[en] One of the codes that the Instituto Nacional de Investigaciones Nucleares (Mexico) has for the nuclear reactors design calculations is the LEOPARD code. This work studies the reliability of this code in reactors design calculations which component materials are the same of the heavy water moderated and cooled, natural uranium fuelled power reactors. (author)

[en] In this study, an analysis of the behavior of ANISN code when the effective criticality constant (k) is applied to systems which simulate the associated conditions with nuclear fuel containers and pool storage with or without the presence of neutron poisons are presented. Different arrangements of assemblies and fuels with enrichments of 2.35 and 4.29 wt/% in Uranium 235 with the aim to determine the reliability of the code in similar conditions to the presented here were studied. (Author)

[en] The MCNP code is used to simulate the radiation transport taking as tools the transport physics of each particle, either photon, neutron or electron, and the generation of random numbers. Developed in the Los Alamos National Laboratory, this code has been used thoroughly with great success, because the results of the simulations are broadly validated with representative experiments. In the one present work the room of radiotherapy of the Institute Zacatecano of the Tumor it is simulated, located in the city of Zacatecas where one is Theratron 780C machine manufactured by MSD Nordion, with the purpose of estimating the contribution to the dose that would be received in different points of the structure, included three directly under the source. Three results of analytical calculations for points located at different distances from the source are presented, and they are compared against those obtained by the simulation. Its are also presented results for the simulation of 10 points more distributed around the source. (Author)

[en] The radiation and natural radioactivity is present in the man's food chain, like it is the case of the milk, and it comes from the natural series of radioactive decay of the ²³⁸ U, ²³⁵ U and ²³² Th, and of the ⁴⁰ K radioisotope. Since the radioisotopes can be found in floor of where its are transferred to the grasses and in the water that serve as food and of drinking to the cows, then to enter the milk and its derived to the human consumption. In this work it is presented the study of the radiation and gamma radioactivity of 40 samples of dairy formulas of the trademarks and presentations more sold in the market of the private and public sectors. The measurements of the gamma ray spectra were carried out with a spectrometry system based on an Hyper pure Germanium detector (HPGe). The detector has a resolution (FWHM) of 1.9 keV for an energy of the gamma ray of 1.332 keV of the ⁶⁰ Co. This study presents the results of the concentration in activity of dairy formulations of the radioisotopes of interest. Also, the results are related with possible damages to the health. (Author)

[en] The ²²⁶ Ra is one of the more radio toxic nuclides since when entering to the organism it continues metabolically to the calcium, accumulating mainly in the bone tissue where it becomes in an internal radiation source. For the analysis of radium in water the methods of radon emanation are generally applied and coprecipitation with barium sulfate. This last is quick and efficient, and the radium in the precipitate can be measured by alpha or gamma spectrometry, or liquid scintillation dissolving the precipitate one with EDTA. In this work it is proposed a procedure for the radium measurement in water based on the coprecipitation with barium sulfate and in the detection by liquid scintillation. The precipitate of Ba(Ra)SO₄ it is carried with water and blended with the liquid scintillator OptiPhase Hi Safe 3, avoiding the dissolution with EDTA. A 92± 1.4% of radium it was recovered and it was reached a minimum activity detectable of 4.2 ± 0.9 mBq^-1. The procedure was essayed with natural mineral water with a knew activity in concentration of ²²⁶ Ra. The analytic result it coincided with the reported value with a relative error of 9%. (Author)