Contamination of Japan 23 – Results of the Nuclide Analysis of Plutonium and Strontium by MEXT Japan

September 30, 2011

Results of the Nuclide Analysis of Plutonium and
Strontium by MEXT

The results of nuclide analysis of plutonium 238 and 239+240, and strontium 89 and 90 were
compiled as follows, in the course of the project commenced on June 6, 2011, under the 2011
Strategic Funds for the Promotion of Science and Technology, entitled “Establishment of the Base for
Taking Measures for Environmental Impact of Radioactive Substances — Study on Distribution of
Radioactive Substances.”

1. Objective of the survey
In order to continuously check the impact of radioactive substances deposited on the ground
surface on the health of residents and the environment, MEXT measured air dose rates at around
2,200 locations within approximately 100 km from the Fukushima Dai-ichi NPP, and at the same
time collected soil samples from the 5 cm surface layer at around five points at each location to
analyze nuclides, prior to the rainy season, before any changes occurred on the soil surface. (The
measurement results of air dose rates were already publicized on August 2 and 12, and the map of
radioactive cesium concentration in soil and the map of iodine concentration in soil were released
on August 30 and on September 21, respectively.)
At the same time, in order to check the deposition of alpha and beta-emitting nuclides, which
were released from the Fukushima Dai-ichi NPP together with gamma-emitting nuclides, MEXT
conducted a nuclide analysis of plutonium (one of the representative alpha-emitting nuclides) and
strontium (one of the representative beta-emitting nuclides) at 100 locations (one point for each
location) out of around 2,200 locations where it had carried out the soil monitoring survey.
The Review Meeting for the Preparation of Distribution Map of Radiation Dose, etc.
(Attachment 1), which was established within MEXT, verified the validity of the results of the
measurement of plutonium 238 and 239+240,* and strontium 89 and 90, and compiled the results
* Because the alpha particle energy emitted from plutonium 239 and 240 is almost the same,
these cannot be distinguished through the usual analysis method adopted for alpha-emitting
nuclides measurement. Therefore, the analysis is conducted for the sum of these two nuclides.

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This data represents the search for levels of plutonium and Strontium particles. The search is enabled due to the fact that these poisons are radioactive. Hot Particles do exist despite what extremist nukers claim to be the be all and end all – external dose. Internal dose from hot particles as internal emitters is important both at the time a disaster occurs and for years into the future.