8.9 earthquake in Japan: tsunami warnings

[nismaratwork]

Question: Can severe radiation poisoning really make you start bleeding from every bodily orifice?

Yes, 'bleeding' from mucous membranes (eyes, nose, GI tract from mouth to... end) can happen. It's not like Ebola after organs begin to 'fade', but rather a result of rapid-dividing cell death, and large-scale production of schistocytes (destroyed leukocytes).

At those levels 2-6 Sv, you can expect every organ system that involves rapidly dividing cells to suffer within 1-7 days, followed by a "latent" period for some, and then emergence of major symptoms as the dead cells fail to be replenished (immune collapse, GI collapse, MOF).

It's not a way to go if you have a choice.

 

[Al68]

Gotcha, thanks Al...

... 300-500 REM total body exposure is still considered the lethal threshold for acute exposure?

450 rem is generally considered to be the LD/50/30 dose. Doses greater than 1000 rem are generally considered lethal, with dire prognosis even with medical attention.

By the way, why the lack of love for Sv? In the case where we have a mix of gamma and alpha it seems useful to stick that quality factor in.

The quality factor has nothing to do with converting between rem and Sv. 1 Sv=100 rem regardless of radiation type. The quality factor is used to convert between rad and rem, or between gray and Sv (1 gray=100 rad).

Both rem and Sv include the quality factor, which is why they are the units used for dose limits.

The reason I prefer rem/rad to Sv/Gy units is just because that's what I've always worked with, and that's what all the limits are stated in for the NRC, DOE, and the U.S. Navy, unless they've changed since I've been in. All doses received are stated in rem, dose rate meters read out in rem, etc.

It's the same reason I prefer my car speedometer to show mph instead of kph.

 

[Lancelot59]

Yes, 'bleeding' from mucous membranes (eyes, nose, GI tract from mouth to... end) can happen. It's not like Ebola after organs begin to 'fade', but rather a result of rapid-dividing cell death, and large-scale production of schistocytes (destroyed leukocytes).

At those levels 2-6 Sv, you can expect every organ system that involves rapidly dividing cells to suffer within 1-7 days, followed by a "latent" period for some, and then emergence of major symptoms as the dead cells fail to be replenished (immune collapse, GI collapse, MOF).

It's not a way to go if you have a choice.

That does sound like an awful way to die.

 

[nismaratwork]

450 rem is generally considered to be the LD/50/30 dose. Doses greater than 1000 rem are generally considered lethal, with dire prognosis even with medical attention.The quality factor has nothing to do with converting between rem and Sv. 1 Sv=100 rem regardless of radiation type. The quality factor is used to convert between rad and rem, or between gray and Sv (1 gray=100 rad).

The reason I prefer rem/rad to Sv/Gy units is just because that's what I've always worked with, and that's what all the limits are stated in for the NRC, DOE, and the U.S. Navy, unless they've changed since I've been in. All doses received are stated in rem, dose rate meters read out in rem, etc.

It's the same reason I prefer my car speedometer to show mph instead of kph.

Gotcha, and I've always worked with Gy/Sv... I understand completely. I'd just add, I think that LD/50/30 is WITH medical attention.. it all gets quite dire without it.

AFAIK 1 REM of say, strong alpha = 20x when converting to Sv? Again, you can see I've just not workedwith REM, just Sv and Gy (damn you SI!).

 

[nismaratwork]

That does sound like an awful way to die.

It is indeed, just look at Aleksander Litvinenko...

http://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvinenko

Acute radiation poisoning is incredibly rare, and most of it occurred during "excursions" or cirticality accidents early in the nuclear story, except for the obvious bombings in WWII.

Frankly, it just shuts your body down, an the "walking ghost" period is terrifying to consider. Beyond that, if you survive, your chances of developing some horrific cancers and blood disorders skyrockets.

Rare though... very rare.

 

[Al68]

Gotcha, and I've always worked with Gy/Sv... I understand completely. I'd just add, I think that LD/50/30 is WITH medical attention..

No, the 450 rem LD/50/30 assumes no medical attention.

AFAIK 1 REM of say, strong alpha = 20x when converting to Sv.

No, 1 Sv = 100 rem and 1 Gy = 100 rad for any radiation type. It's like converting from feet to meters, the same factor regardless.

For high energy alpha, QF=20:

1 rad = 20 rem and 1 Gy = 20 Sv.

Rad and Gy are units of absorbed dose. Rem and Sv are units of dose equivalent. Dose equivalent = absorbed dose times quality factor.

 

[nismaratwork]

No, the 450 rem LD/50/30 assumes no medical attention.No, 1 Sv = 100 rem and 1 Gy = 100 rad for any radiation type. It's like converting from feet to meters, the same factor regardless.

For high energy alpha, QF=20:

1 rad = 20 rem and 1 Gy = 20 Sv.

Gotcha... sheesh I really should have studied the "older" units.. especially since they never really went away.

Maybe I need to bone up on my curie/sunshine units and Roentgen.

I also should have intuited this from the name, "Radiation Equivalent Man"... oh well.


Thanks Al!

 

[Proton Soup]

Would filtration work? Using activated carbon, sand, and plants (water hyacinth?).

yes, activated carbon will adsorb iodine. http://en.wikipedia.org/wiki/Activated_carbon#Properties

just keep in mind that there is a limit to how much of anything it adsorbs before you have to throw it away.

sand is useless, sorry. good for large particulates, or as a bacterial substrate in biological filters (ammonia/nitrite).

don't know about plants. plants are decent at nitrate/phosphate removal.

distillation i don't know. depends on the design of your still i think, but most commercial distilled water is very pure.

http://en.wikipedia.org/wiki/Reverse_osmosis" is perhaps the purest affordable home filtration you can buy. not a high output, and produces a lot of waste water, but plenty reasonable for drinking water. it has one major drawback, that it needs pressurized water (tap water pressure). so as long as your disaster doesn't disable your running water, you're fine. otherwise, you might want to have one of those pour-through carbon or chemical adsorption filters handy.

 

[nismaratwork]

Ohhhh DA...

[1:51 p.m. ET Thursday, 2:51 a.m. Friday in Tokyo] Low radiation levels have reached as far as Sweden, according to the Swedish Radiation Safety Authority. Leif Moberg, head of research for the authority, said there have been readings of radioactive iodine in Sweden, as expected, but the amount is "very low and it does not pose any health risk at all for humans or the environment."

Don't worry, it's not significant, but I know this is the kind of thing you do love.


edit: One thing Proton, reverse Osmosis also wastes quite a bit of water, so unless a Pur or Brita or whatever really is impossible, it's not ideal.

 

[Borek]

Don't worry, it's not significant

The best comment I heard about was in todays news in Polish TVN. They asked a nuclear scientist about the radiation, and he asnwered in serious tone and with a dead face - yes, the cloud is coming to Poland and we are seriously concerned; we are not sure if our devices are sensitive enough to measure the contamination.

 

[nismaratwork]

The best comment I heard about was in todays news in Polish TVN. They asked a nuclear scientist about the radiation, and he asnwered in serious tone and with a dead face - yes, the cloud is coming to Poland and we are seriously concerned; we are not sure if our devices are sensitive enough to measure the contamination.

The sad thing is that he probably terrified some people... *facepalm*

 

[lisab]

The best comment I heard about was in todays news in Polish TVN. They asked a nuclear scientist about the radiation, and he asnwered in serious tone and with a dead face - yes, the cloud is coming to Poland and we are seriously concerned; we are not sure if our devices are sensitive enough to measure the contamination.

That's awesome.

 

[nismaratwork]

Lord... I told that to my aunt and this is her response, note that my family is 1/4 Polish!:

Me: *Quotes Borek*
Her:"You mean the because it's Poland?"
Me: "What?!"
Her: "You know, they don't have the right equipemnt..."
Me: "Are you joking?... No, I can see you're not..."
Her: "So, why can't they detect it?"
Me: "*deep sigh* It's a JOKE, the levels are too low"
Her: "Oooooooh *dead air* ... OK."
Me: *Dies a little inside*

Fin.

 

[lisab]

Lord... I told that to my aunt and this is her response, note that my family is 1/4 Polish!:

Me: *Quotes Borek*
Her:"You mean the because it's Poland?"
Me: "What?!"
Her: "You know, they don't have the right equipemnt..."
Me: "Are you joking?... No, I can see you're not..."
Her: "So, why can't they detect it?"
Me: "*deep sigh* It's a JOKE, the levels are too low"
Her: "Oooooooh *dead air* ... OK."
Me: *Dies a little inside*

Fin.

I have relatives just like that, ahahaha...erm...lots of them actually...sigh.

Salt of the Earth, bless their hearts.

 

[nismaratwork]

I have relatives just like that, ahahaha...erm...lots of them actually...sigh.

Salt of the Earth, bless their hearts.

See, this is where you're a good pixie, and I'm an evil bastard.

Alternate: Burn their hearts and salt the Earth.

 

[nismaratwork]

http://www.cnn.com/2011/WORLD/asiapcf/03/25/japan.nuclear.reactors/index.html?hpt=T2

Unfortunate.

STORY HIGHLIGHTS
An official says high radiation in water indicates nuclear fuel in Unit No. 3 is damaged
Plant operator is urged to improve its radiation control measures
Work continues to control temperatures at all the plant's six reactors
Pressure had risen at the No. 1 unit, though it now seems "rather stable"

 

[Al68]

http://www.cnn.com/2011/WORLD/asiapcf/03/25/japan.nuclear.reactors/index.html?hpt=T2

Unfortunate.

"Some 17 people already have been exposed to 100 or more millisieverts of radiation since the plant's crisis began two weeks ago after a 9.0-magnitude earthquake and subsequent tsunami struck."

The implication is that no one has received a dose high enough to be an immediate health concern, including those present initially. Am I missing something here? Are they including those present initially? Or could "100 or more mSv" mean much, much, more?

Between the melodramatics and the obvious fact that the writers of these articles don't know anything about the subject matter, as evidenced by the way they word things, it's hard to tell what's really going on.

 

[rhody]

Local News Radio is reporting the core for reactor #1 is compromised and will complicate efforts to contain radiation. A quick scan of local cybernews came up empty. Personally, I am surprised since the explosion at reactor #3 was greatest. On second thought though, imagine you sneezing and trying to suppress it to contain it, that may do more damage than letting it fly. I hope they (media source ) are incorrect.

Rhody...

P.S. Unlike Chernobyl, the 6 reactors are close to water, and one would assume, the water table. If I remember correctly they pumped liquid nitrogen near the burning core from wells driven at an angle to converge below where the core was. Might this be a desperate measure now given consideration, given the circumstances ?

Finally, I would think they would be considering using heroic, self-sacrificial robots to do some of the dirty work of inspection at deeper levels, (if possible) to assess reactor integrity and containment around it. It may not be possible given the situation, but it was a thought.

Edit: 6:38 am The same radio news reiterated the story 15 minutes later with an official audio newsclip of what sounded like a Japanese reporter who said it was reactor #3, not reactor #1 as I reported above. In the race to be the first, sometimes these folks get it wrong.

Thanks Astronuc for your explanation on Mox fuel many posts ago, but I know you already know that.

 

[nismaratwork]

Local News Radio is reporting the core for reactor #1 is compromised and will complicate efforts to contain radiation. A quick scan of local cybernews came up empty. Personally, I am surprised since the explosion at reactor #3 was greatest. On second thought though, imagine you sneezing and trying to suppress it to contain it, that may do more damage than letting it fly. I hope they (media source ) are incorrect.

Rhody...

P.S. Unlike Chernobyl, the 6 reactors are close to water, and one would assume, the water table. If I remember correctly they pumped liquid nitrogen near the burning core from wells driven at an angle to converge below where the core was. Might this be a desperate measure now given consideration, given the circumstances ?

Finally, I would think they would be considering using heroic, self-sacrificial robots to do some of the dirty work of inspection at deeper levels, (if possible) to assess reactor integrity and containment around it. It may not be possible given the situation, but it was a thought.

Edit: 6:38 am The same radio news reiterated the story 15 minutes later with an official audio newsclip of what sounded like a Japanese reporter who said it was reactor #3, not reactor #1 as I reported above. In the race to be the first, sometimes these folks get it wrong.

Thanks Astronuc for your explanation on Mox fuel many posts ago, but I know you already know that.

You'd be right, and they've found cobalt isotopes in the ocean water around the plant...

... somewhere in that previously closed circuit, that water which has been poured in has been in contact with the core, then leaked out. This is disastrous for the workers, and the environment in the area (at least).

I don't think robots would function well in that kind of radiation field, or send images... I could be wrong.

 

[nismaratwork]

http://www.cnn.com/2011/WORLD/asiapcf/03/25/japan.nuclear.reactors/index.html?hpt=T1

STORY HIGHLIGHTS
NEW: The threat to workers exposed to contaminated water is akin to sunburn, expert says
NEW: The development does not necessarily indicate a catastrophic failure, he says
Water contamination in unit No. 3's basement is likely from reactor core, an official says
The plant's operator has been urged to improve its radiation control measures

 

[WhoWee]

P.S. Unlike Chernobyl, the 6 reactors are close to water, and one would assume, the water table. If I remember correctly they pumped liquid nitrogen near the burning core from wells driven at an angle to converge below where the core was.

I've been wondering if it was possible to use cooling techniques. Have you read any assessments of potential danger to the containment structure from the liquid nitrogen?

 

[Astronuc]

I've been wondering if it was possible to use cooling techniques. Have you read any assessments of potential danger to the containment structure from the liquid nitrogen?

Lack of ductility and thermal contraction would be an issue, besides the fact that Liquid nitrogen would become gaseous as it is heated.

I'm not sure how one would add liquid nitrogen to containment or how it would be kept cold. Dry ice might be better. Either way, one then has to contend with a massive volume of inert gas or CO₂, which is hazardous in large volume. Suffocation of plant personnel would be a concern.

 

[nismaratwork]

Lack of ductility and thermal contraction would be an issue, besides the fact that Liquid nitrogen would become gaseous as it is heated.

I'm not sure how one would add liquid nitrogen to containment or how it would be kept cold. Dry ice might be better. Either way, one then has to contend with a massive volume of inert gas or CO₂, which is hazardous in large volume. Suffocation of plant personnel would be a concern.

Then again, suffocation seems kindness next to radiation poisoning...

 

[IMP]

Seems somewhat relevant to the current discussion:
http://www.groundfreezing.com/index.html


See also some of the projects:
http://www.groundfreezing.com/projects.html

 

[nismaratwork]

"Some 17 people already have been exposed to 100 or more millisieverts of radiation since the plant's crisis began two weeks ago after a 9.0-magnitude earthquake and subsequent tsunami struck."

The implication is that no one has received a dose high enough to be an immediate health concern, including those present initially. Am I missing something here? Are they including those present initially? Or could "100 or more mSv" mean much, much, more?

Between the melodramatics and the obvious fact that the writers of these articles don't know anything about the subject matter, as evidenced by the way they word things, it's hard to tell what's really going on.

It is hard to tell, but it seems fairly clear that there is loss of containment and damaged rods in #3...

...Honestly I just find it hard to believe, based on what's emerging that the doses have been so low, especially when the pool in 4 first started to boil-off.

 

[nismaratwork]

This is heartbreaking...

http://www.cnn.com/2011/WORLD/asiapcf/03/25/otsuchi.japan.quake/index.html?hpt=C1

 

[Al68]

It is hard to tell, but it seems fairly clear that there is loss of containment and damaged rods in #3...

...Honestly I just find it hard to believe, based on what's emerging that the doses have been so low, especially when the pool in 4 first started to boil-off.

Well, like you, I was most concerned about the initial doses, since they weren't reporting them, and it's possible that the dose limits were exceeded by mistake, even with alarming radiation detectors that were most certainly present. But it's starting to look like maybe (hopefully) no one hung around long enough (and close enough) to be a major problem.

After that, there is a much smaller risk of a huge mistake resulting in unacceptably large doses.

 

[rhody]

I've been wondering if it was possible to use cooling techniques. Have you read any assessments of potential danger to the containment structure from the liquid nitrogen?

WhoWee,

I went back and reread http://www.guardian.co.uk/world/2006/mar/26/nuclear.russia" for lessons to be learned from Chernobyl that I had posted before, excerpts below:

The graphite in Reactor No 4 had been burning for almost 24 hours when the Chernobyl Commission decided the only way to extinguish the fire was to smother it. The scientists suggested sand, boron and lead, to absorb radiation and cool the melting core - 4,000 tons would do it, dropped into the blazing reactor from the air. On the afternoon of the 27th, two Mi-8 helicopters from Kiev began the first of hundreds of firefighting sorties. The pilots navigated through a forest of pylons surrounding the power station to hover 100 metres above the burning building, and, aiming by eye, dropped individual bags of sand from the helicopters' open doors. The radiation directly over the reactor was such that the pilots soon began being sick in the air; eventually they started flying in respirators, and sliding lead panels under their seats. By 1 May, they had dropped 4,450 tons of sand into the reactor.

But on 2 May, the engineers and physicists at Chernobyl made a horrifying discovery: the temperature of the core and the volume of radionuclides rising from it were both increasing. They suspected that the whole helicopter operation had been a terrible mistake: the sheer weight of everything they had dropped on the reactor from the air - including 2,400 tons of lead - had not only caused structural damage but was pressing the hot reactor core against its concrete base. And if the uranium reached meltdown temperature - 2,900C -a single sphere of molten fuel would burn through the concrete foundations of the reactor building, and keep going until it reached the water table. At that moment, there would be another explosion, exponentially more devastating than the first; the three remaining reactors would be destroyed in a nuclear blast that would render Ukraine, Belarus and Russia uninhabitable for decades to come.

For the cleanup effort:

During May and June 1986, the 600,000 liquidators were set to work: soldiers were sent to Kiev to cut the leaves from every bush and tree in the city and bury them; helicopter crews sprayed a special polymer film from the air to capture radioactive particles on the ground; the Pripyat was dammed to prevent irradiated water flowing into the Dnieper; 135,000 people were evacuated from the exclusion zone; 70 villages were so contaminated that they were flattened and buried in their entirety.

To collect pieces of fuel and graphite from the roofs around Reactor No 4, three lightweight robots were bought in Germany for one million gold roubles. But up on the roofs, the machines were useless: their electronics failed in the intense fields of radioactivity; they got bogged down in the melted bitumen and became entangled in abandoned fire hoses. 'The best robots,' Steinberg explains bitterly, 'were people.'

So, 3,400 army reservists with picks and shovels were sent to clear the roofs. The men were given strict time limits - 20 seconds, 25 seconds, two minutes - to limit their exposure, and makeshift lead clothing made from metal torn from the walls of the plant. But little practical protection was possible: 'It could reduce radiation by two or perhaps three times, but it wasn't enough,' Steinberg says. 'The dose was immense.'

Although they were volunteers - two minutes on the roof was said to count for two years of military service - few had any real understanding of the risks they were taking. One soldier later described a friend climbing the tower overlooking Reactor No 4 to hoist a flag, 'to symbolise man's power to conquer radiation'. Sometime afterwards, the soldier became paralysed.

With the clean-up complete, the Sarcophagus - the huge prefabricated steel and concrete shell built to contain the ruins of Reactor No 4 - was put together by cranes; a six metre-thick wall protected the builders from gamma radiation. It took five months. On 1 October 1986, the turbines of Reactor No 1 at Chernobyl came back online; No 2 and No 3 followed soon afterwards.

Here is a follow on report on the state of the Sarcophagus, as of December 2000, when the remaining 3 reactors were shut down and the site began decommissioning.

Under extremely hazardous conditions, thousands of "Liquidators" worked to contain the remains of the fourth reactor. The shelter surrounding the reactor was completed less than six months after the explosion during peak radioactivity levels. The massive concrete and steel "Sarcophagus", quickly constructed using "arms length" methods, has deteriorated over the years, creating a potentially hazardous situation. Several repairs were made to the current shelter, including the stabilisation of the ventilation stack and reinforcement of the roof. In addition, a plan for the construction of a more secure and permanent structure to be built around the existing Sarcophagus was drafted; work has already begun on the infrastructure of this new shelter. The plan, called the Shelter Implementation Plan, is a project of the Chernobyl Shelter Fund. Both efforts, whose combined expected expenditures over the next eight or nine years exceed $765 million, are administered by the European Bank for Reconstruction and Development.

Rhody...

P.S. The biggest concern at the time was that the molten core of uranium and graphite not being allowed to continue to spew radioactive particles into the air and into the environment, second, that the core not be allowed to reach underground water tables. Every effort was made to prevent that at all costs. It appears that they succeeded on both counts.

 

[nismaratwork]

Well, like you, I was most concerned about the initial doses, since they weren't reporting them, and it's possible that the dose limits were exceeded by mistake, even with alarming radiation detectors that were most certainly present. But it's starting to look like maybe (hopefully) no one hung around long enough (and close enough) to be a major problem.

After that, there is a much smaller risk of a huge mistake resulting in unacceptably large doses.

I hope you're right, but the information that's evolving would seem to indicate that there must have been a serious amount of gamma radiation pounding that core 50-150 workers. Remember, dosimeters are great at warning you to get out, get away, but they're less effective at estimating long-term exposure.

Now, with this breach of the #3 reactor vessel itself, it's hard to believe that these poor bastards weren't exposed to some pretty horrendous isoptopes of cobalt, cesium, iodine, and more. Now they have to contend with high levels of Beta radiation in this water... that's going to be hell as they open and close valves by "hand", but at least that requires some serious contact.

Honestly, based on TEPCO's history, and the state of Japan after the Tsunami... I'd be surprised if the dose estimates WERE honest. I would bet that the workers know it too, and recognize that they probably killed themselves to save others.

I suppose the next month will tell us a lot about what kind of acute exposures occured, and then the next decade or so for the emergence of leukemia. Here's to hoping that there was SOME luck in this mess.

Really, the tsunami... as bad as Fukishima is... I'm finding it hard to take the coverage of the tsunami. These elderly men and and women who've seen generational homes, shrines, and entire families/villages simply wiped away as though they'd never been. Fukishima could melt down and as bad as that would undoubtedly be, it would still be the mild end of this catastrophe.

 

[Borek]

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

I guess you meant detectors, not dosimeters.

 

[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.