Investigation of The Accuracy of the Radiation Monitoring Posts placed in Fukushima Prefecture

by the Japanese Government

How have we come to suspect? We have found that the dose values (Sv/hr) on the official

monitors were lower than the values obtained by other instruments.

We suspected that the dose values on the monitors may be made artificially lower than the true values.

We have found that the vicinity of monitors is usually cleaned and decontaminated (intentionally or unintentionally), or that a metallic plate is placed under the monitor.

We decided to investigate it ourselves.

Monitoring Posts(there are two different types)

Movable Type Real time Dosimeter

Data to verify the monitors

In the following figures: (A) is the reading on the monitor (B) reading on our meter (Aloka….), when it was

placed as close as the monitor (C) reading on our meter at 2 m from the monitor (at

1 m high above ground) (D) reading on our meter at 5 m from the monitor (E) the average of readings on our meter 1 m above

soil exposed ground within 15 m from the monitor. Our meter is Aloka……., and its accuracy has been

verified comparing with several different instruments.

The figures on the next two slides In both of these figures, the names at the bottom

(in Japanese) are the locations of monitors. The data shown are the relative values of the

actual readings under several different conditions (as shown in (B)-(E) above) to those on the monitors (A), expressed in %.

The First figure is of the city of Minami-Soma The second is of the city of Koriyama These figures indicate that people may actually

be exposed to radiation as high as 5 times of the monitor’s value.

Spatial dose rate as of Sept. 26, 2012(published by Ministry of Science and Education)

We’ve observed often higher than 2 mm Sv/hr in Koriyama-shi.

Conclusion Our investigation has shown that:(1) The officially set monitors do not necessarily show

accurately the real dose rate, for several reasons. One important factor is that the vicinity of a monitor is usually cleaned and decontaminated so that it does not reflect the dose just outside of the cleaned area, where people actually live.

(2) It seems that the government is intent on making the level of contamination look lower than the real value in many different ways.

(3) This attitude of government would jeopardize the people’s lives; this is clearly a violation of the basic human rights.