Monday, March 21, 2011

One Day in A Nuclear Age, They May Understand our Rage

One group of people whose rage I can understand is Japanese farmers.   Recently, spinach and milk samples have turned up with radioactivity levels above the legal maximum in districts near Fukushima Dai-Ichi nuclear plant.  In this story/video:

We see an 80 year old Japanese woman, who is dismayed when a news crew with Geiger counters finds her spinach radioactive.     I sympathize with such farmers and hope they are adequately compensated by TEPCO.    A few points regarding this story:

--Why spinach?  Does it soak up Iodine or other isotopes more readily?   Its only been days since the first releases of radation...that seems a little quick to me.

--The story assumes that the radiation in food  was caused by the recent releases.  But were they even checking before?  Its seems possible that the Fukushima plant (which has one of the worst safety records in Japan) could have been releasing low level radiation for some time and that the radioactivity has been in the food all along.   A scientific response to hearing any measurement is:  "in comparison to what?"

--Press is saying that although some food exceeds rad. limits, there's still "no immediate health risk" from eating it.   Here's one way to translate that statement:

"no immediate health risk" = " get lethal thyroid cancer in 10 years"

One thing I've learned recently about radiation is that it is much more dangerous when ingested.  Surprisingly, our skin is a useful barrier to radiation just as it keeps out other foreign substances.  And many types of radiation can only penetrate a few milimeters.   (This is especially true for "Alpha" particles).  This implies however that eating radioactive food is much worse than simply holding it nearby.

Regarding the power plants, we have some good news to report.  The good news is that we now appear to be facing a quadruple catastrophe.   Doesn't sound good?  It is good because two days ago it was looking like a sextuple catastrophe, with all 6 reactors at risk, with rising temps.   The two mostly undamaged reactorss (#5, #6) now have power restored and are cooling.

However reactors 1,2,3,4 are still problematic.   #1 & #2 seem to have decreasing pressure levels in the cores which is a good sign.   A couple of days ago, physicist Michio Kaku described the aerial water drops as "trying to put out a forest fire with a squirt gun."  I thought that was an accurate, if harsh analogy.  However the next day workers set up an automatically firing hose that sprayed some hundreds or thousands of tons of water into a reactor over a period of 7 hours.  This sounded more powerful to me.  But then I  read   that this effort resulted in the water temperature going below 100C !!!!  Hello? 100C is the boiling point of (unpressurized) water, so all water is  below 100C!   These are not high-pressure water reactors, so I'm at a loss to see that this is any form of success.    In contrast, core temps. in reactors 5&6  are at meaningfully low "safe" levels: only (95F = 35 C):

The above page is a good resource for current status of the reactors.  The fact that there ARE NO TEMP. READING for reactors 1,2,3,4 is worrying.  It probably means that the  thermometers there were all destroyed in the explosions and fires those reactors experienced.

One final item:  workers had to back off of reactor 3 due to high radiation levels.  This is a bad sign.  Unless people can get close to the reactors, its going to be hard to fix anything.   Japan is now rotating workers in in groups of 100 people, letting them get irradiated to somewhat above normal permissible maximum, then bringing in a fresh 100 people.   This is probably (but not definitely) the best strategy, since we don't know how people will ultimately be irradiated this way....possibly thousands, or whether they can do much good without getting close in.  Is it better to allow 50,000 people to get unhealthy levels of radiation or to allow 5, 10 or 20 people to get lethal dose of radiation?  I'm glad I don't have to make that decision.


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