8.9 earthquake in Japan: tsunami warnings

[nismaratwork]

I guess you meant detectors, not dosimeters.

Well, I was thinking of simple film-exposure dosimeters... and still over the long-term they tend to max out regardless of the type. Detectors have a range, like a Geiger Counter, that can track CPM over time.

The other issue with dosimeters is that the good ones are fixed, the the ones worn by workers are more in the "get out idiot" range.

Having read accounts of radiological incidents, it doesn't seem that degree of exposure is an exact science; the biological element is too random, mobile, and likely to make a mistake and lick their fingers (crude example).

 

[Borek]

dosimeters are great at warning you to get out

Well, I was thinking of simple film-exposure dosimeters...

Then as far as I can tell you are just wrong. Dosimeter integrates the radiation, giving dose - but doesn't tell you "get out from here, radiation is too strong". Detector tells you "radiation level is xxx, get out from here", but doesn't tell you anything about the dose.

 

[nismaratwork]

Then as far as I can tell you are just wrong. Dosimeter integrates the radiation, giving dose - but doesn't tell you "get out from here, radiation is too strong". Detector tells you "radiation level is xxx, get out from here", but doesn't tell you anything about the dose.

Hmmmm...

Maybe this will help clarify what I mean: http://en.wikipedia.org/wiki/Comparison_of_dosimeters

When the film develops, run, and otherwise we're talking about strapping on (at least one) geiger counter. I don't know what's generally used in Japan, but it strikes me as insufficient.


Still, me being wrong would hardly be earth-shaking.

 

[Al68]

Remember, dosimeters are great at warning you to get out, get away, but they're less effective at estimating long-term exposure.

I was referring to the dose rate detectors installed in the facility, which are intended as a warning, not to estimate dose received. The doses received are normally estimated from personal dosimeters.

Having read accounts of radiological incidents, it doesn't seem that degree of exposure is an exact science...

Of course not, but a dose estimate doesn't need to be very accurate to tell the difference between a lethal dose and a harmless one.

 

[nismaratwork]

I was referring to the dose rate detectors installed in the facility, which are intended as a warning, not to estimate dose received. The doses received are normally estimated from personal dosimeters.Of course not, but a dose estimate doesn't need to be very accurate to tell the difference between a lethal dose and a harmless one.

Really... I for one would love to know if I'm getting 2 Sv, or 4, not a general range that tops out fairly quickly unless you're toting a GC with you all day. As for a harmless dose, unless you're a believer in radiation hormesis, I can't imagine that there is such a thing in this context, only risky, truly dangerous, and generally lethal.

Then again, you can snag 7+ Sv and live if that dose is fractionated, compared to someone getting 6 or so who dies. (See Brazil)

In a situation that is an evolving catastrophe with little in the way of consistant information being released by a company with a track-record of lying to the point of doctoring video, I'm inclined to believe the worst.

 

[Al68]

Really... I for one would love to know if I'm getting 2 Sv, or 4, not a general range that tops out fairly quickly unless you're toting a GC with you all day. As for a harmless dose, unless you're a believer in radiation hormesis, I can't imagine that there is such a thing in this context, only risky, truly dangerous, and generally lethal.

Of course there is such a thing. Would you not consider a dose of 10 mrem harmless in this context?

As far as the specific accuracy of the dosimeters worn in this case, I don't know what they wore, but I'm sure they were far more accurate than any geiger counter. A geiger counter is not an accurate way to measure dose, even if it integrates the dose rate.

 

[nismaratwork]

Of course there is such a thing. Would you not consider a dose of 10 mrem harmless in this context?

As far as the specific accuracy of the dosimeters worn in this case, I don't know what they wore, but I'm sure they were far more accurate than any geiger counter. A geiger counter is not an accurate way to measure dose, even if it integrates the dose rate.

No, I don't pretend to know what generations of nuclear scientists don't; is there a purely linear relationship between dose and risk, or is there hormesis? I certanly wouldn't wet myself over that dose, but harmless? No. I don't call a .22 harmless just because someone is firing a .50 machinegun at me, I simply recognize that both are potential risks, but separated by orders of magnitude. Still, harmless?... a chest X-Ray isn't harmless, it just has more benefits in the proper situation than harm. Hell, a sunny day in Colorado City isn't harmless either, but again, compare it to a leaking nuclear core and yeah, it seems pretty benign. I see no reason to diminish one simply because another risk of greater import exists.

As for the geiger counters, see my previous post with the dosimetry link... the more effective ones are essentially gussied-up geiger counters. In part, this is why I made the case that they're better at telling you when to run, than measuring your dose over prolonged periods. After all, this is not what they were designed for; 24hr exposure over days for some of these people.

 

[nismaratwork]

Speaking of innacurate information and changing facts on the ground...

http://www.cnn.com/2011/WORLD/asiapcf/03/27/japan.nuclear.reactors/index.html?hpt=T1

 

[Al68]

As for the geiger counters, see my previous post with the dosimetry link... the more effective ones are essentially gussied-up geiger counters. In part, this is why I made the case that they're better at telling you when to run, than measuring your dose over prolonged periods. After all, this is not what they were designed for; 24hr exposure over days for some of these people.

That's what personal dosimeters are for, but like I said, I don't know what kind they wore.

But generally, they are accurate enough for this purpose.

As a side note, geiger counters cannot really measure dose at all in any accurate sense, they can only count the number of interactions with the detector, without taking the energy of the radiation into account. That's why they are not generally used as dose rate meters or dosimeters. They are commonly used to measure radioactivity of a source, not dose rate.

 

[nismaratwork]

That's what personal dosimeters are for, but like I said, I don't know what kind they wore.

But generally, they are accurate enough for this purpose.

As a side note, geiger counters cannot really measure dose at all in any accurate sense, they can only count the number of interactions with the detector, without taking the energy of the radiation into account. That's why they are not generally used as dose rate meters or dosimeters. They are commonly used to measure radioactivity of a source, not dose rate.

Radex RD1008... two G-M tubes... the only thing that makes it more than a GC is keeping track of CPM.

 

[Al68]

Radex RD1008... two G-M tubes... the only thing that makes it more than a GC is keeping track of CPM.

Never used that particular model, but it looks like junk to me (Russian ), and from what I can tell, it maxes out at 999 mSv. Not only not very accurate, but doesn't have an adequate range for this purpose. Like I said, personal dosimeters that measure absorbed dose are far better for this purpose.

 

[nismaratwork]

Never used that particular model, but it looks like junk to me (Russian ), and from what I can tell, it maxes out at 999 mSv. Not only not very accurate, but doesn't have an adequate range for this purpose. Like I said, personal dosimeters that measure absorbed dose are far better for this purpose.

That is a personal dosimeter, one of the higher ends that was listed on Wikipedia. From what little I've seen of plant workers in Fukishima on TV, they're not wearing anything even that effective.

This is the information we know: http://www.americanbankingnews.com/...icker-personal-radiation-dosimeters-to-japan/

although that is not for plant workers.

The Fukishima workers, well... whatever they're toting around, I don't know, and I don't know how to find out. As I say, from what I've seen it's nothing overly fancy, more again in the lines of, "you should be leaving now" types.

 

[nismaratwork]

http://www.cnn.com/2011/WORLD/asiapcf/03/27/japan.nuclear.reactors/index.html?iref=NS1

Hmmm...

 

[Al68]

That is a personal dosimeter, one of the higher ends that was listed on Wikipedia. From what little I've seen of plant workers in Fukishima on TV, they're not wearing anything even that effective.

This is the information we know: http://www.americanbankingnews.com/...icker-personal-radiation-dosimeters-to-japan/

although that is not for plant workers.

The Fukishima workers, well... whatever they're toting around, I don't know, and I don't know how to find out. As I say, from what I've seen it's nothing overly fancy, more again in the lines of, "you should be leaving now" types.

It seems we are talking about two different things here. Personal doses are not normally estimated from such instruments, at least not in the U.S., unless workers were not wearing personal dosimeters that measure absorbed dose. Such instruments are normally instead used as real-time indicators to workers. (It's beyond the scope of this thread to explain why GM detectors do not accurately measure dose rates.)

http://en.wikipedia.org/wiki/Thermoluminescent_Dosimeter" are commonly used in the U.S. to estimate external doses, and are worn as a matter of policy during routine operations. They provide no real-time indication whatsoever, as that's not their purpose. They are used for the sole purpose of estimating doses received after the fact, during both normal operations and emergencies.

I would assume the same is true in Japan, unless they have a very different way of doing things.

 

[nismaratwork]

Surely this is hell.

http://www.cnn.com/2011/WORLD/asiapcf/03/28/japan.tsunami.hospital/index.html?iref=NS1

 

[nismaratwork]

It seems we are talking about two different things here. Personal doses are not normally estimated from such instruments, at least not in the U.S., unless workers were not wearing personal dosimeters that measure absorbed dose. Such instruments are normally instead used as real-time indicators to workers. (It's beyond the scope of this thread to explain why GM detectors do not accurately measure dose rates.)

http://en.wikipedia.org/wiki/Thermoluminescent_Dosimeter" are commonly used in the U.S. to estimate external doses, and are worn as a matter of policy during routine operations. They provide no real-time indication whatsoever, as that's not their purpose. They are used for the sole purpose of estimating doses received after the fact, during both normal operations and emergencies.

I would assume the same is true in Japan, unless they have a very different way of doing things.

OK... so my original point which sparked all of this,

Remember, dosimeters are great at warning you to get out, get away, but they're less effective at estimating long-term exposure.

Was correct? I feel like you're arguing the same point I was making as a layman.

 

[Astronuc]

Devastating power of tsunami flood at Kesennuma port.
Kesennuma on Google Maps - http://maps.google.com/maps?hl=en&q=Kesennuma port&um=1&ie=UTF-8&sa=N&tab=wl

(by the river)
(another place by the river/bay)
The eaves of the building in the foreground should be at ~7 m (21 ft) - the water is probably at ~5 m (15 ft).

(some neighborhood in the city)


For all the criticism is directed at the Fukushima Daiichi plant for not protecting against tsunami, it's pretty clear from the videos that the population and governments along the NE coast of Honshu did not expect such a tsunami given the amount of infrastructure that was wiped out - whole cities 4+ m underwater.

 

[rhody]

Surely this is hell.

http://www.cnn.com/2011/WORLD/asiapcf/03/28/japan.tsunami.hospital/index.html?iref=NS1

nismara,

That was moving, mind blowing and surreal all at the same time...

Rhody...

 

[nismaratwork]

Devastating power of tsunami flood at Kesennuma port.
Kesennuma on Google Maps - http://maps.google.com/maps?hl=en&q=Kesennuma port&um=1&ie=UTF-8&sa=N&tab=wl

(by the river)

(some neighborhood in the city)


For all the criticism is directed at the Fukushima Daiichi plant for not protecting against tsunami, it's pretty clear from the videos that the population and governments along the NE coast of Honshu did not expect such a tsunami given the amount of infrastructure that was wiped out - whole cities 4+ m underwater.

Who could have forseen an event that MIGHT happen once a millenia... a world-killer for a coastal civilation in the past certainly? Some perhaps, but not enough... not as you say, 4+m under and 6 mi INSLAND. The sheer amount of energy released in a short time, transmitted through the ocean and dumped onto land is terrifying! I look at that long-shot of the Tsar Bomba, and remember: that's less than an 1/8th the energy released without the vertical outlet at this event.

@rhody: It is too much to wrap one's head around... alone it's awful, but with whole villages and cities gone, generations of shrines, generations of homes and familliar haunts, and just plain generations of PEOPLE gone in minutes. We're not designed to understand or fully grasp that, only cope... and even that is an open question.

 

[Al68]

OK... so my original point which sparked all of this,

Remember, dosimeters are great at warning you to get out, get away, but they're less effective at estimating long-term exposure.

Was correct?

Not of dosimeters in general, no. But your point is very true of the Radox RD1008 and similar instruments, which is exactly why we don't use that type of instrument to estimate worker doses, and I think it's safe to assume that the Japanese don't either.

But the exact opposite is true for the dosimeters actually used to estimate workers' doses, typically http://en.wikipedia.org/wiki/Thermoluminescent_Dosimeter" (in the U.S. at least). TLD's, especially modern multi-chip TLD's, are very good at estimating doses received (after the fact), but worthless as a warning device.

 

[IMP]

Another interesting video taken from a helicopter:
http://www.picassodreams.com/picasso_dreams/2011/03/crane-collapses-on-fuel-rods-at-fukushima.html

 

[Astronuc]

Still some healthy aftershocks - http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0002dr3.php

Magnitude: 6.1
Date-Time:
Tuesday, March 29, 2011 at 10:54:33 UTC
Tuesday, March 29, 2011 at 07:54:33 PM at epicenter

Location: 37.417°N, 142.269°E
Depth: 13.8 km (8.6 miles)

Region: Off the East Coast of Honshu, Japan
Distances:
127 km (78 miles) ENE of Iwaki, Honshu, Japan
152 km (94 miles) SE of Sendai, Honshu, Japan
162 km (100 miles) ESE of Fukushima, Honshu, Japan
294 km (182 miles) NE of TOKYO, Japan

Location Uncertainty:
horizontal +/- 13 km (8.1 miles);
depth +/- 4.4 km (2.7 miles)

 

[Astronuc]

Nice summary of the Mag 9 earthquake event.

http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2011/20110311.php

 

[rhody]

Another heartbreaking story: punishing those caught up in the tragedy because of fear:

http://www.telegraph.co.uk/news/worldnews/asia/japan/8416302/Japan-nuclear-crisis-evacuees-turned-away-from-shelters.html"

Hundreds of people evacuated from towns and villages close to the stricken Fukushima nuclear plant are being turned away by medical institutions and emergency shelters as fears of radioactive contagion catch on.

and

The eight-year-old daughter of Takayuki Okamura was refused treatment for a skin rash by a clinic in Fukushima City, where the family is living in a shelter after abandoning their home in Minamisoma, 18 miles from the crippled nuclear plant. "Just being forced to live in a shelter causes us anxiety," Mr Okamura, 49, said. "The institution's refusal to treat my daughter came as a great shock to us."

Words cannot describe how that young girl must have felt, being refused treatment because of fear on the part of the health care workers assisting in treating those injured.

Rhody...

 

[alt]

http://www.smh.com.au/environment/fears-nuclear-shutdown-could-take-30-years-20110330-1cg9u.html

Mr Katsumata held a press conference after it was reported the radioactive core in a reactor at Fukushima appeared to have melted through the bottom of its containment vessel and on to a concrete floor, raising fears of a big release of radiation at the site.

I try to be an optimist most times, but can't see much cause for optimism here.

 

[Borek]

To quote other part of the same page:

Richard Lahey, who was the head of safety research for boiling-water reactors at General Electric when the company installed the Fukushima units, said workers appeared to have ''lost the race'' to save the reactor , but there was no danger of a Chernobyl-style catastrophe.

That means it is more of an economic problem than an ecological one.

 

[Astronuc]

Region - near the east coast of Honshu, Japan - is still getting some good aftershocks.

Mag 6.2
Date-Time:
Thursday, March 31, 2011 at 07:15:30 UTC
Thursday, March 31, 2011 at 04:15:30 PM at epicenter

Location: 38.954°N, 142.017°E
Depth: 39.6 km (24.6 miles)


Distances:
112 km (69 miles) SE of Morioka, Honshu, Japan
125 km (77 miles) NE of Sendai, Honshu, Japan
165 km (102 miles) ENE of Yamagata, Honshu, Japan
414 km (257 miles) NNE of TOKYO, Japan

Location Uncertainty:
horizontal +/- 14.9 km (9.3 miles); depth +/- 6.7 km (4.2 miles)

 

[Astronuc]

Tsunami-hit towns forgot warnings from ancestors
http://news.yahoo.com/s/ap/20110406/ap_on_re_as/as_japan_earthquake_warnings_in_stone

MIYAKO, Japan – Modern sea walls failed to protect coastal towns from Japan's destructive tsunami last month. But in the hamlet of Aneyoshi, a single centuries-old tablet saved the day.

"High dwellings are the peace and harmony of our descendants," the stone slab reads. "Remember the calamity of the great tsunamis. Do not build any homes below this point."

. . . .

 

[turbo]

Tsunami-hit towns forgot warnings from ancestors
http://news.yahoo.com/s/ap/20110406/ap_on_re_as/as_japan_earthquake_warnings_in_stone

So sad that ancient knowledge has been allowed to fade. It will be interesting to see if Japan limits reconstruction/rebuilding in damaged areas. Certainly, the US hasn't learned that lesson WRT to hurricanes, allowing people to rebuild in areas that have been devastated many times.

 

[OhDASoSad]

This may be small, but the Tokyo Electronics/Gaming Expo(s) going ahead... I admire the ability to perservere, and this will allow continuity of income. Other major Sony products (their new playstation phone for instance) are not delayed, which is also a good sign for their economy.

Small victories at this point, for a nation that has to still be shocked before mourning can properly begin.