Excessive cesium-134 at Daiini. Evidence of criticality there April 2012 or after.

This table was recently released by Tepco. The first row shows radioactive cesium measurements made of fallout at Fukushima Daiichi on December 25, 2013. Note that the amount of cesium-134 is about 39% that of cesium-137. At 3/11 the ratio of Cs-134 to Cs-137 was around 100%. Cs-134 has a half-life of 2 years, and has now decayed to around 35-40% of Cs-137.

The second row shows radioactive cesium measurements made of fallout at Fukushima Daiini on December 26, 2013. The amount of Cs-134 is about 57% of Cs-137.

From Wikipedia,

Caesium-134 has a half-life of 2.0652 years. It is produced both directly (at a very small yield because 134Xe is stable) as a fission product and via neutron capture from nonradioactive Cs-133 (neutron capture cross section 29 barns), which is a common fission product. Caesium 134 is not produced via beta decay of other fission product nuclides of mass 134 since beta decay stops at stable 134Xe. It is also not produced by nuclear weapons because 133Cs is created by beta decay of original fission products only long after the nuclear explosion is over.

So cesium-134 is mainly an activation product, which means it needs neutrons flying around and interacting with nonradioactive cesium-133 to be produced in significant quantities.

I used a radioactive decay application to figure how far back in time Cs-134 would have to have been produced to get the current ratio of 57% of Cs-137. The Cs-134 would have been produced around April 1, 2012.

This means there has been a criticality at Daiini sometime after April 1, 2012. How long after this date is unknown.

8 thoughts on “Excessive cesium-134 at Daiini. Evidence of criticality there April 2012 or after.

  1. bruce on August 9, 2013 at 1:47 am said:

    Huge radiation spike yesterday afternoon in Fukushima.
    道の駅ならは MichiNoEkiNaraha(?)
    Like the spike a few days ago, this is not so near Fukushima Dai-ichi, but is nearer to Fukushima Dai-Ni !
    near J-Village


  2. Oh brother, what next? We people are crazy, there’s no doubt about it.
    I have been reading about “Valley Fever” in the news. The “experts” say that it is a Southwest illness caused by fungus in the soil there. It is found mainly in California and Washington. There is no cure. It has been around since the 50’s, (since atomic testing began), but there has been an exponential increase lately. It is breathed into the lungs through the air, and people, dogs, cats, and other animals get it. It causes lung tumors, lesions, and respiratory failure. Any of this sound familiar?

  3. This is the first real news that i’ve heard in like over two years concerning Daini!
    Ah, think i see what it is you are saying.
    Due to the stark difference in Cesium isotopic ratios between the two sites, it could not have occurred in Daichi, yet must have been local to Daini.
    Did i gather this correctly? It seems unclear in your article. I hope you can make this link clearer and strengthen your argument.
    Pound that wooden stake deeper; i still see movement from that vampire!!!

      • ‘scuse me? “Lately”???

        Truthfully say it ain’t so!
        Otherwise, just give it to me, straight up.

        After three years of horrible news following bad news, i can take it. Feeling “punch drunk” and haven’t drank any punch. What’s one more shot to the head (other than concussion syndrome)? I’d rather know and have others “think” i’m crazy, rather than not knowing and/or not caring like the children that are leading now. The children ARE leading now! That is, those with minds of children…. d’oh 🙁

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