Fukushima Technical Discussion

[WhiteBlue]

WB has researched his own area and I believe we should all do the same. Checking reactors and delaying building them is hardly a knee jerk reaction is it.

It is always good if the people do not leave politics to the politicians but have a look into issues that can affect their lives in a drastic way. I would support autogyro in that proposal.

Something which I have realized when I checked some open safety issues of nuclear power plants is the different level of information you find from sources like Wikipedia depending of the language you use. This for instance is the German version of the level 2 incident in the Swedish Forsmark NPP. If you check the English version most of the relevant information about the 2006 accident is missing although it is now considered to be the most important accident between Chernobyl and Fukushima in terms of nuclear plant safety.

In Forsmark something similar happened to Fukushima just with a better outcome. The power was lost after a shut down caused by an external problem with the grid and vital parts of the control room instrumentation was lost. Luckily the engineers were very competent and well trained. They tweaked the faulty UPS system in such a way that they could bring the emergency generators back on line. So no serious damage was done. Nevertheless the same faulty design of the electric systems could have had much graver consequences. I bet the faulty design still exists in many plants and waits to be triggered by some idiots like those who ran Chernobyl. The English Wickipedia text about this safety problem is totally misleading.

Another issue I would not be happy with is the assumption of Californian utilities that the quakes at Californian NPP locations cannot exceed a magnitude of 7. They have apparently done all the tsunami simulation right but they gamble that they will not get the big one with a 9 magnitude. I would not accept that if I were living there.

I could add more examples for instance of hydrogen explosions in NPPs and why it is bad news for them to happen but I don't want to solve other people's problems.

But there is one point I want to cover and that is the possible replacement of nuclear by renewable sources in Germany in the next years. As a society we are dedicated to do it and surely we will. The question atm is only if we should do it by 2020, 2030 or later. That is the only point of discussion in Germany. We are not going to use nuclear and we will not build new nuclear plants. We are prepared to build a better grid than we even have today and create electricity storage to compensate for times when wind and sun produce no electricity. And we are happy enough to pay a little more for the pleasure to live with the knowledge that none of our power plants will have a fatal radiation accident.

Populist grandstanding. Germany's needless reactor shutdown is pure theater that's going to cost them almost $4 billion.

That is peanuts in energy politics. You cannot even buy one state of the art nuclear power plant for less than $7 billion, and that is after your national government has spent 20 billions to oil the wheels of the industry. Wall street is as keen on nuclear as I'm on collecting dog sh!t.

http://www.boston.com/business/articles ... expensive/

[Pup]

Today's post is a bit late - sorry for the delay.

First, there's an extraordinarily broad range of figures being reported for radiation levels. The reason for this is simple: they vary wildly depending on where and when you measure. Specifically, they spike during steam releases and are strongest right next to the reactor or in the steam cloud itself. The press of course likes to report the spikes. Not that they don't occur or aren't important, but it's just as important to keep them in perspective. There has been a slow overall rise of radiation over the past few days due to the steam that is continuously rising off of the cooling pools, although that has apparently decreased now that they are replenishing the water in the pools. This graph from the NYT shows both the spikes and the overall increase...



You can read more about it here, including info on the levels of exposure the workers are receiving, the types of radiation involved, and the various decay rates, etc.

There has also been a lot said recently about the number of people working on site, questioning why they have so few people there. The answer is quite simple - workers are only allowed by law to receive 50mSv of radiation per year. Accident workers are allowed 100mSv, and some emergency workers are allowed 250mSv. Regardless of the rate, once an individual has received that dosage, they go home - for good. So if the plant brought in all it's workers at once, they'd run the risk of everyone receiving their maximum dosage and then they'd have no one at the plant at all.

So, they rotate crews and keep as few people at each reactor as possible - and, very importantly, when they vent steam they pull everyone off site but the very few required to actually do the work. It's time consuming, and it slows up progress, and from the outside it might even appear like bureaucratic tail-covering or that they don't appreciate the situation, but it's the way it has to be done.

It is reported that they have increased the crew size now that radiation levels have decreased.

So, the news - one diesel unit is back up, and is alternating refilling the pools of reactors 5 & 6. When that is done, it will switch to powering the reactor pumps for those units which will allow some emergency generators to move to the other units.

Apparently there is no indication that the fuel in reactors 3 & 4 was ever exposed.

There will be another venting of unit 2 in a bit - at which time the press will report that daemons have escaped the earth's core. I'll leave it to WB to give us those peak radiation levels - I'm sure he can't wait. Importantly though, after the release they plan to hook up an outside power line which is now complete and waiting. That should make a big difference. I'm guessing that it can't power the entire site, since they're still talking about using generators; but it will at least ease the load so that they don't have to juggle power as much from unit to unit like they have been doing.

As an fyi, here's a list of injuries and contamination cases so far among the workers at both Daini and Daiichi:

Casualties among power plant workers

• Two Tepco employees have minor injuries.
• Two contractors were injured when the quake struck and were taken to hospital, one suffering two broken legs.
• A Tepco worker was taken to hospital after collapsing and experiencing chest pains.
• A subcontract worker at an "important earthquake-proof building" was found unconscious and was taken to hospital.
• Two Tepco workers felt ill whilst working in the control rooms of Fukushima Daiichi units 1 and 2 and were taken to the medical centre at Fukushima Daini.
• Four workers were injured in the hydrogen explosion at Fukushima Daiichi 1. They were all taken to hospital.
• Eleven workers (four Tepco workers, three subcontract workers and four members of Self Defence Force) were hurt following a similar explosion at Fukushima Daiichi 3. They were transferred to the Fukushima Daini plant. One of the Tepco employees, complaining of pain in his side, was later transferred to hospital.
• The whereabouts of two Tepco workers, who had been in the turbine building of Fukushima Daiichi unit 4, is unknown.
• Only one casualty has been reported at the Fukushima Daini plant. A worker in the crane operating console of the exhaust stack was seriously injured when the earthquake struck. He subsequently died.

Contamination cases

• One Tepco worker working within the reactor building of Fukushima Daiichi unit 3 during "vent work" was taken to hospital after receiving radiation exposure exceeding 100 mSv, a level deemed acceptable in emergency situations by some national nuclear safety regulators.
• Nine Tepco employees and eight subcontractors suffered facial exposure to low levels of radiation. They did not require hospital treatment.
• Two policemen were decontaminated after beng exposed to radiation.
• An unspecified number of firemen who were exposed to radiation are under investigation.

I'm still plowing through the news, so I'll update this post if I see anything of interest.

update - this paragraph is from the article I just posted, but I think it merits emphasis...

A note about predictions of future radiation doses: in recent days a map has circulated the internet, purporting to predict high doses to the Western U.S. This map bears the seal of the Australian Radiation Service, which did not produce it. The map has been refuted by the U.S. NRC, and experts state that it more closely resembles predictions for doses after deployment of a nuclear weapon than those for a situation such as that unfolding at present.

[Pup]

This looks like a very good article at MIT on Worst Case Scenarios that was just posted - I haven't read it all yet, but I'm eager to learn just how wrong I was in what I posted yesterday.

http://mitnse.com/2011/03/17/on-worst-case-scenarios/

[segedunum]

Hmmmm. If I was in Japan would I be worried about the minimal radiation exposure around that plant or would I be worried about the tens of thousands of bodies in amongst all that tsunami sludge, that also contain sewage and goodness knows what else, that will cause a massive public health problem not long from now and how it's going to be cleaned up?

It's amazing what people fixate on.

[autogyro]

edited out by autogyro

Stay calm.

[WhiteBlue]

This is the first time I see a graph of the radiation at the gate of the plant. Why was this information not available during the crisis? Apparently MIT had access to some continuous data but was not sharing those data with the public. The late Wednesday and Thursday radiation figures probably were the worst during this whole crisis, but they are not recorded on this graph.

Official Japanese TV was reporting much higher figures inside the plant at different times. Tuesday we had peaks of 400 mSv/h. On Wednesday they stopped giving absolute figures at all and said it was largely exceeding 50 mSv/h. What was that supposed to mean? The maximum reported figures reached 3,700 mSv/h on Thursday. Are we supposed believe this figure was true or was it a mix up between mSv/h and μSv/h?

It is reassuring to finally get an assessment by MIT what will actually happen in a GE Mark I reactor when the core melts and burns through the reactor vessel and the concrete catch pool. It would have been comforting to have this information around on Thursday when it looked like TEPCO completely lost control of the events. Thanks to Pup for posting it at last.

I'm glad that whatever was emitted from the Fukushima plant on Wednesday and Thursday was largely blown out to the sea and wasn't washed out by rain over the land. Some good luck in a sea of bad news. I keep my fingers crossed that the utility will regain more control of the reactors and fuel pools and that the Japanese people will be relieved from more radiation fears ASAP.

[Pup]

Here's an interesting read about Japan's electrical grid. Because two different companies began producing power in two separate regions, and each chose a different technology, Japan today is essentially split down the middle with two incompatible power grids...

http://www.itworld.com/business/140626/ ... -blackouts

[marekk]

Good news at least. they'll managed to restore provisional connection to external grid.

Tokyo Electric Power Co, which operates Fukushima Daiichi, says it has now connected an external power line to its stricken plant and would first supply reactor 2 because it is less damaged, Reuters reports. The power is needed to operate the plant's badly-needed cooling systems, which were damaged last Friday.

[forty-two]

Against my better judgement, I have done an incredibly un-scientific thing, purely for visual comparison, and even then it's still far from accurate but it gives an idea of the physical scale of the fukushima daiichi reactor buildings and the Chernobyl reactor 4 building.

Before anyone complains, I am not comparing these two sites as comparable in terms of their damage, technology or likely environmental impact, instead I am merely posting this to illustrate the scale of the buildings in question's relative 2D footprint.



On the left, of course is Chernobyl, after it's impromptu repairs, and pasted over the top of the image, on the right at the same scale is an image of reactor buildings 1-4 of Fukushima Daiichi.

It struck me that the two images give the impression that the Chernobyl reactor building is approximately four times the footprint of each of the Fukushima reactors.

Here's a quick and dirty overlay for comparison:


As I have said above, I am making no comparison to the type of reactors in use (of course, Chernobyl was a completely different type of reactor to the BWR types employed at Fukushima, it was a RMBK, a class of BWR different to the ones used at Fukushima), and nor am I suggesting that the consequences of the Fukushima disaster will be on the same scale as those of the Chernobyl disaster.

That said, Chernobyl involved only one reactor which was deliberately shut down and then very badly managed by the operators during an "experiment gone wrong", where Fukushima was as a result of bad design/risk-assessment, allowing the plant to be exposed to both an earthquake and then a Tsunami, knocking out the vital backup generators, but certainly involves three active (at the time of the incident) reactors plus another reactor building which was housing spent fuel rods.

[Dragonfly]

I am no expert but am afraid you make quite wrong conclusions. Starting from the size. What we see is the concrete tomb over the Chernobyl reactor.
If you see an image just after the catastrophe, you'll see its not that bigger and also the state of devastation of the whole building.

For those who understand Russian here is a brief presentation explaining how things went before and after, what were the damages and how they buried the reactor.
At the upper right corner there is a blinking button "ВПЕРЕД" (Next) which moves to the next page. On some of the pages there are contained blocks with text and pictures with left and right arrows for navigation.
http://eco.rian.ru/ecoinfogr/20090425/169208464.html

[forty-two]

Well, i did cavaeat my comments with the warning that it was completely un-scientific.

I only wish I could read the Russian text as that animation looks to be very interesting. Thanks for sharing though, interesting images.

As for whether it's larger or smaller, granted, the "tomb" which was created when they filled the thing with Concrete might well be larger than it was, but Reactor 3 (seen above the one which blew up) was AFAIK not entombed and what you see in the image above is as it was before the accident, and it looks to be roughly the same size as reactor building 4.

Anyway, I've already strayed off topic enough, so enough of this for now.

[Dragonfly]

Well, I didn't say they are not different in size. They are of different type and AFAIK different power output.
I did not agree with your conclusions because in Ukraine there was a ruined reactor, open at the top, exposing and blowing into the atmosphere everything lethal, like Pandora's box. The reactor was active and went out of control, when the control rods got stuck, could not be lowered to full length to stop the reaction.
While at Fukushima all reactors were immediately shut down and all the grave consequences came from damages in the support and cooling systems.

Don't know at what price, but it seems to me they are taking the situation under control slowly in Japan. And that's good news.

[marekk]

Thanks for link, dragonfly. My russian not that sharp anymore, but best animations and explanations of this event i've seen.

Einstein, once asked about infinity, said something like: i know just two infinite things - universe and human's stupidity, but i'm not quite sure about universe.
I think both tschernobyl and fukushima are 2 more proofs to that.

[manchild]

Don't know at what price, but it seems to me they are taking the situation under control slowly in Japan. And that's good news.

There is no progress at all, no control at all. They menage to take some action when ongoing disaster allows them, and when they decide to sacrifice lives of workers.

Today two reactors got in flame again. Radiation leakage and pollution of air, soil and sea never stopped since day one. Control would consider having no radiation leakage. That was never managed with any of attempts.

Spraying reactors with water reduces local radiation, but does more harm to whole planet as evaporated water forms clouds that will rain god knows where and enter food chain.

Today two reactors got in flames again. It is not big bang as Chernobyl, but slow one, with even worse consequence for the planet.

Japan's N-crisis escalates as smoke belches from two reactors
Tokyo/Fukushima, Mar 21 (PTI)

Japan's nuclear crisis escalated today with critical work to reconnect power lines at the crippled Fukushima plant being stalled after smoke rose from two reactors, fuelling fears of fresh radiation leaks.

UPDATE: Japan Extended Reactor’s Life, Despite Warning

http://www.nytimes.com/2011/03/22/world ... &ref=world

[Arterius]

Follow the link for a good presentation putting radiation dosages into perspective.
http://xkcd.com/radiation/