Thursday, April 19, 2012

Professor Yukio Hayakawa Takes a "Radioactive Walk" In Abiko City and Kashiwa City in Chiba

The Gunma University professor took a walk in part of Abiko City and Kashiwa City, in the so-called "Tokatsu area" in the northwest corner of Chiba Prefecture with elevated radiation levels.

He says there is a statistically significant difference between the radiation levels on the ground levels and the levels at 1 meter off the ground, with the levels at 1 meter off the ground 20 to 30% less than at the ground levels.

The radiation levels of "black dust" he found along the way (in microsievert/hour):


Professor Hayakawa's walk from Abiko City to Kashiwa-no-ha in Kashiwa City on April 16, 2012:


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Anonymous said...

I don't understand his comment on "statistically significant difference" at different height; I have mentioned before that these devices are not made for close to surface readings and you get a crazy mix of alpha/beta/gamma all converted to Sievert units.

On top of that, of course increasing distance will lower the radiation level (not sure if it is double distance = quarter intensity (inverse square law)).

arevamirpal::laprimavera said...

"statistically significant", as opposed to merely "significant". two different meanings.

The device is not meant for surface readings, as you say. His survey meter is only for gamma rays. I think what he's saying about the measurements in this particular area is that unlike other places he measured, there is a meaningful difference between the radiation 1 meter off the ground and near or on the ground. I've seen other locations he and others measured where the radiation 1 meter off the ground was no different than the radiation right near the ground.

Anonymous said...

OK, thanks - yes that makes sense now.

I lived in that area until Oct 2011 and that "statistically significant difference" was the reason for moving.

My average readings (using Medcom Inspector) at 1m were 0.6-0.8 uSv/h (maximum was just under 1 uSv/h) and on surface (concrete) 3.5-5 uSv/h.

I had not noticed black substance in the area.

Anonymous said...

This link is for anyone wanting to find out about doing there own measuring. Easy to understand.

Chibaguy said...

Even with a uncalibrated Geiger counter one can infer what they are measuring is not normal. I started with a Ludlum 3 and established a baseline. Once I got my hands on a more modern device the statistical difference was the same for the most part.

Anonymous said...

Isnt this Hayakawa guy all for burning radioactive garbage? Sounds like a bullshitter to me..

arevamirpal::laprimavera said...

I wouldn't call him that. He is for burning and disposing radioactive disaster debris. I don't think he has said anything about garbage, other than to say "If you are against burning disaster debris, particularly in Tohoku and Kanto, you should be against burning the household debris in those areas because they are just as radioactive". (I don't necessarily agree with that..)

He is dead set against having any farm produce out of Fukushima, he was against taking vehicles from contaminated areas in Fukushima, for which he was called uncaring racist.

He is against wide-area disposal of disaster debris. As an academic, he seems a bit naive about how the waste management industry and the government work.

But that doesn't make him a bullshitter.

Anonymous said...

I think this has shown that it is not just one or two high readings at ground level.

He is doing something. Some are not.

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