Regulation and Supervision of Food Irradiation

Food irradiation consists of a physical process that subjects food to doses of ionizing radiation, which are high enough energy to eliminate or neutralize harmful microbial contaminants without changing the taste or texture of food and without leaving residues. With this irradiation process we can prevent diseases transmitted by food, such as Salmonella and Escherichia coli, prolong the shelf life of foods, control pests that harm fruits by delaying germination and ripening, and finally sterilization, which allows their storage for years without refrigeration. The use of ionizing radiation for food preservation has been studied for several decades and is regulated in the USA by the Food and Drug Administration –FDA. In 1997, the World Health Organization - WHO released the use of the technique for all types of food. In Brazil, the first studies on food irradiation were carried out by the Center for Nuclear Energy in Agriculture - Cena, in the 50's. Currently, Brazilian legislation follows the international recommendations suggested by the Food and Agriculture Organization - FAO, the International Atomic Energy Agency - IAEA and Codex Alimentarius. The scope of this work is a survey, analysis and evolution of national and international legislation related to ionizing irradiation practices in food. For the preparation of this research, bibliographical reviews were carried out, consultations in Brazilian and international legislation, Internet sites, and in the documentation of the Gamma Irradiation Laboratory of the Nuclear Technology Development Center - CDT

Shielding Verifications for a Gamma Irradiation Facility Considering the Installation of a New Automatic Product Loading System

A new system has been designed to automatically load the samples to be irradiated at the gamma irradiation facility of the Nuclear Technology Development Centre (CDTN) at Belo Horizonte, Brazil. The objective of this system is the optimization of the experiments performed at the Gamma Irradiation Laboratory for short-time irradiations without interruption of the irradiator cycles. The installation of this new system requires the opening of a hole at the labyrinth door to allow the loading of irradiating products. Due to this alteration on the original design, the door opening into the labyrinth requires shielding verification. The dose rate with the door open is calculated using Monte Carlo MCNPX v 2.6.0 code. The Monte Carlo source simulations were validated with experimental measurements of dose rate. The simulation demonstrated that a hole can be opened at the labyrinth entrance when installing an automatic loading system. Not only does it comply with dose constraint requirements, but it also complies with national and international standards

Evaluation of the aging management system for the Triga research nuclear reactor in Brazil / Avaliação do sistema de gerenciamento do envelhecimento do reator nuclear de pesquisa Triga no Brasil

As most research reactors have over 40 years of operational experience, maintenance, modernization and renovation are increasingly important for safety and operational life extension. This is due to the monitoring and development of techniques to control and mitigate the negative effects of operating conditions on structures, systems and components. Aging management is a strategy of engineering, operation, maintenance and other actions to control, within acceptable limits, the aging degradation of the facility. The first criticality of the IPR-R1 Triga research reactor (Training, Research, Isotopes, Atomics) occurred in 1960 with a maximum thermal power of 30 kW. Therefore, this reactor has been operating for more than 60 years. One of the issues that comes from the long time of the operation is the management of aging. This includes functions and issues related to operation, inspections, design changes, testing, and others. The IPR-R1 reactor is a North American project. So, the requirements of United State Nuclear Regulatory Commission (U.S.NRC) are applicable. This article discusses the International Atomic Energy Agency (IAEA), and U.S.NRC requirements to implement an aging management system for the CDTN IPR-R1 Triga Reactor

Dose response assessment of conventional Fricke: a relationship between UV-Visible and nuclear magnetic resonance techniques

Conventional Fricke is an aqueous ferrous sulfate solution that has been widely studied in the field of chemical dosimetry. The feasibility of its use has become attractive for high dose measurements that are of clinical interest in the field of radiotherapy and for industrial purposes, in the irradiation of blood bags and the sterilization of surgical material. The derivation of the absorbed dose of Fricke depends on the radiation-induced oxidation of iron (II) ions (Fe2+) present in the aqueous solution to iron (III) ions (Fe3+), which occurs after exposure to ionising radiation. In this paper, it is proposed to evaluate the dose response of the Fricke dosimeter using two different analytical techniques, ultraviolet-visible spectrophotometry (UV-Vis) and nuclear magnetic resonance spectroscopy (NMR). Twelve groups of samples were analysed in triplicate, irradiated with doses between 0 and 800 Gy, using a cobalt-60 source (60Co). The dose rate of Fricke dosimeters was evaluated against the practical values obtained. The different methods allowed an analytical correlation of the species of oxidised iron (Fe3+) using a linearity curve as a function of the applied radiation dose

Desenvolvimento de Metodologias e Aplicação de Técnicas de Análise e Gerenciamento de Riscos para Melhorias no Controle, Segurança e Licenciamento de Centrais Nucleares e Instalações Radioativas/ Development of Methodologies and Risk Analysis and Management Application Techniques for Improvements in the Control, Security and Licensing of Nuclear Power Plants and Radioactive Installations

As revisões das recomendações regulatórias da Agência Internacional de Energia Atômica (AIEA) no cenário mundial, após o acidente nuclear em Fukushima e o cenário nacional da criação da Agência Reguladora do Setor Nuclear, reforçam a necessidade de revisão e atualização contínua dos processos de licenciamento, avaliação de segurança e gerenciamento de risco à luz das lições aprendidas. Técnicas como Avaliação Probabilística de Risco, Engenharia de Confiabilidade e Inspeção Baseada em Risco, serão adaptadas e incorporadas aos processos de licenciamento nuclear e ambiental de centrais nucleares e instalações radioativas, buscando a melhoria dos projetos e a redução dos riscos envolvidos no ciclo de vida destas instalações. Este trabalho descreve o projeto de pesquisa em andamento no Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), que tem como meta o desenvolvimento e a aplicação de metodologias de análise e gerenciamento de risco, tendo em vista a melhoria dos processos de licenciamento instalações nucleares. O estudo visa contribuir para a otimização no projeto das centrais nucleares e instalações radioativas do programa nacional, bem como melhorias de segurança e eficiência e eficácia no processo de seus licenciamentos. Os sistemas desenvolvidos poderão ser aplicados tanto para reatores nucleares de potência, reatores de pesquisa, instalações radioativas, quanto para as demais instalações do ciclo do elemento combustível

Monitoramento de parâmetros termohidráulicos do núcleo do reator de pesquisa TRIGA IPR-R1

O reator TRIGA IPR-R1, é um reator de piscina refrigerado por circulação natural de água leve com potência máxima de 250 kW. Os canais do núcleo vão desde a placa inferior, que sustentam os elementos combustíveis, até a placa superior. A água entra nos canais pelos furos da placa inferior, passa pela região ativa removendo o calor gerado e sai do canal através do espaço existente entre o terminal do elemento combustível e o furo da placa superior. As forças de circulação provêm das diferenças de densidade do fluido devido à variação de sua temperatura ao longo do canal. Este trabalho apresenta os experimentos realizados no reator nuclear IPR-R1, onde foram monitorados alguns parâmetros termohidráulicos tais como: velocidade do refrigerante, fluxo de massa e o número de Reynold’s para o canal quente do núcleo. Foram monitorados também a dilatação da água do poço e os níveis de radiação ionizante no ambiente