JulianLS

Jd and Julian, thanks for the interesting posts re the radiology of cesium (and plutonium) in the environment...

But it's early morning, and my reading eyes are still bleary, so can one of you give me the non-tech shortcut on those things???

It's OK to drink plutonium in lethal doses, but don't eat cesium contaminated pidgeon breasts???

Who eats pidgeons anyway???

Sorry, cant find any simple links on the topic. But key points re: caesium vs iodine are:

- Cs is excreted from the body over a period of months. It's not stored within the body.

- with the 30 year half life of Cs137, it means that most of it would not decay within the body (hence not emit radiation) and would be harmlessly excreted still as Cs137.

- but still, continuous ingestion of Cs137 could pose a long term radiation risk, dependent upon the amounts and duration.

- cf iodine, which is stored in the thyroid and given the short half life, will decay and will emit radiation.

With regards to pigeon consumption, that's more or less the conclusion that BNFL reached In fact, better to avoid them totally, cos the feathers showed a much higher radiation level than the meat!

During the Manhattan Project in 1944 and 1945, 26 men accidentally ingested plutonium in quantities that far exceeded what is now considered to be a lethal dose. Since there has been a consistent interest in the health effects of this brand new substance (first discovered by Glenn Seaborg's team at the University of California in 1940), these men were closely tracked for medical studies.

As of 1987, more than four decades later, only four of the workers had died and only one death was caused by cancer. The expected number of deaths in a random sample of men the age of those in the group is 10. The expected number of deaths from cancer in a similar group is between two and three.

Not sure if I want to open this debate, but there are theories which suggest that low level radiation doses, somewhat above background level, over a long period of time can actually help to prevent cancer by invoking an enhanced level of damage repair. It's called radiation hormesis. A study of residents of apartments in Taiwan (in which the construction steel had been contaminated with Cobalt-60 leading to significant radiation exposure over 30 years) came up with lower than average levels of cancer in the exposed group. Mainstream science has said the study is flawed, and that may well be true (I haven't gone into it in detail, tho it did seem as if they compared to national stats which was not a good control sample). Here's the link if anyone is interested.....

http://www.ecolo.org/documents/documents_in_english/low-dose-Cobalt-taiw-06.pdf

No doubt at the time, mainstream science would have questioned the sanity of Jenner giving cow pox to people to protect them against smallpox.....

But still, for the time being I am gonna keep an open mind on the theory, and avoid radiation in the interim

I have been following the debate about caesium 137, though I am not sure I can add much. The fact that caesium is not at all abundant in everyday life, and plays no role in biology, means it is not a topic that is high on the agenda in regular biochemistry. It really only becomes relevant in the context of nuclear waste (so maybe its higher up the agenda now!)

So then, caesium behaves in a similar fashion to other alkali metals (sodium, potassium). The Cs+ ion though, due to its large size, is likely to form more complex bonds with other elements when compared to sodium or potassium,. But still, it is very soluble in water and likely to be taken up by plants. And by animals that eat plants. The big difference with iodine though, comes from the fact that iodine is collected by the body and used in the thyroid. Whereas, caesium is likely to be excreted over time, like sodium and potassium in sweat, urine, etc.

So then, one can see why iodine is considered the bigger threat: it is collected and stored in the body in a localised way, and has a short half life (likely to emit radiation). Whereas caesium is likely to pass through your body in time, and the long half-life means that most likely, it will go in as caesium-137 and leave as caesium-137 (ie no radiation emitted by most atoms). So whilst the long half-life is bad in terms of it hanging around in the soil, its a good thing when it happens to be in your body!

I found a couple of relevant articles. One about caesium-137 retention in and excretion from the human body. This shows the average half retention to vary between 80 and 130 days. With a half life of 30 years, then the majority would be excreted still as Cs 137 from a single dose. Alas the article is in rems.....

http://iopscience.iop.org/0031-9155/7/2/302/pdf/0031-9155_7_2_302.pdf

And another about Cs-137 in contaminated pigeons around Seascale, where they do make an estimate of exposure in mSV based on Bq/kg readings (they estimate that eating 6 pigeon breasts, showing levels of 0.11 MBq/kg would result in an exposure dose of 1mSv.) Taking a rough approximation that 6 pigeon breasts weigh approx 1kg, then that gives a very rough guideline of 0.11 MBq of Cs137 (or 110 kBq, or 110,000 Bq) translating to 1mSv.

http://archive.food.gov.uk/maff/archive/food/incid_1/bnfp23.htm

Not sure if that helps.

Bottom line, as mentioned earlier by other posters, is the actual amount and duration of ingestion. One dose of Cs-137 is likely to pass through harmlessly. But if it is continually ingested over a long period, it would no doubt reach steady state levels (ingestion = excretion). And then over 30 years, it might add to a serious amount of exposure. Prussian Blue is a drug (well, actually its a dye with good Cs binding properties) used to remove cs-137 (and other radioisotopes) from the body by scavenging it in the gut (and excreting it much more quickly than mentioned above, via feces). Useful in an accident situation, but not practical if you happen to live in an area where the veggies are contaminated with low levels and you are eating it daily....

Power restored to control room of No.3 reactor

Tokyo Electric Power Company says it has restored the electricity supply for the control room of the Number 3 reactor at the quake-damaged Fukushima Daiichi nuclear plant.

TEPCO said lights in the control room were switched on again on Tuesday night.

Eleven days have passed since the massive earthquake devastated northeastern Japan and cut off external power to the Fukushima Daiichi nuclear plant.

TEPCO reconnected power cables to the Number 3 and Number 4 reactors earlier on Tuesday.

The lights are now working in the control room of the Number 3 reactor. This will make it easier to repair the reactor's cooling system.

TEPCO will now try to reactivate vital monitoring systems in the control rooms, such as those for measuring temperatures inside the reactors and water levels in the spent fuel storage pools.

TEPCO says it will transmit electricity to the cooling pump for the Number 3 reactor on Wednesday. The company says if the pump functions normally, it will begin cooling the reactor and the spent fuel storage pool.

Wednesday, March 23, 2011 02:01 +0900 (JST)

Source: NHK

Yes indeed, a very interesting report. Thanks for posting, Superskunk!

...

You should take a look at page 18 in the report. They localised the position of the radiation source with a flourescent screen attached on a bamboo pole... <deleted>... no Geiger counter in this country?

Yes I saw that, I read the report from start to finish. The fluorescent screen and bamboo pole even got a mention in the "learnings" section as a innovative approach to find the source. But it seems the technique only works when the moon isn't shining brightly. Lol

Wow... that's a very interesting official report... I'd never heard about that incident before...though it was some years back.

Anyone interested in radiation issues really should read this official account of a bunch of rube Thai junk yarders who tried to disassemble by hand, using a hammer, chisel and blow torch, an abandoned hospital radiological device they found out in a Samut Prakan junkyard.... and a number ended up dying from severe radiation exposure for it.

The report says a lot, by implication, about how a nuclear future for Thailand likely would fare.... VERY scary stuff.

Interestingly, the report talks about the team of Thai folks who ended up retrieving the cracked open nuclear device, and indicates the highest total exposure among them was 32 mSv... The highest exposure among the Tokyo FD crew from their work the other day at Fukushima was 27 mSv... The report on the Thai incident doesn't appear to indicate if there were any subsequent health effects for the 32 mSv guy on the retrieval crew.

The report on the Thai incident also says the cracked open device was giving off radiation levels of 200 to 300 microsievert (uSv)per hour at the edges of the perimeter for the site where it was found.

I,m not sure it was in this topic already...

Here a report about a nuclear accident in Samut Prakan / Bangkok in the year 2000.

http://www-pub.iaea....Pub1124_scr.pdf

(*** contains graphic material)

Yes indeed, a very interesting report. Thanks for posting, Superskunk!

Just to extract the key info for the 10 people who rec'd the highest exposures:

Of the ten people highly exposed to the radiation, the four involved in the scrap collection were estimated to have received 1 - 2 Sv (whole body) all survived*. They did however have very serious injuries from localised radiation burns, from being in close or direct contact with the cobalt-60 source for limited periods of time (hours rather than days).

Of four people at the junkyard estimated to have exposures in excess of 6 Sv, three died within two months whilst one survived*. These four people were exposed to the radiation for many days. There is no estimate of the exposure of two other people at the junkyard, who also suffered radiation sickness but survived*.

* I assume that they survived at least 2 years, as the report was published two years after the accident

NHK:

TEPCO underestimated tsunami, quake -- claims 14 meter tsunami

Tokyo Electric Power Company says its nuclear power plants in Fukushima were hit by a 14-meter-high tsunami. That was more than double the maximum expectation.

The electric company on Monday checked the walls of the Fukushima Daiichi and Daini nuclear power plants. It found that the water reached higher than 14 meters above sea level.

The company had only expected a tsunami of 5.7 meters at the Daiichi plant and one of 5.2 meters at the Daini.

The Fukushima Daiichi plant lost sufficient cooling functions when the tsunami destroyed facilities along the coast, such as seawater pumps and emergency diesel generators.

The buildings that house the reactors and turbines are built on grounds 10 to 13 meters above sea level, but became partially inundated.

The power company said it had underestimated the biggest earthquake to be magnitude 8. It said it admits that this month's magnitude 9 quake was beyond its calculation.

Tuesday, March 22, 2011 05:08 +0900 (JST)

http://www3.nhk.or.j...lish/22_05.html

This revelation by Tepco beggars belief!!!

Even the townspeople of Miyako expected a tsunami to be much higher than that (from previous experiences in 1611, 1896 and 1933) and built a tsunami protection wall 10 meters high (almost double the Tepco assumption). And as we know, that town was also inundated by the tsunami which breached the wall. There are many previous reports of tsunamis well above 10 meters, let alone 5.7 meters.

And I counted 14 earthquakes in Japan at or above magnitude 8 in its history (some earlier ones estimated), 12 of which occurred prior to the construction of the Fukushima Daiichi plant.

Any idiot could see that these assumptions were too small, and I am sure the people setting these limits were not idiots......

BTW, from diagrams I have seen it looks as if at least part of these reactors is actually underground (the suppression pool), so I think perhaps the comment about the "buildings" being 10 to 13m above sea level may be misleading. Having said that, these diagrams are generic ones of the reactor type used, rather than actual plans of the reactors in Fukushima.

Seeing the aerial images of the fire engines lined up outside the Fukshimi Daiichi plant reminded me of the "vehicle graveyards" of all the emergency and clean up vehicles used at Chernobyl. Too radioactive to use again, they were left within the Chernobyl exclusion zone in various "graveyards". One of the larger examples can be seen at N 51 09 12 E 29 58 55 (cut and paste into google earth "fly to" box)

Hopefully it wont come to that.... The signs seem quite good over the last few days, there is light at the end of the tunnel I feel.

>> Earlier today, 5 and 6 reactors were at 194 and 152 degrees respectively. Now they are both below 100 degrees C. It looks like they diverted power to cooling the storage pools, and having cooled them, put power back to the reactor cooling system. These units have been running off an single emergency generator (at unit 6) since soon after the quake/tsunami.

Water temp at 2 reactors below boiling point

Tokyo Electric Power Company says cooling functions were restored by Sunday evening for the No.5 and No.6 reactors at the Fukushima Daiichi nuclear plant.

Coolant water temperatures have now fallen below 100 degrees Celsius.

The tsunami triggered by the massive earthquake that hit northeastern Japan on March 11th damaged the emergency diesel generator at the No. 5 reactor, causing the coolant water levels to drop.

The No.5 reactor had been halted for regular inspections when the earthquake and tsunami struck, but nuclear fuel rods had already been placed inside the reactor.

TEPCO restored the cooling functions of the No.5 reactor on Sunday afternoon using the emergency diesel engine generator of the No.6 reactor, which escaped damage from the quake and tsunami.

The cooling function of the No.6 reactor was restored by 7:30 PM.

Sunday, March 20, 2011 23:46 +0900 (JST)

Source: NHK Website

No, there is no system to ignite the hydrogen. The idea is not to ignite it! The explosions earlier in the week were accidental ignition, either from an electrical spark or from pyrophoric compounds in the vented gases (uranium itself is pyrophoric when finely divided). The hope is that the hydrogen dissipates naturally without igniting. They have knocked holes in the upper walls of reactors 5 and 6 to facilitate dispersal of any hydrogen gas.

As I understand, the plant does not generate hydrogen in normal operation. They believe the hydrogen came from water (steam) reacting with (accidentally) exposed fuel rods. So there isn't a system in place to dissipate the hydrogen safely that I am aware of. Apart from knocking holes in the wall....

The reason I ask is from this document https://netfiles.uiu...0Structures.pdf which shows and mentions recombiners. Just wondering if this is applicable to these reactors. I can not help think there would be some contingency to get rid of the hydrogen in a safe manner although in the case of Fukushima that may not have been possible due to the nature of failures caused by the tsunami.

The Fukushima unit #3 was constructed in 1970, and went online in 1974. I dont think hydrogen release in a low coolant situation was even considered prior to TMI accident in 1979. Which is why I think it's unlikely that they have any hydrogen flaring systems (as well as the fact that earlier, they vented a number of reactors which subsequently led to hydrogen explosions in Units 1, 2 and 3. And unit 4, but there the source must have been the storage pool not the reactor)

I don't really have a view of how many reactors in the world have such a system, but at a guess, I would say very few. Some of the experts here might have a much better idea than me....

True at the top of the building..... But bear in mind that the plant is partly underground. And they were considering venting the reactor into the pressure suppression pool. Which is the toroid structure at the bottom. An explosion down there could potentially send the core shooting up into the air like a rocket

Something I've been wondering about. Is the suppression pool supposed to have an igniter to burn off the potentially dangerous hydrogen gas and if so is there no backup way of safely venting should the ignition system fail?

No, there is no system to ignite the hydrogen. The idea is not to ignite it! The explosions earlier in the week were accidental ignition, either from an electrical spark or from pyrophoric compounds in the vented gases (uranium itself is pyrophoric when finely divided). The hope is that the hydrogen dissipates naturally without igniting. They have knocked holes in the upper walls of reactors 5 and 6 to facilitate dispersal of any hydrogen gas.

As I understand, the plant does not generate hydrogen in normal operation. They believe the hydrogen came from water (steam) reacting with (accidentally) exposed fuel rods. So there isn't a system in place to dissipate the hydrogen safely that I am aware of. Apart from knocking holes in the wall....

TEPCO announces pressure has stabilized inside No3 reactor vessel at #Fukushima N-plant, will not release steam for time being./RT@DailyYomiuri

That I think is very good news!

More on Japan reactor setback: Radioactive gas will be released to ease pressure/RT@BreakingNews

This is worrying. Last time they vented unit 3, the building exploded soon after....... Let's hope they do it slowly so any hydrogen has chance to disperse.

Nothing much left to explode in #3, outside 'structure' is all but gone, Hydrogen won't have a problem to escape that pile of rubble, even if it ignites.

True at the top of the building..... But bear in mind that the plant is partly underground. And they were considering venting the reactor into the pressure suppression pool. Which is the toroid structure at the bottom. An explosion down there could potentially send the core shooting up into the air like a rocket

More on Japan reactor setback: Radioactive gas will be released to ease pressure/RT@BreakingNews

This is worrying. Last time they vented unit 3, the building exploded soon after....... Let's hope they do it slowly so any hydrogen has chance to disperse.

Temperatures rising in reactors 5 and 6. This may be because available power has been used to cool water in the storage pools of units 5 and 6, rather than the reactors themselves (which in any case, were shut down before the earthquake). Let's hope it is that, and not low water levels and/or exposed rods in the reactors. It seems these reactors have not been severely affected by explosions (being somewhat separated from units 1 to 4), we very much want it to stay that way! Under current circumstances, reactors 5 and 6 cannot be classed as being in "cold shutdown" (as the temperature has to be below 100 degrees C to be considered as cold shutdown).

Article from NHK below.

Water temperature drops in fuel rod pools

The water temperature is dropping in the spent fuel rod pools of the No.5 and No.6 reactors at the Fukushima Daiichi nuclear power plant.

The Tokyo Electric Power Company restored a power generator at the No.6 reactor on Saturday morning.

A backup generator at the reactor had been used since the quake to cool the spent fuel rod pools at both the No.5 and No.6 reactors.

But as water temperatures rose, a single generator was unable to supply enough power for the two reactors.

The newly restored generator is being used to activate a cooling pump in the No.5 reactor.

The power company measured the water temperature of the spent fuel pool in the No.5 reactor and found it had decreased from 68.8 degrees Celsius at 5 AM Saturday to 43.1 degrees at 3 AM Sunday.

After the cooling pump at the No. 6 reactor was restored, the water temperature dropped more than 15 degrees, from 67.5 degrees Celsius at 11PM Saturday to 52 degrees at 3 AM Sunday.

On the other hand, the water temperature of the reactor vessels is rising.

The water temperature was 194.5 degrees Celsius in the No.5 reactor and 152.4 degrees in the No. 6 reactor at 6 PM Saturday.

Those temperatures are lower than when the reactors are in operation, but they are increasing.

The power company says it will begin cooling the reactor water as soon as the spent fuel rod pools are cooled down.

It hopes to restore connections to external power sources to cool down the reactors in a stable manner.

Sunday, March 20, 2011 09:19 +0900 (JST)

Water spraying at No.4 reactor ends

Japan's Self-Defense Forces have finished spraying water to cool the storage pool for spent nuclear fuel in the No.4 reactor at the quake-hit Fukushima Daiichi power plant.

The operation started at 8:20 AM local time on Sunday and continued for more than an hour.

Using 11 fire trucks, including one borrowed from the US military in Japan, the workers sprayed 80 tons of water during the operation.

Employees of Tokyo Electric Power Company will try to repair equipment to supply outside electricity to the No.4 reactor.

Fire fighters of the Tokyo Fire Department are to start spraying water at the No.4 reactor at around 6 PM and continue spraying until Monday morning.

Cooling systems haven't worked since the initial March 11 quake, raising concern about leakage of radioactive materials.

Sunday, March 20, 2011 10:38 +0900 (JST)

Source: NHK Website

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).

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.

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....

Here's another chart from the L.A. Times that shows the 50 MSv standard for public service workers, and says 8 mSv for an abdomen CT.

The radiation dose depends on the type of scan and also on the settings on the CT machine - which often can be left set higher than required to ensure a good scan.

Good chart! I notice that the chernobyl workers come out at 33MSv.

The Chernobyl figure is for people evacuated from the Chernobyl area, not the Chernobyl plant workers. Some of those rec'd lethal doses.

Sorry, have to quote a German source again. Many times they are faster than English media.

The office of the Japanese PM opened a twitter account this morning (German time) to advice people how to protect themselves from radiation. Within the 30km radius move only by car and not to get in touch with the air outside. Wear long-sleeve shirts and masks. Avoid rain.

+++ Regierung gibt per Twitter Sicherheitstipps +++

[09.00 Uhr] Am Samstagmorgen deutscher Zeit veröffentlichte das Büro des japanischen Premierministers Naoto Kan per Twitter Anweisungen zum Schutz vor Strahlung innerhalb des 30-Kilometer-Radius um das AKW Fukushima I: Man solle sich möglichst im Auto fortbewegen, um der Luft nicht ausgesetzt zu sein, langärmelige T-Shirts, Handschuhe und eine Schutzmaske tragen sowie Regen meiden. http://www.spiegel.d...,751914,00.html

You missed the gloves

Efforts to restore cooling function continue at nuke plant

TOKYO, March 19, Kyodo

Tokyo Electric Power Co. on Saturday accelerated efforts to restore lost cooling functions at reactors at the troubled Fukushima Daiichi nuclear plant, aiming to reconnect electricity through outside power lines.

Reconnection of the No. 2 reactor is expected to be completed during the day. However, it will still take time to reactivate devices to cool down the reactors and overheating spent fuel pools once electricity is restored as equipment needs to be checked, according to TEPCO, the operator of the crippled plant.

Earlier Saturday, the Tokyo Fire Department joined the operation to cool down the No. 3 reactor by discharging 90 tons of water.

MORE: http://english.kyodo...1/03/79511.html

Judging by the state of the site, it's likely to take days rather than hours to get the power to where it is needed. Photos show quite severe damage to the infrastructure, primarily it seems from the explosions that occurred earlier. If many repairs need to be undertaken, alas that means more radiation exposure to the workers.....

For those people trying to fix the 10171 error at TV, this info might be useful:

On clicking the attachment link in post #1695, the following link is opened;

/forum/index.php?app=core&module=attach&section=attach&attach_id=135328

(I have remove the http and TV website address to avoid it being displayed as a link)

This code seems as if it is in "attach" instruction not a "download" instruction???? If clicking the link tries to attach rather than download, it is not surprising to get a "no permission" error.

17 page press release (update on damage / status) of Fukushima plant and area dated last night. A good background read on the situation on the ground..from the Ministry of Trade, Industry etc : not a Tepco release...

Could you post a link please, bkkjames? As with some attached images, I just get error 10171 trying to view the file.

Status of quake-stricken reactors at Fukushima nuclear power plants

-- Reactor No. 4 - Under maintenance when quake struck, no fuel rods in reactor core, temperature in spent-fuel storage pool reached 84 C on Monday, fire Tuesday possibly caused by hydrogen explosion at pool holding spent fuel rods, fire observed Wednesday at building housing reactor, pool water level feared receding, renewed nuclear chain reaction feared, only frame remains of reactor building roof.

MORE: http://english.kyodo...1/03/79482.html

Whoa...... I thought they were reasonably happy with the water level in unit 4 storage pool, after taking the photos (the small area of white which they interpreted as the reflection from the surface of the storage pool - not that I was convinced, it could have been anything). I haven't seen "renewed nuclear chain reaction feared" before!!!! The rods overheating and melting is one thing, but an uncontrolled chain reaction in an open space is much more frightening....

The latest Tepco status report doesn't mention unit 4 storage pool, only the one at unit 3. Is this then just poor reporting?