[ RadSafe ] New research reveals significant Fukushima radioactive particle release

[Roger Helbig]

https://www.eurekalert.org/pub_releases/2018-05/uom-frp052418.php
UNIVERSITY OF MANCHESTER Scientists say there was a significant
release of radioactive particles during the Fuku"
Respond to this post by replying above this line

New post on nuclear-news

New research reveals significant Fukushima radioactive particle release

by Christina MacPherson

Fukushima radioactive particle release was significant says new
research https://www.eurekalert.org/pub_releases/2018-05/uom-frp052418.php
 UNIVERSITY OF MANCHESTER

Scientists say there was a significant release of radioactive
particles during the Fukushima-Daiichi nuclear accident.

The researchers identified the contamination using a new method and
say if the particles are inhaled they could pose long-term health
risks to humans.

The new method allows scientists to quickly count the number of
caesium-rich micro-particles in Fukushima soils and quantify the
amount of radioactivity associated with these particles.

The research, which was carried out by scientists from Kyushu
University, Japan, and The University of Manchester, UK, was published
in Environmental Science and Technology.

In the immediate aftermath of the Fukushima Daiichi nuclear accident,
it was thought that only volatile, gaseous radionuclides, such as
caesium and iodine, were released from the damaged reactors. However,
in recent years it has become apparent that small radioactive
particles, termed caesium-rich micro-particles, were also released.

Scientists have shown that these particles are mainly made of glass,
and that they contain significant amounts of radioactive caesium, as
well as smaller amounts of other radioisotopes, such as uranium and
technetium.

The abundance of these micro-particles in Japanese soils and
sediments, and their environmental impact is poorly understood. But
the particles are very small and do not dissolve easily, meaning they
could pose long-term health risks to humans if inhaled.

Therefore, scientists need to understand how many of the
micro-particles are present in Fukushima soils and how much of the
soil radioactivity can be attributed to the particles. Until recently,
these measurements have proven challenging.

The new method makes use of a technique that is readily available in
most Radiochemistry Laboratories called Autoradiography. In the
method, an imaging plate is placed over contaminated soil samples
covered with a plastic wrap, and the radioactive decay from the soil
is recorded as an image on the plate. The image from plate is then
read onto a computer.

The scientists say radioactive decay from the caesium-rich micro
particles can be differentiated from other forms of caesium
contamination in the soil.

The scientists tested the new method on rice paddy soil samples
retrieved from different locations within the Fukushima prefecture.
The samples were taken close to (4 km) and far away (40 km) from the
damaged nuclear reactors. The new method found caesium-rich
micro-particles in all of the samples and showed that the amount of
caesium associated with the micro-particles in the soil was much
larger than expected.

Dr Satoshi Utsunomiya, Associate Professor at Kyushu University,
Japan, and the lead author of the study says "when we first started to
find caesium-rich micro-particles in Fukushima soil samples, we
thought they would turn out to be relatively rare. Now, using this
method, we find there are lots of caesium-rich microparticles in
exclusion zone soils and also in the soils collected from outside of
the exclusion zone".

Dr Gareth Law, Senior Lecturer in Analytical Radiochemistry at the
University of Manchester and an author on the paper, adds: "Our
research indicates that significant amounts of caesium were released
from the Fukushima Daiichi reactors in particle form.

"This particle form of caesium behaves differently to the other, more
soluble forms of caesium in the environment. We now need to push
forward and better understand if caesium micro-particles are abundant
throughout not only the exclusion zone, but also elsewhere in the
Fukushima prefecture; then we can start to gauge their impact".

The new method can be easily used by other research teams
investigating the environmental impact of the Fukushima Daiichi
accident.

Dr Utsunomiya adds: "we hope that our method will allow scientists to
quickly measure the abundance of caesium-rich micro-particles at other
locations and estimate the amount of caesium radioactivity associated
with the particles. This information can then inform cost effective,
safe management and clean-up of soils contaminated by the nuclear
accident".