Abstract: Radionuclides can accumulate in fly ash and slag in the process of coal burning at different levels and fall into the soil resulting in radioactive contamination. The sampling points were located within 1 km to the Qunli and Hulan coal-fired power plants, and each sampling point was divided into three layers of different depth: A layer for 0—10 cm, B layer for 10—20 cm, and C layer for 20—30 cm. The natural radionuclides in soil samples were measured by high-purity germanium gamma spectrometer, and the specific activities of ²³⁸U, ²³²Th, ²²⁶Ra and ⁴⁰K in the soil surrounding the coal-fired power plants were analyzed and compared with the measurement results of natural radionuclides in soils from the Heilongjiang province. Results showed that the long-term operation of the coal-fired power plants has increased the radiation levels, but it is still below the national standards.

Key words: coal-fired power plant, soil, radioactivity