RAFAELLA MENEZES AYLLON

RAFAELLA MENEZES AYLLON

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Activity concentration of natural radionuclides (238U, 226Ra, 232Th, 228Ra, 210Pb and 40K) in soil amended with niobium tailings
2023 - AYLLON, R.M.; TORRECILLA, J.K.; SAUEIA, C.R.; NISTI, M.B.; EL HAJJ, T.M.; FURLAN, M.R.; SILVA, P.S.C.
The storage of tailing from anthropic activities like mining, which may contain radionuclide traces, is a problematic situation consequent from NORM industries activities and for which they seek alternatives. The study presented in this paper is related to carbonate deriving from niobium extraction. This carbonate is stored in dams, which can cause an increase in radionuclides and metals concentration, imposing restrictions on its use. To ensure the safe usage of the residue, it is assessed the activity concentration of 238U, 226Ra, 232Th, 228Ra, 210Pb and 40K in soil samples as well as mixture soil + carbonate, soil + carbonate + lime, soil + lime and soil. The techniques used were gamma spectrometry and instrumental neutron activation analysis. Activity concentration evaluation was performed before and after the tillage of lettuce (Lactuca sativa) and bean (Phaseolus vulgaris), and the soil-plant transfer factor was determined for lettuce. The study of radionuclides and metals availability in the soil solution is important for a better understanding of the mobility of contaminants in water/soil systems, in order to estimate the real environmental impact. Preliminary results show samples with niobium traces presented values within the recommended world values.
Th-232 radiological aspects of carbonate niobium mining waste use as agricultural amendment
2023 - AYLLON, R.M.; FURLAN, M.R.; EL HAJJ, T.M.; SILVA, P.S.C.
The use of mining residues in agriculture may be possible, as long as there be previous studies in different areas, one of them being the analysis of the involved radionuclides behavior. This study determined the concentrations of 232Th activity in soil, soil treated with lime, soil with carbonate residue from niobium mining, soil with the mixture of lime and carbonate, in two moments. The transfer factor of 232Th from the soil to the plant was analyzed, in this case, lettuce (n=20), in the different types of treatment and in two moments. The addition of carbonate to the soils did not significantly alter the levels of radioactivity for 232Th radionuclide in lettuce. The effective dose resulting from the lettuce ingestion varied from 0.09 to 0.3 µSv y-1.
Th-232 radiological aspects of carbonate niobium mining waste use as agricultural amendment
2022 - AYLLON, R.M.; FURLAN, M.R.; EL HAJJ, T.M.; SILVA, P.S.C.
Social representations of ETEC teachers about nuclear technology
2022 - AYLLON, RAFAELLA M.; SEMMLER, RENATO; SANTOS, DENISE M. dos; FARIAS, LUCIANA A.; SILVA, PAULO S.C.
Este artigo apresenta um estudo que visa compreender a representação social da tecnologia nuclear feita por um grupo de professores e coordenadores de Escolas Técnicas Públicas (ETEC) do estado de São Paulo. Após este grupo ter participado em palestras ministradas por pesquisadores do Instituto de Pesquisas Energéticas e Nucleares (IPEN), que incluíram visitas ao Instituto e ao Reator Nuclear de Pesquisa IEA-R1. O estudo foi realizado por meio de questionários semiestruturados. Os resultados demonstraram que, para a maioria dos participantes, a representação social da tecnologia nuclear mudou positivamente após um evento de três dias, mesmo que eles já tivessem algum conhecimento sobre o assunto. Também foi possível detectar alguns erros conceituais e corrigi-los, evidenciando que o contato técnico mais próximo foi fundamental para essa mudança.
Evaluation of recovery yields of 60Co and 137Cs in extraction procedures
2022 - ALMEIDA, M.A.; AYLLON, R.M.; ANGELINI, M.; VICENTE, R.; SILVA, P.S.C.
Nuclear technology has been implemented in several sectors of society, among them, it is possible to highlight medicine, industry, research, among others. The high demand of these nuclear applications has caused problems with regard to the generation of radioactive waste. The laser ablation method has been pointed out in the last years for the decontamination of surfaces and the contamination removed is completely retained in paper filters. This requires a safe and inexpensive method to perform the characterization of the radioisotopic inventory present in the laser filter samples. In this study, the extraction and quantification of the radionuclides present in the filter was evaluated using 60Co and 137Cs radionuclides. Two forms of extraction were tested: with Soxhlet equipment and by digesting the filter samples in a beaker, both using 3M HNO3 as extractant. The chemical yield was calculated using gamma ray countings obtained before and after extraction. It was observed that the extraction method by digesting the filter directly in a beaker presented the highest yield recovery results.
Análise por ativação neutrônica instrumental em carbonato gerado na mineração de nióbio
2022 - AYLLON, RAFAELLA M.; TORRECILHA, JEFFERSON K.; SILVA, PAULO S.C.
O armazenamento de rejeitos provenientes de atividades antrópicas é uma preocupação devido a possíveis problemáticas ambientais. A CNEN define indústrias NORM, como aquelas que lidam com materiais radioativos de origem natural, incluindo os processos de transformação de matérias-primas que podem ocasionar um aumento na concentração não intencional dos radionuclídeos naturais. A obtenção de nióbio é proveniente da mineração de rochas sendo um metal de importância econômica devido a sua utilização em ligas para melhorar as propriedades físicas de aços. O resíduo da mineração do nióbio contém traços de radionuclídeos que devem ser armazenados cumprindo as normas estabelecidas enquanto as indústrias NORM, responsáveis pela mineração, buscam alternativas para sua utilização. O resíduo de interesse deste trabalho é um carbonato obtido por meio da extração de nióbio e o Brasil não possui normas sobre os limites que possibilitem o uso deste material. O estudo busca apresentar a concentração dos elementos As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Yb e Zn presentes no carbonato, que foram obtidas por análise instrumental de ativação de nêutrons, utilizando o reator IEA-R1. As amostras foram bombardeadas com nêutrons térmicos, sob um fluxo da ordem de 1012 n cm-2 s-1 por oito horas. A técnica apresenta alta sensibilidade para detecção de quantidades traço e não necessita de grandes quantidades de amostras.
Evaluation of recovery yields of 60Co and 137Cs in extraction procedures
2021 - ALMEIDA, MATHEUS A. de S.; AYLLON, RAFAELLA M.; ANGELINI, MATHEUS; VICENTE, ROBERTO; SILVA, PAULO S.C.
Radiological and mineralogical characterization of the tailings of a niobium ore treatment plant in Brazil
2019 - AYLLON, RAFAELLA M.; EL HAJJ, THAMMIRIS M.; SILVA, PAULO S.C. da; TORQUATO, HENRIQUE; SCAPIN, MARCOS A.; GARCIA, RAFAEL H.L.
External gamma exposure due to the application of carbonate niobium tailing as soil amendment
2019 - AYLLON, RAFAELLA M.; TORRECILHA, JEFFERSON K.; SAUEIA, CATIA H.R.; NISTI, MARCELO B.; TORQUATO, HENRIQUE; EL HAJJ, THAMMIRIS M.; ZAHN, GUILHERME S.; SILVA, PAULO S.C. da
The storage of tailing from anthropic activities like mining, which may contain radionuclides, is a problematic situation consequent from NORM industries and for which alternatives should be sought. This paper presents the preliminary results for the use of a carbonate tailing derived from niobium extraction as soil amendment from the point of view of the radiological indices, since this material is a NORM residue. The activity concentration of radionuclides 226Ra, 228Ra and 40K were determined in six samples of carbonate by gamma spectrometry and the radiological hazard indices were calculated for the carbonate itself and simulated for soil application. The results indicated that the dilution of the carbonate in the soil do not increase the radiological hazard indices.
Social representations and choice energy: a matter of education?
2013 - FARIAS, LUCIANA A.; FAVARO, DEBORAH I.T.; AYLLON, RAFAELLA M.