According to the Federal target program “Provision of the nuclear and radiation safety in 2016-2020 and up to 2030”, activities on the liquidation of the nuclear legacy are performed in the Russian Federation. The nuclear legacy includes mines, pits, industrial facilities, burrows and tailings of the uranium processing facilities (objects of uranium legacy), objects of extraction and processing of precious and rare elements and mineral ore, producing the wastes with the increased concentration of natural radionuclides. Due to the damage or lack of the barriers, preventing the distribution of radionuclides, natural radionuclides contaminate the environment and expose the population residing in closely located communities. Radionuclides of radium ( 226Ra and 228Ra), radon (222Rn) and their daughter have the main contribution to the doses and corresponding radiation risks to the public residing in a vicinity of such facilities. According to the Russian legislative documents, exposure of the public residing in the area of location of the objects of the uranium legacy and objects and territories, contaminated by the natural radionuclides due to the past activities of the non-nuclear facilities is attributed to the natural exposure with the subsequent compliance to the requirements of NRB 99/2009 and OSPORB 99/2010 on limitations of natural exposure. The main direction of the use of the objects and territories contaminated by the natural radionuclides due to the past activities of nuclear and non-nuclear facilities is their unlimited use for the industrial purposes. The main criteria for the unlimited use of remediated areas and territories of buildings and constructions are the requirements of NRB-99/2009 and OSPORB-99/2010 for the construction of the residential and public buildings. The criteria of NRB-99/2009 and OSPORB 99/2010 for the industrial buildings would be applied for the use of the remediated areas and territories of buildings and constructions with the residual contamination by the natural radionuclides. 

This study is focused on the evaluation of the levels of accumulation of the man-made radionuclides by several components of Yenisei River close to the water discharge spot of the Mining and chemical plant containing a significant amount of man-made radionuclides. The study was performed during the period of activity of the third nuclear reactor, belonging to this facility and included measuring the concentration of the gamma-emitting man-made and natural radionuclides. Gamma-spectrometry indicated significant amounts of man-made activation radionuclides (24Na – up to 1950 Bk/kg, 51Cr – up to 2860 Bk/kg) in biological objects. With some assumptions at the dose rate assessment, the highest does were estimated for the following organisms (mkGy/day): water plants – up to 39, fish – grayling 22,3 and pike 36,4. These values are significantly lower compared to the accepted dose from ionizing radiation for the water biota – 10 mkGy/day.

Objective of the study: To conduct a comprehensive analysis and assessment of the dynamics of internal exposure levels in the territories contaminated due to the activities of the Mayak Production Association, based upon the results of long-term monitoring of the long-lived anthropogenic radionuclide body burden in residents of the Urals region. Materials and methods: The data of postmortem and in vivo examinations for three groups of population were analyzed: 1) residents of riverside villages of the upper and middle reaches of the Techa River, contaminated in 1949-1956 with liquid radioactive waste; 2) people who were exposed as a result of the 1957 accident on the territory of the East Urals Radioactive Trace; 3) residents of the Ozyorsk city, located at an 8 km distance from the enterprise. The following methods of the examinations were used: 1) radiochemical analysis of specimens of organs and tissues sampled at autopsy; 2) in vivo measurements with the use of the whole body counters. The results of measurements of cesium-137, strontium-90 and trans-uranium radionuclide body burden over the period 1950s – present are provided. Data analysis made it possible to distinguish two historically formed groups of population with the maximum levels of current strontium-90 and plutonium body burden. The first group included people who lived in the early 1950’s in the basin of the Techa River, for whom the levels of oral intake of 90Sr reached 1.4 MBq/year. The second group comprised residents of the Ozyorsk city, for whom the levels of inhalation intake of plutonium in the period 1951–1958 reached 8 Bq/year. Conclusion: Estimates of the committed effective doses due to the intake of long-lived radionuclides over the period from 1949 through 2012 for critical groups of residents of the Urals were: 300 mSv for former residents of the Muslyumovo settlement on the Techa River (90Sr contribution – 85%) and 13 mSv for residents of the Ozyorsk city (the contribution of trans-uranium radionuclides is 30%).

The study was conducted on Kunashir, Shikotan and Iturup Islands (Sakhalin Region of Russia) in order to evaluate the impact of the Fukushima accident on the “soil–grass–cow’s milk” exposure pathway. A total of 22 samples of cow’s milk were collected in the May 2011 – September 2012 period. Radiocaesium was isolated from thermally treated specimens using the antimony–iodide radiochemical method. The activity concentrations of 134Cs and 137Cs were measured by γ-ray spectrometry using high purity germanium detectors. Caesium-134 was detected in 18 of the total 22 samples of milk. The activity concentration of 134Cs in the samples varied from 0.08 Bq kg–1 to 2.00 Bq kg–1. Caesium-137 was quantified in all 22 samples: range = 0.088–2.43 Bq kg–1. On average, more than a half of the total 137Cs in the milk samples from Sakhalin Region was of Fukushima origin (mean = 60%, median = 57%, range = 13–95%). The highest activity concentrations and values of the soil–to–milk aggregated transfer coefficient, Tag, for 134Cs (and Fukushimaderived 137Cs) were observed in milk samples collected in mid-May 2011. The mean Tag values decreased in the May–October period of 2011 from 12 × 10−3 m2 kg–1 to 2.3 × 10−3 m2 kg–1. In September 2012, the Tag values remained unchanged (mean = 2.8 × 10−3 m2 kg–1) compared to those in September–October 2011. In the autumns of 2011 and 2012, the calculated values of Tag for Fukushima-derived radiocaesium were on average 17 times larger than the ones for pre-Fukushima 137Cs. The higher transfer of Fukushima-derived 137Cs (compared to pre-Fukushima 137Cs) for milk reflected the difference between the “new” and “aged” radiocaesium in the intensity of the radionuclide transfer from soil to grassland plants which were the major component of the cow’s diet in the area of our study. The ratio between the 137Cs activity concentration in the milk (fresh weight) and that in the grassland plants (dry weight) ranged from 0.028 to 0.11. The effective dose from ingestion of Fukushima-derived radiocaesium in locally produced cow’s milk for critical group of adult residents of the southern Kuril in the first year after the accident is conservatively estimated as 0.0027 mSv. The Fukushima accident has had a negligible impact on radiocaesium contamination of cow’s milk and the corresponding human exposure on the southern Kuril Islands: Shikotan, Kunashir and Iturup.

Research and Technical Center of Radiation-Chemical Safety and Hygiene (RTC RCSH), Moscow, Russia Generalized radiogenic risk models presented in ICRP Publication 103 have a number of attractive features. The models themselves and the corresponding models of background risks are generalized by a single function containing only three parameters specific to the localization of cancer, sex and risk indicator (absolute or relative; mortality or morbidity). However, there are several discrepancies in the values of model parameters for the individual cancer sites and in some predictions based on these models. The aim of this study was to clarify the possibility of refining the parameters of the ICRP models using the LSS cohort data. The method of calculation of the parameters of these models has been developed and verified based on the data on baseline mortality in the cohort and among entire Japanese population. The method consists in the averaging of the local estimates of the parameters calculated based on the values of the rate of the mortality in the ends of different segments of age at exposure and attained age within the entire examined area of change of these variables. The latest published mortality data in the cohort and mortality tables for Japan from the WHO database were used to calculate the mortality rate matrices. Data on the baseline mortality from solid cancers in LSS were in good agreement with statistically more reliable data for the entire Japanese population. Hence, the latter were used for verification of the method.According to the criteria of absolute and relative standard deviation, the ICRP models at whole better approximate baseline and radiogenic mortality from solid cancers in the cohort based on the values of parameters calculated using the proposed method compared to the values from the ICRP. The sets of parameter values for men and women, calculated from LSS data and for the Japanese population differ significantly, while in ICRP models they are almost the same. 

The aim of the study was to obtain 234U and 238U specific activity in the water of groundwater supplies of Leningrad region and St-Petersburg and to estimate the possibility of their using from the point of view of radiation and chemical toxicity of the main dose-forming uranium isotopes usually containing in the underground waters. The study was focused on the water of functioning and exploratory groundwater supplies concerning the safety of water consumption taken into account radiation and chemical index. Data on the levels of natural uranium isotopes specific activity in the sources under investigation was obtained using radiochemical analysis with the subsequent alpha-spectrometric measurement of the counting samples. 58 samples of natural groundwater were analyzed during the period from February of 2011 till the May of 2017. The volume of the native water samples was from 10 l to 30 l, measuring time for each counting sample was 6 – 12 hours, which allowed measuring the radionuclides specific activity value at the level of 0.0002 Bq/kg. The values of 238U specific activity varied within 0.0002 Bq/kg – 0.06 Bq/kg, the average value was 0.007 Bq/kg. The values of 234U specific activity varied within 0.0006 Bq/kg – 0.111 Bq/kg, the average value was 0.013 Bq/kg. The average value of the specific activities ratio 234U/238U was 2.12 and the range of this value was 1.00 – 8.00. The results of carried out investigations demonstrates that the specific activity values of uranium isotopes could differ more then by an order of magnitude even in the borders of same aquifer of a small settlement. 238U specific activity value does not exceed 0.02 Bq/kg and 234U specific activity value does not exceed 0.04 Bq/kg for the vast majority of analyzed sample. The value of the ratio 234U/238U was 1.00 – 4.00 for 98.3% of analyzed sample. It is possible to conclude with a high probability that the water from the groundwater supplies of Leningrad region and St-Petersburg is safe for consumption by population concerning 234U and 238U content as from the point of view of radiological factor, so from the point of view of chemical toxicity. 

The implementation of the State program of the Russian Federation “Development of nuclear power industry”, Federal target program «Ensuring Nuclear and Radiation Safety from 2016 to 2020 and up to 2030», introduction of new imaging modalities in medicine that are associated with high patient and staff doses, poor public awareness of the presence and level of hazard of natural sources of ionizing radiation determine the relevance of the current study. The aim of the study was to develop the effective methods of risk communication for the improvement of the radiation protection and safety of the population, to introduce these methods in the daily practice of Rospotrebnadzor and, eventually, to assist in the formation of a risk-oriented society in the Russian Federation. Currently, Russian-language terminology in the field of risk communication is not developed; Russian terms are frequently just poor adapted/translated versions of English terms. This manuscript is focused on the definition of the basic concepts of risk communication and the formation of uniform terminology in the field of the radiation safety of the population. A glossary of basic terms in the field of riskcommunication is attached to the manuscript. The authors, considering the analysis of scientific data, suggest the following definition of risk communication: a process of interaction with other participants that is intentionally initiated by one of the participants in the information field of risk and is aimed at the evaluation of the attitudes on risk, their formation or change in other participants; formation or change of own attitudes on risk. 

Survey of the buildings in the Lesnoy city, Sverdlovsk region, on the indoor radon were performed. Measurements of radon volume activity were carried out by integral method using radon track exposimeters REI-4. Exposimeters were installed for measurements at 2–4 months in the heating and warm periods of the year in the same premises. 17 kindergartens, 7 schools, 20 dwelling houses, 22 medical institutions and 3 other institutions were surveyed. The values of the equivalent equilibrium concentration of radon and indoor radon doses are obtained. The results of determining the radon equivalent equilibrium concentration in the premises on different floors of buildings belonging to different groups in the heating and warm period of the year, as well as the estimated average annual values of equivalent equilibrium concentration are presented. Average annual values of equivalent equilibrium concentration for kindergartens, schools, dwellings houses and medical institutions are in the range of 34–51 Bq/m3, and only for other institutions reach 79 Bq/m3. Average values of equivalent equilibrium concentration for all premises of the city Lesnoy were: for the heating period -  46 Bq/m3, for warm – 38 Bq/m3, average annual - 42 Bq/m3. It is shown that both for separate periods and for the annual the ratio of average equivalent equilibrium concentration values in the rooms on the second floors in relation to the first floors of different groups buildings is 0.6–0.8. For higher floors of dwellings houses the radon equivalent equilibrium concentration values does not depend on the floor. This can be explained by both the small statistics of measurements in the rooms on the upper floors and the relatively low values of equivalent equilibrium concentration, that is typical for most buildings of the city. The estimates showed that the average radon concentration in brick houses is less than in slag-block houses: the values of radon equivalent equilibrium concentration – 6 – 188 and 10 – 235 Bq/m3, the average annual values – 41 and 54 Bq/ m3, respectively. Conservative estimates of annual doses of radon in all the surveyed premises do not exceed 10 mSv/year, and the average annual doses for most groups of buildings (kindergartens, schools, dwelling houses, medical institutions) are in the range of 2 – 3 mSv/year, and only for the group «Other institutions» - up to 4 mSv/year. 

This study is focused on the issues of remediation of sites and territories contaminated with radionuclides as a result of the past activities of the facilities. Actions performed at the territory of the «Mosrentgen» plant, contaminated by 137Cs after the radiation accident in 1962, are evaluated as an example. This paper provides a detailed description of the actions performed in 2012–2017 and the analysis of the mistakes made during the radiation survey, leading to the detection of the large volume of the radioactive wastes during the excavation at the construction of the industrial building at the decontaminated site. The authors propose a method of preliminary assessment of the 137Cs activity concentration in soil based on the gamma-radiation exposure rate on the surface of the soil batch. The results of the study indicate a necessity of development and implementation of the legislative base regulating the structure and types of surveys for remediation of facilities and territories.

Dose limits are commonly not applied for the radiation protection from medical exposure in the international practice; the principles of justification and optimization are used instead. However, the Russian Norms of the Radiation Safety NRB 99/2009 provide for the limitation (non-exceedance) of the doses for the healthy individuals undergoing X-ray examinations related to the employment-related, legal or screening purposes by 1 mSv per year. The aim of the study was to assess the feasibility of limiting the doses for the healthy individuals undergoing diagnostic medical X-ray examinations in the context of the revision of the Norms of the Radiation Safety. The study included the analysis of the existing Russian legislative documents regulating the medical exposure related to the employment-related, legal and screening purposes; evaluation of the imaging modalities commonly used for these purposes and conservative estimation of the effective doses per employment-related medical examination or a periodic health assessment. The results of the study indicate that a limit of 1 mSv per year is systematically exceeded for the healthy individuals undergoing X-ray examinations related to the employment-related, legal or screening purposes. Implementation of the modern screening methods (low-dose computer tomography, breast tomosynthesis) would lead to the significant increase of the effective dose per periodic health assessment up to 3-8 mSv per year. Hence, it is proposed to use the principle of the optimization with the establishment of the diagnostic reference levels for the screening X-ray examinations for the radiation protection of healthy individuals from medical exposure.