Autoridad Regulatoria Nuclear

Puerto Rico, Argentina

Autoridad Regulatoria Nuclear

Puerto Rico, Argentina
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Aguiar J.C.,Autoridad Regulatoria Nuclear | Di Rocco H.O.,National University of Costa Rica | Di Rocco H.O.,CONICET
European Physical Journal D | Year: 2013

The 4s4p configuration of Zn is analyzed using the Relativistic jj-coupling approach. The experimentally determined relativistic Slater integrals are compared with the results of numerical codes, both quasi- and fully-relativistic ones. In this work, they are estimated, semi-empirically, the two J = 1 levels up Z = 70 and the 1P1 level up Z = 92 by judicious interpolation and extrapolation of energies. The comparison with extensive relativistic configuration-interaction calculations indicates that differences between both approaches are of the order of measurement accuracies. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

PubMed | Public Health England, University of Federal Defense Munich, Health Canada, Oak Ridge Associated Universities and 4 more.
Type: | Journal: Radiation protection dosimetry | Year: 2016

The BioDoseNet was founded by the World Health Organization as a global network of biodosimetry laboratories for building biodosimetry laboratory capacities in countries. The newly established BioDoseNet image repository is a databank of ~25000 electronically captured images of metaphases from the dicentric assay, which have been previously analysed by international experts. The detailed scoring results and dose estimations have, in most cases, already been published. The compilation of these images into one image repository provides a valuable tool for training and research purposes in biological dosimetry. No special software is needed to view and score the image galleries. For those new to the dicentric assay, the BioDoseNet Image Repository provides an introduction to and training for the dicentric assay. It is an excellent instrument for intra-laboratory training purposes or inter-comparisons between laboratories, as recommended by the International Organization for Standardisation standards. In the event of a radiation accident, the repository can also increase the surge capacity and reduce the turnaround time for dose estimations. Finally, it provides a mechanism for the discussion of scoring discrepancies in difficult cases.

PubMed | National University of Colombia, Brazilian Radiological Protection and Dosimetry Institute (IRD), Eletrobras, Hospital San Juan Of Dios and 14 more.
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2016

Internal dosimetry intercomparisons are essential for the verification of applied models and the consistency of results. To that aim, the First Regional Intercomparison was organised in 2005, and that results led to the Second Regional Intercomparison Exercise in 2013, which was organised in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear of Argentina. Four simulated cases covering intakes of (131)I, (137)Cs and Tritium were proposed. Ninteen centres from thirteen different countries participated in this exercise. This paper analyses the participants results in this second exercise in order to test their skills and acquired knowledge, particularly in the application of the IDEAS Guidelines. It is important to highlight the increased number of countries that participated in this exercise compared with the first one and, furthermore, the improvement in the overall performance. The impact of the International Atomic Energy Agency (IAEA) Projects since 2003 has led to a significant enhancement of internal dosimetry capabilities that strengthen the radiation protection of workers.

PubMed | Autoridad Regulatoria Nuclear and Autonomous University of Barcelona
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2016

Mitotic Index (MI) estimation expressed as percentage of mitosis plays an important role as quality control endpoint. To this end, MI is applied to check the lot of media and reagents to be used throughout the assay and also to check cellular viability after blood sample shipping, indicating satisfactory/unsatisfactory conditions for the progression of cell culture. The objective of this paper was to apply the CellProfiler open-source software for automatic detection of mitotic and nuclei figures from digitized images of cultured human lymphocytes for MI assessment, and to compare its performance to that performed through semi-automatic and visual detection. Lymphocytes were irradiated and cultured for mitosis detection. Sets of images from cultures were analyzed visually and findings were compared with those using CellProfiler software. The CellProfiler pipeline includes the detection of nuclei and mitosis with 80% sensitivity and more than 99% specificity. We conclude that CellProfiler is a reliable tool for counting mitosis and nuclei from cytogenetic images, saves considerable time compared to manual operation and reduces the variability derived from the scoring criteria of different scorers. The CellProfiler automated pipeline achieves good agreement with visual counting workflow, i.e. it allows fully automated mitotic and nuclei scoring in cytogenetic images yielding reliable information with minimal user intervention.

PubMed | Hospital Of Quemados Del Gobierno Of La Ciudad Of Buenos Aires, Medicina Regenerativa Y Terapias Celulares Del Centro Unico Of Ablacion E Implantes Of La Provincia Of Buenos Aires Cucaiba and Autoridad Regulatoria Nuclear
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2016

Acute and late radiation-induced injury on skin and subcutaneous tissues are associated with substantial morbidity in radiation therapy, interventional procedures and also are of concern in the context of nuclear or radiological accidents. Pathogenesis is initiated by depletion of acutely responding epithelial tissues and damage to vascular endothelial microvessels. Efforts for medical management of severe radiation-induced lesions have been made. Nevertheless, the development of strategies to promote wound healing, including stem cell therapy, is required. From 1997 to 2014, over 248 patients were referred to the Radiopathology Committee of Hospital de Quemados del Gobierno de la Ciudad de Buenos Aires (Burns Hospital) for the diagnosis and therapy of radiation-induced localized lesions. As part of the strategies for the management of severe cases, there is an ongoing research and development protocol on Translational Clinical Trial phases I/II to evaluate the safety and efficacy of adult mesenchymal stem cells from bone marrow for the treatment of large burns and radiological lesions. The object of this work was to describe the actions carried out by the Radiopathology Committee of the Burns Hospital in a chronic case with more than 30 years of evolution without positive response to conventional treatments. The approach involved the evaluation of the tissular compromise of the lesion, the prognosis and the personalized treatment, including regenerative therapy.

Lazarte A.I.,Autoridad Regulatoria Nuclear | Ferreri J.C.,Institute Tecnologia
Annals of Nuclear Energy | Year: 2014

In the analysis of the nuclear safety of complex nuclear systems, almost one-dimensional system thermal-hydraulics codes will be used perhaps for a couple of decades from now. Computational Fluid Dynamics (CFD) tools are accepted at present to be a support of such analyses and they are used coupled to systems codes or as separate analysis tools for isolated components with boundary conditions obtained from systems codes. The restricted acceptance of "pure" CFD codes is due to many reasons but two of them are relevant, namely (a) the apparent lack of CFD grade experimental data and (b) the need for a complete verification and validation (V&V) and the uncertainty quantification for the codes currently available. There is plenty of experimental data related to integral test facilities (ITFs) that constitute macroscopic systems behavior information and a consolidated data base for such purposes. Despite of this, additional verification cases may be added to the above mentioned consolidated data. In the present paper, flow oscillations in parallel channel configurations with system codes are studied in diverse configurations. Different models, calculation options and, in particular, in-phase or out-of-phase oscillations were studied, both in heated and cooled parallel channels. The emphasis is on the effects of concentrated irreversible pressure losses coefficients at the inlet and at the outlet of the channels. In the case of cooled steam generator channels, the results of the Semiscale Integral Test Facility operating in natural circulation conditions are revisited. The results presented in this paper, show how a validation case lead to find a not still reported (in the Authors knowledge) verification case. The problem is related to twin-parallel-boiling and condensing, inverted U-tubes channels and connected through common plena. This is, of course, a problem that deserved many tens of papers in the last four decades. Flow splitting without reversal was computationally found and to explain this behavior a theoretical model limited in scope was developed that was a posteriori verified using a particular systems code (RELAP5) commonly applied to perform safety analyses of nuclear power plants. The rationale followed, the theoretical analysis performed and the confirmatory computational results found are summarized in this paper. © 2014 Elsevier Ltd. All rights reserved.

Aguiar J.C.,Autoridad Regulatoria Nuclear | Di Rocco H.O.,CONICET
High Energy Density Physics | Year: 2015

The screened hydrogenic model (SHM) is one of the atomic models commonly used in plasma physics, especially in the high energy density range. However, for low-ionization degrees, the radial hydrogenic wavefunctions of the valence electrons are very different from those arising from Hartree Fock (HF) calculations. In this work we used the time-honored concepts of screening and quantum defects to calculate the atomic structure and spectra of not very highly ionized atoms. We showed that, although for neutral and few ionized atoms the screened hydrogenic radial wave functions are far from the HF values, the combined use of the screening and the quantum defect parameters produces better calculations of the dipolar moments that using only the SHM. © 2015 Elsevier B.V.

Aguiar J.C.,Autoridad Regulatoria Nuclear | Di Rocco H.O.,CONICET
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2014

We check the consistency of the known energy levels of the p2, p3 and p4 isoelectronic sequences tabulated at the NIST Atomic Spectroscopy Database. We used a screening parameter formulation using the Slater integrals arising from the jj-coupling relativistic expressions for the matrix elements. The general conclusion is that the use of the screening parameters is very adequate to check the consistency of level values along their isoelectronic sequences, more suitable than comparison of Slater integrals or other criteria, such as the widely used difference between theoretical and observed values. © 2014 Elsevier Ltd.

Ferreri J.C.,Autoridad Regulatoria Nuclear | Ferreri J.C.,CONICET | Ferreri J.C.,National Academy of science
Journal of Physics: Conference Series | Year: 2011

The prediction of unstable flows by means of so-called systems-codes is discussed in this paper. In the nuclear field, verification and validation (V&V) of codes applicable to predict the behavior of complex nuclear installations is a matter of huge collective effort presently. Multi-Physics-Multiple-Scales models, coupled with the needed wall laws is just one example if length scales go into wall layers or minute geometrical details. The validity of physical models as applicable to situations of interest in developing nuclear technology systems (e.g. natural circulation systems, super-critical conditions flows, very high temperature gas-cooled reactors) is now under consideration in the technical literature. This even applies to very simple problems, like cavity flows or one-dimensional (1D) systems. Some basic problems are presented for V&V that must correctly be solved by any systems code. Based on this, conclusions are drawn in relation to some present systems-codes, regarding the sensitivity to code options influencing its numerical approach and physical closure correlations.

Ferreri J.C.,Autoridad Regulatoria Nuclear | Ferreri J.C.,CONICET
Science and Technology of Nuclear Installations | Year: 2011

The analysis performed to establish the validity of computer code results in the particular field of natural circulation flow stability calculations is presented in the light of usual engineering practice. The effects of discretization and closure correlations are discussed and some hints to avoid undesired mistakes in the evaluations performed are given. Additionally, the results are presented for an experiment relevant to the way in which a (small) number of skilled, nuclear safety analysts and researchers react when facing the solution of a natural circulation problem. These results may be also framed in the concept of Engineering Judgment and are potentially useful for Knowledge Management activities. Copyright 2011 J. C. Ferreri.

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