Avaliação do fluxo de nêutrons em liga de Al-Au de diferentes dimensões no reator TRIGA IPR-R1 utilizando o método de Monte Carlo

• Ano de defesa: 2012
• Autor(a) principal: Jean Anderson Dias Salomé
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Análise por ativação por nêutrons; Reator TRIGA IPR-R1; Fluxo de nêutrons; MCNP; Tecnologia nuclear
• Link de acesso: http://hdl.handle.net/1843/BUBD-92WHJW

Neutron Activation Analysis technique is applied in several procedures determining chemical elements - range of trace to percentage - in many materials; in radiochemical processes; archaeological and geological studies, in nuclear medicine and biochemical analysis and in forensic cases. It consists in submit a sample to a neutron flux and measure theinduced activity by gamma spectrometry. Although it is a very useful method, the technique presents a limitation related to sample dimensions. The technique is applied in samples with micrograms to milligrams, or a few microliters to milliliters, when the density is negligible. In this work, using the Monte Carlo MCNP5 code, the effects of irradiated samples of different dimensions were simulated in the reactor TRIGA IPR-R1 of CDTN/CNEN, evaluating the total and thermal neutron fluxes. The values were compared to experimental values of thermal neutron flux determined for 11 most representative irradiation channels inthe rotary rack. Statistical tests were used to evaluate the MCNP models. The results pointed out that a sample with 0.43 cm high, 0.48 cm radius and 1100 g.L-1 density, can be analyzed as it were a punctual sample, like soil sample, without disturbance of thermal neutron in the sample. For the total neutron flux, it can be concluded the same. Besides, 97% of the results are inside 95% confidence interval related to experimental values, as well as, 97% of the results are satisfactory for z-score. It points out the good performance of the modeling.