Radiation Safety And Regime
The Department of Radiation Safety and Regime (DRSR) is an independent structural unit of Polesye State Radiation-Ecological Reserve performing full scope of activities on radiation control during works in the zones of radioactive contamination. It aims to secure safe working conditions for the employees, operating on contaminated territories, as well as to execute measures on preventing transfer of radionuclides outside the reserve territories.
The Department of Radiation Safety and Regime includes the sector of individual radiation monitoring of external and internal exposure doses, and the sector of radiation monitoring of environmental objects.
The DRSR is headed by the department manager and counts 17 employees; 10 of them are working in Khoiniki district, 5 – in Bragin district and 2 – in Narovlya district.
Main responsibilities of the Department of Radiation Safety and Regime:
• monitoring of the radiation factors, influencing internal and external exposure load, which are: control of gamma dose rate, flux density of beta particles and content of radioactive caesium in human body;
• evaluation of radionuclides concentration in the water systems of Polesye State Radiation-Ecological Reserve;
• dosimetric support of works performed by the employees of the reserve on the territory with the dose rate of over 11.7 mcSv/h;
• organization and execution of transportation contamination control and control of freights, exported from the contaminated area at the checkpoints on the perimeter of the reserve;
• monitoring of decontamination quality of special equipment, work wear and transportation at the decontamination stations in Babchyn, Savichi, Konotop;
• systematic control of radiation environment at workplaces, in the facilities and on the premises of the objects, located on the territory of radioactive contamination, sanitary-protective zone and observation zone, and also control of radioactive waste disposal;
• annual radiation safety examination of heads of departments and staff;
• conduct of regime activities aimed at registration of visits by employees of exterior organizations, co-ordination of transport itineraries of persons on business trips, check-up of permits of exterior organizations’ employees arriving to work in the exclusion zone, control of the reserve’s mode of operation, etc..
External exposure of the personnel
Major radionuclides contributing to external exposure dose on the reserve territory are Cs-137, the dose forming contribution of which is about 90%, and Sr-90. Monitoring of individual external exposure doses is carried out using thermoluminescent dosimeters (TLD). In 2015 the volume of personnel monitoring in the reserve was 671 people.
Internal exposure of the personnel
Direct source of information on radionucliedes content and internal exposure of the population is permanent monitoring of γ-emitting radionuclides inside the body using human radiation spectrometers. This data is essential for decision making about conduct and effectivity of measures on personnel protection from ionizing radiation.
Major objectives of intravital incorporate activity monitoring inside the human body are the following:
- case detection of radioactive substances uptake above average age values in certain citizens for the purpose of excessive uptake source detection and taking specific measures on exposure reduction;
- forecasting and study of medical consequences of internal exposure of workers and other employees on the reserve territory;
- securing the rights of workers and other employees for obtaining timely and accurate information on internal exposure doses;
-forecasting internal exposure limits for the personnel of the reserve.
Radiation monitoring of environmental objects
Within the scope of works performed by the DRSR, radiation monitoring includes:
- record of the personnel actual work time on radionuclide contaminated territory;
- monitoring of area and objects at work grounds, including gamma dose rate and flux density of alpha and beta particles;
- work wear and footwear contamination with alpha- and beta- emitting radionuclides monitoring among the personnel working in the zone of radioactive contamination;
- monitoring of alpha- and beta-emitting radionuclides in administrative, manufacturing buildings, warehouses, located in the zone of radioactive contamination; monitoring of gamma radiation at the objects;
- monitoring of alpha- and beta-emitting radionuclides in transportation and freight exported from the territory of radioactive contamination;
- control of decontamination efficiency of work wear, machine and tractor fleet at decontamination stations (DS “Babchyn”, DS “Konotop”, DS “Savichy”).
Radiation monitoring at reference points
Aiming to evaluate changes in radiation environment in the reserve, in 1997 8 reference sites were set near former settlements and in settlements adjacent to the reserve territory. The reference sites’ layout was designed in order to embrace the territories with different contamination densities.
The reference sites could be divided into 3 groups by gamma dose rate at the altitude of 1 meter: group 1 – up to 1mcSv/h ( “Babchyn”, “Novoselki”, “Savichy”); group 2 – 1-5 mcSv/h (“Pogonnoe”, “Masany”, “Orevichy”, “Kulazhyn”); group 3 – over 5 mcSv/h (“Kruki”).
Maximum values of gamma-radiation (up to 9.28 mcSv/h) are observed in Kruki.