Siberian Chemical Combine Research Articles

Radioecological State of the Agrosphere in the 30-km Zone of the Siberian Chemical Combine During the Pre-Startup Period of a Prototype Power Complex

The results of radioecological monitoring of agricultural activities within the 30-km impact zone of the Siberian Chemical Combine are examined. The surface activity of 137Cs in soil and the specific activity of 137Cs in plants with similar indicators characteristic for NPP sites are analyzed and compared. The obtained data make it possible to evaluate the impact of a prototype electric power complex (PEPC) on the soil-and-vegetation cover and the products of agricultural activity, since the data make it possible to differentiate information on two basic parts – that associated with the activity of the Combine, on the one hand, and the other with the possible contribution of PEPC, on the other.

EXPANSION OF CYTOGENETICALLY MODIFIED FORM OF OPISTHORCHIS FELINEUS IN THE TOM RIVER BASIN

In 1993, karyotyping of Opisthorchis felineus sporocysts, isolated from aquatic mollusks Bithynia inflat a in the industrial wastewater of the Siberian Chemical Combine discovered cytogenetically modified 12-chromosome specimens. In 2012-2013, a repeated study of the spread of these mutant trematodes in the lower course of the river Tom was carried out. It was established that specimens with sporocysts of O. felineus having 2n=12 were found in 8 of 10 places of catching. The caught goldfish were used to isolate metacercariae to infest golden hamsters in the experimental conditions. After 5 months, the hamster livers were processed to extract marita specimens and the number of chromosomes in their ovaries and testes was cytogenetically determined. The results of analysis of the spread of O. felineus carried out by this method showed the presence of 12-chromosome form of the Opisthorchis marita in all places of fishing out in the lower course of the river Tom. Analysis of the 12-chromosome karyotype allows to conclude that this mutation was a result of Robertsonian fusion of chromosomes 3 and 6 of 14-chromosome form of karyotype.

РH process as a technology for reprocessing mixed uranium–plutonium fuel from BREST-OD-300 reactor

A technology for reprocessing mixed uranium–plutonium nitride fiel (MUPN) from BREST reactor is considered. The technology should ensure reprocessing of spent nuclear fuel with the storage time after irradiation of no more than 1 year, 10–15% content of fissile materials (FM), and burn-up of 10% of heavy atoms. The target product of the technology is a mixture of actinide oxides separated from fission products with the separation factor of ~106. A PH (Pyro–Hydro) process was suggested for MUPN SNF reprocessing. It involves pyroelectrochemical fuel reprocessing with separation of U, Np, and Pu from the major fraction of fission products responsible for the heat release from the fuel and for the radiation load on process media, a series of hydrometallurgical operations for final purification of the target products (U–Pu–Np–Am), and radioactive waste (RW) management. The PH process is being developed since 2011 by the teams from the Bochvar High-Tech Research Institute of Inorganic Materials, Khlopin Radium Institute, and Research Institute of Atomic Reactors with active participation of the Leading Research Institute of Chemical Technology, Siberian Chemical Combine, and institutes of the Russian Academy of Sciences, primarily Frumkin Institute of Physical Chemistry and Electrochemistry and Vernadsky Institute of Geochemistry and Analytical Chemistry.

Environmental, economic and social risks of nuclear power engineering (the case of the southern part of the Ob-river basin)

The Siberian Chemical Combine, the largest nuclear plant not only in Russia but also in the world, which afforded ‘heat and electricity to our houses’, was built in 1954 in the south-east of Tomsk Oblast. Tomsk is in close proximity (10–12 km) to this plant located in the closed city of Severesk; hence the radiological situation in Tomsk may be estimated as potentially dangerous. The Russian Federation’s Ministry for Atomic Energy tries to continue developing the nuclear power industry in the region and suggests new projects including a plant for nuclear fuel production and development reactor BREST-OD-300, calling this an ‘innovative project’, a ‘breakthrough’. Where will this breakthrough lead us? Is the nuclear power industry really innovative and hi-tech? The paper focuses on the analysis of economic, ecological and social risks of the nuclear power industry; it also discusses whether it is worth developing in Siberia with its huge resource potential.

Radioactive Contamination of Spent Reactor Graphite

The radioactive contamination of the spent graphite of uranium-graphite reactors is analyzed. The formation of the radioactive contamination during irradiation for 30–35 years is described. The contamination of graphite samples by radionuclides, including the products of activation of impurities and fission products, and by actinides is examined for three commercial uranium-graphite reactors at the Siberian Chemical Combine, the AM-1 reactor at the Physics and Power Engineering Institute, and the thermal column of the IRT reactor at the Moscow Engineering Physics Institute. It is concluded that 14C makes the main contribution to the activity of the graphite. The mass of the radionuclides in the bricks of the I-1, EI-2, and ADE-3 reactors at the Siberian Chemical Combine is presented. Some questions concerning the handling of the spent graphite are examined.

Regional flow and transport simulation of liquid radioactive waste disposal at the Siberian chemical combine for long- and super-long-term postinjection periods

Regional groundwater flow and transport models were substantiated for the site of underground disposal of liquid radioactive waste from the Siberian Chemical Combine. The migration of a neutral component and two radionuclides (90Sr and U) in groundwaters was predicted for the long-(1000 years) and super-long-term (10 000 years) periods using the microdispersion and macrodispersion approaches. A local model-insert of the lithological and hydraulic heterogeneity was developed for substantiating the macrodispersion parameters. The simulation results show that, during the long-term period, the contaminated waters will be mainly localized within the injection zone (below buffer horizon IV), and during the super-long-term period about 90% of the total amount of neutral wastes will be discharged into the drainage network, whereas uranium will be fully retained within the disposal site.

Computation of radiation power from standard radioactive emissions of radiochemical plant at frequencies of 1420 and 1665–1667 MHz

A radiation power of an emission plume from the Radiochemical Plant (RCP) of the Siberian Chemical Combine, as an example, was theoretically calculated at 1420 and 1665–1667 MHz. Experimental and theoretical data on the radiation power of an RCP plume were compared, as well as radiation powers of plumes from RCP and the nuclear power plant (NPP).

Current State of the Rare Earth Industry in Russia and Siberia

The paper presents an evaluation of the rare earth industry in the former Soviet Union, Russia and the world. Main areas of use of rare earth metals, primary resources of rare earth metals are considered, forecast for the industry development is given. The conclusion about the prospects and opportunities of the organization of production and separation of rare earth metals at the Siberian Chemical Combine in the West Siberian region is made, and possible sources of raw materials for this production are analyzed.

Up-to-date concentrations of long-lived artificial radionuclides in the Tom and Ob rivers in the area influenced by discharges from Siberian chemical combine

The Siberian Chemical Combine (SCC) is located in Seversk (formerly known as Tomsk-7) in the Tomsk Region of the Russian Federation. The main contribution of radionuclides in the SCC process water discharged into the Tom River was from the single-pass reactors, now removed from service (the last SCC reactor was shutdown on June 5, 2008). The data on the concentrations of 90Sr, 137Cs, 239,240Pu and other artificial radionuclides in water, bottom sediments and flood-plain soils of the Tom and Ob rivers from Tomsk to the confluence of the rivers, are presented and discussed. The results of measurements carried out after shutdown of the last SCC single-pass reactor indicated no radiologically significant consequences of SCC activities for the studied water environment compartments. Contemporary activity concentrations of long-lived artificial radionuclides 3H, 90Sr, 137Cs and 239,240Pu in river water were below the intervention levels established by current regulations of the Russian Federation for these radionuclides. The results of 3H analysis in water from the Tom and Samuska rivers demonstrated no inflow of contaminated formation water to surface water from the sites where liquid radioactive wastes of the SCC were injected below the surface. However, the density of flood-plain soil contamination by long-lived 137Cs in the area influenced by SCC liquid discharges was higher than regional technogenic background. There were local flood-plain areas contaminated not only by 137Cs, but also other gamma-emitters, such as 60Co and 152Eu.

Chemical absorbent for catching halogen-containing gases discharged from isotope separation plants

The results of industrial tests of a cascade of chemical absorbents for catching spent halogen-containing processes gases during discharge into the atmosphere are discussed. It is noted that the volume of the discharged gases decreases as a result of CO2 absorption. The HF and Cl2 content in passing gas can serve as a criterion for the completion of each catching step; Cl2 detection after the last step is a service life criterion for all chemical absorbents of a facility without exception. The average catching efficiency is 99.7 and 98.5% with respect to fluorine- and chlorine-containing components, respectively. An approximate calculation of the near-ground concentration of HF and Cl2 is performed. The gases discharged by the isotope separation plant at the Siberian Chemical Combine were purified at the level of the maximum admissible concentration for the working zone and not at the level of the technical norm established individually for each industrial enterprise. Equipping nuclear fuel cycle enterprises with such systems will make it possible to decrease environmental contamination considerably.

History of Highly Enriched Uranium Production in Russia

Between 1949–1963, the Soviet Union built four large industrial uranium-enrichment plants. All initially used gaseous diffusion for isotope separation. Starting in 1964, however, the Soviet Union b...

Modelling of transport of radioactive substances from the Siberian Chemical Combine by the Tom and Ob rivers

Observations carried out in the frame of the ISTC project 3547 [1] were used to parametrize and validate the model of radionuclides transport from Siberian Chemical Combine (SCC) by the Tom and Ob rivers and also to assess discharges of radioactive substances from SCC to the Tom River and to estimate possible contamination of the rivers in case of accidents.

Neutralizing accidental discharges of uranium hexafluoride from the isotope separation plant at the Siberian chemical works

The processes occurring during accidental discharges of liquid uranium hexafluoride in the production rooms of the Chelnok-T section in the isotope separation plant at Siberian Chemical Combine are examined. The purification system, which uses KhP-MMD and KhP-MD chemical absorbers, permits localizing very quickly any accidental discharges of uranium hexafluoride and protect the atmosphere in the plant from harmful effects of fluorine-contained gases. The absorbers effectively catch HF (99.97%) and UF6 (>99.9%) and have a high working capacity 30.5 mass% with respect to the fluorine ion. The system for catching and dispersing harmful contaminants provides the required sanitary standard with respect to atmospheric air on the territory of the plant and at the nearest populated points.

Assessment of the long-term safety of radioactive waste disposal: 1. Paleoreconstruction of groundwater formation conditions

Isotopic characteristics (δ2H, δ18O, 234U/238U, Ar, 3H) of natural and technogenically affected waters were determined in the area around the burying grounds of the Siberian Chemical Combine with the aim to assess the circulation conditions of natural waters and the safety of radioactive waste disposal in reservoir beds.

Geoecological investigations of artificial radionuclides in the aquatic system of the Ob River and Kara Sea

Numerous studies have considered whether run-off from large Siberian rivers, in particular the Ob River, has the potential to transport radioactive contaminants from the nuclear sites – SPA “Mayak” and Siberian Chemical Combine (SCC), located in the vicinity of these rivers, to distant locations including the Kara Sea. The plutonium-producing radiochemical plant of SPA ''Mayak'' stored a lot of radioactive wastes in Lake Karachai. Radioelements are carried to the rivers with flood and ground waters [1]. As contamination is transported, radioactivity is removed through Techa-Iset’-Tobol-Ob river system but has the potential to reach the Kara Sea and further to other seas within the Arctic basin via ocean currents. The Siberian Chemical Combine, is located in Seversk city on the bank of Tom River, that drains into the Ob network. SCC liquid wastes were detected in the Tom River, which flows into the Ob River [2]. In this paper the data of our investigations during last years on studying the radioecological situation in two parts of the Ob river-Kara Sea aquatic system Ob-Irtysh river’s system and Ob Bay and adjacent part of the Kara Sea, with a main focus on the behavior and migration pathways of man-made radionuclides are presented.

Radioisotope contaminations from releases of the Tomsk–Seversk nuclear facility (Siberia, Russia)

Soils have been sampled in the vicinity of the Tomsk–Seversk facility (Siberia, Russia) that allows us to measure radioactive contaminations due to atmospheric and aquatic releases. Indeed soils exhibit large inventories of man-made fission products including 137Cs (ranging from 33,000 to 68,500 Bq m −2) and actinides such as plutonium (i.e. 239+240Pu from 420 to 5900 Bq m −2) or 241Am (160–1220 Bq m −2). Among all sampling sites, the bank of the Romashka channel exhibits the highest radioisotope concentrations. At this site, some short half-life gamma emitters were detected as well indicating recent aquatic discharge in the channel. In comparison, soils that underwent atmospheric depositions like peat and forest soils exhibit lower activities of actinides and 137Cs. Soil activities are too high to be related solely to global fallout and thus the source of plutonium must be discharges from the Siberian Chemical Combine (SCC) plant. This is confirmed by plutonium isotopic ratios measured by ICP-MS; the low 241Pu/ 239Pu and 240Pu/ 239Pu atomic ratios with respect to global fallout ratio or civil nuclear fuel are consistent with weapons grade signatures. Up to now, the influence of Tomsk–Seversk plutonium discharges was speculated in the Ob River and its estuary. Isotopic data from the present study show that plutonium measured in SCC probably constitutes a significant source of plutonium in the aquatic environment, together with plutonium from global fallout and other contaminated sites including Tomsk, Mayak (Russia) and Semipalatinsk (Republic of Kazakhstan). It is estimated that the proportion of plutonium from SCC source can reach 45% for 239Pu and 60% for 241Pu in the sediments.

Simulation of the distribution of radionuclides in the reservoir bed for deep-well injection disposal of acid liquid radioactive waste

A mathematical model was developed for describing the changes in the state of the reservoir bed for dee-well injection disposal of acid liquid radioactive waste. The model considers the multicomponent filtration of the solution in the heterogeneous bed, sorption-desorption of radionuclides, taking into account the dependence of the distribution coefficient on the temperature and pH, as well as radioactive decay, interaction of acids with minerals, radiation-chemical and thermochemical decomposition of the acids, and dynamics of the temperature field, taking into account the convective heat transfer, thermal conductivity, and radiogenic heat release. The results of the simulation of the migration of radionuclides were reported, as well as of the distribution of the acids and the dynamics of the temperature field in the vicinity of the injection well of the site for deep-well injection disposal of the waste from Siberian Chemical Combine. A technogenic barrier is formed in the vicinity of the injection well, hindering the spread of radionuclides in the reservoir bed.

Distribution and activity of microorganisms in the deep repository for liquid radioactive waste at the Siberian Chemical Combine

The physicochemical conditions, composition of microbial communities, and the rates of anaerobic processes in the deep sandy horizons used as a repository for liquid radioactive wastes (LRW) at the Siberian Chemical Combine (Seversk, Tomsk oblast), were studied. Formation waters from the observation wells drilled into the production horizons of the radioactive waste disposal site were found to be inhabited by microorganisms of different physiological groups, including aerobic organotrophs, anaerobic fermentative, denitrifying, sulfate-reducing, and methanogenic bacteria. The density of microbial population, as determined by cultural methods, was low and usually did not exceed 10(4) cells/ml. Enrichment cultures of microorganisms producing gases (hydrogen, methane, carbon dioxide, and hydrogen sulfide) and capable of participation in the precipitation of metal sulfides were obtained from the waters of production horizons. The contemporary processes of sulfate reduction and methanogenesis were assayed; the rates of these terminal processes of organic matter destruction were found to be low. The denitrifying bacteria from the underground repository were capable of reducing the nitrates contained in the wastes, provided sources of energy and biogenic elements were available. Biosorption of radionuclides by the biomass of aerobic bacteria isolated from groundwater was demonstrated. The results obtained give us insight into the functional structure of the microbial community inhabiting the waters of repository production horizons. This study indicates that the numbers and activity of microbial cells are low both inside and outside the zone of radioactive waste dispersion, in spite of the long period of waste discharge.

Possibility of Salvaging Spent Graphite Sleeves from the Reactors of the Siberian Chemical Combine by Incineration

Several thousand metric tons of spent graphite sleeves, which are being kept at solid-wastes storage facilities, have now been accumulated. The construction and state of most of the storages sites do not meet modern requirements because of the long time that these sites have been in operation and because the depths reach ground water, if the required protective barriers are absent. Consequently, there is a real danger that the radionuclides will contaminate the ground waters and the surrounding environment. To prevent this from happening, a system of measures must be instituted to put into place the required safety barriers or the sites must be liquidated.

Experimental Study of the Radioactive Contamination of Graphite Masonry in the Commercial Reactors at the Siberian Chemical Combine

The graphite masonry from decommissioned commercial uranium–graphite reactors is contaminated with radionuclides and is a significant fraction of the radioactive wastes from the nuclear industry. Information about the composition and degree of contamination of the graphite is needed to choose methods and time periods for handling this graphite. The results of investigations performed on I-1, EI-2, and ADE-3 reactors at the Siberian Chemical Combine in 1996–2001 are presented in this paper. Analysis of a large number of samples made it possible to construct a detailed picture of the contamination of the masonry, study the distribution of the radionuclides of different origin in the masonry, construct schemes for making estimates, and estimate the content of certain radionuclides, including 14C, 3H, 90Sr, 241Am, 244Cm, 238–241Pu, 137,134Cs, and 60Co.