Speakers
Description
The automatic network of environmental radioactivity, REMRAD, managed by the National Inspectorate for Nuclear Safety and Radiation Protection (ISIN), consists of highly sensitive radiological monitoring stations through automatic sampling and spectrometric analysis systems of atmospheric particulate matter, deposited on a large filter splitted into 15 separate circular areas where the same particulate matter is collected; the monitoring stations are able to detect in “almost real time” the minimal radiometric anomalies present in the air. The extremely high detection sensitivity of the REMRAD stations is guaranteed both by the high sampling rate, up to 500 m3/h, and by the measurement configuration adopted. The stations are equipped with both an "early alarm" system, based on a LaBr3(Ce) spectrometric detection system placed in an orthogonal position with respect to the sampled filter, patented by ISIN, and which guarantees measurement sensitivity below 10 mBq/m3 on Cs-137, and a BeGe "Broad Energy Germanium" detector type, which operates in delayed mode on the same filter, guaranteeing sensitivity below 10 µBq/m3, always with reference to the Cs-137 radionuclide. The technological advancement of these monitoring stations mainly lies in the "early alarm" which allows the quantitative definition of any radioactive contamination in the air thanks to the use of the proprietary patent which allows the calculation of the absolute detection efficiency using the Monte Carlo calculation code, which is used for modelling the LaBr3(Ce) scintillation based radiation detector and a structure containing the absolute glass fibre filter. The absolute efficiency curve is functional with respect to the LaBr3(Ce) scintillation based radiation detector, component of the high volume airborne particulate sampling system, as it permits the “quantification” of the radionuclides in terms of radiological activity deposited in the 15 circular areas of the glass fibre filter, and the subsequent determination of the airborne radioactive concentration. The absolute efficiency curve is calculated with respect to the particulate deposited in the 15 circular areas of the filter system. Each of the 15 circular areas of the glass fibre filter contributes with its own specific probability of particulate deposition to the computation of the absolute efficiency curve.
A customized management software integrates this powerful algorithm and allows multiple authorized recipients to receive prompt SMS and email in case of alarm or malfunctions.
Indeed, these stations can function without operator intervention for up to a month thanks to a software that manages all the hardware devices automatically performing the spectra acquisitions, quantitative analysis and saving measurements in a proper database. The energy calibration of the "On line" detector is constantly checked and updated while Quality Assurance is automatically performed every filter change on the Germanium detector by measuring a source installed on the robot. A Control Center Software allows authorized users to manage remotely a network of up to 36 stations. Main features are: Area surveillance via webcam, system parameters and thresholds setup, real-time display of the measurements status in progress, display of the latest measurement data including weather parameters, query the historical measurements archive with visualization of trend graphs.
