Bringing Up Turing’s ‘Child-Machine’ (revised) – PhilSci-Archive

Bringing Up Turing’s ‘Child-Machine’ (revised) – PhilSci-Archive.

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Alan Turing Year / “Bringing Up Turing’s ‘Child-Machine’ “

Alan Turing Year / “Bringing Up Turing’s ‘Child-Machine’ “.

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Fukushima Current Status: “cold shutdown” is cold comfort — remaining problems are “immense”

I’m back from my hiatus due to an emergency at home.  Today TEPCO announces that a status called “cold shutdown” has been achieved at the Fukushima-Daiichi nuclear electrical-generating station complex I have blogged so much about in the past.

Well, they had hoped to do this by year’s end.  Yet, I doubt it is actually the milestone originally envisioned when the goal was set.  I don’t think the term ‘cold shutdown’ was originally meant, or has ever before been used, to describe a plant that is in such a condition:  a plant with molten fuel outside the reactor vessel,  a plant still producing radioactive effluent that it cannot accommodate, a plant needing a tent-like cover over it that will need to be replaced repeatedly, and so on.

The Wall Street Journal article “After Nuclear Milestone:  A Long Road” seems to me to be clear-eyed and very informative.   The authors know what they don’t know and shouldn’t be trying to speculate about; they write that:

Indeed, there can be few firm declarations about the plant’s status. Daiichi’s reactors are littered with debris. Many measurement and control systems are on the blink. Radiation levels are too high for people to get close to the reactors, leaving engineers and scientists to make important judgments using computer simulations, scattered bits of data and guesses.

This modeling has led to dire assessments, such as Tepco’s announcement late last month that fuel in the complex’s No. 1 reactor likely melted completely through its pressure vessel and into a cement floor of the surrounding containment vessel. Hard information is so scarce that Tepco officials say they still aren’t sure how the meltdowns unfolded and about the current state of the nuclear fuel.

Even if cold shutdown is attained, it will take decades for isotopes to decay to safe levels, and to remove the last fuel and completely dismantle the plant. For now, the unknowns are so great that authorities aren’t even sure how to start tackling some of the biggest problems, which include locating and stopping the flow of toxic water and removing the melted nuclear fuel.

The full article is here:    http://online.wsj.com/article/SB10001424052970204336104577096281099680526.html

I highly recommend the WSJ above for its comprehensiveness and its usefulness in providing an overview.  There are links and videos in the article.

ADDED after 8 pm:  Nature has an article basically in line with the above.  It has a nice discussion of what the term “cold shutdown” was meant to refer to.  http://www.nature.com/news/fukushima-reaches-cold-shutdown-1.9674

The IAEA has a page on the topic, too, here:  http://www.iaea.org/newscenter/focus/fukushima/

ADDED around 10 AM:  Here is a very interesting, descriptively colorful pooled account of the site on the November day that the media were allowed to visit: “A Look Inside Fukushima Daiichi”, illustrated with slides so you get some idea of what a visit would be like.

http://online.wsj.com/article/SB10001424052970204358004577033522244084162.html?mod=slideshow_overlay_mod#articleTabs%3Darticle

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Brief Hiatus

Due to a family emergency on October 19th, I have not posted in awhile.  It may be a few more weeks until I return to posting again.

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Fukushima Daiichi Nuclear Plant Current Situation: An analogy (UPDATED on May 22nd, May 30, June 21, July 3rd, August 4th, September 22nd, and October 17th, 2011)

Fukushima Daiichi Nuclear Plant Current Situation: An analogy (UPDATED on May 22nd, May 30, June 21, July 3rd, August 4th, September 22nd, and October 17th, 2011).

I’ve updated this post, adding the following today:

UPDATED October 17th, 2011:  Although I expect an update to the Roadmap soon, it’s worth reporting now that last week the first cover over one of the reactor buildings was completed.  Here’s a brief article on it, including a photograph of it: http://mdn.mainichi.jp/mdnnews/news/20111015p2a00m0na019000c.html

There is a sense of calm in seeing it, perhaps, and it is significant.  Now that the air around the reactor is enclosed, it can be “processed”, i.e., run through air filters to remove the radioactive particulates.  That’s a big public health benefit.  But, to put this into perspective, it is just a temporary step.  This is going to be a decades-long project.  This cover alone is only meant to last two years, and they still have to put covers on two of the other reactors whose buildings’ walls were blown out by explosions.  And,  it’s not meant to serve all phases of the decontamination process, either:

TEPCO is also considering replacing the cover with a stronger one should the firm decide to remove the fuel from the reactor.

I’ve been reading some of the commentary on the accident that emphasizes that there haven’t been immediate deaths due to radiation release from it.  I really don’t get that complacent reaction.   There have been mass evacuations and relocations, abandoned homes, homesteads, farms, croplands and herds.  Some schools in use are dealing with radioactivity in their schoolyards. Even if you think nobody is going to be hurt (which is unrealistic), these plants are now big sores on the landscape that require massive amounts of attention and money.

There are piles of radioactive refuse already, and they will continue to be produced.  Here’s an article about the problem of used radioactive gear, showing that because there is nowhere to put it at the moment, it is just being placed into a very large pile:

http://www.majiroxnews.com/2011/10/16/tepco-releases-photos-of-huge-piles-of-used-radiation-protective-gear/

The out-of-scale pile is an icon to remember.  The reactor building pictured may be covered, but there will continue to be a steady stream of used radioactive filters, used radioactive gear, and, perhaps someday, even used radioactive damaged fuel, emerging from it.  The cover will have to be replaced, like a bandage on a wound, again and again.  I suppose the used and dismantled covers produced as the years go on will themselves constitute radioactive waste, as well.  All of this will be passed on for safekeeping.    It’s good to cheer this milestone, but it’s also valuable to keep it in perspective.

 

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Applying what we’ve learned from the accident at Fukushima: what’s being done?

Applying what we’ve learned from the accident at Fukushima: what’s being done?.

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New Report out on Financial Risks of New Nuclear Power Plants

New Report out on Financial Risks of New Nuclear Power Plants.

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