bring, although I've forgotten the details right now.

In principle, under certain circumstances, adding water can increase the chances of a nuclear reaction re-starting; unless they add enough boron to the water.

It's all to do with slowing down the neutrons emitted by one fuel rod so they're more likely to be absorbed when they hit another fuel rod - "moderation" of the neutrons in the jargon. Or, conversely, boron absorbing the neutrons.

 

[TitanSound]

Video explaining Millisieverts.

 

[Fuchs66]

Its been mentioned a few times in the press, although with more emphasis on what the salt water does to the equipment such as pumps than what it does to the fuel.

Yes all I've noticed are comments along the lines: Salt water + Electronics = Bad. Which is obvious.

I'm thinking more along the lines of the detrimental effect any salt crusting would have on the cooling of the fuel.

 

[TitanSound]

Yes all I've noticed are comments along the lines: Salt water + Electronics = Bad. Which is obvious.

I'm thinking more along the lines of the detrimental effect any salt crusting would have on the cooling of the fuel.

In a video I posted earlier they were saying the sodium in the sea water could cause damage to the metals used within the reactors.

 

[ATOMIC SUPLEX]

Where abouts are you?
.

I'm in the UK but am supposed to fly out soon. Tokyo. If it was just me it would be a no brainer but I'm taking my daughter.
Everyone I know in japan are not in the slightest bit worried though I have heard some shops are out of milk and bread. Da da daaaaaa. Not really japanese staples anyway.

 

[Minnie_the_Minx]

I'm in the UK but am supposed to fly out soon. Tokyo. If it was just me it would be a no brainer but I'm taking my daughter.
Everyone I know in japan are not in the slightest bit worried though I have heard some shops are out of milk and bread. Da da daaaaaa. Not really japanese staples anyway.

Think you might have problems with insurance (if anything went wrong) if you go against UK Gov advice

 

[ATOMIC SUPLEX]

Think you might have problems with insurance (if anything went wrong) if you go against UK Gov advice

I had thought of that but currently that is one of the least of my worries.

 

[Minnie_the_Minx]

I had thought of that but currently that is one of the least of my worries.

understandable, although there's your daughter to consider as well

 

[elbows]

I'm in the UK but am supposed to fly out soon. Tokyo. If it was just me it would be a no brainer but I'm taking my daughter.
Everyone I know in japan are not in the slightest bit worried though I have heard some shops are out of milk and bread. Da da daaaaaa. Not really japanese staples anyway.

OK well a risk assessment on such things is not easy at the best of times but here is how I would personally make such a decision.

If I had kids, I would delay going back. I would not return until it was pretty certain that there would be no more large releases from the plant that could coincide with the wind sending the stuff in Tokyo's direction. Once that stage was reached I would then return, unless there were any indications that serious amounts of radioactive cesium or iodine were lurking in the Tokyo area.

Of course all of this has to be weighed with the implications for delaying a return. As far as what people who are there who you know think, Im afraid they have no special insight into the radioactive realities at all, you should not be reassured by what they say at all Im afraid. The only context to which their opinion can sway the balance of decision making is that if they all think there is no problem, the implications for you delaying a return may be worse.

 

[elbows]

And as for the differing advice from the USA compared to Japan, its easily explainable even if they both have the same sense of the problem & share data fully.

Its practical for other countries to call on its citizens to leave, and to relocate their embassies away from Tokyo. And they have data that shows a theoretical risk from what has already happened so far, and concerns about future problems, which when combined with a duty of care to their own people, makes the decision relatively straightforward, err on the side of caution.

The Japanese government does not have the same luxuries, so they will err on the side of not having massive unmanageable evacuations.

 

[rutabowa]

As far as what people who are there who you know think, Im afraid they have no special insight into the radioactive realities at all, you should not be reassured by what they say at all Im afraid.

they can at least tell you that life is going on pretty much as normal in tokyo though... ie there aren't huge food shortages etc, which you might think from the general tone of the news here.
it is a tricky one tho... guess you just have to keep following the news.

 

[elbows]

they can at least tell you that life is going on pretty much as normal in tokyo though... ie there aren't huge food shortages etc, which you might think from the general tone of the news here.
it is a tricky one tho... guess you just have to keep following the news.

Very true. I should make it clear that I've only been talking about the immediate nuclear stuff rather than the wider picture.

 

[elbows]

Spoke too soon. Following data shows that at the area of the plant that has been measuring levels in the 3000-4000 microsievert range in recent days (3-4 millisieverts), around 3.20pm JST the levels started to go back up again. They had fallen as low as 3345 microsieverts but as of 4pm when the data ends, had gone back up to 4485 microsieverts (4.485 millisieverts).

The next set of data came out. Levels continued to climb, reaching 5055 microsieverts (5.055 millisieverts) at that location at 5PM, and the falling back, down to 3611 microsieverts by the time the data from that location ends at 8PM. The data at another location at plant boundary, I believe the one that featured in news stories I was complaining about, where levels had dropped to 289 microsieverts, also went back up at the same sort of time, and is also now back on the decrease but is still well above the levels mentioned in earlier stories.

Its hard to know if something new happened, or if its mostly to do with wind on site. Wind direction data is supplied with these figures, but it often changes frequently without having tended to make any obvious difference to the numbers. Further away from the plant the wind direction at different points in time has made a pretty huge difference to which places have suffered the worst contamination.

There has not been any new bad news about caesium or iodine for some days now, and its probably much too early to expect to hear about how much of this stuff may be spread over an area, or how big that area really is.

Edited to add that it has now become clear where the location on the site that I quote these numbers in the 3000-4000 microsievert (3-4 millisievert) range is. Its not on the site boundary like most of the other reading sites, it is 0.5km away from reactor number 2, north west of it to be precise. So approximately twice as close to the reactors as the other monitoring points on site, which tend to give readings ten times lower than these, are. Cannot really use these numbers to estimate the level right close to the reactors, but guess it could easily involve shifting the decimal place several points.

Not much other news from the IAEA & Japanese authorities, although data on the shared fuel pool seems to now be available and it is said to be ok at the moment.

 

[elbows]

Finally some data showing stuff happening over a much wider area, with animation.

http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-18GMT09:52

I've not had time to take it in yet, save that it does seem to show that wind took stuff inland some while back as it looked like it might based on predictions and readings at the time.

 

[ATOMIC SUPLEX]

understandable, although there's your daughter to consider as well

Don't worry she always comes first of course. Looks like we might be able to sort a months delay. The worst casualties will only be my wallet and the loss of three gigs.

 

[Minnie_the_Minx]

Don't worry she always comes first of course. Looks like we might be able to sort a months delay. The worst casualties will only be my wallet and the loss of three gigs.

What occurred to me earlier was that I don't know whether your daughter has dual nationality etc. and how things work if she has but isn't resident in Japan. How does it work? If, for example, she fell over and broke her ankle (which hopefully she wouldn't), how does the healthcare work over there? (Sorry, totally unrelated to nuclear reactor topic, but I'm just interested). Do you have to pay for healthcare there or are children treated free?