Assessment of the Influence of the Underlying Surface Composition on the Results of Aerial Radiation Reconnaissance

The influence of the composition of the underlying surface on the results of aerial radiation reconnaissance of contaminated areas is considered. The analysis of the probability of the presence of various compositions of the underlying surfaces in Russia. The values of the exposure dose rate over the contaminated area were calculated depending on the height and type of the underlying surface using a specialized software package for mathematical simulation of gamma radiation transport and registration processes for the design of spectrometric systems for aviation radiation control.

COMPARISON OF THE RADIATION SITUATION IN THE AGRICULTURAL AND OIL REGIONS OF THE ATYRAU REGION

The article is devoted to the comparison of radiation levels in the Issatay and Makhambet districts of the Atyrau region. Atyrau region belongs to the regions of the oil-producing industry, which in turn can lead to environmental pollution, including radiation. Therefore, a radiation analysis was carried out to measure the exposure dose on the territory of the Isatai region, in which the oil-producing industry is developed, and for comparative analysis, the same measurements were carried out in the Makhambet region, where there is no industrial activity and the region belongs to an agricultural region. The studies carried out show that, according to the average values of the exposure dose in both regions, it is in close values, which range from 9 to more than 14 mR/h in the industrial region (Issatay region) and from 10 to 11 mR/h in the agricultural region (Makhambet region). In the Issatay district, according to the average values, there is a slight increased content. The data on the exposure dose rate at the entrance to the village and in the center of the village show that in the Makhambet district, the exposure dose data is higher in the center of the village than at the entrance to the village, while in the Isatai district the indicators at the entrance to the villages are, on the contrary, higher. In the Issatay region, within the villages, the data are similar to the Makhambet region, and outside the settlements, there is a slight increase associated with the additional load from oil pollution. The data on the level of measurement height show that at the level of the earth's surface and at the level of 50 cm, the values of the exposure dose are close in the values of the two regions, while there is a difference at the level of 1 m. In the Issatay region, the exposure dose is higher than in the Makhambet region, this may be due to the relatively greater accumulation of gaseous radioisotopes that accumulate as a result of evaporation from oil fields. The background radiation in both regions does not exceed the maximum permissible dose and is not hazardous to health.

Influence of Chronic Ionizing Radiation on the Variability of Mitotic Activity of Pinus sylvestris L. Tissues

The development of nuclear power engineering will increase in the future, due to the continued likelihood of radionuclides entering the environment. The relevance of studying the genetic material of conifers as a reliable bioindicator was revealed. It is known that under the influence of ionizing radiation there is an accumulation of genetic abnormalities in pine (Pinus sylvestris L.) progeny. The stages of gametogenesis, zygotes and young seedlings of plant organisms are most sensitive to ionizing radiation. It is important to determine the variability of the mitotic index (MI) of tissues of Scots pine (Pinus sylvestris L.) progeny in areas with different levels of ionizing radiation, including in the exclusion zone. The exposure dose rate was measured at the soil level and 1 m from the ground surface. Germination of seeds was carried out in a thermostat on wet filter paper. Roots of seedlings 0.5–1 cm long were fixed in a mixture of 96 % ethanol and glacial acetic acid. Root staining was carried out in a solution of acetocarmine. Tissue softening was carried out with a strong chloral hydrate solution. The total number of dividing cells, as well as pathological mitoses (PM) were counted on squash preparations using a microscope. The mitotic index and the duration of the phases of mitosis were determined. An increase in the level of radioactive contamination increases the cell division rate in prophase, anaphase, and telophase, but decreases the duration of metaphase, and also changes the relative duration of mitosis phases. With an increase in the exposure dose rate, the number of pathological mitoses naturally increases. The spectrum of mitosis disorders is represented by various abnormalities of the chromosome apparatus in anaphase: exit and lagging of chromosomes, bridges. Herewith, the number of anaphases with bridges increases significantly with simultaneous exit and lagging of chromosomes.

RADIATION AND PROTECTIVE PROPERTIES OF CONTAINERS FOR NPPS’ SALT MELT CONDITIONING IN UKRAINE

Considering that the problem of liquid radioactive waste management of Ukrainian nuclear power plants with WWER reactors is still unresolved, it is noted that the current level of scientific achievements provides grounds for creating a technology for the salt melt (SM) disposal without its processing. Since the exposure dose rate (EDR) for barrels with SM can significantly exceed the value of 5 mSv/h, the radiation-protective properties of the hypothetical packaging for conditioning of the salt melt formed by placing radioactive waste (RW) in a reinforced concrete container and its immobilization are considered. Exposure dose rate simulation was performed using the PHITS software package (Japan). The calculations were performed for a packaging consisting of 4 barrels of SM, placed in a universal protective container UZZK. Variants with different radionuclide composition of the SM, due to the duration of exposure of the SM – from 100% 137Cs to 137Cs-65%, 134Cs-15%, 60Co-20%, are considered. The specific concentration of radionuclides was taken from 5E7 to 1E9 Bq/kg. There are also 2 options for filling the voids: the first option involves filling the voids with the conditioning product of the bottom residue in the form of alkaline cement with a saline content of 25%, while the second option does not include radioactive salts in alkaline cement. The calculations showed the acceptability of the proposed conditioning of the salt melt by forming a package of 4 KRO-200 containers, universal reinforced concrete container UZZK TU U 29.2-26444970-005 and filling voids with the product of conditioning of the bottom residue in the form of alkaline cement with salinity -protective properties. A necessary condition for the implementation of practical measures for the conditioning of the salt melt accumulated in WWER reactors, followed by transfer to landfills is the corresponding changes in OSPU-2005 in terms of classification of the SM and its classification as solid radwaste.

Effect of Extensive Use of Granite Countertops on the γ-Radiation Dose to Occupants of the New Buildings of King Abdulaziz University

Exposure dose due to γ-radiation was measured in the new buildings of King Abdulaziz University using an advanced car-borne monitoring system to evaluate the effect of the extensive use of granites on the exposure dose rate to occupants. The measurements were conducted inside and outside the new buildings. For comparison, measurements inside the old buildings of limited granite use were conducted. The results indicated that the average exposure dose rate in the corridors of granite countertops was 0.115 μSv/h compared to 0.093 μSv/h in corridors of marble floors in the old buildings. About 4.2% increase in the annual effective dose due granite use was estimated. A maximum excess fatal cancer risk to an individual working in the new buildings due to exposure to excess γ-radiation from granite countertops was estimated by 1.4x10-6. The obtained results are discussed in detail and some conclusions are drawn.

Characterisation of MR Reactor Pond in NRC “Kurchatov Institute” Before Dismantling Work

In this work complex α-, β-, γ-spectrometric research of water, bottom slimes and deposits on walls of the reactor pond and the storage pond of the MR reactor was made. Identify, that the main dose forming radionuclide, during dismantling work on the reactor MR, is Cs-137. It is shown, that specific activity of radionuclides in bottom slimes considerably exceed specific activity of radionuclides in water from ponds, and near to high level radioactive waste. It is detected that decreasing the water level in reactor ponds on 1m, increase the exposure dose rate at a distance 1m from the pond in 2 times. The observed increase in exposure dose rate can be explained by contribution on dose rate the cesium-137 deposed on walls of the storage pond. Effectiveness of cleaning of walls of the pool of storage from deposits by a water jet of high pressure is investigated.