Japan's fears of nuclear mayhem recede as nuclear reactor starts to cool

[abqmufc]

Source: The Guardian

"For a few unnerving hours, Japan faced a bleak and unsettling prospect. The devastation wreaked by Friday's earthquake and tsunami seemed set to be followed by a nuclear meltdown that could have spread radioactive waste over large parts of the country.

The nation was one short step away from enduring genpatsu-shinsai – an atomic disaster triggered by earthquake that leading Japanese seismologists had been predicting for several years."

<SNIP>

"For several hours, observers feared the worst: loss of coolant inside one of the plant's six reactors had caused a dangerous build-up of heat. A second, more deadly explosion – one that would have released a vast radioactive plume over the nation – seemed a real prospect until it was announced that, although the outer structure of the 40-year-old reactor building had been blown off by the blast, the actual reactor inside had not been breached.

Disaster had been avoided – but by the narrowest of margins. It was confirmed last night that radioactive caesium, one of the elements released when overheating causes core damage, had been detected around the plant. The discovery indicates that meltdown, caused by a nuclear reaction running out of control, had indeed affected the reactor's fuel rods – although possibly only to a limited extent. The revelation did little to reassure local people."

<SNIP>

"The operators of the Fukushima plant announced they had started to fill the containment vessels in which the reactor rests with sea water in a bid to cool it down, a process that would take from five to 10 hours, an official told reporters."

<CUT>

Read more: http://www.guardian.co.uk/world/2011/mar/12/japan-nuclear-meltdown-fukushima-reactor

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Well written, good timeline given, AND the part about it taking 5 to 10 hours to fill the containment vessels with sea water to cool down the core is key info we'd been missing. Who ever came up with that idea, is a true McGyver.

[bbinacan]

1. Good news! n/t

[Dogmudgeon]

2. The seawater cooling method is S.O.P. for most coastal and riparian reactors

It's a second-stage cooling system.

It means that there were enough problems with the primary systems so that there will be extensive investigations -- but that the safety systems worked well enough to keep the core isolated and (after a lot of masonry being excreted by the reactor workers and residents) cooled down.

There are also procedures in place in the unlikely case the seawater doesn't work. But at this point, the burden is on the operator (Tokyo Electric and Power COmpany), not the designers.

Several DUers focus 100% on nuclear issues, but the real issue in Japan will be the earthquake. This will subsume the nuclear issue, which will probably upset most of the more intense antis. However, Japanese engineers are quite thorough, not just with reactors, but with poor office building and house architecture, gas line safety, and overall preparedness.

--d!

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Remember: text REDCROSS to 90999 to donate $10 to the international relief fund for Japan.

[SkyDaddy7]

10. Thank-you for posting the REDCROSS DONATION in your sig!!!

[Yo_Mama]

3. They also injected boric acid

Which would absorb neutrons and stop the chain reaction. Or should. It's harder if the rods had gotten to the point at which they had completely melted down, but you'd expect much higher radiation levels if that had happened.

In any case, I am very happy for them. We won't know for sure how well this worked until tomorrow.

[sofa king]

12. I thought that was just in case of radioactive super-roaches.

[jannyk]

4. Thank you for real 'news'! k&r

[girl gone mad]

5. Looks like they were right on the brink of absolute catastrophe.

It will be interesting to see a real investigation. The operators clearly lost control for many hours.

[SoulSearcher]

6. whew..!

That is a indicator of how bad it got ( or perhaps still is!).
When they made the decision to let the seawater in, that mean the reactor will have to be scrapped
later - no way the materials can be re-used once contaminated with sea-water.
But a hell of a lot better than being contaminated with a huge nuclear disaster!!!

I just hope that did it - that was the third time the reactor mgmt issued a news
release that things were under control (still scary).

[grahamhgreen]

7. I thought the seawater was SOP.

[nadinbrzezinski]

8. Only when you are willing to concede reactor loss

but it is...

[driver8]

15. You know a lot about nuclear power!!

I operated nuclear plants for the Navy for six years, but I have been out for almost twenty years and have forgotten a lot!

I have enjoyed reading your very informative posts -- thank you so much for posting!

[Overseas]

9. Thank goodness.

I hope the sea water cooling works well.

[sofa king]

11. In a related story, Godzilla is slowly sinking back into Tokyo Bay.

I hope someone in Japan can laugh at that.

[IthinkThereforeIAM]

14. I made that comment yesterday...

... when standing in a line, reading news off my blackberry, "Hey, check out this MSNBC headling, Godzilla is coming back!".

[Peace Patriot]

13. This doesn't seem to gel with a report that the explosion was possibly CAUSED BY a meltdown.

"Meltdown Caused Nuke Plant Explosion: Safety Body"

"TOKYO (Nikkei)--The Nuclear and Industrial Safety Agency (NISA) said Saturday afternoon the explosion at the Fukushima No. 1 nuclear plant could only have been caused by a meltdown of the reactor core. (MORE)

http://e.nikkei.com/e/fr/tnks/Nni20110312D12JFF03.htm

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Apparently, flooding with sea water is a last resort SOP, to prevent a meltdown. It means the reactor will have to be scrapped.

Is there a difference between a "meltdown" and the "more deadly explosion" that would have "released a vast radioactive plume over the nation," described in the above Guardian article? i.e., a "meltdown" occurred but the explosion was averted?

Or, is the Guardian article a later report, and the NISA was wrong about the cause of the first explosion (meltdown), i.e., meltdown and second explosion were both averted?

[AtheistCrusader]

16. The fuel rods likely melted.

But they did not escape the inner metal shell of the core, or the concrete containment.

I'm still not clear on whether the concrete containment is still intact or not, after the explosion.

[left on green only]

17. Sounds to me like....

Yes, you are so right. Flooding with sea water *is* a last resort to prevent a meltdown of a reactor's core. It can also be used as an attempt to minimize the extent of meltdown, once one has begun to occur. It seems to be entirely a matter of 'spin'. The word used to be 'lie', and people in civilized societies were taught to eschew it. But those were during much more harsh times. Now the word is called spin, and people in the media are actually encouraged to embrace it (especially right wing media). For example, there were previous reports coming from the 'authorities' stating that no explosion had occurred at the reactor. We were told that the video we had watched showing the reactor, and then a concussion, followed by all of the smoke was merely the walls and the roof of the reactor housing falling in. And shame on us for even questioning the occurrence of an explosion, because everybody knows that the walls and roof of reactor housings fall in on a regular basis, all by themselves.

Elsewhere in the media's reporting came the good news that we can now all breathe a sigh of relief because the radiation levels being reported at the site of the reactor are now lower than they were before the walls and the roof fell in. Well duuh! Of course the readings are now lower. The reason is because now there are no longer any walls and roof of the housing to contain the radiation in the vicinity of the reactor. Now they are dissipating directly into the atmosphere and are therefore not nearly as highly concentrated.

Move along, move along now folks. Nothing to see here! :sarcasm: