MARCIA PIRES DE CAMPOS

MARCIA PIRES DE CAMPOS

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Radon concentrations in a nuclear reactor center in Brazil
2021 - SILVA, PAULO S.C. da; CAMPOS, MARCIA P. de; EL HAJJ, THAMMIRIS M.; REIS, GUILHERME de L.
Radiation workers are normally exposed to doses resulting from their day-to-day activities. Besides that, background radiation, such as radon, can contribute to the exposure rates. The radionuclide 222Rn is a noble gas belonging to the uranium series, and its indoor concentration in the air depends on the exhalation from surrounding soil and the exhalation from building materials. Radon exhaling from porous building materials containing high uranium concentrations can become a significant exposure factor in areas with limited ventilation. The objective of this study was to evaluate the 222Rn concentrations in the radiochemistry and radiometric laboratories in the nuclear reactor building of the Nuclear Reactor Center (CERPq) located in the Institute of Nuclear and Energy Research (IPEN), São Paulo, Brazil. Measurements were done using a Radon Gas Monitor, model RAD7, equipped with a solid-state alpha detector. A passive method (SSNTD) was also used, consisting of square pieces of C-39 foils (2.5 cm × 2.5 cm) placed within small diffusion chambers. The CR-39 detectors were etched in KOH 30% solution at 80 °C for 5.5 h in a constant-temperature bath. After etching, the detectors were washed, dried, and scanned using a microscope to obtain the track density measurements. The activity concentrations measured with both techniques varied from 52 to 103 Bq m−3 in the studied areas of the CERPq. These values may be compared to the reference level of 100 Bq m−3 established by the World Health Organization to ensure safety environments.
Radiological evaluation of bricks made with NORM residue
2019 - CAMPOS, MARCIA P. de; NISTI, MARCELO B.; PASCHOALIN FILHO, JOAO A.; MAZZILLI, BARBARA P.
Radiological implications of using phosphogypsum as building material
2020 - MAZZILLI, B.P.; CAMPOS, M.P.; NISTI, M.B.; SAUEIA, C.H.R.; MADUAR, M.F.
Phosphogypsum, a waste byproduct derived from the production of phosphoric acid, is being worldwide stock-piled, posing concerns about the environmental problems originating from this practice. Considerations about the viability of the safe reuse of this material have been raised, among them its potential use as building material. However, as phosphogypsum can contain natural radionuclides in significant concentrations, using it as a build-ing material has radiological implications, which presently prevent such application. In order to evaluate the feasibility of using phosphogypsum in the manufacturing of building elements such as bricks and plates, a com-prehensive research was undertaken in Brazil, following a multiple approach. This research included studies related to: Brazilian phosphogypsum characterization; experimental determination of radon exhalation rate; and application of theoretical models to forecast both radon exhalation and external doses in dwellers. In this paper, a comprehensive review of the research carried out in Brazil is presented.
Calibração de detectores sólidos de traços nucleares do tipo CR-39 para medidas de Rn-222 no ar
2015 - CAZULA, C.D.; CAMPOS, M.P.; MAZZILLI, B.P.
No método de detecção com detectores sólidos de traços nucleares, quando uma partícula pesada incide sobre a superfície do detector, provoca um desarranjo em sua estrutura molecular formando um traço. Uma das aplicações mais comuns desses detectores está na medição da concentração de Rn-222 no ar, um gás nobre radioativo, membro da série do U-238, emissor de partículas alfa e importante em estudos epidemiológicos para proteção dos indivíduos à radiação natural. Para determinar a concentração de Rn-222 no ar em um ambiente é necessário conhecer a densidade de traços (traços/cm2) na superfície do detector, o tempo de exposição e o fator de calibração. A determinação do fator calibração para os detectores CR-39 foi feita a partir da exposição destes a uma concentração conhecida de Rn-222. Para tanto, os detectores foram inseridos no interior de uma célula de Lucas adaptada e posteriormente expostos a uma concentração de Rn-222 de 15 kBq/m3, por meio do aparelho RN-150 da Pylon Eletronics Incorporation, que possui uma fonte de Ra-226 e libera concentrações conhecidas de Rn-222. Foram realizadas seis determinações do fator de calibração, o valor médio obtido foi de 0,0534 ± 0,0021 (traços/cm2 por Bq/m3 dia). Os resultados são compatíveis com os valores da literatura para o mesmo tipo de detector e apresentaram boa reprodutibilidade.
Radon concentrations on the nuclear and radioactive instalations of nuclear reactor center – CRPQ/IPEN
2019 - SILVA, PAULO S.C. da; CAMPOS, MARCIA P. de; REIS, GUILHERME de L.
Nuclear and radioactive workers are normally exposed to dose resulting from their day by day activities. Besides that, the ubiquitous radon distribution can also contribute for the exposure rates. The radionuclide 222Rn is a noble gas belonging to the uranium series and its indoor concentration in the air depend on exhalation from surrounding soil and on exhalation from building materials. Radon emanating from porous building materials may achieve large relevance in areas with high uranium concentrations and areas with limited ventilation. The objective of this study was to evaluate the 222Rn concentrations in the radiochemistry and radiometric laboratories and in the reactor nuclear building of the Nuclear Reactor Center (CERPq) located in the Nuclear and Energy Research Institute (IPEN). Measurements were done by using a Radon Gas Monitor, model RAD7, produced by Durridge Company equipped with a solid state alpha detector and a passive method, with SSNTDs placed within small diffusion chambers, as detectors square pieces (2.5 cm × 2.5 cm) of CR 39 foils were used. The CR 39 detectors were etched in KOH 30% solution at 80 °C for 5.5 h in a constant temperature bath. After etching, the detectors were washed, dried, and scanned under a Carl Zeiss microscope to obtain the track density measurements. The activity concentrations varied from 52 to 103 Bq m 3 for the measured areas in CERPq. These values are in accordance with what is stablished by the World Health Organization for safe environments of 100 Bq m 3.
Determinação da taxa de exalação do 222Rn no solo do IPEN
2019 - NISTI, M.B.; CAMPOS, M.P.; SILVA, G.M.; MAZZILLI, B.P.
Radiological implications of using phosphogypsum as building material
2018 - MAZZILLI, B.P.; CAMPOS, M.P.; NISTI, M.B.; MADUAR, M.F.
Phosphogypsum recycling in the building materials industry: assessment of the radon exhalation rate
2017 - CAMPOS, M.P.; COSTA, L.J.P.; NISTI, M.B.; MAZZILLI, B.P.
Phosphogypsum can be classified as a Naturally Occurring Radioactive Material (NORM) residue of the phosphate fertilizer industry. One of the main environmental concerns of its use as building material is the radon exhalation. The aim of this study is to measure the radon exhalation rate from plates and bricks manufactured with phosphogypsum from three installations of the main Brazilian producer, Vale Fertilizantes, in order to evaluate the additional health risk to dwellers. A simple and reliable accumulator method involving a PVC pipe sealed with a PVC pipe cover commercially available with CR-39 radon detector into a diffusion chamber was used for measuring radon exhalation rate from phosphogypsum made plates and bricks. The radon exhalation rate from plates varied from 0.19 ± 0.06 Bq m 2 h 1, for phosphogypsum from Bunge Fertilizers, from 1.3 ± 0.3 Bq m 2 h 1, for phosphogypsum from Ultrafertil. As for the bricks, the results ranged from 0.11 ± 0.01 Bq m 2 h 1, for phosphogypsum from Bunge Fertilizers, to 1.2 ± 0.3 Bq m 2 h 1, for phosphogypsum from Ultrafertil. The results obtained in this study for the radon exhalation rate from phosphogypsum plates and bricks are of the same order of magnitude than those from ordinary building materials. So, it can be concluded that the recycling of phosphogypsum as building material is a safe practice, since no additional health risk is expected from the radiological point of view.
Medida da exalação de Rn-222 no solo do Ipen com detectores de traços nucleares
2016 - REIS, G.L.; CAMPOS, M.P.
O homem está constantemente exposto a várias fontes de radiação, entre elas, a radioatividade natural, os testes nucleares, as atividades ocupacionais, as aplicações médicas e a geração nucleoelétrica. De todas as fontes de radiação, a radioatividade natural é, sem dúvida, a mais importante, contribuindo com aproximadamente 70% da dose efetiva recebida pela população (UNSCEAR, 2000). As fontes naturais de radiação podem ser classificadas em fontes externas, tais como os raios cósmicos e elementos radioativos presentes no solo e nos materiais de construção e em fontes internas que resultam da inalação e ingestão de elementos radioativos naturais presentes no ar e na dieta alimentar. A exposição ao 222Rn é conhecida como um importante risco ao sistema respiratório, principalmente pela incorporação dos seus descendentes de meia-vida curta (218Po, 214Pb, 214Bi e 214Po), elementos sólidos que sozinhos ou agregados a outras partículas podem se depositar nos pulmões (Porstendorfer, 1993). Determinar a exalação de Rn-222 no solo em diversos pontos do IPEN (Instituto de Pesquisas Energéticas e Nucleares) utilizando a técnica de câmara de acumulação com o uso de detectores de traços nucleares. A determinação da taxa de exalação de radônio no solo será feita utilizando-se uma câmara selada contendo uma amostra de solo e um detector de traços, técnica conhecida como câmara de acumulação (Amrani e Cherouati, 1999, Sharma and Virk, 2001, Ujic et al., 2008). Por meio do conhecimento concentração de radônio, determinada pelo detector de traços, do tempo de exposição, do volume do recipiente e da superfície de material que exala o radônio será calculada a taxa de exalação de radônio. Os resultados obtidos por meio dos dois (2) métodos de leitura dos detectores sólidos de traços nucleares mostram que a variação média entre eles é menor que 5%, mostrando que é possível adotar qualquer um deles para a leitura dos detectores. A partir desses resultados definiu-se que para valores elevados de densidade de traços se adotará o protocolo 10X10 e para valores mais baixo se adotará o protocolo 15x15. Os resultados apresentados mostram que a concentração de 222Rn durante os períodos de monitoramento variam entre 2601 á 6133 (Bq m-3), valores estes de concentração que estão dentre a média, comparados com os valores de 26300 ± 1800 (Bq m-3) em Belo Horizonte, 4000 ± 1800 (Bq m-3) em Porto Alegre e, 2800 ± 1700 (Bq m-3) em Curitiba - Região de Pinheirinhos (E. LARA IISBPR, 2014).
Assessment of 222Rn concentration in the soil around IPEN facilities
2016 - CAMPOS, MARCIA P.; REIS, GUILHERME L.; NISTI, MARCELO B.; MAZZILLI, BARBARA P.