Recently, great attentions have been paid to microbial fuel cells (MFCs) due to their mild operating conditions and using variety of biodegradable substrates as fuel. The traditional MFC consisted of anode and cathode compartments but there are single chamber MFCs. Microorganisms actively catabolize substrate, and bioelectricities are generated. MFCs could be utilized as power generator in small devices such as biosensor. Besides the advantages of this technology, it still faces practical barriers such as low power and current density. In the present article different parts of MFC such as anode, cathode and membrane have been reviewed and to overcome the practical challenges in this field some practical options have been suggested. Also, this research review demonstrates the improvement of MFCs with summarization of their advantageous and possible applications in future application. Also, Different key factors affecting bioelectricity generation on MFCs were investigated and these key parameters are fully discussed.

Microbial fuel cell as new technology for bioelectricity generation: A review

In May 2002, an 'Exploratory Meeting of Experts to Define an Action Plan on the Application of Computational Fluid Dynamics (CFD) Codes to Nuclear Reactor Safety Problems' was held at Aix-en-Provence, France. One of three recommended actions was the formation of this writing group to report on the need for guidelines for use of CFD in single phase Nuclear Reactor Safety (NRS) applications. CSNI approved this writing group at the end of 2002, and work began in March 2003. A final report was submitted to GAMA in September 2004, summarizing existing Best Practice Guidelines (BPG) for CFD, and recommending creation of a BPG document for Nuclear Reactor Safety (NRS) applications. The present document is intended to provide an internally complete set of guidelines for a range of single phase applications of CFD to NRS problems. However, it is not meant to be comprehensive; it is recognized that for any specific application a higher level of specificity is possible on questions of nodalization, model selection, and validation. This document should provide direct guidance on the key considerations in known single phase applications, and general directions for resolving remaining details. The intent is that it will serve as a template for further application specific (e.g. PTS, induced break) BPG documents that will provide much more detailed information and examples. The document begins with a summary of NRS related CFD analysis in countries represented by the authors. Chapter 3 deals with definition of the problem and its solution approach. This includes isolation of the portion of the NRS problem most in need of CFD, and use of a classic thermal hydraulic (TH) safety code to provide boundary conditions for the CFD based upon less detailed simulation of the balance of plant. Chapter 4 provides guidance in choosing between various options, and also discusses use of a transient calculation with tightly coupled CFD and TH codes. Chapter 5 discusses selection of physical models available as user options. As is appropriate for single phase CFD, most of the emphasis is on selection of turbulence models. Recommendations are provided for high level selection between Reynolds Averaged Navier Stokes (RANS), Large Eddy Simulation (LES), and hybrid approaches such as Detached Eddy Simulation (DES). Chapter 7 focuses on the numerical approximations available to solve the flow equations. Guidelines are provided for nodalization, and for choice of discrete approximations to the differential equations. Guidance is also given on convergence of iterative solutions, and numerical techniques for following free surfaces. Chapter 7 discusses general assessment strategy. Chapter 8 covers approaches to limiting errors associated with discretization and numerical solution methods (verification). This step is a necessary precursor to quantifying errors associated with physical models (validation) as described in Chapter 9. Guidance on documentation is provided in Chapter 10. Chapter 11 provides some examples of NRS applications; the first two examples are boron dilution and pressurized thermal shock; the third example explores the use of Fluent for simulation of dry cask storage of spent fuel (this example is highly suited to single phase CFD analysis)

Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety Applications

A scoping study of debris bed formation in the DEFOR test facility

Motivated to understand the processes which govern the formation and characteristics of a debris bed and hence its coolability during a postulated severe accident of a light water reactor, a new research program called DEFOR (DEbris FORmation) was initiated at the Royal Institute of Technology (KTH). This paper presents results obtained in scoping experiments conducted during an initial phase of the DEFOR program. The DEFOR-E test campaign is concerned with the DEFOR test facility commissioning and exploratory study of phenomena occurred during a debris bed formation. Binary oxide mixtures at different superheat temperatures were used as the corium melt simulants. The scoping experiments revealed the effect of water pool depth and subcooling, melt mass and material properties on the debris bed characteristics. Insights gained from the DEFOR-E test campaign help guide the scaling, design and operation of the subsequent experiments in the DEFOR program.

Hee-Dong Kim

Papers

Fuel coolant interaction experiments in TROI using a UO2/ZrO2 mixture

Spray effect on the behavior of hydrogen during severe accidents by a loss-of-coolant in the APR1400 containment

Experiments on the interactions of molten ZrO2 with water using TROI facility

The effect of corium composition and interaction vessel geometry on the prototypic steam explosion

Three-dimensional behaviors of the hydrogen and steam in the APR1400 containment during a hypothetical loss of feed water accident