A. S. Danilovich

Experience of Application of New Remote Controlled Instruments for Scanning of Distribution of Radioactive Contamination in Rooms With High Dose Rate

When carrying out the decommissioning of nuclear facilities is necessary to measure the distribution of radioactive contamination in the rooms and the equipment at high levels of background radiation. In the decommissioning of the reactor in the MR NRC “Kurchatov Institute” for such problems is developed and applied a few special systems with remote control. For a survey of high-level objects used mounted on the robot radiometric system. To determine the composition of pollutants and use a portable collimated spectrometric system. To obtain a detailed distribution of contamination of used remote-controlled gamma camera.Copyright

Visualization of Radioactive Sources Without Gamma-Radiation With UV Imaging Systems

New UV cameras are suitable for imaging of α-contamination by fluorescence of atmospheric air the near ultraviolet (wavelength — 280 – 390 nm) region. Their parameters are: FOV for detecting in UV spectral region is 8° × 6°. The optical FOV is about 48° × 36°. DayCor SUPERB UV camera has sensitivity 3×10−18 W/cm2 enables detection and displaying corona emission as weak as 1.5 pC at distance 8 m, and capture moving targets without smearing the output image. Instruments sensitivity for alpha contamination registration in terms of minimum measurable activities (MMA) have been estimated as, 40–100 Bq/cm2 (measurement time is 3600–600 sec correspondently).Copyright

Portable gamma camera with a rotated coded mask for the remote measurement of radioactivity at nuclear installation

New gamma imager - portable gamma camera with a rotated mask for the remote measurement of radioactivity in the reactor areas was developed. The constructions and main parameters of this instrument are described. The imaging with instrument is based on combined position sensitive detector: scintillating plate + fiber optic taper + image intensifier with 2 MCP + digital video camera with industrial CCD. Scintillating plate has useful diameter 38 mm and thickness 3 mm. As the aperture for gamma imaging is used rotated coded mask (hURA) of 9 ranks. Interesting feature of masks of type hURA consists that the mask turns to the contrast - an antimask at turn on 60°. Mask turn on 600 is carried out by the electromotor, established on the device case. Procedure a mask-antimask allows: 1) to lower influence of background radiation on the detector, 2) to eliminate influence imperfect of the mask having a finite thickness. The dimensions of detecting head are: length ∼50 cm and diameter ∼12 cm. A special portable computer with software package is used for control all gamma imager sub-systems by operator, for processing of gamma images, storage and displaying and for operation with images. The distance between detecting head and computer may be up to 50 meters.

The Simulation of Decontamination Works in Premises of the Research Reactor in NRC “Kurchatov Institute”

Application of remote sensing methods using a spectrometric collimated system allows obtaining information about features of a formation of radiation fields in contaminated premises. This information helps in a preparation of a phased plan for dismantling of contaminated equipment. When the survey of technological premises of the research reactor at the Russian Research Centre “Kurchatov institute” was conducted the remote controlled collimated spectrometric system was used [1]. With its help the scanning of surveyed premises were carried out. As a result of this work, the distribution pattern of radionuclides activity was restored. The simulation of decontamination works was carried out and maps of the distribution of activity and dose rate for surveyed premises were plotted and superimposed on its photo for situations before and after decontamination. The use of obtained results will allow significantly reduce radiation dose for staff at work on dismantling.Copyright

Remote Measurements of Radioactivity Distribution With BROKK Robotic System

Robotic system for the remote measurement of radioactivity in the reactor areas was developed. The BROKK robotic system replaces hand-held radiation measuring tools. The system consists of a collimated gamma detector, a standard gamma detector, color CCD video camera and searchlights, all mounted on a robotic platform (BROKK). The signals from the detectors are coupled with the video signals and are transferred to an operator’s console via a radio channel or a cable. Operator works at a safe position. The video image of the object with imposed exposure dose rate from the detectors generates an image on the monitor screen, and the images are recorded for subsequent analysis. Preliminary work has started for the decommissioning of a research reactor at the RRC «Kurchatov Institute». Results of the remote radioactivity measurements with new system during radiation inspection waste storage of this reactor are presented and discussed.Copyright