On Brazil’s participation in the first ten years of the INPRO project and perspectives ahead.

In September 2001, the International Atomic Energy Agency (IAEA) launched the International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) to help ensure that nuclear energy is available to contribute to meeting the world energy needs of the 21st century in a sustainable manner. To achieve its objective INPRO brings together technology holders and technology users to consider jointly the international and the national actions to achieve the desired innovations in nuclear reactors, fuel cycles and institutional approaches. This paper reviews INPRO’s main achievements in its first ten years of existence and highlights Brazil’s contributions to the project and the benefits gained from its membership. Among INPRO’s main achievements are the development of the INPRO assessment methodology, key studies and collaborative project results, and the establishment of the Dialogue Forum between technology holders and technology users. Brazil contributed to the project by providing a cost-free expert to the INPRO Coordination Group in 2002, by performing an assessment of two small sized reactors for deployment in the country using INPRO methodology published in 2009, and by participating in two collaborative projects related to technology innovations, which shall be completed by the end of this year. The paper concludes with a short presentation of the opportunities for the country’s participation in the activities of the INPRO Action Plan for the biennium 2012-2013, currently under preparation

Economic assessment of the iris reactor for deployment in Brazil using inpro methodology

This paper presents the main results of the evaluation of the economic competitiveness of the International Reactor Innovative and Secure (IRIS) for deployment in Brazil using the assessment methodology developed under the International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO), co-ordinated by the International Atomic Energy Agency (IAEA). INPRO was initiated in 2001 and has the main objective of helping to ensure that nuclear energy will be available to contribute in a sustainable manner to the energy needs of the 21st century. Among its missions are the development of a methodology to assess innovative nuclear energy systems (INS) on a global, regional and national basis, and to facilitate the co-operation among IAEA Member States for planning the development and deployment of INS. Brazil joined INPRO since its beginning and in 2005 submitted a proposal for the screening assessment of two small-sized integral-type PWR reactors as alternative components of an INS completed with a conventional open nuclear fuel cycle based on enriched uranium. This paper outlines the rationale and the main results of the economic assessment of the IRIS-based INS completed in August 2008. The study concluded that IRIS reference design satisfies most of INPRO criteria in the area of economics

On the precision and accuracy of the acoustic birefringence technique for stress evaluation

This paper presents a numerical procedure for estimation of the precision and accuracy of the acoustic birefringence technique as used in the Instituto de Engenharia Nuclear (IEN) for evaluation of residual and applied stresses in structures and components, mainly of the nuclear power industry. This procedure shall be incorporated to the signal processing module of the ultrasonic system used at IEN’s Ultrasonic Laboratory to account in an automatic and systematic way for the uncertainties in the input data and their propagation throughout the calculations. The acoustic birefringence is generally defined from the speeds of two mutually orthogonal volumetric waves of normal incidence, but when the use of a pulse-echo measurement system is feasible, the birefringence can be defined directly from the time-of-flight of the waves, since they travel the same physical space. The times-of-flight of the waves can thus be regarded as the primary variables of interest. They are estimated by coupling the mathematical techniques of cross correlation and data interpolation, whereas the material’s acoustoelastic constant is determined via a weighted linear regression. An Excel spreadsheet performs all calculations taking into account the uncertainties and the number of significant digits in the results. As an example of the procedure developed, the estimation of the precision and accuracy in the evaluation of the stresses acting in a beam under bending is presented. The analytical solution derived from the strength of materials theory was used as the reference value for accuracy estimation purpos

Análise dinâmica linear por superposição modal de cascas finas arbitrárias pelos métodos dos elementos finitos

O presente trabalho tem por objetivo a análise dinâmica linear de cascas finas arbitrárias pelo método dos elementos finitos. São utilizados elementos triangulares planos com dezoito graus de liberdade. As equações gerais de movimento são obtidas a partir do Princípio de Hamilton e resolvidas pela aplicação do método de Superposição Modal, podendo-se considerar a atuação de amortecimento viscoso por meio de percentagens do amortecimento Crítico. Elaborou-se um programa automático de linguagem FORTRAN IV para o computador BURROUGHS B-6700, que permite obter as propriedades vibratórias e a resposta dinâmica a diversas solicitações de caráter determinístico, inclusive gradientes térmicos. Apresenta-se por fim alguns exemplos numéricos

Análise dinâmica linear por superposição modal de cascas finas arbitrárias pelo Método dos Elementos Finitos

The main purpose of this work is to study the linear dynamic behavior of arbitrary thin shells by the Finite Element Method. Plane triangular elements with eighteen degrees of freedom each are used. The general equations of movement are obtained from the Hamilton Principle and solved by the Modal Superposition Method. The presence of a viscous type damping can be considered by means of percentages of the critical damping. An automatic computer program was developed to provide the vibratory properties and the dynamic response to several types of deterministic loadings, including temperature effects. The program was written in FORTRAN IV for the BURROUGHS B-6700 computer. Finally, some numerical examples are presented.O presente trabalho tem por objetivo a análise dinâmica linear de cascas finas arbitrárias pelo método dos elementos finitos. São utilizados elementos triangulares planos com dezoito graus de liberdade. As equações gerais de movimento são obtidas a partir do Princípio de Hamilton e resolvidas pela aplicação do Método de Superposição Modal, podendo-se considerar a atuação de amortecimento viscoso por meio de percentagens do amortecimento crítico. Elaborou-se um programa automático em linguagem FORTRAN IV para o computador BURROUGHS B-6700, que permite obter as propriedades vibratórias e a resposta dinâmica a diversas solicitações de caráter determinístico, inclusive gradientes térmicos. Apresenta-se, por fim, alguns exemplos numéricos

On the creep brittle rupture of structures

This work is concerned with the application of the finite element method to the study of creep brittle rupture of structural components. In the formulation material behavior is described by an elastocreep model in which the total strain rates are assumed to be the sum of elastic and creep components. The elastic strain rates are given by Hooke’s law while the creep strain rates and the damage rates are espressed by the multiaxial form of the Kachanov-Rabotnov equations proposed by Leckie and Hayhurst. The incremental equations of motion are derived from the principle of virtual work using an updated Lagrangian formulation which accounts for geometric effects due to large displacements, large rotations and deformation dependent loadings. The finite element incremental equations are developed according to a displacement-based formulation. Isoparametric elements with quadratic shape functions are employed for the domain discretization and simple numerical procedures are developed to deal with the presence of partially and/or fully ruptured elements in the mesh. For integration of the creep strain rate equations a family of implicit time marching schemes is developed which can be regarded as Runge-Kutta methods of second order. The integration of the coupled damage rate equations is performed using a first order predictor-corrector scheme with automatic time step length control. For material nonlinear problems only, a substructuring technique is employed in conjunction with the time integration algorithms. Selected numerical applications are presented and discussed in detail. Comparison with alternative numerical, analytical and/or experimental results is made whenever possible

Closed-form solution for the creep rupture behaviour of a two-bar structure under constant load

The integro-differential equation governing the isothermal creep rupture behaviour of a kinematically determined two-bar structure under steady load is derived and solved in analytical form. One of the bars is described by an elasto-creep material model that accounts for the three phases of creep deformation and for the full coupling between the creep deformation and damage processes. The second bar is assumed to have a linear elastic behaviour. The non-linearity of the constitutive equations and the stress redistribution induced by the development of creep damage are the major physical features dealt with in this study. Numerical applications illustrate the mathematical features of the analytical solution obtained.A equação integro-diferencial que governa o comportamento isotérmico de fluência por deformação de uma estrutura de duas barras determinada cinemática sob carga constante é derivada e resolvida em forma analítica. Uma das barras é descrita por um modelo de material linear-elástico que responde pelas três fases de deformação por deformação e pelo acoplamento total entre os processos de deformação por fluência e danos. Supõe-se que a segunda barra tenha um comportamento elástico linear. A não linearidade das equações constitutivas e a redistribuição de estresse induzida pelo desenvolvimento do dano por fluência são as principais características físicas tratadas neste estudo. Aplicações numéricas ilustram as características matemáticas da solução analítica obtida.   Enviar feedback Histórico Salvas Comunidad

Integridade estrutural do vaso de contenção metálica da central nuclear de Angra II- efeitos estruturais da retirada do apoio elástico ("elastic bedding") cosiderando a configuração como construída ("as built")

Neste documento é apresentado um parecer técnico sobre o relatório Eletronuclear BQ/2JMA00/BB001/010189 submetido em resposta ao Ofício no. 103/01 de 12.07.01 da /divisão de Reatores da CGLC/DRS o qual, com base em recomendação de parecer técnico anterior da divisão de Reatores do IEN, questiona os efeitos estruturais decorrentes da ovalização da esfera e da eliminação do apoio elástico no estado de tensões atuantes na esfera. Na avaliação da DIRE/SETER, os argumentos apresentados pela Eletronuclear em seu último relatório são suficientes para esclarecer à questão levantada, não tendo mais questionamentos a interpor sobre o assunto

Estimation of the secondary and tertiary creep parameters from the Larson-Miller relationship

This work discusses how the material parameters requires for the creep rupture analysis of metallic components under the framework of Continuum Damage Mechanics can be estimated from the Larson-Miller extrapolation curves. Particular attention is dedicated to the discussion of the aproximations involved and their influence on the objective proposed. An inportant feature of the approach suggested is that the temperature dependence of each material parameter is derived naturraly. The approach is illustrated by a numerical application.This work discusses how the material parameters requires for the creep rupture analysis of metallic components under the framework of Continuum Damage Mechanics can be estimated from the Larson-Miller extrapolation curves. Particular attention is dedicated to the discussion of the aproximations involved and their influence on the objective proposed. An inportant feature of the approach suggested is that the temperature dependence of each material parameter is derived naturraly. The approach is illustrated by a numerical application