Meltdown Likely Under Way At Japan Nuclear Reactor

[Shurup]

Interesting to see people worried about trace amounts of radiation in food, when much food is irradiated already - to lengthen its shelf life. Plus, look at what the average Joe and Jane eat and drink normally, and it's even more nutzoid. Fermented sugar (alcohol), fermented fish (fish sauce), fermented dairy (cheese), fake oils (trans-fats) which fool the body in to thinking it's ingesting real fats, when later the body finds it can't digest the trans-fats, so has to eject them or store them somewhere - which results in a bloated sickly populace.

When looking at the entire picture of what the average person ingests, a tiny bit of radiation doesn't look so bad after all.

That is true... for a lot of people but not all. I for once don't eat junk and I definetelly don't want to consume any rad contaminated food.

[Lite Beer]

Japan officials: radioactive iodine in Tokyo water

TOKYO — The Japanese government reports that trace amounts of radioactive iodine were detected in tap water in Tokyo and five other areas, amid concerns about leaks from a damaged nuclear power plant.

A government ministry reported Saturday that small amounts of the iodine was found in tap water in Tokyo and five other prefectures. The ministry says the amounts did not exceed government safety limits but usual tests show no iodine.

But the findings add to public concerns about radiation leaking from the Fukushima nuclear power plant crippled by the earthquake and tsunami.

http://www.chron.com/disp/story.mpl/ap/top/all/7480214.html

[Tywais]

Irradiated food is not the same as food contaminated with radioactive particles, the former doesn't re-radiate anything after treatment, it's just sterile.

Yep.

3. Does irradiation make food radioactive?

No. Radioactivity in foods can occur by two routes: contamination of foods with radioactive substances or by penetration of energy into the nuclei of the atoms that make up the food.

The irradiation process involves passing food through an irradiation field; however, the food itself never contacts a radioactive substance. Also, the ionizing radiation used by irradiators is not strong enough to disintegrate the nucleus of even one atom of a food molecule.

Food irradiation

I had designed such a system and it's pretty much the same as the particle accelerators used for patient cancer treatment (X-ray). Haven't heard of a radioactive patient from such procedure.

[Lopburi99]

NHK:

Tokyo Fire Department to start spraying water [saturday afternoon]

The Tokyo Fire Department plans to use a temporarily unmanned fire engine to spray water into the No. 3 reactor's storage pool at the quake-hit Fukushima Daiichi nuclear power plant.

Greetings from Michigan. Surely you guys have discussed why this wasn't done long ago (the use of unmanned devices) but I can't find that discussion. Or the use of robots with cameras. Could somebody please give me a quickie recap of your thoughts. Thanks.

Edited March 19, 2011 by Lopburi99

[Alphonso]

NHK just did a report on the Japan Govt's radiation monitoring results for today (Saturday) from 28 locations around the Fukushima plan in a 30 to 60 Kilometer radius...

At least one of the results -- the highest -- is surprisingly bad... The town of Namie northwest of the plant measured at 0.136 micro-sievert per hour...

With 720 hours in a month, if someone was staying outside continuously, that works out to an exposure of 98 mSv per month, or more than 3 mSv per day... which would be a cause for health concern.

(136 microsievert X 720 hours in a month = about 98,000 microsievert, or 98 millisievert per month)

That reading was taken at 10:20 am Saturday...and was lower than a 140 microsievert measurement taken at the same location the day before (Friday).

Looks like Namie is a little less than 10km NNW of the reactor site.

Here are some more figures for Fukushima prefecture.

Info can be found here http://www.worldvillage.org/fia/kinkyu_english.php

[WarpSpeed]

NHK:

Tokyo Fire Department to start spraying water [saturday afternoon]

The Tokyo Fire Department plans to use a temporarily unmanned fire engine to spray water into the No. 3 reactor's storage pool at the quake-hit Fukushima Daiichi nuclear power plant.

Greetings from Michigan. Surely you guys have discussed why this wasn't done long ago (the use of unmanned devices) but I can't find that discussion. Or the use of robots with cameras. Could somebody please give me a quickie recap of your thoughts. Thanks.

Didn't have the proper equipment, requires specially shielded robotics to be able to work in that environment..

[jfchandler]

Here's the text from the NHK website of the same story I already recounted re radiation levels in Namie...

I'm a bit puzzled by the distance reference from the reactors, though. Like the poster above, when I went to look about Namie, I also found it appeared to be 9 or 10 Km north of Fukushima Daiichi... But the article says 30 Km...

Radiation level at 30km spot from plant still high

The government says the level of radiation in a town 30 kilometers from the damaged nuclear plant remains relatively high. It says those in the rest of the area are not immediately harmful to human health.

The science ministry released the data on levels of outdoor radiation monitored at 28 locations in a 30 to 60-kilometer radius of the Fukushima Daiichi nuclear plant from 7 AM to 3 PM local time on Saturday.

It says the level at Namie Town, 30 kilometers northwest of the plant, marked the highest level of 136 microsieverts per hour around 10:20 AM.

But the figure is slightly lower than the 140 microsieverts per hour that was detected in the same place at noon on Friday.

Associate Professor Keiichi Nakagawa of the University of Tokyo's Medical School said that if a person is exposed to a level of outdoor radiation of 140 microsieverts per hour for one month, the accumulated dose of 100,000 microsieverts would be harmful.

But he said that people need not worry too much as long as they stay indoors and avoid outdoor exposure.

He also expressed concern that psychological stress may affect people's health.

He added that it is important to reduce the amount of radioactive substances released from the nuclear plants as soon as possible.

Saturday, March 19, 2011 18:56 +0900 (JST)

http://www3.nhk.or.j...lish/19_22.html

Edited March 19, 2011 by jfchandler

[jfchandler]

NHK:

Two reactors connected to external power sources

Two of the damaged reactors at the Fukushima Daiichi nuclear power plant are likely to have power again after engineers managed to install cables.

Tokyo Electric Power Company says it will do its best to resume the reactors' cooling function by Sunday, but as many parts of the facilities are soaked in seawater. It is not known if this can be done quickly.

Power company engineers finished connecting the No.1 and No.2 reactors to external sources on Saturday evening.

The nuclear plant lost its cooling function for the reactors and the spent fuel rod pool due to malfunctions of emergency power generators after the quake.

The situation could lead to a massive leakage of radioactive substances.

The power company will check the reactors' cooling equipment before deciding whether to use electricity.

The Nuclear and Industrial Safety Agency says the power company will turn on meters to check the condition of the reactors and then work on the cooling function of the reactors and the spent fuel rod pool.

The agency says the company aims to restore power for the remaining 4 reactors by Sunday.

Saturday, March 19, 2011 21:07 +0900 (JST)

http://www3.nhk.or.j...lish/19_29.html

Edited March 19, 2011 by jfchandler

[jfchandler]

Didn't have the proper equipment, requires specially shielded robotics to be able to work in that environment..

I'm not sure about that WS... While we're not getting a lot of detailed info about the activities there, I haven't seen any indication that any of the fire engine apparatus being used are in any way being modified or protected from radiation. The crews yes... The equipment, no sign of that.

The big fire trucks are presumably running diesel engines and powered water pumps that spray the water out through hoses and metal nozzles... I'm not sure the radiation levels 50 to 100 meters away from the reactors at present would cause problems for that kind of equipment.

Once the Japanese ordered the Tokyo Fire Department units up from Tokyo, they departed via roadway early one morning and arrived to Fukushima that afternoon. What didn't happen for days after the original quake, though, was anyone actually ordering them up. I've yet to see any explanation from the Japanese of why they waited until the end of the week to do so.

[Crushdepth]

The power company will check the reactors' cooling equipment before deciding whether to use electricity.

Maybe should have done that before exposing people to radiation laying potentially useless power cables?

[JulianLS]

It's interesting to look back at the title of this thread, "meltdown likely underway.....". Early on, I though it was quite a high probability. But now I am quite optimistic that this wont end in a meltdown and a mega release of radioactive isotopes. It has been over a week, which means that residual decay (and therefore heat output) in the reactors is subsiding. The storage pools, perhaps neglected in the first few days because of bigger reactor concerns, are now being addressed. There is a much higher level of activity on site to recover the storage pools. Yes, there has been quite some release of radioactive materials, but so far it's at a concerning level not a catastrophic level.

But some doubts remain. Radioactivity levels at the site may have gone down slightly, but are far from 'normal' levels. Which begs the question, where is it coming from? Is a reactor vessel breached? Are reactor fuel rods still exposed? Are pipes burst and radioactive coolant leaking out? Is it coming from the storage pools? Or maybe all of the above? I am inclined to believe that the answer is all of these across the 4 troubled units. Things look stable now, but with the number of aftershocks in the region, they could suddenly change so lets keep our fingers crossed or keep praying (whatever your preference).

During Chernobyl, workers were sent to "take a look in the reactor hall and report back". Given what had happened there, it was a death sentence (albeit unknowingly). There has been some pushing of the safety boundaries in Japan, but ultimately they are being far more cautious with the exposure of workers than in the Chernobyl days. It deserves some recognition. Okay, it's likely that heads will roll, whatever the outcome. But really the blame should be placed on the people who allowed a "standard reactor design" to be built in a location that is so prone to earthquakes and tsunamis. Unimaginable events? Of course not. Predictable? Absolutely.

Early on, it seems that the plane was flying them. But now they seem to be flying the plane (or at least trying to). I am sincerely hoping for good news from Japan from now on....

[WarpSpeed]

Didn't have the proper equipment, requires specially shielded robotics to be able to work in that environment..

I'm not sure about that WS... While we're not getting a lot of detailed info about the activities there, I haven't seen any indication that any of the fire engine apparatus being used are in any way being modified or protected from radiation. The crews yes... The equipment, no sign of that.

The big fire trucks are presumably running diesel engines and powered water pumps that spray the water out through hoses and metal nozzles... I'm not sure the radiation levels 50 to 100 meters away from the reactors at present would cause problems for that kind of equipment.

Once the Japanese ordered the Tokyo Fire Department units up from Tokyo, they departed via roadway early one morning and arrived to Fukushima that afternoon. What didn't happen for days after the original quake, though, was anyone actually ordering them up. I've yet to see any explanation from the Japanese of why they waited until the end of the week to do so.

I was answering the query about the cameras and robotics in close proximity which was part of the original question, not externally in terms of a fire truck..

[jfchandler]

Alphonso, thanks for posting those radiation readings from Fukushima...

I was having trouble viewing the image you posted. Dunno if anyone else was having the same issue...

So I'll try reposting it as a jpeg file and see if it works any better.

I'm still trying to get the full report in pdf file off the web site link you posted... Very slow to download... Perhaps many people interested in it.

What is the unit of measurement for the readings?

[Tywais]

What is the unit of measurement for the readings?

Top right of chart says uGy/hour = uSv/hour

[Jdietz]

top right hand side of the graphic states the units in microGray/h = microSievert/h

Edit: Tyways beat me to it.

Edited March 19, 2011 by Jdietz

[elcent]

It's interesting to look back at the title of this thread, "meltdown likely underway.....". Early on, I though it was quite a high probability. But now I am quite optimistic that this wont end in a meltdown and a mega release of radioactive isotopes. It has been over a week, which means that residual decay (and therefore heat output) in the reactors is subsiding. The storage pools, perhaps neglected in the first few days because of bigger reactor concerns, are now being addressed. There is a much higher level of activity on site to recover the storage pools. Yes, there has been quite some release of radioactive materials, but so far it's at a concerning level not a catastrophic level.

But some doubts remain. Radioactivity levels at the site may have gone down slightly, but are far from 'normal' levels. Which begs the question, where is it coming from? Is a reactor vessel breached? Are reactor fuel rods still exposed? Are pipes burst and radioactive coolant leaking out? Is it coming from the storage pools? Or maybe all of the above? I am inclined to believe that the answer is all of these across the 4 troubled units. Things look stable now, but with the number of aftershocks in the region, they could suddenly change so lets keep our fingers crossed or keep praying (whatever your preference).

During Chernobyl, workers were sent to "take a look in the reactor hall and report back". Given what had happened there, it was a death sentence (albeit unknowingly). There has been some pushing of the safety boundaries in Japan, but ultimately they are being far more cautious with the exposure of workers than in the Chernobyl days. It deserves some recognition. Okay, it's likely that heads will roll, whatever the outcome. But really the blame should be placed on the people who allowed a "standard reactor design" to be built in a location that is so prone to earthquakes and tsunamis. Unimaginable events? Of course not. Predictable? Absolutely.

Early on, it seems that the plane was flying them. But now they seem to be flying the plane (or at least trying to). I am sincerely hoping for good news from Japan from now on....

unit 1: electricity is there. Cooling pumps should be in work soon. Not sure if they still function

unit 2: electricity is there. Not sure if the cooling still will be functioning. The inner reactor skin is damaged, radioactivity is released from there.

unit 3: more than 1000 tons of seawater was poured over the reactor. Successfully according to the govt. The fuel rods include highly dangerous Plutonium. Cooling failed. The inner reactor skin should be intact.

unit 4: Water should be sprayed on the reactors. The outer protection wall shows many holes, the roof is damaged. Radiactivity is realeased from it's containmentvessel.

unitt 5 and 6: Holes were drilled in the roof to let hydrogenic gasses out and to avoid an explosion. Containmentvessels are cooled by Diesel generators.

+++Überblick: Zustand der Reaktoren in Fukushima+++

• Reaktor 1: Stromkabel sind verlegt. Wasserpumpen sollen bald angeworfen werden und für Kühlung sorgen. Ob die Geräte noch funktionieren, ist unklar.
• Reaktor 2: Stromkabel sind verlegt, es ist unklar, ob die Kühlung noch funktioniert. Die innere Reaktorhülle ist beschädigt, Radioaktivität tritt aus.
• Reaktor 3: Wasserwerfern haben zur Kühlung mehr als 1000 Tonnen Meerwasser auf den Reaktor gespritzt. Mit Erfolg, sagt die Regierung. Die Brennelemente des Reaktors enthalten hochgefährliches Plutonium. Das Kühlsystem ist ausgefallen, die innere Reaktorhülle soll noch intakt sein.
• Reaktor 4: Wasserwerfer sollen den Reaktor kühlen. Durch Explosionen klaffen Löcher in der Außenwand des Gebäudes, das Dach ist zerstört. Radioaktivität tritt aus einem Abklingbecken aus.
• Reaktoren 5 und 6: In die Dächer beider Reaktoren-Gebäude wurden Löcher gebohrt. Dadurch soll Wasserstoff entweichen, um Explosionen vorzubeugen. Brennelementebecken werden mit Notstrom aus Dieselgeneratoren gekühlt. http://www.spiegel.de/panorama/0,1518,751914,00.html

[Jdietz]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

[elcent]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

this maybe can be explained through temporary cooling of reactor unit 2 which was treated with 1000 tons of sea-water. Due to the damage the outcome at the end is still far from clear. That one exploded about the time before the peak of radiation.

unit 4 may still release amounts of radiation.The rods lay more or less in the open and the vessel is damaged. As unit 2, still very serious and the outcome at the end is far from clear.

Edited March 19, 2011 by elcent

[Alphonso]

I'm still trying to get the full report in pdf file off the web site link you posted... Very slow to download... Perhaps many people interested in it.

Here are some of the reports I've placed on a file server.

http://www.sendspace.com/file/7el03e

[elcent]

drinking water near the plants exeeding the the official recommondation and radiation limits. It's adviced not to drink water from there. SPON

[Alphonso]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

Ibaraki prefecture info can be found here http://www.ia-ibaraki.or.jp/kokusai/english/index.html

Horiguchi reported at 0.538µSv as of 19-Mar 16:00 local time. KitaIbaraki-shi 0.891µSv.

[JulianLS]

It's interesting to look back at the title of this thread, "meltdown likely underway.....". Early on, I though it was quite a high probability. But now I am quite optimistic that this wont end in a meltdown and a mega release of radioactive isotopes. It has been over a week, which means that residual decay (and therefore heat output) in the reactors is subsiding. The storage pools, perhaps neglected in the first few days because of bigger reactor concerns, are now being addressed. There is a much higher level of activity on site to recover the storage pools. Yes, there has been quite some release of radioactive materials, but so far it's at a concerning level not a catastrophic level.

But some doubts remain. Radioactivity levels at the site may have gone down slightly, but are far from 'normal' levels. Which begs the question, where is it coming from? Is a reactor vessel breached? Are reactor fuel rods still exposed? Are pipes burst and radioactive coolant leaking out? Is it coming from the storage pools? Or maybe all of the above? I am inclined to believe that the answer is all of these across the 4 troubled units. Things look stable now, but with the number of aftershocks in the region, they could suddenly change so lets keep our fingers crossed or keep praying (whatever your preference).

During Chernobyl, workers were sent to "take a look in the reactor hall and report back". Given what had happened there, it was a death sentence (albeit unknowingly). There has been some pushing of the safety boundaries in Japan, but ultimately they are being far more cautious with the exposure of workers than in the Chernobyl days. It deserves some recognition. Okay, it's likely that heads will roll, whatever the outcome. But really the blame should be placed on the people who allowed a "standard reactor design" to be built in a location that is so prone to earthquakes and tsunamis. Unimaginable events? Of course not. Predictable? Absolutely.

Early on, it seems that the plane was flying them. But now they seem to be flying the plane (or at least trying to). I am sincerely hoping for good news from Japan from now on....

unit 1: electricity is there. Cooling pumps should be in work soon. Not sure if they still function

unit 2: electricity is there. Not sure if the cooling still will be functioning. The inner reactor skin is damaged, radioactivity is released from there.

unit 3: more than 1000 tons of seawater was poured over the reactor. Successfully according to the govt. The fuel rods include highly dangerous Plutonium. Cooling failed. The inner reactor skin should be intact.

unit 4: Water should be sprayed on the reactors. The outer protection wall shows many holes, the roof is damaged. Radiactivity is realeased from it's containmentvessel.

unitt 5 and 6: Holes were drilled in the roof to let hydrogenic gasses out and to avoid an explosion. Containmentvessels are cooled by Diesel generators.

+++Überblick: Zustand der Reaktoren in Fukushima+++

• Reaktor 1: Stromkabel sind verlegt. Wasserpumpen sollen bald angeworfen werden und für Kühlung sorgen. Ob die Geräte noch funktionieren, ist unklar.
• Reaktor 2: Stromkabel sind verlegt, es ist unklar, ob die Kühlung noch funktioniert. Die innere Reaktorhülle ist beschädigt, Radioaktivität tritt aus.
• Reaktor 3: Wasserwerfern haben zur Kühlung mehr als 1000 Tonnen Meerwasser auf den Reaktor gespritzt. Mit Erfolg, sagt die Regierung. Die Brennelemente des Reaktors enthalten hochgefährliches Plutonium. Das Kühlsystem ist ausgefallen, die innere Reaktorhülle soll noch intakt sein.
• Reaktor 4: Wasserwerfer sollen den Reaktor kühlen. Durch Explosionen klaffen Löcher in der Außenwand des Gebäudes, das Dach ist zerstört. Radioaktivität tritt aus einem Abklingbecken aus.
• Reaktoren 5 und 6: In die Dächer beider Reaktoren-Gebäude wurden Löcher gebohrt. Dadurch soll Wasserstoff entweichen, um Explosionen vorzubeugen. Brennelementebecken werden mit Notstrom aus Dieselgeneratoren gekühlt. http://www.spiegel.d...,751914,00.html

I am not sure whether this is a reporting issue or a translation issue...... Unit 4 has no fuel rods in the reactor so should not be generating heat and does not need cooling. The storage pool, yes, that certainly needs dousing (or douching ). I think the assumption is that the radiation is coming from the storage pool, not the reactor containment vessel or even secondary containment.

[elcent]

I am not sure whether this is a reporting issue or a translation issue...... Unit 4 has no fuel rods in the reactor so should not be generating heat and does not need cooling. The storage pool, yes, that certainly needs dousing (or douching ). I think the assumption is that the radiation is coming from the storage pool, not the reactor containment vessel or even secondary containment.

Yes my bad, should have been into the building on the containment vessels.In German Reactor means also the whole building complex.

The logic behind thatl is that through the holes in the outer protectionwall and the damaged roof radioactivity is was/is released.

[jfchandler]

I believe I've finally come across the real and official radiation readings for areas around the Fukushima Site, including the readings that document the NHK report earlier today about the town of Namie...

The official government site for those radiation reports, the English version, is:

http://www.mext.go.j...sai/1303946.htm

Right now, that date set is the second series on the page, titled:

Readings at Monitoring Post out of 20 Km Zone of Fukushima Dai-ichi NPP

And, here are the charts for March 18 and 19 that show the results, in microsievert per hour for about 30 locations around Fukushima, but all outside the 30 Km evacuation and stay indoor zone... Each location shows one, two or three readings per day at different times...

Location #32 appears to be the Namie town NHK mentioned, since the readings for both days match the ones NHK reported. And that location indeed has by far the highest readings for March 19 among the 30 some locations in this survey list -- assuming the equipment there is accurate. Location #33 nearby appears to have the next highest readings, but only about one-third of #32.

March 19 results

March 18 results

Edited March 19, 2011 by jfchandler

[pedro01]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

this maybe can be explained through temporary cooling of reactor unit 2 which was treated with 1000 tons of sea-water. Due to the damage the outcome at the end is still far from clear. That one exploded about the time before the peak of radiation.

unit 4 may still release amounts of radiation.The rods lay more or less in the open and the vessel is damaged. As unit 2, still very serious and the outcome at the end is far from clear.

I have to wonder what happens to all the water they are spraying off this material. Is it contaminated? If so - are they just letting it run off back into the sea?

[elcent]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

this maybe can be explained through temporary cooling of reactor unit 2 which was treated with 1000 tons of sea-water. Due to the damage the outcome at the end is still far from clear. That one exploded about the time before the peak of radiation.

unit 4 may still release amounts of radiation.The rods lay more or less in the open and the vessel is damaged. As unit 2, still very serious and the outcome at the end is far from clear.

I have to wonder what happens to all the water they are spraying off this material. Is it contaminated? If so - are they just letting it run off back into the sea?

That may explain the water radiation. Haven't thought about that, but it must be along this way I think.

[jfchandler]

By the way, here are the PDF files of those Fukushima Area reports for March 18 and 18 listing the detailed data for each monitoring station.

Radiation 20K March 19 1 pm.pdf

Radiation 20K March 18.pdf

Before those, on the same Japanese govt. web page, are the prefecture by prefecture based reports, again in English....

But I'm having a more difficult time deciphering those reports, since they seem to include hour by hour data...for each location.

But I've been focusing on the Fukushima area stations, so I haven't spent as much time looking at the prefecture level data. But it's all there.

Reading of environmental radioactivity level　（English version）

(English version) Reading of environmental radioactivity level by prefecture

• 19:00 Mar 19, 2011 （PDF:146KB）

• Monitoring data at Ibaraki prefecture(19:00 Mar 19, 2011) （PDF:158KB）

• 13:00 Mar 19, 2011 （PDF:392KB）

• Monitoring data at Ibaraki prefecture(13:00 Mar 19, 2011) （PDF:403KB）

• 19:00 Mar 18, 2011 （PDF:132KB）

• Monitoring data at Ibaraki prefecture(19:00 Mar 18, 2011) （PDF:125KB）

• 10:00 Mar 18, 2011 （PDF:350KB）

• Monitoring data at Ibaraki prefecture(13:00 Mar 18, 2011) （PDF:363KB）

• 19:00 Mar 17, 2011 （PDF:363KB）

• Monitoring data at Ibaraki prefecture(19:00 Mar 17, 2011) （PDF:347KB）

Edited March 19, 2011 by jfchandler

[elcent]

Six workers received a dose of more than 250mSV during their work at the plants. - Kyodo News - TEPCO.

Due to the catstrophy the Ministry of Health increased the limit to 250 mSv.

In comparation with German nuclear workers, the limit there's 20mSv/year. For all others who are exposed to radiation due to their jobs, the limit is 1mSv/year

+++Sechs Fukushima-Arbeiter haben zu viel Strahlung abbekommen+++

[17.21 Uhr] Bei sechs Männer, die am Atomkraftwerk Fukushima einsetzt waren, wurden mehr als 250 Millisievert gemessen, teilte die Nachrichtenagentur Kyodo mit Verweis auf den Kraftwerksbetreiber Tepco mit. Damit lag ihre Strahlenbelastung über dem Grenzwerte. Welche Aufgaben die Arbeiter hatten, teilte Tepco nicht mit.

Wegen der Katastrophe hatte das Gesundheitsministerium den Grenzwert für Arbeiter an dem zerstörten Kraftwerk von 100 auf 250 Millisievert hochgesetzt. In Deutschland gilt für Menschen, die beruflich etwa in einem Atomkraftwerk Strahlung ausgesetzt sind, ein Grenzwert von 20 Millisievert pro Jahr. Für alle anderen Menschen, die beruflich künstlicher Strahlenbelastung ausgesetzt sind, liegt die erlaubte Jahresdosis bei 1 Millisievert.

Edited March 19, 2011 by elcent

[jfchandler]

And for the conspiracy theory fans out there, the prefectural radiation reports are footnoted with an explanation of why the data from Fukushima and Miyagi is missing... though some of those data points apparently are covered, perhaps from other sources, in the separate 20 Km reports I've listed above.

Edited March 19, 2011 by jfchandler

[JulianLS]

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.

this maybe can be explained through temporary cooling of reactor unit 2 which was treated with 1000 tons of sea-water. Due to the damage the outcome at the end is still far from clear. That one exploded about the time before the peak of radiation.

unit 4 may still release amounts of radiation.The rods lay more or less in the open and the vessel is damaged. As unit 2, still very serious and the outcome at the end is far from clear.

I have to wonder what happens to all the water they are spraying off this material. Is it contaminated? If so - are they just letting it run off back into the sea?

That may explain the water radiation. Haven't thought about that, but it must be along this way I think.

Wrt the sea water being used for cooling in the reactors and for spraying, it's too much I think (?) to be able to be stored in the low level (!) waste storage, so I assumed it is making it's way back to the sea. Let's hope it gets dispersed and diluted quickly.

Wrt the drinking water, it's unlikely that it could be contaminated by sea water, I think. More likely that radioactive particles in the air are being washed down by rain and snow, and entering the freshwater system that way. Ditto the spinach and the ditto the milk (via either water or grass).