Ukrainian Nuclear Power Plants Research Articles

Chernobyl: assessing the health effects, 30 years later

Earlier this year, Ukraine marked 30 years since the Chernobyl disaster. Sanjeet Bagcchi reports. Radiation and risk of thyroid cancer: Fukushima and Chernobyl30 years have passed since the accident at the Chernobyl nuclear power plant in Ukraine, and 5 years have passed since the crisis at the Fukushima Daiichi nuclear power plant. After the Chernobyl disaster, a significant increase in thyroid cancer was reported among children and adolescents exposed to radioactive iodine released at the time of the accident in Belarus, Russia, and the Ukraine.1 On the basis of the experience of Chernobyl, thyroid ultrasound examination is being done within the framework of the Fukushima Health Management Survey. Full-Text PDF

ІMPLEMENTATION OF SEWAGE TREATMENT OF PLANTS FOR THERMAL DEMERCURIZATION

There are currently ways and means demercurization have significant drawbacks, not safe and effective. The analysis of the dynamics of the production of non-radioactive waste at the South Ukrainian nuclear power plant for the 2013-2015 biennium. Proposed to establish production facilities in South Ukrainian nuclear power plant in order to reduce the volume of waste hazard class I, because of mercury used fluorescent lamps, sewage treatment plants for thermal demercurization. Also calculated environmental and economic benefits in the process of implementing the installation for thermal demercurization

Aspects of using a best-estimate approach for VVER safety analysis in reactivity initiated accidents

Abstract At present time, Ukraine faces the problem of small margins of acceptance criteria in connection with the implementation of a conservative approach for safety evaluations. The problem is particularly topical conducting feasibility analysis of power up-rating for Ukrainian nuclear power plants. Such situation requires the implementation of a best-estimate approach on the basis of an uncertainty analysis. For some kind of accidents, such as loss-of-coolant accident (LOCA), the best estimate approach is, more or less, developed and established. However, for reactivity initiated accident (RIA) analysis an application of best estimate method could be problematical. A regulatory document in Ukraine defines a nomenclature of neutronics calculations and so called “generic safety parameters” which should be used as boundary conditions for all VVER-1000 (V-320) reactors in RIA analysis. In this paper the ideas of uncertainty evaluations of generic safety parameters in RIA analysis in connection with the use of the 3D neutron kinetic code DYN3D and the GRS SUSA approach are presented.

Radioactive Waste Management at Ukrainian Nuclear Power Plants. State and Challenges.

The paper considers methods and approaches to radioactive waste management used at Ukrainian nuclear power plants and advanced technologies to be applied after completed construction of radioactive waste processing facilities at NPP sites.

Some Characteristics of Hypothetic TVSA with Fuel Enriched beyond 5% for VVER1000

The paper presents comparison of regular TVSA with average enrichment of 4,386% and hypothetical TVSA with enrichment of 10% based on design parameters and materials of TVSA fuel assemblies produced by TVEL (Russia), which today are widely used at nuclear power plants in Ukraine. It is shown that implementation of new fuel assemblies will result in improved use of fuel and increase of installed capability factor. At the same time, fresh and spent fuel management systems shall be modernized to meet relevant nuclear safety criteria. The paper analyzes possible criticality initiation at different stages of severe accidents related to core melt and using fuel with higher enrichment.

Nuclear and radiation safety issues and risks associated with the coming replacement of Russian nuclear fuel with US fuel at nuclear power plants in Ukraine

Nuclear and radiation safety issues arising in the process of replacement of Russian nuclear fuel with US fuel produced by Westinghouse are discussed.

Criteria for NPP industrial site flooding by combined impact of tornadoes and earthquakes in the cooling pond

The results of analysis of the impact of extreme natural phenomena on safety of nuclear power plants in Ukraine, held in the pre and post-Fukushima periods have shown that tornadoes and earthquakes are the most likely events. However, the results are contradictory in relation to probability assessment of security-critical tornadoes, and do not take into account the possibility of the NPP industrial site flooding under the combined effect of tornadoes and earthquakes in the station reservoirs. Hydrodynamic model of NPP industrial site flooding wave during tornadoes and earthquakes, based on the assumption of the flooding wave formation under the influence of tornado lift and seismic shock, as well gravity and internal dissipation forces; cylindrical shape of the flooding wave; conservative isothermal exposure of the flooding wave near the coast was developed. The flooding wave emergence and development process is conventionally divided into two different time-scale phases: the initial phase of the combined (in general) earthquake and tornado, the final stage of the tornado impact. Based on the developed hydrodynamic model, deterministic criteria of possible NPP industrial site flooding at the combined (in general) impact of the tornado and earthquake in the cooling pond were defined. The analysis was performed on the example of the Zaporizhzhya NPP, due to which it was found that there was no flooding under tornadoes below the 2-intensity grade and earthquakes with response acceleration at the cooling pond bottom of less than 10 m/s 2 and duration of about ten seconds.

Using quality indicators for assessment of occupational safety organization in power industry

Розглянуто статистичні показники організації охорони праці на однієї з українських атомних електростанцій. З використанням пакета STATISTICA, контрольних карт дана оцінка якості, встановлені основні причини його зниження. Зроблено висновки про можливості використання в керуванні якістю діяльності служби охорони праці методів і інструментів, традиційно прийнятих в оцінці якості промислових виробництв і їх продукції

Assessment of doses to game animals in Finland

A study was carried out to assess the dose rates to game animals in Finland affected by the radioactive caesium deposition that occurred after the accident at the Chernobyl nuclear power plant in Ukraine in 1986. The aim of this assessment was to obtain new information on the dose rates to mammals and birds under Finnish conditions. Dose rates were calculated using the ERICA Assessment Tool developed within the EC 6th Framework Programme. The input data consisted of measured activity concentrations of 137Cs and 134Cs in soil and lake water samples and in flesh samples of selected animal species obtained for environmental monitoring. The study sites were located in the municipality of Lammi, Southern Finland, where the average 137Cs deposition was 46.5 kBq m−2 (1 October 1987). The study sites represented the areas receiving the highest deposition in Finland after the Chernobyl accident. The selected species included moose (Alces alces), arctic hare (Lepus timidus) and several bird species: black grouse (Tetrao tetrix), hazel hen (Bonasia bonasia), mallard (Anas platurhynchos), goldeneye (Bucephala clangula) and teal (Anas crecca). For moose, dose rates were calculated for the years 1986–1990 and for the 2000s. For all other species, maximal measured activity concentrations were used. The results showed that the dose rates to these species did not exceed the default screening level of 10 μGy h−1 used as a protection criterion. The highest total dose rate (internal and external summed), 3.7 μGy h−1, was observed for the arctic hare in 1986. Although the dose rate of 3.7 μGy h−1 cannot be considered negligible given the uncertainties involved in predicting the dose rates, the possible harmful effects related to this dose rate are too small to be assessed based on current knowledge on the biological effects of low doses in mammals.

The Chernobyl accident as a source of new radiological knowledge: implications for Fukushima rehabilitation and research programmes

The accident at the Chernobyl nuclear power plant in Ukraine in 1986 caused a huge release of radionuclides over large areas of Europe. During large scale activities focused on overcoming of its negative consequences for public health, various research programmes in radioecology, dosimetry and radiation medicine were conducted. New knowledge was applied internationally in substantial updating of radiation protection systems for emergency and existing situations of human exposure, for improvement of emergency preparedness and response. Radioecological and dosimetry models were significantly improved and validated with numerous measurement data, guidance on environmental countermeasures and monitoring elaborated and tested. New radiological knowledge can be of use in the planning and implementation of rehabilitation programmes in Japan following the Fukushima nuclear accident. In particular, the following activity areas would benefit from application of the Chernobyl experience: strategy of rehabilitation, and technology of settlement decontamination and of countermeasures applied in agriculture and forestry. The Chernobyl experience could be very helpful in planning research activities initiated by the Fukushima radionuclide fallout, i.e. environmental transfer of radionuclides, effectiveness of site-specific countermeasures, nationwide dose assessment, health effect studies, etc.

ГЕОДИНАМІКА

The basic directions of the Action Plan to assess seismic hazard and seismic check of existing nuclear power plants, approved SNRCU and NNEGC "Energoatom", which is the basis for work on seismic monitoring systems of nuclear power plant in Ukraine are represented. The experience of expert of IGPH NAS in this field is explined. The basic principles, their aims and objectives are explined too. The spesification for the Rivne NPP is represented as an example. The situation for each of NPP is outlined for short term.

Public exposure formed by atmospheric discharges of nuclear power plants in ukraine

Ukrainian Radiation Protection Institute has developed system for calculation of doses to the population living in the supervision zone of the NPP from atmospheric discharges of Nuclear Power Plants during normal operation. The system analyses daily meteorological data, and also daily and monthly atmospheric discharges of radionuclides. The developed system is applied for dose calculation for Ukrainian population and identification of radionuclides, which form considerable contribution to total doses (noble gases, H-3, I-131). A special attention has been given for variability of actual meteorological conditions and discharges. For example, it has been revealed the case when I-131 discharge from a Ukrainian NPP during 4 consecutive days has made 34 % of annual discharge (and 72% during 3 weeks). Variability of actual discharges is a result of changes in an operation mode of NPP unit and it is a typical situation for Ukrainian NPPs. Apparently, the similar situation can be typical for NPPs in another countries. Such results lead to necessity to consider possible variations of meteorological conditions and discharges for establishment of permissible levels (for example, by introduction of variability factor).

The use of master curve method for statistical re-evaluation of surveillance test data for WWER-1000 reactor pressure vessels

The surveillance fracture toughness test data for WWER-1000 reactor pressure vessel materials from Ukrainian nuclear power plants were re-evaluated using the Master curve methodology. It has been shown that experimental temperature dependence of fracture toughness parameters and a scatter of KJc values are in a good agreement with a Master curve shape and 5 and 95% tolerance bounds for materials in unirradiated condition and after neutron irradiation up to fluence 41. 2·1022 n/m2 (E > 0.5 MeV). For the Khmelnitsky nuclear power plant unit 1 reactor pressure vessel an analysis has shown that normative approach PNAE G-7-002-86 underestimates essentially the measured fracture toughness of unirradiated weld metal. The reference temperature T0 calculated according to the Master curve method was compared with a critical brittleness temperature TK0 for reactor pressure vessel materials in unirradiated condition. It has been found that temperature T0 is much lower than TK0 . Furthermore a difference between T0 and TK0 values varies essentially from one material to another. A correlation between temperatures T28 J defined from Charpy energy curve and T0 values calculated from precracked Charpy specimens test was obtained. The analysis has shown that the results based on precracked Charpy specimens can provide nonconservative assessment of fracture toughness for WWER-1000 reactor pressure vessel materials.

“Fear of radiation” is frightening

The world’s two worst industrial disasters occurred in the early years of my career in radiation physics. The Bhopal gas tragedy was the worst industrial accident and occurred on the night of December 2–3, 1984 at the Union Carbide pesticide plant in Bhopal, India and killed 10,000 people on that one night. The worst ever nuclear accident occurred at the Chernobyl Nuclear Power Plant in Ukraine on 26 April 1986, which led to less than 60 fatalities within 3 months of the accident. These two catastrophic events helped me shape my perception of the risks associated with modern industrial processes. While many have forgotten the Bhopal gas tragedy, the Chernobyl disaster is still fresh in our collective memory. Last year was the 25th anniversary of the Bhopal gas tragedy and I asked my medical radiation students if they had heard of this event. Not a single student out of the 80 in the class had heard of or read about this event. However, more than a handful of students had heard or read about the Chernobyl disaster. The students were shocked to hear that for every one person killed in the immediate aftermath of Chernobyl one hundred more fatalities were recorded in Bhopal. I often wonder why our perception of the risk associated with ionising radiation is so heavily skewed. Who is responsible for this public anxiety? Is it the media, politicians or scientists? I think the burden of responsibility falls equally on all three sections of society. If our perception of the risk is not balanced, we are predisposed to making incorrect judgments. Such decisions are invariably costly and often lead to exposure to the unknown and perhaps more significant risk elements. After more than 100 years of research, the risk radiation poses to humans is still poorly understood at ‘low dose’ level. Most people regard a dose less than 100 mSv as low dose. Public fear of radiation began to develop after the dropping of the A-bombs on Japan during WW2. The fear has been propagated by the blatant lies of the anti-nuclear campaigners and was and is still supported by the mass media seeking sensationalist stories. The saying ‘Never let a fact get in the way of a good story’ unfortunately holds very true when applied to events involving ionising radiation. It is nearly impossible for a scientist to get anything in the mass media that contradicts the prevailing falsehoods. My own experience illustrates that even professional radiation physicists are not spared from radiation phobia. On one occasion I was working near the door of a high dose rate (HDR) brachytherapy room, where the dose rate out of the shielding container is typically 5 lSv/h. My colleague, a physicist, insisted that I move away from that area as they considered the area to be characterized by a ‘high radiation level’. I obliged, as at the time, it was easier than to explain why it was safe for me to work there. I was M. Bhat (&) Adelaide Radiotherapy Centre, Adelaide, SA, Australia e-mail: mbhat@adradcentre.com.au

Scalable diversity-oriented decisions and technologies for dependable SoPC-based safety-critical computer systems and infrastructures

An approach to development and implementation of multi-version technologies (MVT) for creating dependable system-on-programmable chip (SoPC)-based systems and infrastructures is described. It is based on a set of scalable diversity-oriented decisions selected using the proposed MVT-graph. This technique is applied for development of nuclear power plants (NPP) instrumentation and control (I&C) platform. The diverse I&C platform RADIY, which is designed, produced and supplied by the Radiy Company in Ukraine is described and analysed. The results of implementation of the suggested decisions and technologies in safety-critical dependable systems and infrastructures in Ukrainian NPPs are analysed.

Radrue method for reconstruction of external photon doses for Chernobyl liquidators in epidemiological studies.

Between 1986 and 1990, several hundred thousand workers, called "liquidators" or "clean-up workers," took part in decontamination and recovery activities within the 30-km zone around the Chernobyl nuclear power plant in Ukraine, where a major accident occurred in April 1986. The Chernobyl liquidators were mainly exposed to external ionizing radiation levels that depended primarily on their work locations and the time after the accident when the work was performed. Because individual doses were often monitored inadequately or were not monitored at all for the majority of liquidators, a new method of photon (i.e., gamma and x rays) dose assessment, called "RADRUE" (Realistic Analytical Dose Reconstruction with Uncertainty Estimation), was developed to obtain unbiased and reasonably accurate estimates for use in three epidemiologic studies of hematological malignancies and thyroid cancer among liquidators. The RADRUE program implements a time-and-motion dose-reconstruction method that is flexible and conceptually easy to understand. It includes a large exposure rate database and interpolation and extrapolation techniques to calculate exposure rates at places where liquidators lived and worked within approximately 70 km of the destroyed reactor. The RADRUE technique relies on data collected from subjects' interviews conducted by trained interviewers, and on expert dosimetrists to interpret the information and provide supplementary information, when necessary, based upon their own Chernobyl experience. The RADRUE technique was used to estimate doses from external irradiation, as well as uncertainties, to the bone marrow for 929 subjects and to the thyroid gland for 530 subjects enrolled in epidemiologic studies. Individual bone marrow dose estimates were found to range from less than one muGy to 3,300 mGy, with an arithmetic mean of 71 mGy. Individual thyroid dose estimates were lower and ranged from 20 muGy to 507 mGy, with an arithmetic mean of 29 mGy. The uncertainties, expressed in terms of geometric standard deviations, ranged from 1.1 to 5.8, with an arithmetic mean of 1.9.

The Turndown of Soviet Modernity: from Chernobyl and Ignalina to the Green Movement and Sąjūdis

The modern governments are conceived as to draw their legitimacy based on universal rational knowledge and the concept of controllable and calculable risks as a tool for ensuring progress and welfare of society. The multiple risks and uncertainties of modernisation that the governments were incapable to deal with caused a deficit of legitimacy and institutional ambiguity (or the institutional void as Hajer suggested calling it). Consequently, new actors and new political arenas or spaces have emerged and are expected to lead to institutional innovation. The Soviet system represents the version of the modern state which based its legitimacy on the principle of rationalism applicable towards external nature and was challenged by multiple risks and side effects of its industrial development that led to the deficit or even absence of legitimacy. The crisis of legitimacy of the Soviet state and institutional void, this paper argues, was a key premise for the former Soviet republics such as Lithuania to restore its’ statehood and indepe­ndence in search of new democratic participatory modes of governance. The theoretical perspective based on governance transformations induced by the crisis of legitimacy, uncertainties of modernisation and institutional void in the former Soviet system of governance is illuminated by two empirical cases rooted in the nuclear energy sector, namely the accident at Chernobyl Nuclear Power Plant in Ukraine in 1986, and public controversy around the Ignalina Nuclear Power Plant in Lithuania.

Analysis of tests performed on materials of VVER-1000 vessels for impact toughness according to the standard control-sample program

An additional assessment and analysis of the degree of radiation embrittlement of the materials used in the VVER-1000 vessels of nuclear power plants in Ukraine are performed according to the standard (regular) program of irradiation and investigation of control samples. New results for samples tested for impact toughness are presented and compared with the results obtained using reconstitutive procedures. It is shown that the results of control-sample tests performed according to the standard program (with a fluence deviation of ±15% above the norm in a group of 12 samples) can be used to assess the state of the material and preliminary substantiation of the serviceability of vessels before obtaining more accurate data on embrittlement using reconstituted samples.

LEUKEMIA FOLLOWING THE CHERNOBYL ACCIDENT

The accident at the Chernobyl Nuclear Power Plant in Ukraine in 1986 led to a substantial increase of thyroid cancer among those exposed as children. The other cancer that is the most sensitive to the effects of ionizing radiation is leukemia, and this paper evaluates the evidence relating exposure to Chernobyl radioactivity and leukemia risk. Two types of objectives are identified, namely, scientific evidence and public health, and two approaches to addressing such objectives are discussed. Empirical studies in affected populations are summarized, and it is concluded that, possibly apart from Russian cleanup workers, no meaningful evidence of any statistical association between exposure and leukemia risk as yet exists. However, it is important to carry on with such studies to satisfy various public health objectives.

Comparison of Prussian blue and apple-pectin efficacy on 137Cs decorporation in rats

Cesium-137 ( 137Cs) is one of the most important nuclear fission elements that contaminated the environment after the explosion of the Chernobyl nuclear power plant in Ukraine (1986). The aim of the study was to compare the efficacy of two chelating agent, Prussian blue and apple-pectin on 137cesium decorporation in rats. Rats were intravenously injected with a solution of 137cesium (5 kBq per rat). Chelating agents, Prussian blue or apple-pectin were given immediately after Cs contamination and during 11 days by addition of each chelating agent in drinking water at a concentration corresponding to 400 mg kg –1 day –1. Efficiency was evaluated 11 days after contamination (at the end of treatment) through their ability to promote Cs excretion and to reduce the radionuclide accumulation in some retention compartments (blood, liver, kidneys, spleen, skeleton and in the remaining carcass). In these conditions after treatment with Prussian blue a fivefold increase in fecal excretion of Cs was observed and was associated with a reduction in the radionuclide retention in the main organs measured. In contrast, no significant differences were observed between untreated rats and rats treated with apple-pectin. These observations were discussed in terms of ability of pectins to bind Cs and compared to recently published results obtained after treatment of Cs-contaminated children with this chelate.