Abstract: As stipulated in China's national standard, measuring items lower than the detection limit in effluent radioactive emission statistics should be submitted to experimental analysis for reasonable estimation. To those truly unable to be estimated, use 1/2 of the detection limit value for emission statistics. Existing running NPPs abide by the standard all. Regarding the low-level radionuclide estimation, the state's nuclear and radiation relevant departments have organized NPPs for specific experimental studies to bring down detection limit. Experimental results show. When the detection limit is down to 1/20—1/2 of conventional limit, radionuclides not detected conventionally is still not detected; detection rate of a small amount of low level radionuclides detected in routine monitoring increases lightly. The detection values were slightly higher than the detection limit.

Key words: nuclear power plant, effluent, low level radionuclide, emissions statistics, experiment