Assessment of long-term trend for environmental radioactivity around Wolsong nuclear power plant in Korea

Highlights: • Wolsong NPP was utilizes to assess the trend of environmental radioactivity level. • Mann–Kendall test was used for assessment with environmental monitoring results. • Results showed that radioactivity accumulation due to NPP operation was trivial. • This study will be useful to establish environmental monitoring plan at other NPPs. - Abstract: The radiological environment around Wolsong NPP site has been monitored since Wolsong Unit 1 started commercial operation in 1983, as required by regulations in Korea. As a result of the periodic safety review on Wolsong Unit 3 & 4 in 2011, the regulator recommended that an assessment on the long-term accumulation trend of environmental radioactivity around Wolsong Unit 3 & 4 should be performed. In response to this, the assessment was performed based on environmental monitoring data and non-parametric statistical tool (i.e., Mann–Kendall Test). The environmental monitoring data included indicator organisms, soil and marine deposit which were usually monitored for verification of the typical radioactivity level. Most results of the assessment showed no trend and only a few results showed a slight increase. It was concluded that the radioactivity accumulation due to the operation of the plant was insignificant and thus no concern has been raised regarding any effect on the safety and health of the residents around Wolsong NPP site. It is expected that the result of this study could be utilized to establish the plan and policy for environmental monitoring at other NPP sites