Metrological Assurance for Radioactive Waste Monitors Based on HPGe Detectors

Abstract

The methods of calibration and parameters measurements of radioactive waste monitors with the purpose to provide the unity and required precision of the characterization of waste activity measurements are reviewed. The monitors based on HPGe detectors are intended for small, medium and large volumes of radioactive waste and are equipped with rotation mechanisms for the barrel with strain-gauge balance and actuator for horizontal shifting, dosimeters for dose rate measurement, software and accounting system by bar code.
 The required range of the measured activity which is necessary for the operation of the spectrometric section without overloadings is ensured by removal or approaching of the barrel to the detector and position change of the vertical lead shields of the collimator. The rotation of the barrel with RAW ensures decreasing the measurement error at the presence of the heterogeneities by density of the filler and inequalities of activity distribution by the barrel volume. The monitors have different mechanisms and accessories for the measurements in various modes.
 The calibration of the monitors by the registration efficiency is performed using standard sources in point geometry as well as by the complex calculation of the efficiencies curves by Monte Carlo simulation method. For calibration of the monitors by the method of direct comparison the volumetric activities sources in real 200, 400 and 700 l barrels with matrix-fillers placed inside were manufactured and certified. The manufactured volumetric measures of activity have been certificated at the All-Russian Research Institute of Metrology named after D. I. Mendeleev.
 An integral part of the metrological support of all developed RAWmonitors is their software, features of which are being considered.