My thoughts are with the poor people of Japan. Is this scenario possible?

[Paper Roses]

http://en.wikipedia.org/wiki/China_Syndrome

I know very little about scientific events like these events in Japan and am afraid for the residents.

I hope my fears are very exaggerated.

[MilesColtrane]

1. I think it is possible that the reactor core could melt through its containment vessel.

Even though the reactor was scrammed when the plant lost power (control rods were put in place to stop the nuclear reaction) it was still very hot.

Now we know that the upper part of the fuel rods have been exposed to the air and were not being cooled.

If the MOX fuel melts and collects at the bottom of the reactor vessel it can go critical and begin to heat up with little way to control the chain reaction other than dumping water and boron on it.

[Name removed]

2. Deleted message

Sub-thread removed by moderator. Click here to review the message board rules.

[Dogmudgeon]

3. Yes, your fears are very exaggerated.

It's a bad situation over there. But the "China Syndrome" just doesn't happen the way we once thought it did.

Over 100 tons of molten uranium metal "corium" was left at Chernobyl #4 after the explosion (which scattered between 15 and 60 tons more of it). It partially melted through a floor and plumbing structure, then stopped. A photograph of it is on the Wikipedia articles about Chernobyl and Corium. (Corium is that molten blob of metal and reactor fuel.)

We don't know how much melting has taken place, and we won't know for sure until the cores are examined, but the containment is holding. Verified radiation releases have been fairly small, the result of venting excess volatile radioactive gasses like isotopic iodine. Most of these gases actually are harmless -- they escape the atmosphere into space within minutes. Some, like cesium, are pretty dangerous. I have only heard of traces of cesium being detected.

We REALLY need to get some education about nuclear issues; but all we get is posturing and politicking -- and rumors, and fear. I hope this is helpful.

--d!

[Atman]

5. Yay! Everything is cool!

Whew. I thought there might be an issue over there. I'm glad you've cleared that up. However, forgive me for doubting you, but I'm tired of hearing self-proclaimed "experts" telling me something can't happen. The shuttle couldn't blow up, the levies couldn't break, the towers couldn't fall, the election couldn't be rigged. It's TWO FREAKIN' DAYS IN. The only FACT we know is that we don't know what the hell is going to happen. Quit posing as if you do. I mean...you do appear to be posing for someone, after all.

[IScreamSundays]

7. + 1000

thank you

[Dogmudgeon]

10. I re-read what I wrote. You are wrong.

The information is available from Wikipedia, the NRC, the Department of Energy, and nearly every undergrad nuclear science course's website.

Easily available. Every word of it. And Reuters has a fairly rumor-free collection of what they know at this point.

If you read, you get to learn about this stuff.

"It's TWO FREAKIN' DAYS IN. The only FACT we know is that we don't know what the hell is going to happen."

Which I've said several times here myself. And guess what? OTHER sarcastic, hostile hotheads blew up at me. Here's one that I recently wrote that earned me the wrath of one non-reader:

"We don't know how much melting has taken place, and we won't know for sure until the cores are examined, but the containment is holding. Verified radiation releases have been fairly small, the result of venting excess volatile radioactive gasses like isotopic iodine. " (http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=439x632849#633154">Source.)

Everything else was the standard information on nuclear core "events".

"Quit posing as if you do. I mean...you do appear to be posing for someone, after all."

Don't tell me how to behave when you don't even have basic social self-control.

--d!

[Joe the Revelator]

11. I mean, its almost like you WANT something to happen

I find that strange.

[Atman]

12. I find it strange, too. And ridiculous. Why would I WANT something to happen?

I also re-read what I wrote, and your reply is rather insulting. After everything the people of Japan are going through, you actually think I would want to see more suffering brought upon them? Really?

My comment was not about the status of the plant, it was about those who keep telling other posters on DU (as well as TV "experts" telling the general public) that they KNOW what is happening/what will happen next. If they actually knew, they would begun pumping seawater in the moment the ground stopped shaking, right? But they told us everything was under control. Why should I believe another poster on DU when the stories coming out of the news don't even match from one channel to the next, one web site to the next, one expert to the next, one hour to the next?

[Rex]

13. What we are seeing here are a few sick individuals projecting

THEIR desire to see mayhem and destruction happen to innocent people, onto posters here that are just asking questions. Ignore them, they seem to have some mental issues that needed resolving.

[Joe the Revelator]

17. How Rovian of you...jujitsu!

[Hannah Bell]

16. amen.

[Atman]

18. Amen schamen, Hannah.

The recent events underscore MY point, not yours. WE ARE BEING LIED TO, and more of the "can't happen here" stuff happened this morning. You keep smiling, you keep saying we're all gonna be okay because those nice government officials told us so. I'll keep being skeptical.

.

[jpak]

4. At the very least, they will 3, possibly 4, heavily damaged highly radioactive reactors to dismantle

on the coast where contamination can enter the local marine food web

and they will have to find a place to bury the debris.

multiple multi-billion dollar accidents

yup

[browntyphoon]

6. Japan is handling this disaster well. You don;t see them looting and rioting but helping

one another out. It's refreshing to see humanity in such a light after recent natural disaster

[IScreamSundays]

8. are you making an inference to some other time?? nt

[lonestarnot]

14. Looting and rioting when it comes to descriptions of poor, borrowing when it comes to uber shitheads

:crazy:

[Motown_Johnny]

9. as I understand it, the core melts through the earth until it hits ground water

and the ground water will then cool the core.


These reactors are right on the ocean's shore. If the core did melt through the containment vessel floor it would hit water very soon, cooling the core.


As with any nuclear accident the problem is the release of radiation that occurs. Once the containment vessel is breached then all bets are off. I assume that if the core did melt through the floor and hit ground water the steam released would be radioactive and the surrounding water and ground would also be exposed to massive amounts of radiation.


I am also not an expert on this subject, but as a resident of Detroit I do have some interest in the subject. The movie "The China Syndrome" is based on an accident which occurred at a plant near here. The book "We Almost Lost Detroit" is also about that accident and has less Hollywood in it than the movie.

[Yo_Mama]

15. It does not seem possible at the present time

The reason is that these things are sitting in containment vessels that have water in them. If the fuel were to melt through the reactor shell, it would hit the water in the containment vessel. Plus, 1 & 3 are now getting boron/boric acid pumped in with the seawater. Boric acid absorbs neutrons and so suppresses the reaction.

Both reactors will have to be decommissioned. They were quite old any way. Until the fuel is cooled, they will have to keep pumping water in with the boric acid or boron.

So far reported releases indicate very little danger for the residents, but the workers are in some real danger.

The worst situation is at Daiichi - the plant with two different reactors that have or have had exposed fuel. This is what NISA's last summary said about radiation detected outside the gates:
http://www.nisa.meti.go.jp/english/files/en20110313-3.pdf
__________________________________________________________________________
The measurement of radioactive materials in the environmental monitoring
area near the site boundary by a monitoring car confirmed the increase in
the radioactivity compared to the radioactivity at 04:00, March 12 now.
MP4(Moitoring car data at the site boundary, North-west of Unit1):
40microSv/h(03:08, March13)
MP6 (at the main gate) 0.07microSv/h(04:00, March 12) ->
3.1microSv/h(04:50, March13)
3.2microSv/h(05:50, March13)
MP8 (at the observation platform) 0.07microSv/h(04:00, March12)
-> 5microSv/h(04:30, March13)
5.2microSv/h(05:50, March13)
__________________________________________________________________________

Radiation levels INSIDE have been reported as high as 1550 milliSieverts. You can see that as this wears on, levels at the gates (just outside the compound) have been rising.

Here I have to get a bit technical so you can understand why the average person in Japan is not in danger.

1 milliSievert is 1000 microSieverts, so 1 microsievert is one-onethousandth of a millisievert, which is one-onethousandth of a Sievert.

Normal background radiation on the earth's surface varies widely, but there is a place in Iran where it seems to peak each year at over 200 milliSieverts. Here is a paper about that place, which I cannot ever spell right for some reason:
http://www.probeinternational.org/Ramsar.pdf

Other areas with high natural exposure rates are India, some places in the UK, Norway, etc. Natural exposure varies widely.

Note the extremely small March 12 level of 0.07 microsievert.

Radiation exposure follows the inverse square law. Here is an example of how to calculate that with radiation:
http://www.ndt-ed.org/GeneralResources/Formula/RTFormula/InverseSquare/InverseSquareLaw.htm

Here also I will link and quote from Wiki's article on background radiation:
http://en.wikipedia.org/wiki/Background_radiation
The Nuclear Regulatory Commission, the United States Environmental Protection Agency, and other U.S. and international agencies, require that licensees limit radiation exposure to individual members of the public to 1 mSv (100 mrem) per year, and limit occupational radiation exposure to adults working with radioactive material to 50 mSv (5 rem) per year, and 100 mSv (10 rem) in 5 years.

The exposure for an average person is about 3.6 mSv/year, 80 percent of which comes from natural sources of radiation. The remaining 20 percent results from exposure to artificial radiation sources, such as medical X-rays, industrial sources like smoke detectors and a small fraction from nuclear weapons tests.

A standard medical X-ray's strength is about 2 mrem or 0.02 mSv but can be over ten times that, depending on the equipment used,.<22> A dental x-ray optimally has a dose as low as 0.0033 mSv but poor machines and technique can give doses as high as 0.11 mSv.<23> The average American and European receives about 0.5 mSv of diagnostic medical dose per year; countries with lower levels of health care receive about one fifth of this dose.<24>

Radiation treatment for various diseases also accounts for some dose, both in individuals and in those around them.

_______________________________________________________________________________________________________________

So what this all adds up to is that even though radiation has been released, even a very small distance from that source drops the exposure massively, and that the current radiation exposures are not a danger to human health. The evacuation zones that have been established are sufficient to ensure that the civilian population is not endangered.

A much greater potential exposure could come from the effect of the hydrogen exposure. Fragments of radioactive dust and concrete got tossed pretty far up in the air. However when you read stuff like the measurement at one place is 700 times normal levels, remember that normal levels are going to be on the order of a maybe a hundreth or a tenth of a microSievert, so 700 X .01 = 70 microSievert = .07 milliSievert, which is considerably less than the radiation you'd get from a CT scan. Admittedly, you don't want people getting even that over a period of time, but it should dwindle quite quickly.

Here's a table for radiation unit measurements:
1 mSv =

Metric
Sievert 0.0010000 Sv

Picosievert 1,000,000,000 pSv

Nanosievert 1,000,000 nSv

Microsievert 1,000.0 µSv

Millisievert 1.0000 mSv

Kilosievert 1.0000*10-6 kSv

Joule per kilogram 0.0010000 J/kg

Kilojoule per kilogram 1.0000*10-6 kJ/kg

Non SI conform
Rem 0.10000 rem

Nanorem 1.0000*108 nrem

Microrem 100,000 µrem

Millirem 100.00 mrem

Kilorem 0.00010000 krem