Влияние турбулентности и восходящих потоков воздуха на дочерние продукты распада радона

In this paper, a simulation of the distribution of radon progeny over the height of the atmosphere, depending on the amount of turbulent mixing and the vertical air velocity, is presented. The obtained results are compared with the change in the activity ratio of Bi-214/Pb-214 isotopes recorded in rainwater during 3-year observations in Prague. It is found that the reasons for the most common values of Bi-214/Pb-214 can be the height of the lower edge of the cloud of 0.2-1.4 km and the vertical air velocity of 0.1 – 0.2 m / s. The ratio changes slightly from changes in the turbulent mixing, the value of the vertical air movement makes the main contribution. It is found that with the increase in the intensity of rain, a shift in the radioactive equilibrium should occur due to an increase in the velocity of vertical air. Atmospheric inversion is able to balance the volumetric activities of the descendants of atmospheric radon, atmospheric inversion can be identified by the equality between the activities of the radon progeny in the atmosphere at different altitudes or in rainwater. It is shown that the search for the relationship between precipitation intensity and gamma radiation is expose to error, without taking into account the influence of the АBi−214/АPb−214 ratio, due to the unequal activities of the atmospheric isotopes Bi-214 and Pb-214. This error of 7-14% when using gamma radiometry, and of 5-9% when using dosimeters is estimated. олучены результаты моделирования распределения дочерних продуктов радона в атмосферном столбе по высоте, объясняющие изменение концентраций радионуклидов в дождевой воде в зависимости от высоты нижней кромки облаков. Значения соотношений активностей АBi−214/АPb−214 радионуклидов дождевой воды от 0.6 до 0.8, могут возникать при высоте нижней кромки облаков от 0.2 до 1.4 км и адвекции от 0.1 до 0.2 м/с соответственно. Произведена оценка шибки от 7 до 14%, возникающая при использовании гамма радиометров, и от 5 до 9% — дозиметров, во время осадков с целью поиска корреляции роста гамма-фона и интенсивности жидких ливневых осадков.

Investigation of the Causes of Violations of the Radioactive Balance between Radionuclides of the Uranium Decay Chain

Throughout the literature, it is mentioned that 15 radionuclides in the uranium decay chain have a constant radioactive equilibrium. Theoretical calculations give the value of the activity of each radionuclide in the uranium decay chain.This article examines various factors that affect the coefficient of radioactive equilibrium between radionuclides in the uranium decay chainThe concept of the coefficient of violations of nuclear equilibrium between radionuclides is adopted to determine the degree of violations in the uranium decay chain.Many nuclear-physical factors influence the radioactive balance between radionuclides. The most important of them is the recoil energy that the daughter nucleus receives when splitting from the mother nucleus.Another critical factor in the violation of the radioactive balance between radionuclides is the technological factor: leaching (acid, mini-reagent, bicarbonate, etc.) when leaching uranium by underground leaching of uranium.In addition, as a theoretical result of the study, the article presents a graphical relationship between the number of nuclear masses and the recoil energy of radionuclides in the uranium decay chain.

The impact of the oil and gas industry on TENORM of the desert sands in Ma’rib, central Yemen

A measurement of technologically enhanced natural occurring radioactivity materials (TENORM) in sand samples in the petroleum-producing communities of Ma'rib Province Yemen was carried out. The HPGe detector was utilized to perform the measurements. The samples were collected from 35 sites. All samples were placed in a properly cleaned container and sealed for 28 days to attain a state of secular radioactive equilibrium before analysis. The radioactivity concentrations for nuclides 40K, 232Th, 226Ra, and 238U ranged between 430.716 - 654.666, 4.347 - 43.935, 4.824 - 27.936, and 1.083 - 15.437 Bq kg-1 respectively, with averages 560.583, 20.676, 14.556 and 9.072 Bq kg-1 respectively. The results did not show any radiation risks.

Environmental radioactivity studies at the Nuclear Engineering Laboratory of the National Technical University of Athens

<p>The Nuclear Engineering Laboratory of the National Technical University of Athens (NEL-NTUA) is among the oldest laboratories conducting radioactivity mesurements in Greece, founded in the early sixties. One of the main activities at NEL-NTUA is environmental radioactivity studies, mainly based on gamma spectroscopic analysis. For this purpose NEL-NTUA is equipped with a variety of Germanium detectors for in-vitro and in-situ measurements. Starting back in the early eighties, environmental radioactivity studies at NEL-NTUA were significantly boosted after the Chernobyl accident in 1986  when they focused on the Chernobyl fallout radionuclides, as well as some natural radionuclides typically determined in environmental studies, namely <sup>232</sup>Th, <sup>226</sup>Ra and <sup>40</sup>K. As a result of these studies maps of nine Chernobyl fallout radionuclides and the three natural radionuclides in continental Greece surface soils were produced. </p><p>Since natural radioactivity in soil is in most cases relatively low, high volume samples had to be analyzed. Over the years, the acquisition of detectors capable of detecting low energy photons (LEGe) along with the development of techniques to correct for self-absorption of low energy photons within the sample, allowed for the accurately determination of radionuclides emitting such photons, like <sup>234</sup>Th (63.29keV), <sup>210</sup>Pb (46.52keV) and <sup>241</sup>Am (59.54keV). These newer studies showed that a significant disruption of radioactive equilibrium in surface soil between <sup>226</sup>Ra and <sup>210</sup>Pb is very common, while radioactive equilibrium disruption between <sup>238</sup>U and <sup>226</sup>Ra is common as well. It is interesting to notice that the mean activity ratio <sup>210</sup>Pb/<sup>226</sup>Ra as obtained from ~300 sample measurements is of the order of ~4, while the mean activity ratio<sup> 226</sup>Ra/<sup>238</sup>U was estimated to be around one. A mapping of radioactive equilibrium disruption that followed provided interesting results.</p><p>In the years to follow studies focused on the vertical distribution of natural (<sup>210</sup>Pb) and artificial (<sup>137</sup>Cs) radionuclides in soil and sea sediments and the study of radionuclides fractionation in soil as well as NORM. Both types of studies require the analysis of small volume samples – of the order of 20-50g or even less. Therefore, the development of techniques for sampling of soil vertical profile and the accurate analysis of small samples was of great importance. These analyses require high efficiency detectors, such as XtRa detectors, background reduction techniques, such as Compton Suppression Systems, optimized sample geometries for higher full energy peak efficiency. Sophisticated techniques for background determination and subtraction, in order to obtain accurate results for natural radionuclides which are often detected in the background, are also required.</p><p>Another field of research at NEL-NTUA is the development and improvement of techniques for monitoring of <sup>222</sup>Rn daughters outdoors using on-line detector systems, as well as for monitoring of natural and artificial radionuclides in atmospheric precipitations and aerosols (<sup>7</sup>Be, <sup>210</sup>Pb, <sup>22</sup>Na) using high volume air samplers.</p><p>Aim of this work is to present the research conducted at NEL-NTUA over the years with regard to the environmental radioactivity, as well as the current activities in the field and those planned for the future.</p>

SOIL AND RADIONUCLIDES OF EASTERN HERZEGOVINA

Soil is one of the most important natural resources. Measurement of natural radioactivity in soil is very important to determine the amount of change of the natural background activity with time as a result of any radioactivity release. Coal mine and thermal power plant in Gacko field is a very important industrial facility. The content of radionuclides of the soil was examined at Gacko area, slag, ash and mullock dumps in thethermal power plant Gacko and soils of dumps in the process of re-cultivation. The gamma – spectrometric measurements were done in the Institute of Nuclear Sciences “Vinča” in Belgrade.Soil samples were collected in 2010/2014 at more locations in eastern part of Republic of Srpska. After removing the stones and vegetation, all soil samples for Gama spectrometric measurements dried up to 0 105 C, sieved, placed in the plastic 500 mL Marinelli beakers and left for four weeks to reach radioactive equilibrium. Given that there are no specific regulations in the Republic of Srpska, the concentration of natural and produced radionuclides in samples from the working and living environment of thermal power plants, comparison with literature data from the region and the world is one way of evaluating the impact of the plant's operation on the soils. The results point to the necessity of regular monitoring of radioactivity in eastern Herzegovina in order to assess the impact of the technologically increased natural radioactivity.