T01_P13

Source Term Analysis and Experimental Measurement Design of Carbon-14 in High-Temperature Gas-Cooled Reactor Pebble-Bed Module

Wang Y¹,  Guo J¹, Cao J¹, Xie F¹, Tong J¹, Dong Y¹, Zhang Z¹

¹Tsinghua University, Beijing, China

As carbon-14 (¹⁴C) plays an important role in the public radiation dose, increasing attention has been paid to the environmental impact assessment of nuclear power plants. Based on the experience and technology of the 10 MW high temperature gas-cooled reactor (HTR-10) and Arbeitsgemeinschaft Versuchsreaktor (AVR), the high-temperature gas-cooled reactor pebble-bed module (HTR-PM) has been designed and is currently under construction in China. In this article, the source terms of ¹⁴C in the reactor core and primary loop of HTR-PM are presented along with a complete theoretical model. The production mechanism, distribution characteristics, reduction route, and release type of ¹⁴C are illustrated. The average activity amount of ¹⁴C per year in the core of HTR-PM was computed as 2.22 × 10¹²Bq, and the activity concentration of ¹⁴C in the primary loop at operating equilibrium was calculated as 2.51 × 10⁴ Bq/m³ (STP). The calculation results indicated the dominant source of ¹⁴C in both the reactor core and the primary coolant is the activation reaction of ¹⁴N in the fuel elements. The ¹⁴C sampling system in the helium purification system (HPS) of HTR-PM has been designed and illustrated, which can generate reliable activity concentration values of ¹⁴C in the primary loop.