March 12, 2011

Random Mutterings On The Nuclear Power Plant in Fukushima

By now this appalling video of the explosion of one of the containment buildings in Fukushima has been seen by pretty much everyone.



This is pretty damned bad.
The ongoing situation is fluid and being widely covered. However, there is a bit more to this situation than  current events, there is also the history of the facility.

Something about this plant rang a bell when I first heard it. Now I remember why. This plant has had a very chequred record.

In 1978 this plant had what Market Watch describes as an
 accident at its Fukushima nuclear power plant resulted in an uncontrolled nuclear chain reaction for more than seven hours that the company failed to report to the government.


The article goes on to say that there were close calls in '79 and '80 also involving control rods but no actual nuclear event occurred. (wrong geometry?) The article dates from 2007 and in that year there was, apparently,  another problem with Fukushima involving procedures, but the I'm unclear on the details.

1978 was 33 years ago so I was curious how old the plant was. According to this site the reactor started up in 1970 or 1973. It was to be decommissioned some time this year.

It seems that TEPCO, the company that runs the plant has had a lot of issues with their older plants and actually lost their license to run 2 hydro-electric dams in 2007.

They were under intense scrutiny around that time and the Fukushima facility in particular seems to have been quite intensely audited, to the extent that two additional reactors being built there were delayed by at least a year for safety re-assessment. The two new reactors aren't going to be online before 2013, but that estimate was before the Sendai quake. Note that Wikipedia says that Unit 1 was to be deactivated later this month because of its age.

So there is a history of non-trivial operational screw ups with the company and this facility in particular but there Google and Bing yield no info on anything after 2008.

Some will no doubt charge that this may mean the change in government reduced oversight, but it might also mean that they had gotten there act well in order. Do note that the language barrier removes a lot of pertinent info from a search.

Of course being virtually at ground zero during an 8.9 9.0 is an extreme engineering challenge for anything. From what I have heard the plant suffered a full on, balls out enforcement of Murphys Law. The quake destroyed their primary coolant system and that horrific flaming tsunami destroyed all their backups. Everything was broken up by the quake and it appears that many of the plant workers were injured before the reactor issues even began.Especially given the age and utter obsolescence of the reactor the performance thus far is actually kind of impressive.The staff of the facility is certainly attempting to remedy the situation at great personal peril.

I have some questions about the design. I'm a layman in these matters so bear with me gentle reader, and if you note an error or have some answers, please avail yourself of the comments.

I wonder about the containment building. Most Japanese, French and American reactors have big containment buildings around the containment vessels shaped like pressure vessels, either big tank looking structures or art deco versions of Devils Tower.  This plant SEEMS to have had a less robust containment structure than is the norm in newer reactors. This comment is based on nothing other than the reactor buildings boxy external appearance, which , if it represents the actual containment structure, is, all things being equal, less able to resist internal pressures than the spheres or cylinders that one sees in boilers for instance.

Jerry Pournelle has thoughts:

I am told that some areas around the threatened nuclear power plants are being evacuated. Given the chaotic conditions and limited resources in Japan -- there is no electricity in most of the devastated areas -- this is probably significant, but what it means isn't clear. For the record, I would never have been in favor of licensing nuclear power plants without more sturdy containment structures than appear to have been built at this plant -- but once again, I don't have an accurate picture of what containment structures they had. US regulations require that reactors be housed in very strong containments.

I also find this relevant: http://www.nctimes.com/news/
local/sdcounty/article_46cf4ee3-d38a
-5824-8648-2e7589b063e6.html



I understand that this reactor is a BWR (Boiling Water Reactor).

BWR animation via Nuclear Regulatory Commission

The US and France use mainly pressurized water reactors which add a second heat exchange stage that greatly increases complexity but increase the separation between radioactivity and the world.



Pressurized Water Reactor animation via NRC

I find it significant that even in naval nuclear subs where space is at a premium, the US, UK and France are said to use the more complex and bulkier pressurized water reactors. This may mean something.
*****
Now it appears that the staff are pumping in seawater as coolant, which is wrong in all sorts of ways ( nukes, like any boiler, require ultra pure distilled water for coolant...a BWR even more so as getting salts in your control rods is considered to be "bad") but this may be able to prevent a much bigger disaster.

Brian Wang has posts on this here here and here.

I find this passage of particular note:
The radiation is less than 1 REM per day. It takes 600 REM to kill
BP oil spill had deaths and more damage.


Which jives with a comment over at Bubbleheads blog where there is an extensive discussion by actual Navy Nukes.

"Something tells me to read "radiation levels" as "radioactivity levels"--big difference. I hope I'm not wrong about that.

3/11/2011 8:56 PM"

You're not wrong. This is simply a matter of the media not doing a follow up or any kind of research before sending out their latest press release. I could almost laugh at some of the misinformed sensational journalism I've seen today.


Allahpundit has a running post on this.

Japanese coverage is here, here and here.

On the bright side, the building codes in Japan seem to have worked pretty damned well. There's nothing that could really be done to deal with a flaming tsunami(WTF!?) but Tokyo in particular rode out an event that would have left New York mostly rubble. Via Instapundit there are thoughts on that here and here and there are more thoughts on that here.

Video of building codes in action.



UPDATE: Ace has an in depth open thread on the reactor situation here.

UPDATE 2: One of the stranger comments on this catastrophe from our executive branch was SecState Clinton's announcement that the US Military had delivered "coolant" to this reactor. This was almost universally derided as the coolant for a BWR is water, and Japan is an bunch of islands. The running theory was that the US had delivered pumps. Now via RS McCain comes this interesting article by a member of the 3Mile Island investigative committee.

...so it seems our SecState was pretty close actually...certainly close enough for government work.

Money Quote:

...That’s why the experts didn’t expect it because they are still thinking of how the plant can be saved, but it can’t be.


Though the boiling water reactor has already been turned off by inserting neutron-absorbing control rods all the way into the core, adding boric acid or, more likely, sodium polyborate would turn the reactor
off-er — more off than off — which could come in really handy in the event of a subsequent coolant loss, which reportedly has already happened. But that’s a $1 billion kill switch that most experts wouldn’t think to pull.

 
I’m guessing the US Navy delivered a load of sodium polyborate from some nuclear aircraft carrier reactor supply room in the Pacific Fleet. Its use indicates that the nuclear threat is even worse than presently being portrayed in the news.  Tokyo Electric Power Company has probably given-up any hope of keeping those cooling pumps on after the batteries fail. Eventually they’ll vent the now boron-laced coolant to the atmosphere to keep containment pressures under control.



While the Navy issue flea powder is a neutron inhibitor and not actually a coolant, by inhibiting the nuclear reaction it ought to help bring the temperature down quicker. So the SecStates statement is basically correct.


So they are scuttling at least one, possibly all of the reactors at the site by using a PWR neutron inhibitor that will destroy a BWR in order to prevent a major disaster.

It may be working.
On a lighter note, here is new footage of the tsunami.

Posted by: The Brickmuppet at 09:58 PM | Comments (2) | Add Comment
Post contains 1468 words, total size 16 kb.

1 About 20 miles away from Pond Central is a nuke plant; the cooling towers are visible from a high spot, and the steam clouds it generates are visible from anywhere... but those towers have nothing to do with containment.  In fact, they're separate buildings altogether from the nuclear generators.  In that picture, the containment buildings are the ones that look like ice cream containers to the left of the left tower.

THOSE look roughly similar to the one that went poof in Japan, though I personally hope they're somewhat more robust.  Still, even those don't matter as long as the primary containment vessels are intact.  It wouldn't be NICE to have the containment buildings gone, but I'd be calm about it.

Posted by: Wonderduck at Sun Mar 13 00:59:12 2011 (W8Men)

2 Oh yeah...cooling towers. (facepalm)
Thanks.
I knew that once. I swear. 

Posted by: The Brickmuppet at Sun Mar 13 05:10:12 2011 (EJaOX)

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