Subject:
Study on Tritium Behavior in the Environment
Tritium (3H or T), a radioactive isotope of hydrogen, is released from nuclear facilities into the environment although the amount and concentration is assessed to be safe. The amount of tritium release is projected to increase due to increasing number of reactors, spent fuel reprocessing plants and fusion reactors. Tritium in the environment can take various chemical forms such as hydrogen gas (HT), tritiated water (HTO) and organically bound tritium (OBT). Since HTO and OBT are easily incorporated into human body, it is important to quantitatively understand migration of tritium, to which both physical factors such as molecular diffusion process and biological factors such as microbial activity and plant physiology relate.
We have carried out laboratory experiments on conversion of molecular hydrogen to water (molecular tritium to tritiated water) by microbial activity in soil and quantitatively formulated the conversion. This leads to a precise modeling of tritium deposition, which use to have large uncertainty of several orders of magnitude. We study how variation in soil condition such as land cover/land use, precipitation/evaporation and temperature contributes to behavior of environmental tritium.
Fig. Transfer of tritium in the environment. HT is in hydrogen gas form, HTO in tritiated water, and OBT is organically bound tritium.
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