This was linked from today's guardian:

http://morgsatlarge.wordpress.c...japans-nuclear-reactors/

Very informative and a must read if you are curious about how nuclear reactors operate, what their security chains are and what, exactly, happened at Fukushima Daiichi 1, and - why there is nothing to worry about, believe it or not! There are links at the end to sites that will keep you as informed as you would ever want to be.

Thought it might interest some here, who are naturally untrusting of the wider media outlets.

JBArk

Great link JBArk. An interesting read.

I talked to some of the physicists I work with and they all agree that, yes well, the third containment is meant to hold in the worst case scenario... but it hasn't really been tested if it will, especially after the earthquake. Oh well, we'll have to hope for the best.

My heart really goes out to the workers in the reactors at the moment. Must be pretty scary to be there right now...

I confess, I found the blog-style link difficult and didn't bother to read. But, I am an amateur self-styled expert on nuclear reactors since childhood.

I know for a fact that there is no way a nuclear explosion can happen. I have known from the start that the main dangers were loss of cooling, potential hydrogen buildup leading to an explosion that breaches various levels of containment. Ultimately, meltdown into a slag heap like Chernobyl requiring a "sarcophagus" type of similar ongoing "band-aid" solution.

We passed that days ago. Tell the people in the surrounding countryside being told to shelter in place, to the guys on the U.S. Navy ship going through formal decontamination that there are no worries.

I was SHOCKED to hear they are doing the ultimate No-No with these reactors - the thing you are never supposed to do the action that tells me just how incredibly DESPERATE they are - They Mixed the coolant lines!

Normally the coolant that circulates in the core is completely SEPARATE and contained from the river or ocean water that bleeds off waste heat and spins turbines. This is why everyone likes to say the reactors are safe. Between keeping this all separate and multiple levels of containment, no problem right?

Well, problem if coolant on core boils off, hydrogen builds up, explosions take place, cladding and rods begin to melt into a slag heap and keep doing their fission dance in slow-mo generating tremendous heat that will eventually melt through the 6 inch/foot/whatever inner stainless steel containment vessel. IT IS ONLY A MATTER OF TIME. Then we have a situation like Chernobyl, but potentially worse. Right now we are desparately mixing lines, letting sea water saturated with neutron absorbing boron in there. Who knows what the next hours and days will bring.

Even slow fires and releases can contaminate HUGE swatches of usable land. Minor exposures to certain reaction products can guarantee various cancers, glandular problems and birth mutations within affected populations for decades (or longer) to come.

Seriously, all of the arguments are now bunk as we watch this nightmare unfold. The final nail is being nailed into Nuclear Power's coffin as I write this - it is simply just way too complex a way to boil water.

Now TEP (the plant owner) is evacuating workers. It looks like one of the confinement vessels has been breached. It looks like at least some amount of meltdown in 3 of the 6 reactor cores. Let's hope the wind blows gently west for a few days. There's a big problem over there.

Can it blow up? Powerplants aren't configured like a nuclear weapon. They can blow up from pressure or chemical explosions, but not like a nuclear weapon. They can turn into a large dirty bomb capable of making a much bigger problem.

What a mess. I have friends in Tokyo. I hope they stay safe. This is awful.

Edit: It's awful for Japan (and perhaps other parts of Asia) but the US is pretty far from this event so the radiation has a chance to be absorbed by the ocean and dissipate into the atmosphere. I'm not worried at all, but I'll bet we will be able to measure a background radiation increase on a global scale after this event is over.

For years (45 till early 1960's) the US tested lots of nuclear weapons in air at the Nevada test sites and in the Pacific ocean. I have read that one of the reasons for shifting tests to the Pacific is that the air bursts in Nevada started contaminating the milk of dairy cows in the mid-west US. Since they didn't want to sell contaminated milk, it was turned into cheese. Ummmmm....Cold War Cheese.

Wow and I'll bet that cheese was given away to poor folks by the government - like welfare food programs today.

I wonder is it also true the rumor I heard? Which is one of the reactors was working on experimental plutonium products? Holy half-life, a plutonium release could be much worse than the usual reactor products from uranium fission. Last time I checked it had a half life over 24,000 years. Not to mention that it is the most toxic element known to man and a single atom correctly lodged in lung tissue can guarantee (close to 100% for all) cancers within a couple decades.

Language is lacking here. I need a word that potentiates the combination of tradgedy and nightmare.

Yes I also read that one of the reactors was using a Uranium-Plutonium mix or something like that... Not fun.

They fear that the containment vessel has been breached by the explosion yesterday (Monday)... let's hope they are wrong. Radiation levels have reached the point where there is a health risk for humans. I'm so sorry this is happening.

That being said I wish the wind didn't have to blow in any direction, because there are people living on all sides of this disaster and if there is one thing I don't wish on anyone it's radiation poisoning.

The link has been moved to HERE (and modified by MIT). Has no one read it (except, i think Enoon)? I am not saying it is definitive, but it is certainly a non-spectacle alternative to what we read in papers that need to sell...

Here is a chart that is apparently floating around twitter (i don't twit, so i got this from the twits at the guardian ) (quotes also from the guardian):

"The caption to the chart says current the level of radiation at Fukushima is reported as 400mSv (milli sieverts) per hour."

I understand the media often gets carried away with facts but it appears 2 cores are partially damaged and a containment structure was breached in a third reactor. That falls into the category of a big, big mess. I wish those plant workers safe journey. That is a dangerous place to be.

jbark, Enoon or other scientists, do you have a conversion equation to get these "mini-sievert" numbers translated into REM's? I understand what REM's mean in terms of human health, male, female, young, old, short term and long. But I am not familiar with the term mini-sievert. I did most of my research in the 1980's. It was all rads and REM's back then.

Thanks!

This is not a Chernobyl. Chernobyl was basically a demonstration on "How not to generate nuclear power". There was no containment vessel in that reactor, the staff was improperly trained, and warnings were ignored and downplayed.

The Japanese reactors have performed admirably, considering they were subject to the largest earthquake on record in the country (4th largest in the world) AND a giant tsunami that washed away the fuel tanks for the backup generators (why the cooling pumps haven't been running).

It's also important to keep in mind that modern reactors are designed in such a way that they could not experience cooling problems such as these; a modern reactor overheating will cause the fuel rods to simply drop into the cooling tank. Self-described environmentalists who are against nuclear power are simply uninformed. Compared to fossil fuel, nuclear is much safer and less polluting.

1 Sievert = 100 rem

The Sievert factors in the amount of absorbed radiation and the type of absorbed radiation to create a value that estimates how much damage is being done to a human.

If the radiation source consists of gammas only,
1 Sv = 100 RADs

I think normal background is 2 mSv/year

They are claiming radiation levels of 400Sv near the worst reactor. It's not good.

Edit: I'm not at all against nuclear power and vastly prefer it over coal, but still, this is a bad situation. If nothing else, it's ruined several valuable power plants and contaminated the local area.

"The caption to the chart says current the level of radiation at Fukushima is reported as 400mSv (milli sieverts) per hour."

Unless that is old news and the levels have absolutely skyrocketed, but I have not read that.

yes.....my mistake.

400 mSv not 400 Sv

What's a factor of a thousand amongst friends?

also, as posted above:



And if you look at the chart in the post above that quantity, with prolonged exposure (as I understand the chart) 400 mSv is at the very base of the danger spike, still 100 mSv under the category of reducing white blood cells for a full body exposure, and 200 mSv above the level described as "no clinical conditions recognized".

I am worried about the outcome of all of this, as everyone is, but let's not let the potential sensationalism of the whole affair cloud our judgment and obscure the facts, as they too often do. (assuming we are getting them right here also... )

JBArk