Impacts of the large fusion test facility on tritium in environmental water and natural radiation levels.

In the progress of nuclear fusion development, environmental radiation monitoring in the vicinity of the facility would be an important issue. At the National Institute of Fusion Science (NIFS), the deuterium plasma experiment, which produces tritium and neutrons using d-d fusion reactions, was conducted from 2017 to 2022. Environmental radiation and tritium in environmental water were monitored before and during the deuterium plasma experiment for public acceptance. As a result, there was no significant change in the observed dose rate and tritium concentration in the rainwater, and no statistically significant difference was identified in the statistical analysis of the data observed before and during the deuterium plasma experiment. Therefore, the environmental impact of the deuterium plasma experiments at NIFS is considered to be negligible.