Chernobyl tragedy and its complications

On April 26, 1986, an accident occurred at the Chernobyl Nuclear Power Plant. The accident at the Chernobyl nuclear power plant was perhaps one of the greatest tragedies in human history. The fire, which lasted for nine days, caused great damage. While most of the radioactive cloud that formed after the station exploded was moving toward Eastern Europe, the rest of the "death cloud" was blown south by the winds. In general, the incident caused great damage to the Ukrainian economy. In 12 regions of Ukraine, 50,000 square kilometers were highly polluted. The nuclear accident killed about 15,000 people and affected thousands of others. The largest accident in the history of world energy is the Chernobyl accident. It was decided to mark April 26, 2017 as World Remembrance Day in connection with the Chernobyl tragedy. According to the Society of Chernobyl Disabled People in Azerbaijan, there are currently more than 5,000 participants in the Chernobyl accident in our country. Today, the state is taking necessary measures to strengthen the social protection of Chernobyl victims in Azerbaijan and protect their health. Key words: Chernobyl, Ukraine, AES, Pripyat, “dead city”, tragedy, radiation, “death cloud”

Updated Incidence of Thyroid Cancer in the North East Region of Romania after 35 Years of Chernobyl Fallout. Is There a Link between?

Thyroid cancer (TC) represents a worldwide problem, the consistent growth of the incidence increment issues about management of risk factors and curative treatment. Updated statistical data are not complete in the North East region of Romania and need to be improved. Therefore, through this study, we aim to renew the existing data on thyroid cancer. We conducted a retrospective study covering a period of 10 years. Data were collected from a hospital information system (InfoWorld) between 2009 and 2019. Patients’ age groups were stratified in relation with the age at the moment of the Chernobyl event. A database was obtained (Microsoft Excel) and statistical correlations were applied. In the studied period, 1159 patients were diagnosed: 968 females and 191 males, distributed by region, with the highest addressability in Iasi (529), followed by neighboring counties. Age distribution displayed that most of the thyroid cancers were in the range 4060 years old (50.94%), followed by 60–80 years old (32.41%). Most patients were diagnosed with papillary carcinoma 63.10%, then follicular 14.7%, medullary 6.74% and undifferentiated 1.02%. Romania was in the vicinity of the radioactive cloud at Chernobyl fallout, so we must deliberate whether the increased incidence of thyroid cancer in the age group 40–60 years is associated with radiogenicity (iodine 131) given the fact that over has 35 years and the half-life of other radioisotopes like Caesium-137 and Strontium -90 is completed.

Modelling of Pulse Height Spectra of Gamma Detectors for Simplified Models of a Radioactive Cloud

The paper considers the issues of determining the pulse height spectra of gamma detector from a radioactive cloud. This task is of interest from the point of view of possible improvement of existing systems for monitoring the radiation situation around nuclear power plants and nuclear industry enterprises due to the wider use of gamma-spectrometric equipment. Modeling of pulse height spectra will allow conducting research on the capabilities of monitoring system posts for detecting radionuclides in the radioactive cloud. A general approach to modeling pulse height spectra using division of the radioactive cloud into elementary gamma sources is developed. The pulse height spectra of scintillator NaI ∅63×63 mm are calculated for simplified models of the radioactive cloud in the form of a linear gamma source and a semi-infinite space. The obtained data can be used for rapid estimates of pulse height spectra, while the formulated approach to spectra modeling also allows for more time-consuming calculations for an arbitraryshaped radioactive cloud with an arbitrary radionuclide composition.

Hybrid monitoring concept development. Modeling of pulse height spectra of gamma-radiation emitted from radioactive cloud released from NPP

In emergency situations with the release of radioactivity to the environment, possible radiation doses to the affected public are estimated with computational modeling. However, it should be noted that the estimates to a certain degree depend on various calculation parameters that may make the predicted radiation doses inconclusive. To reduce occurring uncertainties is possible by adjusting estimated outcomes with measurement data. The gamma-radiation spectra from the released radioactive cloud is measured by systems for radiation situation monitoring in the area surrounding the source of radioactive materials release. The feasibility study aimed at obtaining information needed for improvement of radiation doses estimates quality should be carried out. Due to certain problems related to performance of experimental work, there is the need to devel-op new approach to calculate gamma-spectra of radioactivity emitted from the released cloud. The solution of this problem will allow to select the parameters of equipment and measurement parameters necessary for adjusting the forecasts of radiation doses to the population in a case of accidents with a radiation factor based on the results of processing gamma radiation spectra.

Fuel particles in consequences of the accident at the ChNPP

As a result of the nuclear explosion at the fourth block of the Chornobyl NPP (ChNPP), the radioactive cloud containing an aerodispersed system with aerosols formed at the explosion appeared in air above the ChNPP territory. The accident occurred at the end of the reactor company before the assumed reloading of the active zone. Thus, the cloud composition included the products of fission and activation of uranium that were accumulated in the reactor fuel during the company. On that night, the east wind carried the radioactive cloud to the west, by leaving the aerosol fallouts on Earth’s surface as a radioactive trace. The results of the own studies (1986–1990) of aerosol fallouts on the west trace formed at once after the explosion at the ChNPP are presented. On this basis, the characteristics [physico-chemical forms, radionuclidic composition, activity median aerodynamic diameters (AMADs), etc.] of the aerodispersed system created at once after the explosion of the active zone of the reactor are reconstructed. In the frame of the respiratory model given in ICRP Publication 66, the contributions caused by the inhalation of fuel particles (microscopic particles which are fragments of exploded fuel elements and have conserved mainly their radionuclidic characteristics) to the doses of irradiation of parts of respiratory organs and gastrointestinal tract (GIT) are evaluated. It is shown that the cause for a mass cough in the summers of 1986 and 1987 on territories underwent the action of emergency fallouts was the inhalation of radionuclides of ruthenium in the form of RuO4 that was formed in “hot” particles contacting with air and then evaporated from them. The “hot” particles are compact inclusions formed by fission products. They consist mainly of atoms close to noble metals (molybdenum, ruthenium, rhodium, etc.) formed during a regular operating period in fuel tablets and released from the latter at the explosion of the active zone. The reasons for the disagreement between the clinic consequences and the ascribed values of the dose for the sufferers who were present in premises of the NPP at the emergency time and then died from acute radiation sickness in three-four weeks after the accident are explained.

The Chernobyl tragedy

On April 26, 1986, an accident occurred at the Chernobyl Nuclear Power Plant. The accident at the Chernobly nuclear power plant was perhaps one of the greatest tragedies in human history. The fire, which lasted for nine days, caused great damage. While most of the radioactive cloud that formed Eastern Europe, the rest of the “death cloud” was blown south by the winds. In general, the incident caused great damage to the Ukrainian economy. In 12 regions of Ukraine, 50,000 square kilometers were highly polluted. About 15,000 people died and thousands were affected by various diseases the nuclear accident. The largest accident in the history of world energy is the Chernobyl accident.

Unmanned Radiation Monitoring System

The absence of online radiation monitoring systems has been observed in the case of Fukushima nuclear accident. As the tsunami destroyed 23 of the 24 status monitoring points, almost no relevant radiation dose measurements data were available. A rapid deployment of a mobile radiological unit that can quickly determine the activity and direction of the radioactive cloud spread on the ground or in the air can prevent unnecessary deaths and related financial losses. Although the design of the current generation of NPPs incorporates features that minimize the risk of large radioactive releases outside the reactor, it is still important to focus on the development of systems that can mitigate the consequences of such events. In situations when the level of radiation does not permit the personal to perform the required measurements, online unmanned radiation monitoring systems may come to the play. For such a purpose the RMS-00x radiation monitoring system could be used, which is a modular system covering the functionality of dose rate measurement, air sampling and radiation map creation without requiring the human personnel to be present at the measurement site. The main purpose of the RMS-00x radiation monitoring system is the rapid deployment of unmanned monitoring devices to reduce the radiation burden on workers and on public. The system can be applied in the vicinity of a nuclear power plant (NPP) or at any location, where source of ionizing radiation could be present. Before this system is used in real conditions, its components must be thoroughly calibrated, based on certified measurement equipment and state-of-art simulation tools. This paper deals with the description of the RMS-00X sensor modules and demonstrates their functionality in combination with UAV. In addition, demonstration of the use of the developed technology was carried out as part of the regular emergency planning and preparedness of EBO NPP on 26th October 2017.

REFERENCE SURFACE FOR IN SITU GAMMA SPECTROMETRY

Chemical laboratories of the Fire Rescue Service of the Czech Republic are part of the radiation monitoring network and participate in the radiation situation monitoring in the Czech Republic. Measurements in situ are crucial for monitoring the radiation situation in emergencies associated with the deposition of radioactive substances on a large area. Those data can be used for estimating a possible dose obtained either by staying in a contaminated area or by consumption of food produced in the area. For correct setting of device parameters (e.g. efficiency calibration), standard samples should be measured regularly. Unlike in laboratory, verification in field conditions is difficult. Therefore, a search for suitable reference areas containing a higher amount of 137Cs homogeneously dispersed after the fall of a radioactive cloud passing through our territory following the Chernobyl accident was conducted. Small airports in the East Bohemia regions were identified as suitable candidates.