Analysis of the Impact of Precipitation on Tritium Concentrations Based on Nuclear Facility Operation Data

Tritium is a radioactive substance released into the environment through air and water systems during nuclear facility operation, potentially affecting ecosystems. Understanding its concentration variations is essential. This study analyzed tritium concentrations measured in air (unit: Bq/m³) and rainwater (unit: Bq/L) from 2011 to 2022 to evaluate the reliability of sampling methods for atmospheric and precipitation samples. A multi-faceted analysis was conducted using variables such as precipitation, release rates, and seasonal factors. The results showed that increased precipitation led to decreased tritium concentrations in rainwater at all locations, with significant dilution effects observed in northern and western monitoring points (approximately -0.0309 Bq/L and -0.0301 Bq/L per 1mm precipitation increase, respectively). Tritium concentrations in the air also tended to decrease with increasing precipitation, although the magnitude of variation was smaller compared to rainwater. A statistically significant correlation between increased precipitation and decreased air tritium concentrations was observed at the eastern monitoring point (P < 0.01). Comparing tritium concentrations across seasons under similar precipitation conditions revealed no significant differences in most cases; however, slightly higher concentrations were found in winter. This may be related to specific factors such as temperature conditions or emission patterns during winter. This study quantitatively confirmed the environmental behavior of tritium and its dilution effect by precipitation, providing crucial baseline data for the long-term management of radioactive substances around nuclear facilities and contributing to the evaluation of sampling methods' reliability.