The CdZnTe Detector with Slit Collimator for Measure Distribution of the Specific Activity Radionuclide in the Ground

Abstract

-From 2011 in the NRC "Kurchatov Institute" carry out the dismantling of the MR multiloop research reactor. Now the reactor and all technological equipment in the premises of the reactor were dismantled. Now the measurements of radioactive contamination in the reactor premises are made. The most contaminated parts of premises -floor and the ground beneath it. To measure the distribution of specific activity in the ground the CdZnTe detector (volume 500мм3) was used. Detector placed in a lead shielding with a slit collimation hole. The upper part of shielding is made movable to close and open the slit of the collimator. At each point two measurements carried out: with open and closed collimator. The software for determination specific activity of radionuclides in ground was developed. The mathematical model of spectrometric system based on the Monte-Carlo method. Measurements of specific activity of ground were made. Using the results of measurements the thickness of the removed layer of ground and the amount of radioactive waste were calculated.

Radiation and Video Survey of Water Cleanup and Ventilation System of RFT Reactor

“…The highest values of gamma dose rate around the nozzle. The measurement of the distribution of surface activity inside the vent stack by height was carried out using a collimated CdZnTe detector (Vc=500mm 3 ) with an annular collimator [6] (Fig. 7) The increase dose rate at the approach to the bottom of the vent stack (nozzles) and the uneven distribution of surface activity values along the vent stack height can be explained by the fact that the main contribution to the readings of the devices does not give a contaminated vent stack surface, but a rusty construction inside the vent stack and nozzles.…”