A review of developments in electrodes for regenerative polymer electrolyte fuel cells

The design of electrodes for unitised regenerative polymer electrolyte fuel cells (URFC) requires a delicate balancing of transport media. Gas transport, electrons and protons must be carefully optimised to provide efficient transport to and from the electrochemical reaction sites. This review is a survey of recent literature with the objective to identify common components and design and assembly methods for URFC electrodes, focusing primarily on the development of a better performing bifunctional electrocatalyst for the oxygen reduction and water oxidation. Advances in unitised regenerative fuel cells research have yielded better performing oxygen electrocatalysts capable of improving energy efficiency with longer endurance and less performance degradation over time. Fuel cells using these electrocatalyst have a possible future as a source of energy

Terrorism and maritime shipment of nuclear material

Opponents of the nuclear industry often claim that material in transit is vulnerable to attack by terrorist groups who might seek to take the cargo and make a bomb, or otherwise cause a radiological incident. This paper lays out a range of conceivable objectives or attack scenarios in the context of maritime transportation and examines these in the light of what is known of the relevant security arrangements. It concludes that these arrangements provide a very substantial deterrent to any attempt at diversion or sabotage and that any such attempt would have little prospect of success, beyond the immediate media impact of whatever might have occurred

Tempo de ebulição da água em uma piscina de combustível usado com condições adiabáticas e nãoadiabáticas

The Spent Fuel Pool (SFP) of Angra II, from Brazil, has received standard spent fuel (SF) assemblies of Uranium dioxide (UO2) discharged from Pressurized Water Reactors (PWR) of the Nuclear Power Plants (NPP) of Angra since the beginning of its operation. However, in case of using Mixed Oxide (MOX) or Thorium-based fuels, it would require further thermal studies of wet storage. It includes the determination of the water boiling time (Tb) of the SFP in case of breakdown of its external cooling system (ECS). This work presents studies of Tb of a simulated SFP storing mixed SF discharged from PWRs. The types of mixed SF studied include MOX plus UO2, oxide of thorium/uranium (U-Th)O2 plus UO2, and oxide of Thorium/transuranic (TRU-Th)O2 plus UO2. The simulations were implemented in CFX Ansys considering the top of the SFP as either adiabatic or non-adiabatic wall. Tb is considerably higher when the non-adiabatic boundary condition is used.O Pool de Combustível Irradiado (SFP) de Angra II, do Brasil, recebeu desde o início de sua operação conjuntos padrão de combustível queimado (SF) de dióxido de urânio (UO2) descarregado de Reatores de Água Pressurizada (PWR) das Usinas Nucleares (PNPP) de Angra. Entretanto, em caso de utilização de combustíveis à base de óxido misto (MOX) ou de tório, seriam necessários mais estudos térmicos de armazenamento úmido. Inclui a determinação do tempo de ebulição da água (Tb) do SFP em caso de falha de seu sistema de resfriamento externo (ECS). Este trabalho apresenta estudos de Tb de um SFP simulado que armazena SF misturado descarregado de PWRs. Os tipos de SF mistos estudados incluem MOX mais UO2, óxido de tório/urânio (U-Th)O2 mais UO2, e óxido de tório/transurânico (TRU-Th)O2 mais UO2. As simulações foram implementadas no CFX Ansys considerando o topo do SFP como adiabático ou parede nãoadiabática. Tb é consideravelmente maior quando a condição de limite não-adiabático é utilizada.Fil: Pereira de Faria, Fernando. Universidade Federal de Minas Gerais; BrasilFil: Godino, Dario Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Ingeniería Mecánica; ArgentinaFil: Corzo, Santiago Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; ArgentinaFil: Ramajo, Damian Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; ArgentinaFil: Costa, Antonella Lombardi. Universidade Federal de Minas Gerais; BrasilFil: Pereira, Claubia. Universidade Federal de Minas Gerais; Brasi

Radionuclide Source Term for Irradiated Fuel from Prototype, Research and Education Reactors, for Waste Forms with Negligible Heat Generation and for Uranium Tails (KIT Scientific Reports ; 7635)

Radionuclide source terms are derived for different disposal options of a potential final repository in the salt dome Gorleben. The geochemical conditions are analyzed under the precondition that NaCl, MgCl2- or CaCl2-rich solutions are present. Kinetic and thermodynamic mobilization/retention and the influence of temperatures are discussed. Upper limit concentrations for the radionuclides Am, Th, U, Np, Pu, Tc, Zr and rare earth elements are derived for the simplified scenarios