Terrestrial Isotope Transfer Processes Section

Office:1-1-1 A-405 Tennodai TSUKUBA, IBARAKI 305-8572
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Transitory states of radioactive substances in the environment

Transitory states of radioactive substances in the environment

In collaboration with the Fukushima Institute of Environmental Radioactivity, this faculty performs comprehensive research on transition mechanisms and distribution conditions of radioactive substances in the environment to explain the effects of radioactive substances from nuclear accidents on the environment. In particular, we promote research for modeling predictions and monitoring studies in the transition of radioactive substances discharged by water, soil, and sediment in forests and other land-based environments.

Transfer of radionuclides in forest environments

photo:Field observation of radioactivity

Field observation of radioactivity using a forest observation tower
(portable-germanium semi-conductor gmma ray detector)

Approximately 70% of the region affected by radionuclides discharged due to the Fukushima Daiichi nuclear accident includes forests. It is imperative to understand the behavior of radionuclides in forest environments to explain the effects of radiation on the surrounding environment and absorption of radionuclides by vegetation from the soil. We are committed to actively obtaining measurement data that are useful in predicting future transition patterns and conditions, in addition to explaining the mechanisms behind the transfer of radionuclides in forest environments.

photo:Observation devices

Observation devices in a forest
(Equipment for collecting
throughfall and stemflow)

photo:Stream water flow observation

Stream water flow observation

Photo:Monitoring of radiocesium discharge

Monitoring of radiocesium discharge from the forest watershed
Left: Parshall flume flow gauging weir and automatic water sampler
Right: (back to front) Parshall flume flow gauging weir,
triangular weir, suspended sediment sampler

Discharging radionuclides via soil erosion from various land-uses

Photo:Measuring discharge of radioactive substances through paddies

Measuring discharge of radioactive substances through paddies (Flow gauging weirs and turbidity measurement equipment)

Radionuclides deposited on the land surface transition into the wider environment together with soil particles. This department aims to develop techniques for predicting transfer of radionuclides in a wide range of environments wherein various spatial information and monitoring data of soil erosion are integrated using geographic information system (GIS). Using this method, parameters are estimated for the transfer of radionuclides accompanying soil erosion and sediment discharge on the basis of numerical modeling.

Observation of soil erosion and sediment discharge volume from experimental plot

Observation of soil erosion and sediment discharge volume from experimental plot

Long-term predictions for transfer of radionuclides through waterways

Photo: River turbidity measurement system

River turbidity measurement system (Measures turbidity component of river water)

Figure_Observation points

Observation points
in Abukuma and
Fukushima Hamadori rivers

Radionuclides that accumulate on earth’s surface spread downstream through waterways together with water, soil, and sediment, and eventually flow into oceans. The dispersion of radionuclides through waterways is directly connected with land-use policies, which in turn are designed to provide assistance to residents of that watershed.

This department aims to develop models capable of performing such long-term predictions for Fukushima Prefecture and for the surrounding waterways by measuring the concentration of radionuclides in water bodies in both normal and flooded conditions.

Photo: Sampling of suspended sediment and river water

Sampling of suspended sediment (left)
and river water (right) in rivers

Photo: particle_size_analyzer

Laser diffraction particle size analyzer

Coordination with foreign and domestic research institutions

Our aim is to develop a timely solution for addressing the effects of the Fukushima Daiichi nuclear accident through coordinated efforts with foreign and domestic research institutions that have accumulated observational data regarding the transfer state of radiocesium originating from incidents such as the Chernobyl nuclear disaster.

In addition, by enlisting the help of the International Atomic Energy Agency (IAEA), we are able to contribute to the prevention of such accidents by providing technical assistance in formulating policies associated with each of the various ministries. Such measures can improve Japan’s radioactive substance monitoring capabilities to world-leading levels.

Photo_The first JAPAN Proficiency Test 2012

The first JAPAN Proficiency Test 2012 (IAEA-TEL-2011-08) was realized through technical collaboration with the International Atomic Energy Agency (IAEA)

Interdisciplinary Project on Environmental Transfer of Radionuclides

原子力災害による環境・生態系影響リスクマネジメントプログラム(ENEP)

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