Monitoring of gross α and gross β radioactivity levels in the sediment around Tianwan Nuclear Power plant, 2008-2015

Objective To investigate the gross α and gross β radioactivity levels in the sediment around Tianwan Nuclear Power Plant and compare them with the levels in the control area, and to provide data support for the monitoring network of gross α and gross β radioactivity levels around Tianwan Nuclear Power Plant.

Methods According to the requirements of the Technical Criteria for Radiation Environment Monitoring (HJ/T 61-2001), sediment monitoring points and control monitoring points were set at 30 and 300 km away from the Tianwan Nuclear Power Plant, respectively. Samples were collected once every quarter at each monitoring site. From 2008 to 2015, 32 sediment samples were collected from the Tianwan Nuclear Power Plant area and control area, respectively. Gross α and gross β radioactivity levels in the sediment were determinated according to the Standard Examination Methods for Drinking Water-Radiological Parameters (GB/T 5750.13-2006).

Results From 2008 to 2015, the gross α radioactivity levels of total 64 sediment samples from the Tianwan Nuclear Power Plant area and control area were (1.10-7.19)Bq/m² and (1.20-8.24)Bq/m², respectively; there was no significant difference between different areas (t=0.42, P>0.05); the gross β radioactivity levels of total 64 sediment samples from the Tianwan Nuclear Power Plant area and control area were (1.14-24.2)Bq/m² and (2.66-22.3)Bq/m², respectively, and there was no significant difference between different areas (t=0.52, P>0.05). The total of the gross α and gross β radioactivity levels in the sediment samples had a significant difference among different years (F=3.62 and F=3.18, respectively, P < 0.01), and there was no significant difference between different quarters (F=1.30 and F=0.04, respectively, P>0.05).

Conclusion Since the operation of Tianwan Nuclear Power Plant, the gross α and gross β radioactivity levels in the sediment in its surrounding environment have not increased and are comparable to the levels in the control area. It is necessary to continue monitoring the radioactivity of environmental sediment in the future.