Abstract: This article introduces the changes tothe Critical groups、Critical exposure pathway、Critical nuclide (Three Keys) in Yangjiang Nuclear Power Plant since its operation in May 2013, they are causedby the changes in ambient population, environment, as well as the actual discharge of radioactive effluent from Yangjiang nuclear power plant. Through the analysis of above factors, it aims to propose new ideas for the “Three Keys”, peripheral radiation environment and effluent supervision monitoring scheme, and forthe existing sampling and monitoring methods of Yangjiang Nuclear Power Plant.

Key words: Yangjiang NPP, Radioactive effluent, Three keys