Nima Fathi

Thermal-Hydraulic Analysis of Nuclear Reactors

An Introduction to Thermal Hydraulic Aspects of Nuclear Power Reactors.- Thermodynamics.- Transport Properties.- General Conservation Equations.- Laminar Incompressible Forced Convection.- Turbulent Forced Convection.- Compressible Flow.- Conduction Heat Transfer.- Forced Convection Heat Transfer.- Natural or Free Convection.- Mass Transfer.- Thermal Radiation.- Multi-Phase Flow Dynamics.- Convective Boiling.- Thermal Stress.- Heat Exchangers.- Analysis of Reactor Accident.- Probabilistic Risk Assessment.- Nuclear Power Plants.- Nuclear Fuel Cycle.- The Economic Future of Nuclear Power.- Safety, Waste Disposal, Containment, and Accidents.- Appendix A: Table and Graphs Compilations.- Appendix B: Physical Property Tables.- Appendix C: Units, Dimensions and Conversion Factors.- Appendix D: Physical Properties.- Appendix E: Fluid Property Data.- Appendix F: Basic Equations.

Forced Convection Heat Transfer

Convection is the term used for heat transfer mechanism, which takes place in a fluid because of a combination of conduction due to the molecular interactions and energy transport due to the macroscopic (bulk) motion of the fluid itself. In the above definition, the motion of the fluid is essential otherwise, the heat transfer mechanism becomes a static conduction situation. When the term of convection is used, usually a solid surface is present next to the fluid. There are also cases of convection where only fluids are present, such as a hot jet entering into a cold reservoir. However, the most of the industrial applications involve a hot or cold surface transferring heat to the fluid or receiving heat from the fluid.

Nuclear Systems for a Low Carbon Electrical Grid

The intermittency of renewable power generation systems on the low carbon electric grid can be alleviated by using nuclear systems as quasi-storage systems. Nuclear Air-Brayton Combined Cycle systems can produce and store hydrogen when electric generation is abundant and then burn the hydrogen by Co-Firing when generation is limited. The rated output of a nuclear plant can be augmented by several hundred per cent by Co-Firing. The incremental hydrogen to electricity efficiency can far exceed that of hydrogen in a stand-alone gas turbine.Copyright

Turbulent Forced Convection

Turbulence occurs nearly everywhere in nature. It is characterized by the efficient dispersion and mixing of vorticity, heat, and contaminants. In flows over solid bodies, such as airplane wings or turbine blades, or in confined flows through ducts and pipelines, and is responsible for increased drag and heat transfer. Turbulence is therefore a subject of great engineering interest. In this chapter, we will look at the state of fluid motion, which is independent of heat transfer, and it is in this context where we speak of forced convection. Forced convection occurs when an external force, such as a pump, fan, or mixer, induces a fluid flow. On the other hand, natural convection is caused by buoyancy forces due to density differences caused by temperature variations in a fluid. Upon heating, the density change in the boundary layer will cause the fluid to rise and be replaced by cooler fluid, which will also heat and rise. These continuous phenomena are called free or natural convection.

Analysis of Reactor Accident

Since the nuclear reactors based on the fission reaction are getting to be more economically competitive, with other type of electrical power plants such as gas or fossil fuel based. However, there appears to be nearly unlimited supply of fission product fuel, providing the new generation (i.e., GEN IV) concepts are developing over the near term, as a result, the nuclear power reactor is becoming a major source of electric power as well as supply of such source to industrialized society are becoming inevitable. The scope of this chapter is confined to nuclear safety as it pertains to power reactor accident that may lead to release of radioactive materials to the environment. Moreover, we should be concerned and put emphasis to the discussion of those more serious situations with the potential for causing significant public health problem.

Probabilistic Risk Assessment

Probabilistic Risk Assessment (PRA) has emerged as an increasingly popular analysis tool especially during the last decade. PRA is a systematic and comprehensive methodology to evaluate risks associated with every life-cycle aspect of a complex engineered technological entity (e.g., facility, spacecraft, or power plant) from concept definition, through design, construction, and operation, and up to removal from service [1].

An Introduction to the Thermal-Hydraulic Aspects of Nuclear Power Reactors

Nuclear power plants (NPPs) currently generate better than 20% of the central station electricity produced in the United States. The United States currently has 104 operating power-producing reactors, with nine more planned. France has 58 with one more planned. China has 13 with 43 planned. Japan has 54 with three more planned. In addition, Russia has 32 with 12 more planned. Production of electricity via nuclear has certainly come into its own and is the safest, cleanest, and greenest form of electricity currently introduced on this planet. However, many current thermodynamic texts ignore nuclear energy and use few examples of nuclear power systems. Nuclear energy presents some interesting thermodynamic challenges, and it helps to introduce them at the fundamental level. Research activities are currently underway worldwide to develop Generation IV nuclear reactor concepts with the objective of improving thermal efficiency and increasing economic competitiveness of Generation IV nuclear power plants compared to modern thermal power plants. Our goal here will be to introduce thermal aspect of nuclear power reactors as it applies to a variety of issues related to nuclear reactor thermal hydraulics and safety, which deals with energy production and utilization, therefore to have some general understanding of nuclear power plants, is essential. However, that is true for any textual introduction to this science; yet, by considering concrete systems, it is easier to give insight into the fundamental laws of the science and to provide an intuitive feeling for further study.

Comment on “The role of wetting heterogeneities in the meandering instability of a partial wetting rivulet” by Couvreur S. and Daerr A.

Rivulets and their meandering on a partially wetting surface present an interesting problem, as complex behavior arises from a deceptively simple setup. Recently Couvreur and Daerr suggested that meandering is caused by an instability developing as the flow rate

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Numerical–analytical assessment on Manzanares prototype

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