Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[etudiant]

If the Japanese government statement that all three reactors have fuel 'melted through' the RPV is correct, does this not suggest the reactors are much more robust than expected?
Afaik, we have not had any bulk dispersal of core material through steam explosions here similar to what happened at Chernobyl. That has helped Japan avoid a true catastrophe.
The site would in fact appear pretty normal, even if it was awash in radioactivity, and the cleanup would be much less arduous, if the hydrogen explosions had been prevented. That is a separate problem from the reactor breakdown however.

 

[joewein]

Some of it is taken from a nearby lake I think...

Yes, there's a nearby dam. That's where they got their freshwater from.

To your question: the radioactivity of that water is non-trivial. Re-circulating the water would bring that up to deadly pretty quickly.

Exactly. This water was pumped from locations with radiation levels of 1000 mSv/h, which are off-limits for workers.

The pipes to the central storage site where they've been pumping it are laid near one off the walls of the turbine building, so as to be as far away as possible from workers. The pipe areas are clearly demarcated with cones or bright tape.

In several spots where people have to cross the path of the pumping, the pipes have been been covered up with heavy lead wool to absorb the gamma radiation.

Now put yourself in the position of a fireman or other worker who has to replace a broken water injection pump. You'd have to walk up to a hose pipe filled with deadly water, disconnect it from the pump while trying not to spill any of it on yourself, swap the pump, hook up the pipe to the fresh pump and restart it all. Not many people would volunteer for that kind of job.

That's not really feasible until the radioactivity has been reduced by orders of magnitudes.

Which creates an interesting chicken and egg problem: How are they going to maintain AREVA's miracle water treatment system? Is that all radiation shielded? How will they replace chemicals, filters, etc.? This is not inside the La Hague reprocessing plant, there are no robot arms around in Fukushima 1.

 

[swl]

... Why don't they use the contaminated water they have hanging around and pump that back into the (used-to-be) reactors?

The water would become more heavily contaminated each time it passed through but they would no longer have an ever-increasing volume of water to store and dispose of.

I was wondering the same thing.
I fear that doing so would concentrate the contamination of the water, which then would release more contamination into the air as it boils off from the hot, melted, un-contained fuel.

 

[zapperzero]

How are they going to maintain AREVA's miracle water treatment system? Is that all radiation shielded? How will they replace chemicals, filters, etc.? This is not inside the La Hague reprocessing plant, there are no robot arms around in Fukushima 1.

They put the cesium absorption columns inside some kind of building on site. I think I remember reading that they are re-usable; you probably don't even have to move them to get the accumulated cesium out. So there's that.

 

[rowmag]

Seen on twitter:

MIT Faculty Report on Fukushima: Fukushima Lessons Learned (MIT-NSP-025)
http://mitnse.com/2011/06/03/mit-faculty-report-on-fukushima

Seems a bit dated already, right? AFAIK release estimates are now 20% of Chernobyl not 10%, and the containment of #1 and #3 seem to be leaking too.

I am going to disagree with the following bit of advice from that report:

Radiation risk during nuclear accidents should be communicated to the public using a
qualitative, intuitive scale vs. the traditional quantities of dose rate and activity. For
example, the units of ‘natural background dose equivalence rate’ could be adopted. To
avoid the necessity of adjusting for local background variations, the world average dose-rate
from natural sources should be used: 2.4 mSv/year or 0.27 μSv/hr. Thus the elevated levels
due to contamination would be presented in terms of the factor by which natural background
radiation is exceeded. This approach has several advantages. First, no effort is needed to understand the unit used. For instance, 10 times natural background is easier to grasp than
2.7 μSv/hr since no prior learning in a specialized field is required. Second, there is never a
need to convert between unit systems or to be mindful of numerical prefixes (milli-rem,
micro-Sv, etc.). Third, this method of conveying information about radiation levels reinforces
the concept that some level of radiation exposure is both natural and normal. Finally, use of
this unit implies no estimation of the magnitude of the health hazard from the radiation
levels. This is important since we do not know how hazardous chronic, elevated
background dose rates are, though it is noted that there are regions of the world with
background radiation dose rates one order of magnitude higher than the world-average and
yet with no measureable health consequences.

The most frustrating reports have been when instead of absolute numbers, we were told only so many times the legal limit, or so many times above background. Much more preferable to have actual absolute numbers to work with.

When the accident first happened, we were treated to endless variations on the exposure chart: how many Sieverts from one chest x-ray, from one trans-Pacific flight, etc. The public quickly learned the new unit, and later about units such as Bq/kg. This was a good thing, I think.

Also, background varies by location, so using "world average background" as the standard unit adds a layer of confusion. If I live in an area with a normal background rate of 0.1 uSv/h, and it goes up to 0.2 uSv/h, then my background has doubled, even if it is still below the world average of 0.27. How would one express this in a non-confusing way using the proposed units?

Give me numbers, and teach me parenthetically what the numbers mean, if necessary. But don't remove the absolute scale from reports, please.

(And yeah, I understand that the Sievert is a problematic unit, with all kinds of assumptions built in, but it is still better than "N times the legal limit," which tells me nothing. Was the legal limit conservative or aggressive? What was it in numerical terms?)

 

[elektrownik]

I was wondering the same thing.
I fear that doing so would concentrate the contamination of the water, which then would release more contamination into the air as it boils off from the hot, melted, un-contained fuel.

This is not problem of contamination, this is leak problem, they can't keep water in reactors and turbine buildings if they are not sealed and leaking radioactiva water to ground, sea, etc.

 

[Borek]

Give me numbers, and teach me parenthetically what the numbers mean, if necessary. But don't remove the absolute scale from reports, please.

This is off topic - and tricky. Most of PF users will be able to learn these numbers and to deal with them. Joe Public needs calculator to check how much change he will get from paying $3 for three $0.99 hamburgers. It won't work for him.

 

[zapperzero]

Give me numbers, and teach me parenthetically what the numbers mean, if necessary. But don't remove the absolute scale from reports, please.

Ah but you might get scared if you just know the numbers. Banana dose equivalents per football field provides some context, you know? Makes it all more... homely.

Just to think of that huge mountain of bananas you'd get from staying in Iitate village! Yummy!

 

[jim hardy]

i for one am increasingly frustrated by what looks like a psy-op. The release of information is gradually racheting up the severity. we are being spoon fed pablum.

now unit 2's containment cap is leaking? Duhhh,, what was the thud? Shouldn't the closure bolts be the ultimate relief valve?

anybody know of a decent photo of unit 3 roof?

I'm joining the conspiracy theorists.

noparse

 

[thehammer2]

I've been thinking about the water and I'm wondering if the contamination to the water is largely particulates or dissolved matter. If it's dissolved matter, would it be possible to saturate the water with non-radioactive isotopes before it's pumped in an effort to minimize the amount of radio-material it picks up on its pass through the reactor.

Two things I can think of right off the top of my head that might make this concept pretty much worthless are first that the main source of the contamination is very small particulates and not dissolved compounds and second, that when the water boils, it is distilled and drops its load of non-radiocompounds. Then, when it recondenses, it leaches whatever is available without selection, picking up some radioactivity from the core, making the preloading moot.

This is just something I'm wondering for my own curiosity.

 

[Bioengineer01]

I am assuming the water they are pumping in comes from the tap/faucet. The water then emerges, contaminated with radioactive material, and hangs around in ever-increasing volumes.

My question probably has a very obvious answer. Why don't they use the contaminated water they have hanging around and pump that back into the (used-to-be) reactors?

The water would become more heavily contaminated each time it passed through but they would no longer have an ever-increasing volume of water to store and dispose of.

My guess is that if they do that without a proper heat exchanger you would soon have boiling water in all the basements...

 

[vanesch]

My guess is that if they do that without a proper heat exchanger you would soon have boiling water in all the basements...

I think the principal problem is that you don't want to mess around in trucks and pumps and everything with heavily contaminated water so that you can't easily work with those radiating and contaminated machines anymore.

 

[Jorge Stolfi]

Ah but you might get scared if you just know the numbers. Banana dose equivalents per football field provides some context, you know? Makes it all more... homely.

Just to think of that huge mountain of bananas you'd get from staying in Iitate village! Yummy!

[ Moved my post to the political thread https://www.physicsforums.com/showpost.php?p=3343723&postcount=199 ]

 

[rowmag]

This is off topic - and tricky. Most of PF users will be able to learn these numbers and to deal with them. Joe Public needs calculator to check how much change he will get from paying $3 for three $0.99 hamburgers. It won't work for him.

Good point, sorry. I will take it over here:
https://www.physicsforums.com/showpost.php?p=3343652&postcount=197

 

[Bioengineer01]

Those are indeed two stages, but of the same event, i.e. a fuel-air explosion. The fuel in this case is hydrogen. Slightly unusual, because detonating mix can have a wide range of concentrations. Stage one is the flame front. Stage two is ejecta.

Here's a video of the largest fuel air bomb ever built, for reference. The black cloud you see at the beginning is the fuel that's been spread by a small charge. Ignore it. Look what happens when the light turns on. Blast. Ejecta.

In the video the ejecta phase happens a lot sooner than in the Unit 3 explosion, also the plume doesn't go as high by a large margin. Somebody with good video analysis equipment could quantify this differences, any takers?

 

[mscharisma]

This is off topic - and tricky. Most of PF users will be able to learn these numbers and to deal with them. Joe Public needs calculator to check how much change he will get from paying $3 for three $0.99 hamburgers. It won't work for him.

Although off topic, as Joette Public myself, my vote would be for the actual numbers in whatever units AND the numbers converted to average background radiation. Even those of us with nonscientific minds have a responsibility to educate ourselves and at least try to understand and/or check with those of you that are better educated. If all fails, the comparison to average background radiation might be helpful, but it alone does not provide an accurate picture of the situation, as explained by the previous poster. And we all, scientists and laymen alike, have a right to get the actual numbers. The environment belongs to all of us.

 

[jim hardy]

well Jorge after my heart stress (thallium i think it was )test i was >3 mr/h so you'd have got ten or so microsv sitting beside me in an airplane flight.

folks should be aware the conversion from Bq to dose , sv or r , is dependent on the isotope that's why Wiki qualified that conversion as being for K40. Reason for that is; dose is a measure of absorbed energy (cell damage) and higher energy rays hurt more. it's frustrating trying to get a feel for Bq to Sv or R.
Wish i knew what's a middle-of-the-road conversion factor but truth is rays can vary in intensity by 8 orders of magnitude, so the conversion factors do too.

There ought to be a "good guess" factor to use for the iodine and cesium the public is most apt to encounter from Fukushima. Maybe there's a practical minded expert on board?

jim

 

[Bioengineer01]

Antisocial, from the lunaticoutpost, who in the past has demonstrated to be one of the most conservative posters in their Fukushima thread, and undoubtedly a current or ex Nuclear worker with expertize in fission and nuclear reactors has just posted the following:
"The individual I know, along with all of her co-workers that were operating weather stations early on are being treated for internal radiation exposure...
...the number of people exposed to considerable danger during the first week is enormous, and many in the JDF are furious with the government and TEPCO for understating or hiding ... Most have had a pretty good idea what went on for the past few weeks, but as it becomes public they can no longer pretend, and the anger is growing. Humiliated is the word I've heard used a lot, and that's a strong word in Japan.

Just to re-iterate, somewhere between 15% and 35% of the core of #3 was ejected up during the explosion. The remainder was forced down. Its assumed the pressure vessel was damaged and this core material is below it now. The explanation I've seen for the modulation of the radiation is that as water seeps into the primary containment, it acts as a moderator/reflector and when it reaches a "critical" depth, it reflects enough energy back into some of the material that it re-achieves criticality. Once this happens the heat created begins driving off the water and the reaction slows. Remember, water between fuel slows the reaction between the fuel, but water surrounding fuel enhances the reaction. The danger here is a large storm could swamp the building and the water could get deep enough that it can't be driven back by the heat, and a potential explosion could result.

One and Two are melted utterly. No one who values their life will come anywhere near those containments for years to come.

Fuel pools are wildcards. ...
Three is a done deal. Nothing at all can be done about it...

... One is believed to have ablated through the floor to some extent based on seismology readings that aren't being made public. There are sensitive sensors all around the grounds listening for underground activity, as well as satellite based imagery used to locate bunkers and tunnels that can image the ground density. 1300C material generates pressure underground that alters the density of the ground, and these changes can be detected and visualized. It's also theorized that this pressure underground is what's driving the water into the other buildings. As hydrostatic pressure builds moving away from the underground source, the water is pushed up and away and is finding the path of least resistance into other buildings. ...there are volumes of real information being created daily. The level of information being made public is the equivalent of what TEPCO would have known in 1975. It's 2011.

..."
http://lunaticoutpost.com/Topic-Nuclear-Power-plant-Onagawa-on-fire-Fukushima-malfunctions?pid=1231435#pid1231435

 

[zapperzero]

In the video the ejecta phase happens a lot sooner than in the Unit 3 explosion, also the plume doesn't go as high by a large margin. Somebody with good video analysis equipment could quantify this differences, any takers?

Quantify what? It's as easy for you as for anyone else to estimate the speed of the respective plumes. But what good would that do?

 

[Borek]

Just to re-iterate, somewhere between 15% and 35% of the core of #3 was ejected up during the explosion.

Any source to that claim, or is it just some post by someone at some forum?

 

[Bioengineer01]

I am wondering if these pictures of Reactor 3 and the analysis that goes with them have been discussed in the thread. They seem very informative to me. Comments?

http://www.houseoffoust.com/fukushima/R3.html

 

[elektrownik]

Can anyone explain me this graph at page 3, there is big jump in I-131 level between 5/27 and 5/31: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110607e8.pdf

 

[Bioengineer01]

Quantify what? It's as easy for you as for anyone else to estimate the speed of the respective plumes. But what good would that do?

Nothing really, only prove my point that they are way different and not similar phenomena. But doesn't help. I am just frustrated by the lack of detailed information coming out...

 

[Bioengineer01]

Any source to that claim, or is it just some post by someone at some forum?

It is a post from somebody at some forum, but somebody that has posted data in advanced consistently since the event and that has demonstrated to have inside connections with people at Fukushima. I know he could be using his established reputation to now spread misinformation, but he hasn't done so before. You could easily go to "some forum" and search for his historical posts and make up your mind on his credibility or lack thereof. But given the scarcity of truth that has come out in time from TEPCO and the Japanese government and the track record of this guy. I'd advice to not dismiss it out of hand without first checking out his track record.

 

[Bioengineer01]

Can anyone explain me this graph at page 3, there is big jump in I-131 level between 5/27 and 5/31: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110607e8.pdf

And, as we are at this, can somebody explain the increase in I-131 reported by Tepco in between this two reports on the same timeframe as the increase in the previous chart, inside the silt fence of Unit 2 from 5200 Bq/L to 24000 Bq/L, may the scaling factor, something I don't understand has something to do with it, since it changes from 130 to 600 in the measurements of the 2 days. Comments will be appreciated:
For 5/27/11: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110528e5.pdf
For 5/28/11: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110529e3.pdf

 

[zapperzero]

I am wondering if these pictures of Reactor 3 and the analysis that goes with them have been discussed in the thread. They seem very informative to me. Comments?

http://www.houseoffoust.com/fukushima/R3.html

How about if you start perusing the thread and don't stop until you finish? Much insight can be gained that way. I myself came in at about page 300, but I don't remember asking for others to do my homework for me.

Yes, most everything that's on houseoffoust was discussed here. Nancy herself was here, actually, discussing photos of #4 reactor. She re-posted most of those photos from Cryptome, btw, so you may as well go to the source from now on and save the time that you would otherwise spend on her commentary and interpretations.

 

[Bioengineer01]

"In its report, Japan's government informs the IAEA that fuel is assumed to have melted down and may have burnt through the reactor pressure vessels of units one, two and three and into their outer steel containment vessels."
http://news.ph.msn.com/top-stories/article.aspx?cp-documentid=4915540

 

[Bioengineer01]

How about if you start perusing the thread and don't stop until you finish? Much insight can be gained that way. I myself came in at about page 300, but I don't remember asking for others to do my homework for me.

Yes, most everything that's on houseoffoust was discussed here. Nancy herself was here, actually, discussing photos of #4 reactor. She re-posted most of those photos from Cryptome, btw, so you may as well go to the source from now on and save the time that you would otherwise spend on her commentary and interpretations.

Thanks and sorry for abusing. Just trying to keep up with regular work and what is going on at Fukushima is difficult. I will read it as I find time.

 

[zapperzero]

Nothing really, only prove my point that they are way different and not similar phenomena. But doesn't help. I am just frustrated by the lack of detailed information coming out...

Deflagration vs detonation? Again, you are probably correct. Please, please take the time, do the reading. A study by some Japanese institute wrt this very issue has been recently discussed.

 

[jim hardy]

"""Just to re-iterate, somewhere between 15% and 35% of the core of #3 was ejected up during the explosion. The remainder was forced down."""

that's an awfully strong statement to make without backup. I don't buy it at all.

Were it true the scene would have been way more Chernobyl-like and we'd see nobody calmly driving firetrucks, walking around tending equipment and posting radiation signs.

it's easy to scream "FIRE" , it's difficult to sort through information and build a credible train of thought that fits observations.Test any claim by comparing it to observation of reality. Remember Lavoisier's quote: "Instead of applying observation to the things we wished to know, we have chosen instead to imagine them..." not bad for 300 years before computers.

if he backed it up with nuclide analysis of the "highly radioactive debris" noted in NRC's march 26 report i would listen to him. After all, even Don Quixote has some experience with windmills.that's my opinion as an interested observer .