Geochemistry of Technogenesis

TOXICOLOGICAL STUDY OF MOSS COVER IN PINE FORESTS OF BIOGEOCHEMICAL LANDSCAPE IN BACKGROUND AREA OF UKRAINIAN POLISSIA. PART 2. RADIONUCLIDES – 137CS

O.O. Orlov — 2024-09-13

Tasks of this study – to evaluate interspecific differences of 137Cs accumulation by mosses; analyze 137Cs distribution among fractions of mosses; monitor multiyear dynamics of 137Cs content and values of 137Cs concentration ratio in mosses in 2002–2022; calculate dependence between 137Cs activity concentration in Dicranum polysetum and in the soil on the basis of statistical systematical approach; identify spatial heterogeneity of 137Cs activity concentration in moss cover and in the soil and to evaluate it quantitative using fractal geometry. Study was conducted in two stages: in 2002 and 2022 at 3 experimental plots in Zhytomyr Region, Korosten district, Povchanske forest division of Вranch “Lugyny Forestry” of State Enterprise “Forests of Ukraine”. Vegetation was presented by pine forest of association Molinio-Pinetum Matuszkiewicz (1973) 1981, by fairly infertile pine site type (В3). Mosses were sampled by fractions: increment of the 1st year, increment of the 2nd year, increments of earlier period and peat litter. The activity concentration of 137Cs was measured using SEG-001 AKP-С-150 spectrometer analyzer with scintillation detector BDEG-20-R2. Coefficient of biological absorption (СВА) was used as an index of intensity of accumulation of 137Cs in the chain “soil – moss”. In 2002 according with the mean 137Cs content in the increment of the 1st year (increments of 1–2 years) moss species can be placed in such order: Leucobryum glaucum > Dicranum polysetum > Polytrichum commune > Sphagnum palustre > S. capillifolium > Pleurozium schreberi, with interspecies differences of this index in 2,2 times. In 2002 and 2022 distribution of 137Cs activity concentration among fractions of moss species was similar: maximum values of 137Cs activity concentration were in alive, apical parts – increment of the 1st year and increments both the 1st and the 2nd years. Below this part a decrease of this index was observed in increment of the 2nd year and increments of the earlier period and peat litter. In all moss species in 2002-2022 137Cs content significantly decreased – from 2,46 times in Dicranum polysetum to 2 times in Sphagnum capillifolium. Despite a significant decrease of 137Cs activity concentration in fractions of all studied moss species mean values of СВА in 2022 decreased slightly in comparison with those of 2002. In 2022 according with the mean values of СВА moss species can be placed as follows: Leucobryum glaucum (7,42 ± 0,49) > Polytrichum commune (6,72 ± 0,45) > Sphagnum palustre (6,15 ± 0,54) > Dicranum polysetum (6,11 ± 0,43) > S. capillifolium (5,99 ± 0,56) > Pleurozium schreberi (2,97 ± 0,18). Dependence of 137Cs activity concentration in the soil from 137Cs activity concentration in Dicranum polysetum was linear, close (r = 0,76) and reliable (p = 0,000). Spatial heterogeneity of 137Cs contamination of moss cover and soil was high and had a focal character. Decreasing of mean value of 137Cs activity concentration in moss cover and in the soil depending on the grid step is a confirmation of its fractal distribution. We proposed to replace full sampling matrix by Viсsek fractal matrix, with sampling only on central column and central line or on the main diagonals of full matrix, which allows to reduce total number of samples in 5 times, with relative differences of mean values of 137Cs activity concentration in moss and soil in comparison with full matrix less than ±10%.

STATE AND PROSPECTS OF THE IRON ORE INDUSTRY OF UKRAINE

V.H. Hubina — 2024-09-13

The article analyzes the current state and prospects of development of the iron ore industry in Ukraine. The author shows Ukraine's place in the world rankings in terms of iron ore reserves and exports. The state of the existing iron ore mining and processing enterprises is highlighted. According to special permits for the use of subsoil, the balance reserves and production volumes of rich iron ores of enterprises that develop deposits by underground mining and reserves of ferruginous magnetite quartzite, which are mined by open-pit mining and enriched at ore processing plants with further production of iron ore concentrate/pellets, are presented. It is shown that the depth of working horizons in quarries is currently 280–420 m, and working horizons in mines are 1200–1300 m. At the same time, the balance reserves are estimated to a depth of 500–600 meters in the design contours of quarries and up to 1800-1900 meters in deposits in the fields of operating mines, as well as reserves with uncertain commercial value outside the design contours of quarries and in intermine targets in the fields of mines. The problems of iron ore mining and beneficiation at the present stage are highlighted. It is shown that Ukraine has all the prerequisites for further development of the iron ore industry, namely developed infrastructure in the areas where existing enterprises are located; availability of balance reserves of iron ore raw materials at deposits and intermine areas of existing mining enterprises, the possibility of industrial development of small iron ore deposits, involvement of oxidized quartzite in the fields of existing mines and quarries and magnetite quartzite in the fields of existing mines; availability of ready-made technological solutions for mining and lifting iron ore from horizons below 2000 m in mines, transition to underground and open-pit mining of mineral deposits; technological solutions for improving the quality of magnetite concentrate and producing hematite concentrate.

USE OF ALKALINE COMPOUNDS RADIOACTIVE WASTE AS GEOPOLYMER HARDENING ACTIVATORS IN BORON-BEARING STILL RESIDUES CONDITIONING

Yu.H. Fedorenko — 2024-09-13

Cementation of waste, including liquid radioactive waste (LRW), in a mineral matrix is considered an efficient method of waste conditioning for further waste disposal in near-surface storage facilities. Portland cement is widely used as a cementing binder. Though, when waste contains a significant amount of salts, especially borates, the quality of cementation decreases. The option is cementation of waste into geopolymer matrices that are characterized by increased chemical resistance, can strengthen with time, and are more cost-effective. The geopolymer formation process combines two stages – preliminary destruction of the materials (mechanical, chemical, thermal) and creation of conditions for hardening of the obtained materials. The latter is achieved when the materials are combined with alkalis (NaOH, KOH, Na2SiO3, etc.). In an alkaline environment, a geopolymer matrix which contains waste is formed. After evaporation of water, the concentration of alkalis in the still residue waste from nuclear power plants with VVER reactors reaches such levels that the residues themselves can in some cases form geopolymers, the chemical composition and hardening conditions of which are prepared in advance. Thus, the boron-bearing LRW conditioning with alkalis contained in the waste and the conditions under which this process may take place is considered. During the study of compounds based on granulated blast furnace slag from the Mariupol Metallurgical Plant, the hardening of which was carried out with alkalis of imitation boron-bearing LRW, it was found that it is possible to obtain compounds with a compressive strength of about 10 MPa. Further study of the normalized indicators of the obtained compounds can determine the possible perspective of this method of conditioning.

ON THE STRUCTURIZATION OF TECHNOGENICAL FORMATIONS WITHIN THE LIMITS OF THE “PIVNICHNYI” AND “PIVDENNYI” IRON ORE QUARRY’S (KRYVIY RIH CITY)

L.S. Osmachko — 2024-09-13

The research was conducted within the “Pivnichnyi” and “Pivdennyi” iron ore quarries in the city of Kryvyi Rih with the aim of more effective further use of the technogenically transformed areas of the subsoil and the earth’s surface of Kryvbas. The fixation of bedding elements in relatively undisturbed, small-sized blocks (hereinafter – “blocks” or “surviving block”) of quartzites and shales of the saksagan suite and in blocks of demarcation of surviving block – technogenic accumulations was carried out. In relatively undisturbed blocks of quartzite, such elements for banding, schistosity, linearity of mineral aggregates, axes of folded forms, striation, furrows, etc. were measured. Among technogenic accumulations (scree slope, embankments and filled artificial cavities), according to the degree of structuring, unstructured and structured to varying degrees were observed. Layering, mechanical schistosity and linearity are fixed within them. Formation of the system of blocks of the “Pivnichnyi” and “Pivdennyi” quarry’s was carried out by displacement along the vertical and horizontal axes. The emergence of newly formed planes of technogenic accumulations took place with the inheritance of the structural anisotropy existing in the surviving block with the creation of its own stratification. Therefore, the investigated system “surviving block – technogenic accumulations” developed and formed as a complete object, mutually coordinated, years – decades in surface conditions. The transformation of technogenic accumulations, their “completion”/structuring, as a result of which the integrity of disturbed and missing areas of the geological volume is restored, are constructive phenomena. They are practically a natural laboratory of processes of formation of structural and textural elements in loose accumulations. Their tracking in time would make it possible to actually observe the processes of self-creation/reproduction of modern technogenic-natural objects. The ranking of structural neo formations in technogenic accumulations can be used as one of the criteria for assessment the assimilation potential of these accumulations and their suitability for economic reclaim.

PREDICTION OF LONG-TERM NEGATIVE IMPACTS OF URANIUM PRODUCTION LEGACY SITES ON THE HYDROGEOLOGICAL ENVIRONMENT

B.Yu. Zanoz — 2025-03-12

Using the IAEA ISAM (International Safety Assessment Methodology) methodology, information on the habits of the local population and statistical data on food consumption, dose coefficients for uranium-238 radionuclides were calculated for several scenarios of use of groundwater and surface water by the local population in the zone of influence of the uranium production legacy site - Prydniprovsky Chemical Plant, Kamianske City (PChP). These scenarios consider the following exposure pathways: drinking water consumption, crop irrigation, fishing and use of the river beach for recreation. Dose calculations were made with NORMALYSA software with use of mathematical models and radioecological parameters recommended by the IAEA. The dose coefficients obtained as a result of the modelling (which have the dimension of (Sv year)/(Bq m3)) allow calculating radiation doses by scaling them with actual radionuclide concentrations measured in groundwater and surface waters during monitoring or determined by modelling of of radionuclide transport processes in groundwater. The described approach to dose calculation can be applied for assessment of uranium legasy sites located in similar anthropogenic conditions. The described methodology was used to substantiate remediation measures that involve isolation of radioactively contaminated soils located at the PChP Northern Industrial Site using protective soil screens. According to the IAEA recommendations, an annual effective dose of 1 mSv/year was used as a radiological safety criterion for “existing exposure situations”. According to the results of predictive modelling, isolation and storage of contaminated soils within the PChP Northern Industrial Site does not pose unacceptable risks of radioactive contamination of groundwater.

FORMATION OF TECHNOGENICALLY LOADED ENVIRONMENT IN COAL-MINING REGIONS

N.V. Vergelska — 2025-03-12

The formation of a technologically loaded environment in coal mining regions consists of two interrelated processes, which include the disturbance of the upper lithosphere by mine workings and the exposure of sedimentary rocks to the surface. Changes in the geological environment under the influence of coal mining operations are of a geological phenomenon scale both in mine workings and coal spoil heaps. Coal-mining regions have fundamental, mostly irreversible changes in the upper layer of the lithosphere, creating new structures. As a result of more than two hundred years of coal mining operations, significant masses of rocks and coal extracted from the depths have been brought to the surface and have caused the formation of new geological and technogenic structures, which have accelerated downward movements and increased subsidence of the near-surface strata and their deformation, as recorded by engineering geological and topographic observations. Given the requirements of the regulatory documents in force in the field of subsoil use: The Law of Ukraine “On Environmental Protection” and the Subsoil Code of Ukraine, the study of the formation of a technogenically loaded environment in coal mining regions is relevant. In most cases, when determining the impact of coal mining enterprises on the environment of a region, the rocks exposed to the surface are considered first and foremost. Despite this, geological processes in waste heaps remain poorly understood. The newly formed natural-man-made and man-made horizons (sections) are included in endogenous and exogenous processes at the planetary level. The geological process of structure formation has undergone significant changes due to mining operations that have an impact on the depth of up to 2000 m. The processes occurring in the natural and anthropogenic horizons of the coal-bearing massifs complement and to some extent change the course of previous geological processes, but so far their environmental impact has not been recorded. Despite this, it is the processes activated by coal mining in the upper horizons of the lithosphere that are crucial for the formation of a technologically loaded environment and have no less negative impact on the environment than waste heaps.

CONCERNING SOME ISSUES OF SMALL MODULAR REACTORS (SMR) IMPLEMENTATION IN UKRAINE

B.H. Shabalin — 2025-03-17

Abstract. The interest to low-power reactors (SMRs) is growing in many countries. SMR developers consider their application quite promising from many points of view. The growing demand for energy security and low-carbon energy in the context of the climate changes approaches the reality of SMR application. Being composed of separate modules and factory-constructed, SMRs show the promise of significant cost reduction. SMRs can also be used for heat providing for industrial processes, hydrogen production and water desalination. In this regard, balanced and objective information on advances in SMR design and technology development trends is needed by all countries considering application of SMRs. More than seventy SMR projects are under development worldwide. Various types of SMRs are being developed: water cooled, high temperature gas cooled, fast neutron, molten salt and microreactors. The majority of SMRs are in the early stages of design. SMR concepts based on the pressurized water-water reactor technology are in the late stage of design and on the highest levels of technological readiness for deployment. The prospects for the development of water-water SMR technologies have been analyzed based on the published data. The analysis included NuScale (iPWR), SMR-160, Westinghouse SMR, UK SMR advantages and disadvantages, conceptual approaches, characteristics of SF and RW generated during operation and decommissioning, and the existing regulatory documents regarding the selection of sites and disposal of the radioactive waste. Evaluating the prospects for the application of SMR technologies in Ukraine, priority should be given to the water-water projects.