Wednesday, May 31, 2017

Fukushima Logging, Lumber, and Radiation Safety

The Japanese Forestry Agency is allowing logging to be resumed in Fukushima Prefecture. Before logging begins, the radiation level of the lumber will be evaluated:
Forestry Agency to log and ship Fukushima trees in trial starting this fall. JIJI, Kyodo May 16, 2017
The Forestry Agency said Monday that it will resume felling and shipping trees in Fukushima Prefecture this fall on a trial basis...

...Logged trees will be shipped after radiation checks. In the current fiscal year ending next March, the agency will also thin forests in the village of Katsurao and remove surplus trees in the town of Naraha, although they will not be shipped...

...In order to prevent wood with contamination levels higher than national standards from going on sale, the agency intends to ship only trees logged in forests with radiation levels below 0.5 microsievert per hour.

Tepco plans to build a new incinerator to dispose of radioactive logs that have piled up in the premises, company officials said. The logs amassed to about 78,000 cubic meters after the company felled trees to clear land in order to build containment tanks for contaminated water. Construction materials such as mortar was used to cover the soil to isolate radioactive materials. The new incinerator is slated to begin burning logs in fiscal 2020 through March 2021 and the ashes will be moved to storage warehouses by fiscal 2026, according to the company.

The nuclear plant has an incinerator to burn protective gear worn by workers but the fast-growing pile of logs prompted the company to seek a new facility, which would be able to burn 95 tons of waste per day, they said.
The method for evaluating the radioactivity of lumber in Fukushima is questionable. It seems from the article above that the radioactivity of the entire forest will be measured and the level of radioactivity for particular trees derived from that "forest" measurement level.

However, deriving individual measurement from population level measurement is NOT PREDICTIVE when it comes to contamination by radiation.

Individual trees vary in exposure based on their location. Radioactive hot spots occur naturally as the vagaries of terrain, wind and water run-off lead to concentrated areas of radionuclides. Some trees will be exposed to much greater concentrations of radionuclides than other trees.

Individual trees also vary in their concentration, or bio-accumulation, of radionuclides depending upon the nature of the soil within which they are embedded and in relation to the vagaries of their growth.

The proposed method for evaluating the radioactivity of lumber will not predict the radioactivity of individual trees. Instead, the proposed method offers a homogenized representation that, when symbolically spread across the population, represents "little to no" radiation risk.

So, the risk-assessment appears flawed because it extrapolates individual risk from a homogenized representation of collective risk.

In addition, the proposed risk management approach for radioactive forests - incineration - also raises concerns. Is it possible to trap all contaminants when incinerating radioactive waste?

Even if its possible to eliminate unwanted migration of radioactive materials, what happens with the remaining waste captured in the incineration process?

Highly radioactive waste remains.

Chernobyl's forests are still radioactive and every so often concerns are expressed about fire risks to its radioactive trees:
Braxton Little. June 24, 2013. At Chernobyl, Radioactive Danger Lurks in the Trees. Scientific American,

For almost three decades the forests around the shuttered nuclear power plant have been absorbing contamination left from the 1986 reactor explosion. Now climate change and lack of management present a troubling predicament: If these forests burn, strontium 90, cesium 137, plutonium 238 and other radioactive elements would be released, according to an analysis of the human health impacts of wildfire in Chernobyl's exclusion zone conducted by scientists in Germany, Scotland, Ukraine and the United States.

This contamination would be carried aloft in the smoke as inhalable aerosols, that 2011 study concluded.
Logging in Fukushima seems necessary to prevent unwanted forest fires. However, the risk-management system described in the news article doesn't appear to mitigate effectively against radiation risks.


  1. "John Casey Author of UPHEAVAL"

    The very real threat?

    1. Interesting argument. I've been thinking about earthquakes recently.

  2. The Unelected buffoon continues his plan to expand private prisons, and the incarceration nation. Sessions is locking more people in prison for victimless crimes, for long periods than ever. Far worse than a Nazi police state or Stalinist Russia. Evil bastards.


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