LUCIANO ONDIR FREIRE
3 resultados
Resultados de Busca
Agora exibindo 1 - 3 de 3
Artigo IPEN-doc 27928 Potential advantages of molten salt reactor for merchant ship propulsion2021 - FREITAS NETO, LUIZ G. de; FREIRE, LUCIANO O.; SANTOS, ADIMIR dos; ANDRADE, DELVONEI A. deOperating costs of merchant ships, related to fuel costs, has led the naval industry to search alternatives to the current technologies of propulsion power. A possibility is to employ nuclear reactors like the Russian KLT-40S, which is a pressurized water reactor (PWR) and has experience on civilian surface vessels. However, space and weight are critical factors in a nuclear propulsion project, in addition to operational safety and costs. This work aims at comparing molten salt reactors (MSR) with PWR for merchant ship propulsion. The present study develops a qualitative analysis on weight, volume, overnight costs, fuel costs and nuclear safety. This work compares the architecture and operational conditions of these two types of reactors. The result is that MSR may produce lower amounts of high-activity nuclear tailings and, if it adopts the U233-thorium cycle, it may have lower risks of proliferating nuclear weapons. Besides proliferation issues, this 4th generation reactor may have lower weight, occupy less space, and achieve the same levels of safety with less investment. Thus, molten salt regenerative reactors using the U233-thorium cycle are potential candidates for use in ship propulsion.Artigo IPEN-doc 27927 Entering new markets2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. deNuclear ship propulsion and isolated islands energy supply are unexplored markets for nuclear vendors. Carbon taxes and fuel regulations may make fossil fuels more expensive. Such markets pay more for energy because of organization and transport costs and use of small machines, which are less efficient than grid generators. The goal of this work is to find the measures the nuclear industry needs to take to get into new potential markets. This work shows the different actors and their interests and points the natural or physical constraints they face. Considering interests and constraints, this work named the most probable market niches where nuclear power may beat other power sources. After considering natural constraints, this paper analyses human-generated constraints and presents a way on how to mitigate or solve them. This study shows that nuclear industry needs to take technical, administrative, and political measures before nuclear power arrives to a wider market. This work is based on literature review and qualitative analysis and cannot point precise thresholds where nuclear power should be competitive. Future work will consist of statistical analysis to find precise thresholds to help in the decision-making process.Artigo IPEN-doc 27722 Modeling dynamic scenarios for safety, reliability, availability, and maintainability analysis2020 - GABE, CESAR A.; FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. deSafety analysis uses probability combinatorial models like fault tree and/or event tree. Such methods have static basic events and do not consider complex scenarios of dynamic reliability, leading to conservative results. Reliability, availability, and maintainability (RAM) analysis using reliability block diagram (RBD) experience the same limitations. Continuous Markov chains model dynamic reliability scenarios but suffer from other limitations like states explosion and restriction of exponential life distribution only. Markov Regenerative Stochastic Petri Nets oblige complex mathematical formalism and still subject to state explosions for large systems. In the design of complex systems, distinct teams make safety and RAM analyses, each one adopting tools better fitting their own needs. Teams using different tools turns obscure the detection of problems and their correction is even harder. This work aims to improve design quality, reduce design conservatism, and ensure consistency by proposing a single and powerful tool to perform any probabilistic analysis. The suggested tool is the Stochastic Colored class of Petri Nets, which supplies hierarchical organization, a set of options for life distributions, dynamic reliability scenarios and simple and easy construction for large systems. This work also proposes more quality rules to assure model consistency. Such method for probabilistic analysis may have the effect of shifting systems design from “redundancy, segregation and independency” approach to “maintainability, maintenance and contingency procedures” approach. By modeling complex human and automated interventional scenarios, this method reduces capital costs and keeps safety and availability of systems.