Radiological Survey of Schools and Kindergardens in Snezhinsk

Purpose: Radiological survey in schools and kindergardens of Snezhinsk, Chelyabinsk region. Material and methods: Total 209 public premises on the ground floor and basements were examined. Ambient dose equivalent power measurements were performed by DKG-02U ARBITER. SSNTDs were used to measure annual indoor radon concentrations during the warm and cold seasons. Results: Indoor gamma dose rate varies within the range 0.10–0.21 μSv/h. Annual equilibrium equivalent concentration of radon (EECRn) varies over a wide range up to 590 Bq/m3, exceeding 100 Bq/m3 in 10 % of surveyed premises. Average annual values of equivalent equilibrium concentration are about 30 Bq/m3 and characterize the radon situation as generally acceptable. The difference in the values of the EECRn in brick buildings and buildings made of reinforced concrete panels has been revealed. The average annual EECRn values reach 590 Bq/m3 in brick buildings, and 360 Bq/m3 in buildings made of reinforced concrete panels, with average values of 32 and 18 Bq/m3, respectively. Sealing brick and reinforced concrete buildings by installing plastic double-glazed windows enhances these differences. Conclusions: The survey revealed a critical group of buildings with enhanced indoor radon. Old brick buildings (1950‒1970) with unventilated basements and installed plastic double-glazed windows are characterized by the highest indoor radon concentration in public premises. These type of buildings require in-depth radon research and planning of radon protection measures if necessary.