Harmonization of individual dosimetry quality control within metrology system of a small country

Influence of solar activity on ambient dose equivalent H*(10) measured with thermoluminescent dosimeters in Slovenia

Ambient dose equivalent H*(10) is measured to assess general population exposure to ionising radiation. From its spatial and time variations it is possible to identify sources of exposure. In Slovenia, semi-annual H*(10) is measured routinely with thermoluminescence dosimeters at 66 locations around the Nuclear Power Plant (NPP) Krško and at 50 other locations covering the rest of Slovenian territory. Since the Chernobyl accident contamination had ceased to contribute to ambient dose equivalents, we have been calculating correlation coefficients between annual mean number of sunspots and annual H*(10). These correlation coefficients were calculated for five locations in western Slovenia and for five annual H*(10) extracted from measurements around NPP Krško. Their ranges between -0.64 and -0.38 suggest a clear negative correlation between solar activity and H*(10). Mean annual H*(10) averted by solar activity in the past two solar maxima reached 0.070 mSv around NPP Krško (155 m.a.s.l.) and 0.132 mSv and 0.180 mSv at Kredarica (2515 m.a.s.l.). Quantifying the influence of the solar activity on the ambient dose equivalent helps us to better understand exposure of the general population to ionising radiation.

A Transnational Intercomparison of Environmental Dosemeters in Realistic Environmental Conditions

Environmental dosemeters were benchmarked against various dosimetry systems in realistic environmental conditions. For the first time, the dosemeters, provided by two institutions from two different countries, were deployed at 20 sites in Slovenia and Croatia (near the Nuclear Power Plant, NPP Krško, Slovenia) during two semi-annual periods: summer-autumn and winter-spring. The results obtained using the different dosimetry systems show interesting features concerning local environmental peculiarities. The results of the intercomparison demonstrate an excellent agreement of the ambient doses measured independently by two different institutions and three passive dosimetry systems. Such consistency is crucial for the environmental dosimetry.