The exchange of information between several business activities can lead to an increase in productivity and quality. In nuclear area, besides economic benefits, the operating experience exchanged can increase of the safety level of nuclear installations. Thus, it´s necessary to evaluate frequently operational occurrences from different countries and companies to learn with their lessons learned to prevent a recurrent events or unexpected consequences.  Because this, several methodologies are recommended to investigate events in an adequate level of depth and perform reports based on local requirements. Generally, these reports contain plant conditions before and after an event occurs (operation mode, operation limits and condition, date and time, nuclear and electrical power) and their information (failure discovery methods, impact to the safety, classification from INES and national regulation scale, similar events, relation to human factors, activation of emergency plan, recommended actions, root cause and causal factors). To allow the exchange of experience the Nuclear Energy Agency (NEA) and International Atomic Energy Agency (IAEA) maintain an Incident Reporting System (IRS) that permits interaction of several member states. In this system, a local coordinator collects information of the most relevant operating events and performs an evaluation of them based on IRS Guideline presented in an annual meeting. This paper evaluates a set of approximately four hundred events reported in IRS between 2014 and 2018. This evaluation has the objective of identify the most recurrent event root causes, operation mode and the effectiveness of corrective actions in course in the nuclear industry.

ResumoOs processos de obsolescência e desenvolvimento de novos projetos de usinas nucleares demandam por equipamentos/ componentes de Instrumentação e Controle (I&C) com melhor desempenho atendendo a requisitos de segurança cada vez mais rígidos. Em função dessa demanda, a aplicação de sistemas digitais de I&C apresenta-se como uma boa solução tecnológica, mas precisa ser validada por processos específicos de licenciamento. Diante da importância do assunto e da demanda existente, este artigo apresenta algumas atividades que tem sido realizadas para atender aos requisitos e recomendações de diversos reguladores do setor nuclear. Dessa forma, são mostrados os pontos de maior questionamento regulador e experiências sobre o processo de licenciamento de sistemas digitais de I&C em diferentes culturas reguladoras. Palavras-Chave: Usina Nuclear, Licenciamento, Instrumentação e Controle.Tatiane Melo Vital †* , Richard Brandão Nogueira Vital † The challenges of licensing of digital instrmentation and control system in Nuclear Power plants Os desafios do licenciamento de sistemas digitais de instrumentação e controle em Usinas Nucleares AbstractObsolescence process and new nuclear power plant designs demands instrumentation and control equipment and components with better performance and it shall attend stronger safety requirements. To attend this demand, the application of digital I&C appears like a good technologic solution but shall be validated by specific licensing processes. Due the importance and demand of this subject, this paper shows some activities that had been executed to attend requirements and recommendations of nuclear regulators. This work presents the highlights and experiences of digital I&C licensing in different regulator culture.