Radiation Monitoring of the Novi Han Radioactive Waste Repository, Bulgaria (2003 - 2004): Determination of Tritium and Radium-226 in Water Samples using Liquid Scintillation Spectrometry

Data for the specific activity of 3H and 226Ra in natural water obtained through liquid scintillation spectrometry in 2003-2004 in the implementation of the Program for Radiation Monitoring of NHRWR is presented. At the comparatively stable flow rate of ground waters in the area of the site it has been established that the specific activity of Tritium varies within a wide range. The maximum recorded values are several times lower than the regulatory boundary concentration for Tritium in drinking water (20 kBq.l-1) established by BRPS-2000. The values for permanent water sources in the area under surveillance are correspondingly by three orders lower than the listed value. The specific activity of 226 Ra in water samples has been determined through analysis of the daughter 222Rn. The values obtained are comparable with the results for drinking water from the Sofia city water supply system. The obtained results for water samples from control points of the NHRWR permanent monitoring network show that there is no Tritium and Radium-226 in the repository environment in concentrations exceeding the regulatory limits. (authors)