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Objective: scientific substantiation of the new methodology for estimation of passport doses of the settlements which belong to Zone of Unconditional (obligatory) Resettlement, or 2nd zone and Zone of Granted Voluntary Resettlement, or 3rd zone in the framework of dosimetric passportization in accordance with the legislation of Ukraine. Materials and methods. 37 years after the accident, radioactive contamination of the environment has significantly decreased. However, it is still necessary to carry out ecological and dosimetric monitoring and apply countermeasures in certain territories of Ukraine affected by the accident at the Chornobyl Nuclear Power Plant: restriction of the consumption of locally produced milk, forest products, etc. The methodology, which was since 1996 used to estimate the passport doses of Ukrainian settlements, no longer corresponds to the current level of scientific knowledge about radioactive contamination of environment. The new methods of passport doses calculating presented in the work involves the use of a model whose parameters are determined by the types, quality and completeness of radioecological and dosimetric monitoring carried out on the radioactively contaminated territories in 1986-2013. The methodology takes into account the specific of radioactive contamination of each settlement. The passport dose of external exposure is reconstructed only from 137Cs radionuclide, because the contributions of other Chornobyl radionuclides influence the radiation dose only in the first years after the accident. The passport dose of internal exposure is formed as a result of the consumption of 137Cs contaminated food products. It is calculated depending on the availability in the settlement in the current year of the results of measurements of the 137Cs radionuclide activity incorporated in the human body using a whole body counter (WBC) and the activity of 137Cs in the private milk. At the same time, priority is given precisely to the results of WBC measurements of 137Cs. Results and conclusions. A new methodology (Methodology-2023) for passport doses calculation of Ukrainian settlements was substantiated. A comparison of passport doses based on the results of radioecological and dosimetric monitoring in 2011 calculated by Methodology-2023 and passport doses calculated by Methodology-96 was made. Passport doses calculated by Methodology-2023 increased by 40 % on average compared to doses calculated by Methodology-96. At the same time, passport doses of internal radiation calculated by the new methodology increased by 1.5 times, and passport doses of external radiation increased by 1.7 times. The passport dose of 2011, calculated by Methodology-2023, exceeds the legally established limit of 1 mSv in 71 settlements, most of which are located in Korostenkyi raion of Zhytomyr Oblast. [ABSTRACT FROM AUTHOR]

Objective of research is to improve the electronic database of WBC measurements dated 1986 by inputting of new information from paper carriers, reconstruction of information gaps, verification and analysis of new entered data, revision of internal exposure doses that are based on results of WBC measurements dated 1986. Materials and methods. In 2013–2015 during a revision of databases (DB) of WBC measurements results dated 1986–2014, it was discovered a great amount of paper carriers with information about WBC measurements, includ& ing the ones dated 1986, that were not inputted to the electronic DB. The paper carriers were systematized and ordered by the following indicators: place of residence of a person and place of WBC measurement, institution and operator that made the measurement, measurement device and date of measurement. For a comfortable inputting of the information to the electronic DB, it was additionally created a form which exists as an option in existing pro& gram complex Silbody (Version 19.0.9). In the revised DB of WBC measurements dated 1986 internal exposure doses from radio-cesium of Chornobyl origin were computed based on an ecological and dosimetric model for radio-cesium migration in environment and a model for radio-cesium metabolism in human body. In the work, mathematical and statistical methods of research were used. Results. In 2019–2021 additionally 35,319 notes were inputted to the electronic DB of WBC measurement dated 1986, and as a result its volume increased in 2.2 times. Mostly those are data on results concerning residents of Kyiv, Zhytomyr, Donetsk, Cherkasy, Odessa, Ivano-Frankivsk, and Rivne Oblasts. It was established the information on measurement devices and respectively on the minimal detected activity (MDA) for 27,119 notes (76.7 % of all new entered). Information is reconstructed about the body mass of all persons under investigation. Evaluation is made for values of intake of incorporated radionuclides 137Cs and 134Cs for all new entered to DB. Quality of reconstructed information was analyzed. To group 1, «qualitative», it was classified 18,598 notes (53 % of all new entered), measurements in 1986 (including new entered). Dose not exceeding 1 mSv was obtained by 80 % of adults (older than 20), as well as 73 % of persons younger than 20. Conclusion. To DB of WBC measurements, it was additionally inputted 35,319 notes on results of measurements dated 1986. New entered information is verified and distributed by the quality groups. Individual exposure doses evaluated based on those data can be used for further scientific research. [ABSTRACT FROM AUTHOR]

Objective: revision, analysis, and significant improvement of quality of the database of WBC measurements made in 1986-2014 at radioactively contaminated territories of Ukraine by the use of renewal of informational gaps and improvement of the model for assessment of internal exposure doses. Materials and methods. Inthe period from 1986 to 2014 experts of the Whole Body Counters Laboratory of NRCRM accumulated about 1.5 million results of WBC measurementsof radio-cesium incorporated in the body of persons residing at the territories which are radioactively contaminated due to Chornobyl accident. Most of measurements (~64%) were made during the first 15 years after the accident. The most of measurements were made in Kyiv (~23%), Zhytomyr (~36%), Rivne (~20%) and Chernihiv (~5%) Oblasts. Works on revision of database of WBC measurements included: transformation of data saved in paper format into electronic form, checking for correctness and correspondence of information, renewal of lacking information at the fields of database, improvement of the model for evaluation of internal exposure doses by the data of WBC measurements. In the model for evaluation of revised doses, it is assumed uniform content of radio-cesium during a year. Reference values are used of metabolism parameters and anthropometric human parameters recommended in publications of ICRP. Results. Revised doses have been reconstructed for 1,386,585 records of data base of WBC measurements that fit specially elaborated criterions for estimation of quality of results. Among them 604,215 records are WBC measurements of children and adolescents younger than 18, and 782,370 records correspond to adult inhabitants of Ukraine, most of which reside in Zhytomyr, Kyiv, Rivne and Chenihiv Oblasts. Conclusions. Obtained results serve as a ground for further works on improvement of models for evaluation of passport doses and individualized exposure doses of subjects registered in Ukrainian State Register - of persons that affected due to Chornobyl accident. Evaluated doses can be used for epidemiological, clinical and other research. [ABSTRACT FROM AUTHOR]

Study objective. To elaborate an ecological&dosimetric model of reconstruction individualized exposure doses of subjects from the State Register of Ukraine (SRU) - of persons, affected due to Chornobyl accident and reside at the radioactive contaminated territory of Korosten raion of Zhytomyr Oblast, and to calculate exposure doses for those persons. Materials and methods. In the paper, an ecological&dosimetric model is presented which is elaborated in order to individualize exposure doses of people who reside in Korosten raion of Zhytomyr Oblast and are registered in SRU. The model is based on the results of radio&ecological and dosimetric monitoring held in the period of 1986-2013 at the territory of northern oblasts of Ukraine. Annual dose over each post&accidental year consists of the two compo& nents: (a) annual effective dose of external gamma exposure (due to radioactive fallout on the ground), and (b) internal exposure of the whole body (due to consumption of meal contaminated by radioactive isotopes). For 1986, the dose of internal exposure is evaluated out of all main radionuclides of radioactive accidental fallout, and after 1987 only for radioisotopes of caesium (134Cs and 137Cs). The parameterization of the model is based on the pre& vious experience in working out a complex of ecological&dosimetric models for estimation of referent exposure doses of Ukrainian population. Results and conclusions. Individualized doses of external and internal exposure (annual and accumulated) are estimated for the population of various age groups that resides in the settlements of Korosten raion (totally about 100 settlements). Separately the doses are presented for rural settlements of the raion and for the city of Korosten for each year of the post&accidental period of 1986-2016. Estimates of doses are given that were accumulated: (a) during 15 years just after the accident, (b) for the period of 2000-2016, and (c) for 30 year period after the acci& dent. Mean dose accumulated for 30 years after the Chornobyl accident by residents of rural settlements of Korosten raion is estimated as 19.8 mSv, and for inhabitants of the Korosten city as 20.9 mSv. On condition of permanent res& idence in the raion, residents of about 66% settlements of Korosten raion accumulated the doses in the interval 5& 20 mSv during 30 years after the accident. For the residents of about 25% settlements the accumulated dose is in the interval 20-50 mSv, and for 7% of settlements it exceeds 50 mSv. [ABSTRACT FROM AUTHOR]

Objective. Examination and experimental reconstruction of the historical WBC&measuring procedure in 1986 and estimation of the minimum detectable activity (MDA) of those measurements. Materials and methods. The SRP&68&01 gamma&spectrometer with attached scintillation detector based on a NaI(Tl) O 30 x 25 mm2 crystal and NC&482&ВМ one&channel spectrometer (Bicron Co.) with attached scintillation detector based on a NaI(Tl) O 52 x 52 mm2 crystal were used for the study. Protective chamber of the expert&type whole&body counter (WBC) and homogenous human body dummy phantoms filled with dry radioactive material were applied. Results of measurements on the WBC «Screener&3M» were retrieved from the Radiation Registry of the NRCRM. Dosimetry and mathematical methods were applied too. Results and conclusions. The WBC&measurement procedure was reconstructed using the examples tested in 1986 to assay the level of incorporated radioactive cesium in population of contaminated territories. MDA under the WBC& measurements in 1986 was found being from 1.3 kBq per human body using the NC&482&ВМ one&channel spectrom& eter with attached scintillation detector based on a NaI(Tl) O 52 x 52 mm2 crystal up to 7.4 kBq per human body using the SRP&68&01 gamma&radiometer radiometer with attached scintillation detector based on a NaI(Tl) O 30 x 25 mm2 crystal in adults under the 60 seconds measurement time. The respective values for adolescents and chil& dren were within 0.8-5.6 kBq per body and 0.5-3.8 kBq per body. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this research is to make analysis, revision and estimation both reliability and accuracy of all measurements of radioiodine in the thyroid for residents of Ukraine, which were performed in 1986, and to jus% tify the calibration factors to be applied for interpretation of measurements performed by non%calibrated devices. Materials and methods. The radioiodine activity in the thyroid for residents of the most contaminated oblasts of Ukraine has been calculated on the base of 150 thousands direct measurements of the content of 131I in thyroid obtained in the frames of the thyroid monitoring in 1986. A method for the calculation of measurement errors has been developed and the accuracy of the errors has been determined assuming that the density of errors' distribu% tion for main parameters of the measurements is close to Gaussian. Using the results of laboratory measurements, the calibration factors have been determined for integrated radiometers SRP%68%01 - devices which were often used to perform the thyroid dosimetric monitoring. Results. The distribution of estimates on the content of radioiodine in thyroid is close to the lognormal one with geometric mean being equal to 4.8 kBq and geometric standard deviation being equal to 3.8. Most of these esti% mates (90%) are in the range of 0.58-47 kBq, and the main set of their relative errors (90%) are between 0.1 and 0.6. Thus, the model of thyroid activity observation with classical additive error has been obtained. [ABSTRACT FROM AUTHOR]

The objective of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of after-math of the Chornobyl accident through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring. The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014. The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 raions in 12 oblasts during all the post-accident period. Thanks to the works of dosimetric pass-portization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important radiological parameters, namely over 500 thousands of measurements of concentration of 137Cs and 90Sr in the local foodstuff (milk and potatoes); there are more than 1.3 million of measurements of the cesium content in the body of residents of the settlements of Ukraine; there are 100 thousands of dose estimates (both internal and external ones were measured separately) of inhabitants living on the radioactively contaminated areas. The results of the dosimetric passportization served as one of the main exposure criteria for generalized aftermath of the Chornobyl accident represented in the National reports for the first 15, 20 and 25 years after the accident. [ABSTRACT FROM AUTHOR]

Since 2007, the department of dosimetry of NRCRM has been working for to supply the Ukrainian State Register (SRU) of persons affected due to Chornobyl accident by exposure doses estimations. As of now, the individualization of doses has been performed for nine raions located in Kyiv, Zhytomyr, Rivne and Chernihiv oblasts. The structure of raion-specific models used for the reconstruction of individualized doses was described in detail in the previous 19-th issue of this Journal (2014). The choice conditions for persons from the SRU using which for each raion there was formed a contingent of persons for whom the dose could be reconstructed. During the period of 2007-2015, the individualized dose was reconstructed for 244226 persons in 9 raions, representing ~ 58% of all registered in the SRU inhabitants of the raions. The calculation results were transferred to the SRU in formats adapted to the common database structure of the SRU. For each person who satisfied the conditions of selection there were estimated: 1) possible absorbed internal exposure dose of the thyroid by radioiodine in 1986 (assuming that the person in 1986 lived in the same village where he/she was enlisted in the SRU); 2) annual doses of external, internal and total exposure of the whole body for a period of observation in the SRU; 3) total exposure dose of whole body accumulated during the period of observation in the SRU; 4) the total cumulative dose of feasible exposure during the period since 1986 till the decision to be registered in the SRU. There are presented the generalized results of the SRU subjects distribution for different raions in dependence on intervals of doses accumulated at different periods after the accident. The raion matrix tables show the dynamics of accumulation of doses by the SRU subjects both for their stay on the account and for the period of their possible residence in the settlement of registration since 1986. The directions for further research to be implemented for increasing the number of persons for whom it is possible to calculate individualized dose have been formulated. [ABSTRACT FROM AUTHOR]