[en] The conceptual procedure and computational features of the DOSSKIN code are shown. This code calculates, in a very interactive way, skin equivalent doses and radiological risk related to skin radioactive contaminations. The evaluation takes into account the contributions of contaminant daughter nuclides and backscattering of beta particles in any skin cover. DOSSKIN also allows to estimate the maximum time needed to decontaminate the affected zone, using, as input quantity, the limit value of skin equivalent dose considered by users. The comparison of the results obtained by the DOSSKIN code with those reported by different authors are showed. The differences of results are less than 30%. (authors). 4 refs., 3 fig., 1 tab

[en] The monitoring and dosimetry systems used at Industrial Application and Engineering Service Department of the Instituto de Pesquisas Energeticas e Nucleares of the Brazilian Nuclear Energy Commission (GE-IPEN-CNEN/SP) are analyzed,in order to verify the compliance with the condition established by the dose system limitation and the basic radiation protection standards. The criteria about the use of individual dosimetry for persons that work in these facilities are established. In case of an external radiation dosimetry, by using film badge method, a level of 200μGy has been assigned, considering the detection significant threshold. For dose in air due to electromagnetic radiation, using TLD dosimetry of CaSO₄:Dy a quarter year significant threshold is 101μGy. A symbiosis between the workplace monitoring and the individual monitoring became necessary for optimization purpose. (authors). 5 refs., 2 tabs., 1 fig

[en] In this paper, the doses, due to food consumption, received by three villages placed around CEN Juragua (at present under construction) are calculated in the emplacement zone of the Nuclear Center (15 Km. around the facility). The selected villages have different food habits, so they receive different irradiation levels. The ingestion rate of food, the natural radionuclide concentrations existing in the environment (Cs-137, Sr-90, Ra-226, Th-232, Po-210 and Pb-210) and the dose conversion factors given by the International Commission on Radiological Protection (ICRP) were used in the assessment. More than 300 analysis carried out in a period of 6 years were compiled for the study. The doses received by people of Castillo del Jagua are analyzed in detail because they are high consumer of marine products. Groups of people receiving annual dose around 1 mSv, only by this kind of foods, were detected. (authors). 5 refs., 5 tabs

[en] The chemical and physical behavior of the radiotracer I-131 through a porous matrix are described. The study was evaluated using the laboratory column, which contains porous soils. The collected activities have been measured by gamma counting with a NaI(Tl) detector. The indicators were observed and analyzed by using the one dimension mass transport equation. The solution was utilized to interpret the obtaining experimental data. The experimental values of I-131 are in agreement with those calculated by the model. However, the utilization of (I-131) in the punctual hydrogeological studies is proved. (author). 5 refs., 2 figs., 2 tabs

[en] In order to evaluate postclosure off-site doses from a low-level radioactive waste disposal facilities, an integrated safety assessment methodology has being developed at Instituto de Pesquisas Energeticas e Nucleares. The source-term modelling approach adopted in this system is described and the results obtained in the IAEA NSARS 'The Safety Assessment of Near-Surface Radioactive Waste Disposal Facilities' programme for model intercomparison studies are presented. The radionuclides released from the waste are calculated using a simple first order kinetics model, and the transport, through porous media below the waste is determined by using an analytical solution of the mass transport equation. The methodology and the results obtained in this work are compared with those reported by others participants of the NSARS programme. (author). 4 refs., 4 figs

[en] The objective of this paper is to present the basis for shielding calculation used in different situations that could occur during the transport of ¹³¹I utilized in nuclear medicine for diagnostic and therapeutic purposes. The aim of these calculation is to optimize the shielding in order to satisfy the transport of radioactive material. These calculations were proposed for estimated activities around 1,85 GBq (50mCi), 3,7 GBq(100mCi) and 7,4 GBq(200mCi), considering the driver of the cargo company and his assistant as the critical group and the general people considered as effect of collective dose. The population density considered in the models is the one related to Sao Paulo city, because the transport is done by the highway across the city and the radioactive material is distributed from west to north and south, where the airports are located. This area ranges a perimeter of 40 km. For the collective dose calculation, it was considered a population dose of less than 1/100 of the annual limit dose for the public. Our main concern is related to the large volume of radioactive material that is transported per week, specially because 1/3 of this material has activities around 3,7 GBq (100mCi). During the calculations, we have figured out that the activities at the moment of transport are nearly 40% greater than the one related to the calibration date. As for the discrepancy of official alpha value of US$10000/man-Sv and the real value for our country of US$3000/man-Sv,a comparative study was performed. (authors). 3 refs., 2 figs., 2 tabs

[en] The increasing use of ionizing radiation in the medical field as well as in industry and research grants has special importance to the security aspects related to the individual as well as his surroundings, reason for which the implementation of effective Occupational Radiation Protection Programmes constitutes a priority. Presently, in Guatemala, an Occupational Medicine Programme, directed to the Radiosanitary watch over of occupationally exposed personnel does not exist. It is the goal in this project to organize and establish such programme, based on protective and training actions focused toward the employee as the main entity, his specific activities and his work surroundings. Medical watch over together with Radiation Protection will permit the reduction of the occurrence probability of accidents or incidents, as well as the limitation of stochastic effects to the undermost values. The application scope of the present project is, in the first place, directed to the occupationally exposed personnel of the Direcci[n General de Energ[a Nuclear, as regulatory entity of these activities, and afterwards, its application in the different institutions which work with ionizing radiations. All the previously exposed is based on the Nuclear Legislation prevailing in Guatemala as well as the recommendations of international organizations. (author)

[en] The preliminary research studies carried out to implement the liquid radioactive waste conditioning by cementation are described. First of all, different kind of commercial cements in Peru are analyzed. In the first step, the analysis were made without using the radioactive material. The analyzed parameters were density, porosity, setting time and mechanical strength of a cement type called 'Atlas'. Samples of two geometries were used. One of them was a cylindrical sample (48mm diameter and 48mm height) and the another one was a prismatic sample (40x40x160mm). The results of the different kind of analysis are presented in this paper. (authors). 2 refs., 3 tabs

[en] The objective of this work is to introduce the fractal geometry concept to the study of gaseous emanations in solids, specially with reference to radon emission in mineral grains. The basic elements of fractals theory are developed. A fractal is defined as an auto similar subassembly, which fractal dimension is greater than the topological dimension. Starting from this, and making a brief description of the physicals basis of radon emission in solids, a model between emanation power (E_R) and the ratio s/v (surface to volume), is founded. A Gaussian model is assumed for extent of recoil from alpha decay of Ra-226. Using the results of Pfeifer it is obtained that distribution of pore size is scaled like Br^-D-1, where D: fractal[dimension, B: constant and r: pore radius. After an adequate mathematics expansion, it is found that the expression for emanation power is scaled like r₀^D-3 (r₀ grain radius). We may concluded that if we have a logarithmic graph of E_R vs size of grain we can deduce the fractal dimension of the emanation surface. The experimental data of different materials provides an interval into fractal dimension D , between 2.1 to 2.86. (author). 5 refs., 1 tab

[en] Concentration levels of ²²⁶Ra and ²²²Rn have been analysed in most of the mineral spring waters available in the Aguas da Prata region, which is located in the Pocos de Caldas plateau, one of the biggest weathered alkaline intrusions of the world. In this plateau can be found many health resorts[based on springs of thermal and mineral waters. The Aguas da Prata spring waters show a large variety of composition. It has been observed bicarbonates, carbonates and sulphates salts in these mineral waters. The ²²⁶Ra was determined by gross alpha counting of a Ba(Ra)SO₄ precipitate. The measurement was carried out in a low background gas flow proportional counter. The ²²²Rn concentrations were determined by liquid scintillation method. Water samples were randomly collected at 9 spring sites over a period of one year, in order to evaluate the seasonal variation of these radionuclides. Lower concentrations were found mostly in the rainy season (summer), which presents 80% of the annual rainfall of the region (1500 mm/year). Higher concentrations up to 2223 mBq/L for ²²⁶Ra and 131 Bq/L for ²²²Rn have been observed in waters with low level of soluble salts. Waters which present high levels of carbonate and sulphate salts showed maximum values of 316 mBq/L for ²²⁶Ra and 30 Bq/L for ²²²Rn. This behaviour is mainly due to the physicochemical properties of these radionuclides in water as well as to the lithologic structure of the aquifers. (authors). 6 refs., 2 figs., 1 tab