Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Jorge Stolfi]

MARKT plus 1,000 hours [...] A key benchmark value for many graphs I've seen that use log(time) for the abscissa.

... and for certain data files and scripts which had naively allocated 3 digits for the "hours since accident" column.

 

[dh87]

I've updated my plots of #Fukushima reactor variables, up to #NISA release 106 (21/apr 15:30) :

http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

No big news. The drop by a factor of 10 in the CAMS (A) reading in the Unit #1 torus persists. Presumably it is the previous values that were wrong by 1 in the exponent. It is hard to tell
because the (B) redings are intermediate between the two (A) values, old and new, and both have
been changing a lot recently.

In release 103 there was another similar drop, by a factor of 100, in the CAMS (B) reading of Unit #3 torus. Here it is clear that it was a typo in the exponent, since the (A) and (B) readings were previously off by factor of 100 (exponent 1 instead of -1), and now they agree. The question is, are they now both correct, or both wrong?

In their release packet 105, NISA messed up their file names, so intead of the raw TEPCO fax we got a second copy of the redacted NISA press release. The latter does not give the CAMS readings, water pump flows, and core and drywell temperatures. But release 106 was OK.

Thank you for maintaining this record of the data and for trying to deal with the inconsistencies in the reporting. I have been watching your graphs for weeks. There is a NISA document here (http://www.nisa.meti.go.jp/english/files/en20110406-1-1.pdf ) that parallels your graphs, but I don't know whether it's been updated since this version. The graphs are consistent with yours.

 

[|Fred]

Well, maybe i should have written maximal ALLOWED dose for general population (defined by french safety coden but that is the limit in many countries for artificial radiation). Which i expect is a "safe limit" by the way ;o)

It would have be a equally failing understanding. It is not a safe limit it is the threshold that we do not want to exceed for artificial if possible.

The fact is that we see on the map that outside of a certain perimeter, the measures (in grey) are below 1 mSv/year (100 mrem/year). In fact, this last remark let me conclude that we don't know if this study is separating artificial radioactivity from "natural" one?

Nope, this map is for dose induce by radioactive matériel from Fukushima, it take into account decay, external ionization and internal inhaled particule. it assume one is standing outside 247. and does not take into account that radiation exposition would be mitigated by the time you spend indoor (as requested).

As for the 1 mSv you get it from the ²²²Rn present in the air every one breath .. You also get 0,2mSk from your own potassium etc ..
http://www.rchoetzlein.com/theory/wp-content/uploads/2011/03/radiation.jpg

A whole body scanner gives you even more than 10 mSv, But this doesn't mean that there is no risk

Here again this is a miss understanding, on the "no risk concept". Of course there is a risk, every time you take some medication there is a risk, I almost die the first time I toke penicillin, every time you do something there is a risk.. There is no such thing as risk free, But what is commonly admitted is that when the probability of something bad to hapen is low enough or lower that a lot of other thing we consider it risk free. Call in un "abut de language" or convention..

So i don't think that giving that kind of comparison -with doses coming from medical exams- is also very relevant

I mentioned different annual dose for different country France + Dose from this map < annual dose from the states or Sweden..

And in their case, they have absolutely not benefit in taking these extra doses, right?

As low as possible is the word, unless you are Tcup's mice ( I have yet to read the paper), now if you do a proper assessment you have to take into account other choice you make and pose superior threat.

 

[Jorge Stolfi]

... there are plenty of Japanese - ostensibly employed as professionals - who do not read and write English as well as they think they do.

That is irrelevant since the TEPCO faxes and NISA releases are all in Japanese.

Godzilla only knowns how how many hands separate the readings on the instruments to the faxes sent by TEPCO to NISA. Someone along that path seems to be unfamiliar with scientific notation; that would explain the exponent errors (and why the numbers are not being converted to ordinary decimal notation).

I have this old theory that (a) TEPCO has no nuclear experts in their payroll, and (b) their sub-contractors, who actually run the plant, have only technical-level expertise, not engineering- or science-level --- namely, they know standard procedures, but cannot understand or react to situations that are are not in the manuals. I would love to be proved wrong...

I watched a documentary on Chernobyl the other day. One lesson that Japan could have learned from that incident is: do not let the the plant operators remain in charge of disaster contol. At Chernobyl, precious days were lost while the operators (and their bosses and bosses' bosses, up to cabinet level) insisted that "everything was under control". Real action began only after Gorbachev pushed those people aside and put a committee of the country's top nuclear scientists in charge.

Unfortunately it seems much harder to do that in Japan, given the constraints of capitalism (Fukushima-I is still the private property of TEPCO) and the fact that the State is in many ways subordinated to big corporations like TEPCO, GE, Toshiba, etc. So here we are, 1000 hours after the accident and we are still wondering whether there is any real cook in the kitchen.

 

[AntonL]

Has the freshwater supply at Fukushima dried up? Or has SFP 1,3 & 4 always been replenished with seawater.

http://www.tepco.co.jp/en/press/corp-com/release/11042203-e.html"

Previous reports just stated water spraying

On March 25 and 26 reactor cooling was switched from sea water to freshwater.

Unit 2 SFP was regularly filled with fresh water according to Tepco reports. Unit 1, 3 and 4 SFP replenishing is always referred to as water spraying with concrete truck.

 

[rowmag]

Has the freshwater supply at Fukushima dried up? Or has SFP 1,3 & 4 always been replenished with seawater.

http://www.tepco.co.jp/en/press/corp-com/release/11042203-e.html"

Previous reports just stated water spraying

On March 25 and 26 reactor cooling was switched from sea water to freshwater.

Unit 2 SFP was regularly filled with fresh water according to Tepco reports. Unit 1, 3 and 4 SFP replenishing is always referred to as water spraying with concrete truck.

It is a mistake.

The Japanese version just says water spraying with concrete truck, not seawater.

http://www.tepco.co.jp/nu/f1-np/press_f1/2011/htmldata/bi1456-j.pdf

 

[Dmytry]

That is irrelevant since the TEPCO faxes and NISA releases are all in Japanese.

Godzilla only knowns how how many hands separate the readings on the instruments to the faxes sent by TEPCO to NISA. Someone along that path seems to be unfamiliar with scientific notation; that would explain the exponent errors (and why the numbers are not being converted to ordinary decimal notation).

I have this old theory that (a) TEPCO has no nuclear experts in their payroll, and (b) their sub-contractors, who actually run the plant, have only technical-level expertise, not engineering- or science-level --- namely, they know standard procedures, but cannot understand or react to situations that are are not in the manuals. I would love to be proved wrong...

I watched a documentary on Chernobyl the other day. One lesson that Japan could have learned from that incident is: do not let the the plant operators remain in charge of disaster contol. At Chernobyl, precious days were lost while the operators (and their bosses and bosses' bosses, up to cabinet level) insisted that "everything was under control". Real action began only after Gorbachev pushed those people aside and put a committee of the country's top nuclear scientists in charge.

Unfortunately it seems much harder to do that in Japan, given the constraints of capitalism (Fukushima-I is still the private property of TEPCO) and the fact that the State is in many ways subordinated to big corporations like TEPCO, GE, Toshiba, etc. So here we are, 1000 hours after the accident and we are still wondering whether there is any real cook in the kitchen.

Excellent overview, that's precisely what I was feeling. Also, so much was done in Chernobyl in very short time... getting the water out of meltdown's way, etc. All forgotten by the public, Chernobyl made look as the absolute worst case most ineptly handled.

In any case, why would tepco have enough nuclear experts for accident handling on staff before accident? That wouldn't even make sense for each single utility, they should of created a company jointly, ala KHG, so that they together pool for such a team. But they didn't do that, there is no Japanese equivalent of KHG or INTRA.

 

[rowmag]

Don't forget also that with the typhoon season, huge amount of rain water is going to "wash" the big mess on the Fukushima plant (soils, buildings, reactors, etc.). And this water is going to finish its trip into... the ocean.

They have this big, triangular seawall. Can they block off the entrance, and make the whole thing into a giant containment tank? Won't prevent all the contaminated groundwater from leaking out, but couldn't they at least reduce some of the marine pollution that way?

http://upload.wikimedia.org/wikipedia/commons/e/e8/Fukushima_I_NPP_1975.jpg

Seems like it could be a useful next step after the silt fences etc. that they have installed closer in.

 

[tsutsuji]

It seems that the currents are going south in this area of the Japan sea, so I wouldn't be surprise that the plume of contamination follow this costal line... But it is to early to be sure of that.

http://sirocco.omp.obs-mip.fr/outils/Symphonie/Produits/Japan/SymphoniePreviJapan.htm has an "animation of surface currents" and a simulation of the dissemination of the pollutants into the sea through direct release and atmospheric release.

 

[jlduh]

Finally, japanese government starts to move from its original position about evacuation zone and expands it north-west, as we were talking about yesterday on this thread !

http://www3.nhk.or.jp/daily/english/22_20.html

Edano said that due to the possible impact on residents' heath, the government is now urging them to evacuate within about a month.

So is this 20 mSv a "threshold" or a "safe limit"?
(a lit bit of irony inside, i admit ;o))

I think it is now accepted by many specialists that any increase of artificial radiation is also an increase in diseases risks, like it is also with many chemical products that act on health of living organisms WITHOUT ANY THRESHOLD MECANISM. This is called "excess risk" and "relative excess risk":

http://cat.inist.fr/?aModele=afficheN&cpsidt=1886907

http://www.rerf.or.jp/radefx/late_e/cancrisk.html

So in fact you were right and i was wrong: there is probably no "safe limit" for radiation, there is only a threshold for evacuation decision...

 

[tsutsuji]

I watched a documentary on Chernobyl the other day. One lesson that Japan could have learned from that incident is: do not let the the plant operators remain in charge of disaster contol. At Chernobyl, precious days were lost while the operators (and their bosses and bosses' bosses, up to cabinet level) insisted that "everything was under control". Real action began only after Gorbachev pushed those people aside and put a committee of the country's top nuclear scientists in charge.

Unfortunately it seems much harder to do that in Japan, given the constraints of capitalism (Fukushima-I is still the private property of TEPCO) and the fact that the State is in many ways subordinated to big corporations like TEPCO, GE, Toshiba, etc. So here we are, 1000 hours after the accident and we are still wondering whether there is any real cook in the kitchen.

Concerning the management of the crisis, I read the following in the Japanese press :

The lack of management's understanding of the working environment at the plant could lead to a blunder or a delay in the work.
April 21, 2011
http://mdn.mainichi.jp/perspectives/news/20110421p2a00m0na001000c.html

Michio Ishikawa, a top advisor to the Japan Nuclear Technology Institute : "I think TEPCO also needs to review its organization, for example, by having someone who can exert strong leadership [to spearhead the timetable's implementation]."
April 19, 2011
http://www.yomiuri.co.jp/dy/national/T110418004891.htm

 

[jlduh]

Hummm from the article you cited:

TEPCO's roadmap only mentions equipment at the plant. However, it is human resources that will place the plant under control. Therefore, measures to extend support for workers should be incorporated in the roadmap.

Supports its workers?

Well, they do...

http://www3.nhk.or.jp/daily/english/21_38.html

The operator of the troubled Fukushima Daiichi nuclear power plant is to cut annual salaries of its workers by around 20 percent as part of efforts to fund compensation payments over the nuclear accident.

What would you expect from a private company who HAS to stay profitable in the short term to continue to exist, even if the subject is long term effects for the all community around?

That is a big Achille's heel, in my opinion, in this policy where private interests manage so big threats: in case of bankrupcy, will the threat and disaster go bankrupt also?

This is kind of silly...

Private corporations in their current forms have teir own efficiency and no doubt there are benefits from this to the community. No doubt about that. But they are also areas where this is no more true, i think.

This remembers this very clear analysis of "externalities" concept that was done in the documentary The Corporation, from Mark Achbar:

http://www.youtube.com/watch?v=aCGTD5Bn1m0&feature=relmfu

The all documentary ( is very interesting even if it carries a view that is heavily uncomfortable with many considerations that are "trendy" in nowadays societies... This not ideology, this is just logical elements.

 

[tsutsuji]

"to feed the dog with something" that is how the public is feeling about the information "policy" of TEPCO.

But why are they doing so?
To hide the real size of the disaster? -> It's INES 7 already.
To secure "engineering secrets"? -> I do not belief the Iran like to copy this crap.
TEPCO itself do not have more data, pictures and information? -> God forbid.

I wonder if the robot missions are more than a show to please the United States, in a fashion similar to the helicopter drops :

The Kan administration feared that Japan would be abandoned by the rest of the world, and hoped the helicopter mission would help the country overcome the negative images.

"The release of water was a display to the U.S. We were showing them how serious Japan was," a high-ranking Japanese government official commented.
http://mdn.mainichi.jp/mdnnews/news/20110422p2a00m0na005000c.html

 

[jlduh]

Tsutsuji: the articles and site you listed are very interesting, thanks. The last one on helicopters drops confirms my initial impressions when i saw these images...

Back on the 1 mSv/20mSv or whatever threshold or limit or the name you prefer to use, this article about the procedure used for the people living inside the 20 kms zone to quickly visit their home adds some smoke into the clarity (a little smoggy though) of my understanding:

http://mdn.mainichi.jp/mdnnews/news/20110422p2a00m0na009000c.html

The government will only allow the evacuees to be at their homes for up to two hours in order to minimize their exposure to radiation. "We wanted to make sure that residents will not be exposed to more than 1 millisievert of radiation even if they spend five hours, including travel time, in the 20-kilometer zone," said an official with the Nuclear and Industrial Safety Agency.

no more than 1 mSv in 5 hours in the 20 kms zone? Uhhhh, are they basing this procedure onto some radiation data that they have to declare this? This would be 200 microSv/h exposition, which is quite huge...

 

[Astronuc]

Has the freshwater supply at Fukushima dried up? Or has SFP 1,3 & 4 always been replenished with seawater.

http://www.tepco.co.jp/en/press/corp-com/release/11042203-e.html"

Previous reports just stated water spraying

On March 25 and 26 reactor cooling was switched from sea water to freshwater.

Unit 2 SFP was regularly filled with fresh water according to Tepco reports. Unit 1, 3 and 4 SFP replenishing is always referred to as water spraying with concrete truck.

The text has been corrected.

 

[Krikkosnack]

Correct me if I am wrong but, analyzing the previous posts (#2978-#3500 excluding https://www.physicsforums.com/showpost.php?p=3232444&postcount=3058" at page 21 , the design pressure of the containment is 4-5 bar instead of one pressure's probability up to 8 bars. Almost doubled!, (even after the released of hydrogen from RPV).
Due to this release of hydrogen into the building 3, the normally separated ambients, are in strictly contact for a fire propagation.
This explosion had disintegrated the upper part of the containment structure and, due to one de-pressurizzation of the Reactor Pressure Vessel (RPV), aspirated some particles of heavy materials in the air.

 

[jlduh]

Tsutsuji, the link you provided for simulation of local oceanic currents and radioactive dispersion is great (i repost it: http://sirocco.omp.obs-mip.fr/outils/Symphonie/Produits/Japan/SymphoniePreviJapan.htm ).

The poor rough data that i had gathered -before seing this- was giving me a general south current at this coast joining then the big est/north east warm current bringing the water further in the pacific ocean but the model here gives much more nuances, and espcially local nuances (and complexity!).

It "seems" that based on surface currents simulation, the main dispersion of the radioactivity directly rejected into the sea (so leaks from the plant, at ground level + underground discharges maybe?) will create a big plume of dispersion in the NORTH direction (so mainly impacting the north coast from the Daichi plant), even if there is also some south component move . Most of this plume (the direct rejection component) stays along the coasts over a distance of more than 50-70 kms (I'm not saying anything on the levels of contamination, i just look at the general shape of the plume shown).

To this "direct rejected contamination" (dissolved and particulates), they add the dispersion from redeposition into the sea also from particulates and from dissolved elements. Of course this second factor (redeposition) is completely wind (and rain) dependent. This plume (the level in Bq/l is much lower though in their simulation than the direct rejected component, by a factor 20, look at the scales) extends more than 100/150 kms in the North coast.

I put also this extract of their explanation to set the limits of this simulation (any simulation is only a simulation, often very sensitive to values fed and hypothesis done):

Finally, the oceanic currents computed by our model are not the reality: they are the result of mathematical equations too simple to fully represent the complexity of nature. The wind which strongly drives the oceanic currents is also a forecast whose accuracy is not known.

We do not know how much radionuclides have been injected, when they have been injected and how they behave once they reach the sea. That is why we do not claim that our simulations are able to provide an accurate quantification of radioactivity in the sea. However, in order to build our scenarios, special attention has been paid to the measurements of Cesium 137 concentration taken several times every day by TEPCO at 30 and 300m in front of the nuclear plant.

Two sources of radionuclides are considered. One corresponds to a direct emission in the sea in front of the nuclear plant (migration of water contaminated by the reactors), the other one corresponds to fallout of atmospheric particles. In the first case, we introduce a flux at the grid point corresponding to the nuclear plant. This flux is adjusted to produce a concentration close to the values of Cesium 137 measured (see our page of validation). In the last case, we have assumed that the deposition from the atmosphere takes place in a circle of 200km of radius with a concentration maximum at the centre of the circle positioned at the nuclear plant and decreasing with distance. The flux corresponds very roughly to preliminary estimations given by atmospheric model. We intend to improve these values in a next future as results of atmospheric model are available.
For each source (direct release and atmospheric), we consider two cases: one corresponds to dissolved elements, the other one to particles that fall into the sea with a velocity of 10meters per day. Obviously dispersion in the first case will happen at larger scale than for the second case for which deposition of particles on the sea floor reduces the dispersion.

 

[Dmytry]

I wonder if the robot missions are more than a show to please the United States, in a fashion similar to the helicopter drops :
"The Kan administration feared that Japan would be abandoned by the rest of the world, and hoped the helicopter mission would help the country overcome the negative images."

They've been offered nuclear accident robots and other equipment for free by KHG and INTRA . I bet they were also offered crews, but opted not to have any non-TEPCO personnel doing measurements on site. They could get anything they ask for. The losses to nuclear companies from this accident must be incredible. AREVA is offering to do anything possible. Every nuclear company's money are at stake, everyone got strong financial incentive to help. For some reason, it still appears as if only TEPCO employees are doing any measurements.

 

[Dmytry]

Finally, japanese government starts to move from its original position about evacuation zone and expands it north-west, as we were talking about yesterday on this thread !

http://www3.nhk.or.jp/daily/english/22_20.html
So is this 20 mSv a "threshold" or a "safe limit"?
(a lit bit of irony inside, i admit ;o))

I think it is now accepted by many specialists that any increase of artificial radiation is also an increase in diseases risks, like it is also with many chemical products that act on health of living organisms WITHOUT ANY THRESHOLD MECANISM. This is called "excess risk" and "relative excess risk":

http://cat.inist.fr/?aModele=afficheN&cpsidt=1886907

http://www.rerf.or.jp/radefx/late_e/cancrisk.html

So in fact you were right and i was wrong: there is probably no "safe limit" for radiation, there is only a threshold for evacuation decision...

Yes, the thing is that evacuation itself carries risks so there should be a threshold for evacuation. Some threats you can't run away from. Suppose some immense radiological disaster results in 0.1% higher risk of cancer in an area of population ten millions. That is 10 000 dead. But evacuating such population, with associated spike in disease, may kill more. There's nearly nothing you can do about 0.1% excess risk. You can't even measure it directly, only estimate from theoretical considerations (e.g. role of mutations in cancer) so you can't even 'prove' it in the legal sense.
There's also the "stay indoors" orders which really interfere with healtcare and such. Keeping a large area under such order for a month is imo very irresponsible. Mapping may allow to lit the order for most people and evacuate those who have to be evacuated.

 

[tsutsuji]

Also the irobots were not initially requested either by Tepco or by the Japanese governement :

Japanese government officials and relief agencies hadn’t asked for the robots, but the company saw no reason to wait for a request.
...

The company wasn’t asked to send its robots to New York City after the terrorist attacks of Sept. 11, 2001, but it did.

March 26, 2011
Helping hand from iRobot
Bedford firm sends four robots to Japan’s rescue, recovery effort
http://articles.boston.com/2011-03-26/news/29352816_1_irobot-military-robots-packbots

I wonder if the irobots were chosen (among the other Areva, KHG, NUSTEC [1], British [2] robots) because they best fitted the planned mission or because that US company insisted so much that Tepco finally gave in.

[1] http://www.nustec.or.jp/japan/robot_pamphlet.pdf ( reportedly sent to Fukushima as soon as March 16th : http://www.asahi.com/special/10005/TKY201103160428.html )
[2] http://news.bbc.co.uk/cbbcnews/hi/newsid_9460000/newsid_9462600/9462621.stm

 

[Dmytry]

Also the irobots were not initially requested either by Tepco or by the Japanese governement :



I wonder if the irobots were chosen (among the other Areva, KHG, and Japanese robots) because they best fitted the planned mission or because that US company insisted so much that Tepco finally gave in.

there's not only robots that were missing. KHG also has portable isotope analysis equipment, which can and IMO has to be used to recognize criticality, if it happens, as soon as possible.

 

[ascot317]

there's not only robots that were missing. KHG also has portable isotope analysis equipment, which can and IMO has to be used to recognize criticality, if it happens, as soon as possible.

Getting KHG or something similar in there would have been my first task.
Instead, PackBots, T-Hawk and "Technicians" who can't even work with counters.

It's freaking me out, Japan isn't some 3rd world country, is it?

 

[Dmytry]

Getting KHG or something similar in there would have been my first task.
Instead, PackBots, T-Hawk and "Technicians" who can't even work with counters.

It's freaking me out, Japan isn't some 3rd world country, isn't it?

What REALLY bothers me btw is the attitude that you have to theoretically prove that criticality happened before you start doing measurements to see if it happened / may resume. That it is seen as normal they aren't testing for short living isotopes. (they used to, and there was Cl-38 and I-134 figures, if you remember, in that radioactive water from reactor 2. Then the officials said 'it is hard to imagine re-criticality in shut down reactor', never mind that after it was dry for hours, it is not a reactor any more but a mess, almost geology. Back in the day when natural uranium was 3% U-235, there were natural nuclear reactors. This stuff is up to 5%)

 

[ascot317]

What REALLY bothers me btw is the attitude that you have to theoretically prove that criticality happened before you start doing measurements to see if it happened / may resume. That it is seen as normal they aren't testing for short living isotopes. (they used to, and there was Cl-38 and I-134 figures, if you remember, in that radioactive water from reactor 2. Then the officials said 'it is hard to imagine re-criticality in shut down reactor', never mind that after it was dry for hours, it is not a reactor any more but a mess, almost geology. Back in the day when natural uranium was 3% U-235, there were natural nuclear reactors. This stuff is up to 5%)

Yes, that's a very "by-the-book"-approach. Like someone has said earlier, technicians, not scientists or engineers at work.

Instead of saying "Things went wrong and we don't exactly know what and why", they're behaving as if things are still within "normal" parameters.

I remember the I-134 figures. To me it looked like this: Lab workers found the I-134, it got published, later some white-collar-guy with little knownledge said "that's technically impossible" and declared it a "mistake".

I wonder how long it will go on like this. Tepco needs to be released from command of the facility immediately (they sure are still needed for advisory about the facilities).

It really looks like as if they think they know what has happened. So, they either know a lot more than we do, or they are unaware of their own incompetence in assessing the situation.

I have yet to see e.g. an IR photo from the T-Hawk, showing the SFP and reactor area up close. The T-Hawk is capable of doing this (it's unable to deliver high res coverage pictures, but, at least, use it to its full capability!). And why they haven't yet published good pictures of the inside of the upper floors... I don't get it. Doesn't even need a robot for #1, #3 and #4. We've seen enough of the outside of the facilities. More than a month after the explosion of #3, people still wonder about the state of the drywell head, not to mention the SFP's.

 

[TCups]

It would have be a equally failing understanding. It is not a safe limit it is the threshold that we do not want to exceed for artificial if possible.
Nope, this map is for dose induce by radioactive matériel from Fukushima, it take into account decay, external ionization and internal inhaled particule. it assume one is standing outside 247. and does not take into account that radiation exposition would be mitigated by the time you spend indoor (as requested).

As for the 1 mSv you get it from the ²²²Rn present in the air every one breath .. You also get 0,2mSk from your own potassium etc ..
http://www.rchoetzlein.com/theory/wp-content/uploads/2011/03/radiation.jpg Here again this is a miss understanding, on the "no risk concept". Of course there is a risk, every time you take some medication there is a risk, I almost die the first time I toke penicillin, every time you do something there is a risk.. There is no such thing as risk free, But what is commonly admitted is that when the probability of something bad to hapen is low enough or lower that a lot of other thing we consider it risk free. Call in un "abut de language" or convention..
I mentioned different annual dose for different country France + Dose from this map < annual dose from the states or Sweden..
As low as possible is the word, unless you are Tcup's mice ( I have yet to read the paper), now if you do a proper assessment you have to take into account other choice you make and pose superior threat.

I don't believe I have ever read "the paper" (oft cited: W. Russell, Oak Ridge National Laboratory) either. My internet search skills may be deficient, I suppose, else there was no single "paper" on the subject.

Please keep in mind here that the controversial topic is low dose radiation exposure (ie, on the order of background radiation levels), not the high dose exposures that are the current risk at Fukushima.

The "Mega Mouse" Experiment was carried out at Oak Ridge National Laboratories and the study involved testing the genetic mutation rate at various dose rate exposures and various exposure intervals to a genetically selected strain of mice, about 7,000,000 of which were irradiated over the course of the experiment.

See:

http://books.google.com/books?id=6H...&resnum=3&ved=0CCkQ6AEwAg#v=onepage&q&f=false

http://www.21stcenturysciencetech.com/articles/nuclear.html

http://ocw.mit.edu/courses/nuclear-engineering/22-01-introduction-to-ionizing-radiation-fall-2006/lecture-notes/health_effects.pdf

http://www.wmsym.org/archives/1999/03/3-4.pdf

The "LNT" driven guidelines have done a lot of damage in keeping the public fearful about even the slightest exposure to radiation. Most recently, and directly affecting my practice, was the "Dr. Oz" recommendation that women ask for a thyroid shield when they get a mammogram!

See:
http://www.snopes.com/medical/toxins/thyroidguard.asp

Here's my take. Yes, many technologist keep a thyroid shield handy because it is easier to give the patient one than to explain why Dr. Oz (handsome though he is) is wrong when he appears on Opra and Good Morning America making such suggestions. The dose to the thyroid gland from scattered radiation on a 4-view mammogram is comparable to 30 minutes of exposure to average natural background radiation. One of my radiologist colleagues had a useful alternative suggestion: Have the patient put on a thyroid shield, the let her sit an extra 30 minutes in the waiting room before you do the mammogram exam, then do the mammogram without the thyroid shield. The reduction in net exposure to the thyroid gland would be the same. Putting a thyroid shield on during a mammogram or having the dental assistant lay a lead apron on your lap before a dental x-ray is a) useless, and b) helps propagate a widespread exaggerated fear of "radiation exposure" to the general public. Further, compliance with the LNT-based guidelines are another huge bureaucratic regulation boondoggle that wastes vast sums of health care dollars with no real benefit, IMO.

 

[Guest Member]

I appreciate all the input everyone is doing here. I thought this might be interesting to some of you. EPA doesn't publish all results for the public. You can run a custom search on EPA's site and see results for Plutonium and Strontium. Here's the blog that posts the data found and at the bottom of the data, it shows how to do a custom search on EPA's page to get recent data.
http://blog.alexanderhiggins.com/2011/04/21/radioactive-fukushima-plutonium-strontium-bombarding-west-coast-march-18th-19279/

 

[|Fred]

..

You still don't get, or refuse to ... Let's have an other go.

The 1 mSv is not to be understood as a threshold as in threshold vs linearity of ionization effect debate.
It does not mean that if one get dosed over 1mSv you are in danger, It means that we do not want artificial radiation to dose the general public more than 1mSv / year.

Now, since you open the door on the debate about threshold vs linearity of ionization

Initial assessment of radioactivity effect on heath was done on extensive epistemological studies after Hiroshima i.e. Single hight dose. In the absence of comparable studies for low-dose effects the prudent hypothesis of the no-threshold (LNT) was adopted. It extrapolate from the linearly of effects observed at high doses to the same effects at very low doses.

So basically everything you read about danger of low dose of radioactivity Is based on the prudent assumption there is no threshold. Arguing that we did not studies low dose radiation effect in order to claim that the current standard are not safe is basically saying that cumulative low dose radiation exposition are more harmful. This seem highly debatable: You'll probably familiar with the 98's US Nuclear Regulatory Commission and other papers on the subject. From what I read people seems to disagree on the subject and have mixed evidences.. LNT seems Mundane proof to me.


edit: for Tcup http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1533290/pdf/envhper00536-0363.pdf

 

[Dmytry]

re: LNT.
Well, for example camels have a threshold for load on their backs, and the dose response of a camel to load on the back is very complicated, however, when they are loaded with a load of gold that kills 20% of camels and maims another 20%, rest assured, effect of extra straws can be expected to be linear even though straws are very different from gold. Ditto for humans really.
There may well be a weight lifting program for a camel that would dramatically decrease camel's risk of suffering broken back, but haphazardly adding random numbers of straws to already 20% dying camels ain't going to be good, and effect oin the population can be expected to be linear (approximating tiny piece of response curve with a line).
We humans have high mutation load, high enough for 40% cancer rate. Single cell studies have indicated that single particle track through nucleus of single cell sometimes results in mutation. In my book, that is theoretical basis enough to require LNT for safety.
It may not be the basis enough if 'radiation' was a human on trial for murder and innocent until proven guilty applied. Then you'd have real trouble convincing jury for unanimous vote. You could perhaps even pull the trick with genetically engineered mouse to set your client free. But for safety, too many people have died already from 'safe until proven unsafe' approach (google for 'radium dial painters' for example, google for the 'radium medicine', etc).

 

[M. Bachmeier]

Hydrogen peroxide is not combustible.

Yes you are correct. Hydrogen peroxide has to decompose or come into contact with an organic substance. Hydrogen peroxide on a rag can heat and spontaneously combust. My point is that you don't need any source of ignition and it will decompose rapidly at 70 degrees Celsius. If my research is accurate.

 

[Dmytry]

Yes you are correct. Hydrogen peroxide has to decompose or come into contact with an organic substance. Hydrogen peroxide on a rag can heat and spontaneously combust. My point is that you don't need any source of ignition and it will decompose rapidly at 70 degrees Celsius. If my research is accurate.

speaking of combustible stuff, what's about boral plates, can someone comment on that? Aluminium powder, and the bloody things are not even watertight, they swell from hydrogen accumulation and the "solution" was to clip corners so that hydrogen could escape (never mind more water getting in).
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/196.html

 

[Krikkosnack]

Other bits of information..MELCOR Best Practices - An Accident Sequence Walkthrough L. Humphries
"[PLAIN mirror on my web site
[/B][/URL]

http://www.ncnr.nist.gov/trtr2005/Proceedings/Belpomo - Phebus presentation.pdfhttp://www.ornl.gov/~webworks/cpr/v823/rpt/109264.pdf"
"[PLAIN mirror on my web site
[/B][/URL]

source http://forum.atominfo.ru/index.php?showtopic=575&st=520

 

[Dmytry]

Other bits of information..MELCOR Best Practices - An Accident Sequence Walkthrough L. Humphries
"[PLAIN mirror
[/B][/URL]

http://www.ncnr.nist.gov/trtr2005/Proceedings/Belpomo - Phebus presentation.pdfhttp://www.ornl.gov/~webworks/cpr/v823/rpt/109264.pdf"
"[PLAIN mirror
[/B][/URL]

source http://forum.atominfo.ru/index.php?showtopic=575&st=520

what irks me about mox (or even just the old fuel) is that some sort of fractional distillation, or gradual crystallization of molten core, or something of this sort, could result in locally higher concentration of plutonium. It's very different in that respect from u235/u238. It seems to me that it would be very difficult to rule out such a possibility, when you mix salt, water, zirconium, uranium dioxide, plutonium dioxide, etc. and cook it at high temperatures, gradually raising and then lowering the temperature, very slowly.

 

[TCups]

re: LNT.
Well, for example camels have a threshold for load on their backs, and the dose response of a camel to load on the back is very complicated, however, when they are loaded with a load of gold that kills 20% of camels and maims another 20%, rest assured, effect of extra straws can be expected to be linear even though straws are very different from gold. Ditto for humans really.
There may well be a weight lifting program for a camel that would dramatically decrease camel's risk of suffering broken back, but haphazardly adding random numbers of straws to already 20% dying camels ain't going to be good, and effect oin the population can be expected to be linear (approximating tiny piece of response curve with a line).
We humans have high mutation load, high enough for 40% cancer rate. Single cell studies have indicated that single particle track through nucleus of single cell sometimes results in mutation. In my book, that is theoretical basis enough to require LNT for safety.
It may not be the basis enough if 'radiation' was a human on trial for murder and innocent until proven guilty applied. Then you'd have real trouble convincing jury for unanimous vote. You could perhaps even pull the trick with genetically engineered mouse to set your client free. But for safety, too many people have died already from 'safe until proven unsafe' approach (google for 'radium dial painters' for example, google for the 'radium medicine', etc).

We digress off-topic for this thread, and for that I apologize. I certainly can't claim to be knowledgeable enough to debate this topic on a purely scientific basis with experts in the field. I will say that the "one ionizing particle, one cell, one mutation, one cancer" basis for LNT-based regulations seems overly conservative for practical purposes. One nail could cause one flat tire resulting in one accident resulting in one or more fatalities. But it is not appropriate to stringently regulate the nail industry because of this, nor to induce in the public an irrational fear of the absolute risks of death by nail.

Continuous exposure to low dose radiation is an environmental fact of life. Perhaps the nuclear industry is to be lauded for stringent safety regulations with nothing but good and appropriate intentions for doing so, and for following the most conservative approach with the LNT as a guideline. But in practical terms, IMO, it is may be overlooked that one potential harm from such a conservative approach is propagation of the public perception of an irrational fear of radiation - "Oh my God, one particle of radiation and I am at increased risk for cancer! Where's my lead shield?!

 

[ascot317]

what irks me about mox (or even just the old fuel) is that some sort of fractional distillation, or gradual crystallization of molten core, or something of this sort, could result in locally higher concentration of plutonium. It's very different in that respect from u235/u238. It seems to me that it would be very difficult to rule out such a possibility, when you mix salt, water, zirconium, uranium dioxide, plutonium dioxide, etc. and cook it at high temperatures, gradually raising and then lowering the temperature, very slowly.

You mean, leading to "natural" isotope separation causing nests of criticality?

 

[etudiant]

It seems that this accident is gradually worsening, with no coherent strategy to resolve it.
The public parameters certainly show deterioration, with the closing of the immediate 20km zone and the extension of the contaminated zone to the north.
Also, while the official charts summarized here: http://fleep.com/earthquake/ show a reassuring steady decay of the measured contamination, the level privately monitored here http://www.ustream.tv/channel/%E6%94%BE%E5%B0%84%E7%B7%9A%E3%83%AC%E3%83%99%E3%83%AB from Chiba has about tripled since the April 19-21 inland wind and rain, to about 30 microsieverts/hr.
It does seem that the analogy to the frog being slowly boiled is not entirely off the mark.
Must a larger part of Japan become uninhabitable before the Japanese leadership recognizes that the current approach is not working?

 

[rowmag]

new data from Tepco website on underground water contamination:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110419e11.pdf

and pdf with time curves for all reactors samples:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110419e12.pdf

Updated plots:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110421e16.pdf

Looks like the I-131/CS-137 ratio is not changing at Unit 2...

 

[jarvik]

Well, maybe i should have written maximal ALLOWED dose for general population (defined by french safety coden but that is the limit in many countries for artificial radiation). Which i expect is a "safe limit" by the way ;o)

Fred has gone over much of your other text already but I thought you might like to know something further about what actually might be considered a "unsafe" exposure to radiation, as in one that we actually have reason to believe there could be health effects down the road.

From the 3rd table in the sourced linked below:

"100 mSv/year is the lowest level at which any increase in cancer is clearly evident. Above this, the probability of cancer occurrence (rather than the severity) is assumed to increase with dose. Allowable short-term dose for emergency workers taking vital remedial actions (IAEA)"

So a yearly exposure of 100mSv/year or 10,000 mrem /year is likely a more realistic safe limit that if crossed we can expect ramifications to human health to occur with some degree of certainty.

While it is certainly prudent to ensure that public exposure is well below this level and by a healthy margin, which I might add is what the 1 mSv/year guideline is meant to achieve. However it most certainly does not indicate that we need to be panicking the moment 1 mSv /yr is exceeded as it's well short of what we actually expect to be a dangerous level of exposure.

So again this is a bad situation that warrants alot of concern and yes if possible be over cautious with regards to public health (i.e.. try to get children and others out of the red zone NW of the current exclusion zone) but keep in mind evacuation has its own consequences to human welfare that might in this case be a greater likelihood of causing harm than exposure to a level of radiation that is somewhere in the area of 1/5th of the level expected to cause some measurable degree of long-term health effects. We don't have all the facts and additional complications that impact the decisions being made here.

There's lot we don't know about this situation and perhaps it is worse than we are lead to believe but having real information and knowledge is the only way to make headway and not jump at every shadow would be my preferred path.

http://www.world-nuclear.org/info/inf05.html"

 

[dinorobo]

It seems that this accident is gradually worsening, with no coherent strategy to resolve it.
The public parameters certainly show deterioration, with the closing of the immediate 20km zone and the extension of the contaminated zone to the north.
Also, while the official charts summarized here: http://fleep.com/earthquake/ show a reassuring steady decay of the measured contamination, the level privately monitored here http://www.ustream.tv/channel/%E6%94%BE%E5%B0%84%E7%B7%9A%E3%83%AC%E3%83%99%E3%83%AB from Chiba has about tripled since the April 19-21 inland wind and rain, to about 30 microsieverts/hr.
It does seem that the analogy to the frog being slowly boiled is not entirely off the mark.
Must a larger part of Japan become uninhabitable before the Japanese leadership recognizes that the current approach is not working?

That is not 30 microsieverts/hr, it is 0.30/hr

 

[tsutsuji]

...

Another private monitoring in Chiba prefecture : http://www.ustream.tv/channel/%E6%94%BE%E5%B0%84%E7%B7%9A%E6%B8%AC%E5%AE%9A-%E5%8D%83%E8%91%89 (about 0.150 μSv/h right now)

In Fukushima city : http://www.ustream.tv/channel/%E7%A6%8F%E5%B3%B6%E5%B8%82-%E6%94%BE%E5%B0%84%E7%B7%9A%E6%B8%AC%E5%AE%9A%E5%80%A4 (0.600 μSv/h right now)

More private monitoring channels at http://bearishtrader.blogspot.com/p/santa-monica-west-la-live-radiation.html

 

[jarvik]

It seems that this accident is gradually worsening, with no coherent strategy to resolve it.
The public parameters certainly show deterioration, with the closing of the immediate 20km zone and the extension of the contaminated zone to the north.
Also, while the official charts summarized here: http://fleep.com/earthquake/ show a reassuring steady decay of the measured contamination, the level privately monitored here http://www.ustream.tv/channel/%E6%94%BE%E5%B0%84%E7%B7%9A%E3%83%AC%E3%83%99%E3%83%AB from Chiba has about tripled since the April 19-21 inland wind and rain, to about 30 microsieverts/hr.
It does seem that the analogy to the frog being slowly boiled is not entirely off the mark.
Must a larger part of Japan become uninhabitable before the Japanese leadership recognizes that the current approach is not working?

So let's think about this a bit, 0.30 microSv/ hr or 7.2 microSv/ day works out to 2.63 milli Sv/yr or the extra exposure an Englishmen would get from moving to and living in France for a year.

 

[Dmytry]

You mean, leading to "natural" isotope separation causing nests of criticality?

No, not isotope separation. It really ain't going to happen that e.g. u235 would be separated from u238. Chemical element separation. Plutonium is a different chemical element, and it's compounds got different melting temperature from that of uranium, etc.

 

[mscharisma]

Getting KHG or something similar in there would have been my first task.
Instead, PackBots, T-Hawk and "Technicians" who can't even work with counters.

It's freaking me out, Japan isn't some 3rd world country, is it?

I KNOW I read somewhere yesterday that they are bringing in Japan-made robots that are much more sophisticated in their abilities (sorry, the technical details were beyond me, so I can't retell the story). Unfortunately, for the life of me, I can't find where I read it. Will post it when I come across it. Whatever I read said they would try and start operating these robots on Friday, i.e., today.

UPDATE: It's not the article I read yesterday, but here's info on the next step regarding robots:
http://search.japantimes.co.jp/cgi-bin/nn20110423f1.html

 

[etudiant]

So let's think about this a bit, 0.30 microSv/ hr or 7.2 microSv/ day works out to 2.63 milli Sv/yr or the extra exposure an Englishmen would get from moving to and living in France for a year.

Thank you.
It is good news to get this corrected info.
The larger point however is not altered, the exclusion zone is growing and the progress is desultory, with no coherent management evident.
The NRC characterization of the situation as 'static but fragile' conspicuously avoids using the word 'stable' that was reported elsewhere.

 

[NUCENG]

Updated plots:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110421e16.pdf

Looks like the I-131/CS-137 ratio is not changing at Unit 2...

I looked for another earlier or later sample of the sub drains as a sample point. If anyone has that information (concentrations of I-131 and Cs-137) at the same sample point it may give us some information. Without that information it is not possible to say very much. There is still at least 3E16 Bq of I-131 that was initially in the core but has not yet decayed. and about the same amount of Cs-137. If you sampled all of the release streams and the inventories in the RPV, Suppression chamber (wet and air) and the drywell you would expect that the ratio is around 1:1 at this time after shutdown. The samples you cite give an Iodine ratio of I/Cs of about 7:1. But without knowing how the I-131 and Cs have been transported you cannot predict what the ratio should be at a particular sample point. Again, Cs and I have opposite chemical valences and chemical interactions may have affected the two isotopes differently during their trip to the subdrain. The higher level of I-131 probably rules out the sample point having become acidic allowing I₂ gas to reevolve. Has the source of the sample been drained or concentrated by evaporation or boiling? Has the Cs plated out or settled well upstream of the sample point?

One thing you can look at to see if the ratio is completely out of wack compared to the other units. Unit 1 is about 4:1, Unit 3 is about 1:1, and Unit 4 is about 8:1. With that sort of spread I can't guess whether these numbers tell us anything for certain. Give me more data from the same sample points and it may start to be useful.

 

[AntonL]

M5.5 earthquake at 00:25AM April 23 is reported with epicenter 37.224°N, 140.981°E , which is 11km south of the Fukushima II Daini NPP and 22km sout of Fuukushima I Daichi NPP

 

[Samy24]

Updated plots:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110421e16.pdf

Looks like the I-131/CS-137 ratio is not changing at Unit 2...

I did never belief the quotes of criticality events because most scientists told us that there is no evidence for that. But maybe I had to change my mind.

The graphs show roughly two half-lifes and if I do simple math rightly, not only unit 2 but also the readings of the underground water in the area of unit 3,4 and 5 do not fit.

If the places of measurement are the same over the timeline then it reminds me to three possibilities:

1. The amount of iodine at the meassure point increases over time but not the amount of Cs.
But how is this possible? Someone with chemistry knowledge?

2. The source of the contaminated water releases more I-131 than Cs over time.
Why? Is there still something melting an iod is released first?

3. The source of the contaminated water still generates I-131.

 

[Samy24]

I looked for another earlier or later sample of the sub drains as a sample point. If anyone has that information (concentrations of I-131 and Cs-137) at the same sample point it may give us some information. Without that information it is not possible to say very much. There is still at least 3E16 Bq of I-131 that was initially in the core but has not yet decayed. and about the same amount of Cs-137. If you sampled all of the release streams and the inventories in the RPV, Suppression chamber (wet and air) and the drywell you would expect that the ratio is around 1:1 at this time after shutdown. The samples you cite give an Iodine ratio of I/Cs of about 7:1. But without knowing how the I-131 and Cs have been transported you cannot predict what the ratio should be at a particular sample point. Again, Cs and I have opposite chemical valences and chemical interactions may have affected the two isotopes differently during their trip to the subdrain. The higher level of I-131 probably rules out the sample point having become acidic allowing I₂ gas to reevolve. Has the source of the sample been drained or concentrated by evaporation or boiling? Has the Cs plated out or settled well upstream of the sample point?

One thing you can look at to see if the ratio is completely out of wack compared to the other units. Unit 1 is about 4:1, Unit 3 is about 1:1, and Unit 4 is about 8:1. With that sort of spread I can't guess whether these numbers tell us anything for certain. Give me more data from the same sample points and it may start to be useful.

I do understand most of your view, but it is not the total ratio that I feel is wired, it is the fact that at the same measure point the ratio stay the same over time.

 

[jarvik]

Thank you.
It is good news to get this corrected info.
The larger point however is not altered, the exclusion zone is growing and the progress is desultory, with no coherent management evident.
The NRC characterization of the situation as 'static but fragile' conspicuously avoids using the word 'stable' that was reported elsewhere.

No problem.

I'm sure I haven't been following the situation as closely as many on this forum have been, but I to have not been impressed with how TEPCO appears to have been responding to the situation and the amount of information that is readily available leaves many un-answered questions and concerns.

Somedays I also get a bit panicky about numbers (and the reliablility of numbers) until I've had a chance to think a bit about their context and have tried to filter my fears through a bit of number crunching. That being said I don't envy the techs, engineers, scientists and policy makers having to deal with this situation and hope to hell they are more compentent than what TEPCO appears to have been in the first hours after the quake.

 

[NUCENG]

We digress off-topic for this thread, and for that I apologize. I certainly can't claim to be knowledgeable enough to debate this topic on a purely scientific basis with experts in the field. I will say that the "one ionizing particle, one cell, one mutation, one cancer" basis for LNT-based regulations seems overly conservative for practical purposes. One nail could cause one flat tire resulting in one accident resulting in one or more fatalities. But it is not appropriate to stringently regulate the nail industry because of this, nor to induce in the public an irrational fear of the absolute risks of death by nail.

Continuous exposure to low dose radiation is an environmental fact of life. Perhaps the nuclear industry is to be lauded for stringent safety regulations with nothing but good and appropriate intentions for doing so, and for following the most conservative approach with the LNT as a guideline. But in practical terms, IMO, it is may be overlooked that one potential harm from such a conservative approach is propagation of the public perception of an irrational fear of radiation - "Oh my God, one particle of radiation and I am at increased risk for cancer! Where's my lead shield?!

Tcups,

The nuclear industry assumes the LNT approach as a basis of applying ALARA (As Low As Reasonably Achievable) for workers. Basically the three principles of reducing exposure are Time, Distance and Shielding. You keep dose low by spending less time in a radiation area. You try to spend time away from hot spots or local sources wherever possible (distance) and You may install extra shielding to reduce dose. ALARA calculations are often tradeoffs in these principles. For instance by training on a mockup in a non-radiation error, technicians may be able to do the job faster. The people who install temporary shielding to reduce another technician's dose may themselves get more dose than the techician would get without the shielding.

That is for nuclear workers. We treat releases to the environment as a much greater concern. Most plants now have achieved zero-release standards for liquid releases by filtering and other waste processing methods. BWR airborne releases are closely monitored. We work hard to achieve zero defects in fuel because that is the quickest way to start raising the airborne release numbers. Finally out of purely economical reasons we try very hard to reduce the generation of solid waste. Solid waste disposal is very expensive and a huge NIMBY (Not in My Backyard) issue.

My lifetime dose is about 7.5 Rem (75 mSv). That dose was all received while in US Navy submarines and during training in a prototype reactor in Idaho. My lifetime dose from working in commercial nuclear plants is zero. (Admitedly, I haven't been involved in any accidents in those commercial plants.) All rumors to the contrary, but I'm not dead yet!

People have been praying for the operators at Fukushima who are working to stabilize the plants. They deserve our respect because they are taking a risk. But believe it or not in the early hours and days of the accident at TMI2, one of the problems they had was too many people in the control room making it hard to hear orders and creating distractions. People wanted to be there to help figure it out and get the plant into a safe condition. They finally had to order people out of the control room. Plants today have developed Emergency Response orgainzations and facilities outside of the control room to assist operators fighting an accident. The Techical Support Center is usually on site in a shelded and filtered area. The The Emergency Operations Center is located safely offsite and includes environmental monitoring, Communications with state and government organizations and provides a single point of information to the press. Another example of learning from experience.

 

[MadderDoc]

These two photos ...

are linked from the Tepco handout page. Above the links the page says:
"A picture taken from the concrete pumping vehicle, the spent fuel pool, Unit3, Fukushima Daiichi Nuclear Power Station
(pictured on April 14, 2011)"

The picture to the left I cannot recognize as having anything to do with unit 3 at all, nor indeed, a spent fuel pool. I am not sure this photo is even from the vicinity of unit 3.

The picture to the right appears to me as something that could very well be from unit 3, however that would be from the north end of the building, not at the spent fuel pool, which is situated in the south end of the buiding

I wonder if anyone might have been more successful than I, in an effort to locate the motives of these two photos?

For comparison, here's how the roof floor of unit 3 with its SFP (the greeny area) looked in Tepco's skyview from April 15th:

[URL]http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_4.jpg[/URL]