Search

A radiation survey of the reactor hall was conducted at the National Research Center Kurchatov Institute. It was found that the main radionuclide determining the wall contamination in the reactor hall is 137Cs. Its specific activity is >10 times higher than that of 90Sr. The depth of penetration into the walls of the reactor hall is equal to 5–6 mm. In terms of height, the radioactive contamination of the walls of the reactor hall is localized mainly in the lower portion of the walls up to 1 m. No relation was found between the removed surface contamination and the activity of the corresponding thin surface layer of the wall. It is shown that the initial decontamination of the walls of the reactor hall can lessen their radioactive contamination by a factor of 1.5–2. [ABSTRACT FROM AUTHOR]

At the National Research Center Kurchatov Institute, disassembly work is being done on research reactors and work on the disassembly of reactors' technological systems located in buildings neighboring the central reactor hall is being planned. Radiation inspection of the room housing the water treatment system and the ventilation pipe is being done to optimize disassembly. The wastewater treatment system includes six metal compartments, arranged around the base of the ventilation pipe, and two monte-jus. Four radiation inspection openings were drilled in the top cover of the room housing the water treatment system and the wall of the ventilation pipe. A video survey of the rooms was done through these openings and the exposure dose rate and activity of the primary radionuclides over the height of the rooms and inside the ventilation pipe was measured. The results were used to optimize the disassembly of the equipment and to evaluate the amount of radioactive waste. [ABSTRACT FROM AUTHOR]

The MR multicircuit research reactor is being dismantled at the National Research Center Kurchatov Institute. During the disassembly process, the experimental circuits and working channels were moved from the reactor's swimming pool into the storage pool. A spectrometric study of the bottom slag and deposits on the walls of the reactor's swimming and storage pools was conducted. The complex α-, β-, and γ-spectrometric studies showed that the specific activity of the bottom slag and deposits on the walls of the MR pools is significantly higher than that of the water. In terms of these activity values, the slag and wall deposits can be classed as high-level wastes. [ABSTRACT FROM AUTHOR]

The MR multiloop research reactor is now being disassembled at the National Research Center Kurchatov Institute. A complex α-, β- and γ-spectrometric investigation of the water in the reactor's pool and fuel-storage pool has been conducted. It was found that the main dose-forming radionuclide is Cs. U, U, U, U, Pu, Pu, and Pu have been found in the pool water, which indicates that the fuel matrix is present in its components. A reduction of the water level in the pool by 1 m increases the equivalent dose rate at a distance of 1 m from the edge of the pool by a factor of 2, which can be explained by the contribution of Cs settled on the wall of the storage pool. The efficiency with which the walls of the MR reactor's storage pool are cleaned by a high-pressure jet of water and by mechanical means was investigated. The mechanical method of removing the deposits from the pool walls is most effective. [ABSTRACT FROM AUTHOR]