Effect of Dual Surface Cooling on the Temperature Distribution of a Nuclear Fuel Pellet

2018 ◽  
Vol 769 ◽  
pp. 296-310
Author(s):  
Odii Christopher Joseph ◽  
Agyekum Ephraim Bonah ◽  
Bright Kwame Afornu
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Nuclear Fuel ◽  
Solid Fuel ◽  
Nucleate Boiling ◽  
Temperature Management ◽  
Fuel Pellet ◽  
Surface Cooling ◽  
Fuel Pellets ◽  
External Cooling

Heat removal from nuclear reactor core has been one of the major Engineering considerations in the construction of nuclear power plant. At the center of this consideration is the nuclear fuel pellet whose burning efficiency determines the rate of heat transfer to the coolant. This research, focuses on the study of temperature distribution of solid fuel, temperature distribution of annular fuel with external cooling and the temperature distribution of annular fuel with internal and external cooling. We analyzed the different distribution and made a conclusion on the possibility of improving temperature management of Nuclear fuel rod, by designing fuel pellets based on this geometrical and thermal Analysis. To date, a lot of studies has been done on the thermal and geometrical properties of Nuclear fuel pellet, it is observed that annular fuel pellet with simulteneous internal and external cooling can achieve better temperature distribution which leads to high linear heat generation rate, thus generating more power in the design [1]. It has also been observed that annular fuel pellets has low fission gas release [10]. In large LOCA, the peak cladding temperature of annular fuel is about 600 which is significantly less than that of solid fuel (920 ), this is due to the fact that annular fuel cladding has lower initial temperature and the thinner annular fuel can be cooled more efficiently than the solid fuel. One of drawbacks of annular fuel technology is “the fuel gap conductance assymmetry” which is caused by outward thermal expansion, it has a potential effect on the MDNBR (Minimum Departure from Nucleate Boiling Ratio), which is the minimum ratio of the critical to actual heat flux found in the core [10]. In this model, we used the ceramic fuel pellet of UO2 as our case study. All the parameters in this model are assumed parameters of UO2. The Heat Transfer tool (ANSYS APDL) was used to validate the Analytical Model of this research.

Crack nucleation in rod-type nuclear fuel pellet

2018 ◽  
Vol 24 (3) ◽  
pp. 668-685
Author(s):  
Vagif Mirsalimov
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Reactor ◽  
Crack Nucleation ◽  
Singular Integral Equations ◽  
Prefracture Zone ◽  
Fuel Pellet ◽  
Deformation Pattern ◽  
Fuel Pellets ◽  
Nuclear Reactor Fuel ◽  
Material Interaction

A plane problem of fracture mechanics on crack nucleation in a rod-type nuclear fuel pellet is considered. Nuclear reactor fuel pellets in operation may be damaged in various ways; in particular, crack nucleation. We consider a problem for the case of a heat-releasing fuel pellet with cladding: as the heat release intensity increases, zones of heightened stress are formed in the nuclear fuel pellet. The heightened stress will promote the appearance of prefracture bands that are simulated as zones of weakened interparticle bonds of the material. Interaction of prefracture zone faces is simulated by placing bonds between faces that have a specified deformation pattern. The problem of equilibrium of a fuel pellet with prefracture zones is reduced to the solution of a system of singular integral equations. An analysis of the ultimate state of the zone of weakened interparticle bonds of the material is realized on the basis of the criterion of critical opening of prefracture zone faces.

A Variable Heat Flux Model of Heat Transfer in Grinding With Boiling

1996 ◽  
Vol 118 (2) ◽  
pp. 463-470 ◽  
Author(s):  
T.-C. Jen ◽  
A. S. Lavine
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Film Boiling ◽  
Grinding Fluid ◽  
Flux Model ◽  
Background Temperature ◽  
Heat Flux Model

In grinding processes, the grinding fluid is used to suppress the temperature rise in the grinding zone. Under some circumstances, the grinding fluid may undergo film boiling in the grinding zone, causing the workpiece temperature to rise significantly. The onsets of nucleate boiling and film boiling in the grinding zone are investigated in the present study. A model of heat transfer in grinding was previously developed (Jen and Lavine, 1995), which predicts the temperature and heat fluxes in the grinding zone. With some modification, this model is used here to predict the occurrence of film boiling of the grinding fluid. The dependence of the workpiece background temperature on the various grinding parameters is explored. The workpiece background temperature distribution along the grinding zone, and comparisons with experimental results, are presented.

scholarly journals Mechanical and Physical Properties of Khaya senegalensis Solid Fuel Pellet with Different Binder Percentages

2021 ◽  
Vol 2051 (1) ◽  
pp. 012037
Author(s):  
Ras Izzati Binti Ismail ◽  
Abd Razak Shaari ◽  
Khor Chu Yee ◽  
Alina Rahayu Mohamed ◽  
Muhammad Syakirin Bin Abd Rahim ◽  
...  
Keyword(s):  
Solid Fuel ◽  
International Standards ◽  
Fuel Pellet ◽  
Pellet Quality ◽  
Fuel Pellets ◽  
Increased Risk ◽  
High Pollution ◽  
Pollution Emissions ◽  
Strength And Durability ◽  
And Storage

Abstract The characteristics of the solid fuel pellets, such as its strength, durability and density can be used to assess its quality. During the transport and storage, pellets with low strength and durability produces dusts and ultimately resulting in equipment blockage, high pollution emissions, and an increased risk of fire and explosion. Therefore, pellet manufacturing process should be given priority to improve pellet quality. The use of binder in the production of pellets will aid in improving pellet quality. Therefore, this study investigates the influence of different binder percentages on the mechanical properties of K. senegelensis fuel pellets. Durability, unit density, bulk density and diametral compressive strength testing were carried out in compliance with international standards. It was discovered that pellets containing 4% cassava starch binder produces better results, particularly in terms of durability and compressive ldiametral strength.

scholarly journals Detection of the Departure from Nucleate Boiling in Nuclear Fuel Rod Simulators

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Amir Zacarias Mesquita ◽  
Rogério Rivail Rodrigues
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Electric Current ◽  
Nuclear Fuel ◽  
Critical Heat Flux ◽  
Cooling Water ◽  
Nucleate Boiling ◽  
Inlet Temperature ◽  
Fuel Rod ◽  
The Core

In the thermal hydraulic experiments to determin parameters of heat transfer where fuel rod simulators are heated by electric current, the preservation of the simulators is essential when the heat flux goes to the critical point. One of the most important limits in the design of cooling water reactors is the condition in which the heat transfer coefficient by boiling in the core deteriorates itself. The heat flux just before deterioration is denominated critical heat flux (CHF). At this time, the small increase in heat flux or in the refrigerant inlet temperature at the core, or the small decrease in the inlet flux of cooling, results in changes in the heat transfer mechanism. This causes increases in the surface temperature of the fuel elements causing failures at the fuel (burnout). This paper describes the experiments conducted to detect critical heat flux in nuclear fuel element simulators carried out in the thermal-hydraulic laboratory of Nuclear Technology Development Centre (CDTN). It is concluded that the use of displacement transducer is the most efficient technique for detecting critical heat flux in nuclear simulators heated by electric current in open pool.

scholarly journals Iodine release from high-burnup fuel structures: Separate-effect tests and simulated fuel pellets for better understanding of iodine behaviour in nuclear fuels

MRS Advances ◽  
2021 ◽  
Author(s):  
Janne Heikinheimo ◽  
Teemu Kärkelä ◽  
Václav Tyrpekl ◽  
Matĕj̆ Niz̆n̆anský ◽  
Mélany Gouëllo ◽  
...  
Keyword(s):  
Fission Product ◽  
Nuclear Fuel ◽  
Chemical Species ◽  
Outer Edge ◽  
Fuel Pellet ◽  
Fuel Pellets ◽  
Simulated Fuel ◽  
Fission Gas ◽  
High Burnup ◽  
Iodine Release

Abstract Iodine release modelling of nuclear fuel pellets has major uncertainties that restrict applications in current fuel performance codes. The uncertainties origin from both the chemical behaviour of iodine in the fuel pellet and the release of different chemical species. The structure of nuclear fuel pellet evolves due to neutron and fission product irradiation, thermo-mechanical loads and fission product chemical interactions. This causes extra challenges for the fuel behaviour modelling. After sufficient amount of irradiation, a new type of structure starts forming at the cylindrical pellet outer edge. The porous structure is called high-burnup structure or rim structure. The effects of high-burnup structure on fuel behaviour become more pronounced with increasing burnup. As the phenomena in the nuclear fuel pellet are diverse, experiments with simulated fuel pellets can help in understanding and limiting the problem at hand. As fission gas or iodine release behaviour from high-burnup structure is not fully understood, the current preliminary study focuses on (i) sintering of porous fuel samples with Cs and I, (ii) measurements of released species during the annealing experiments and (iii) interpretation of the iodine release results with the scope of current fission gas release models. Graphical abstract

scholarly journals Influence of blending proportions of Teak Sawdust and Cajuput leaves on characteristics of biomass pellets

2020 ◽  
Vol 187 ◽  
pp. 03001
Author(s):  
Wassachol Wattana ◽  
Nattaya Montri ◽  
Manussavee Wongjanakul ◽  
Yingyot Naratta ◽  
Sansanee Duangjinda
Keyword(s):  
Moisture Content ◽  
Physical Properties ◽  
Bulk Density ◽  
Solid Fuel ◽  
Alternative Fuel ◽  
Sustainable Production ◽  
Fuel Pellet ◽  
Fuel Pellets

Fuel pellets made from biomass is considered as a solid fuel that is also an alternative fuel which can substitute for the current fuels and can be considered as a fuel that has sustainable production. This research is the study of the production of fuel pellets from Teak sawdust blends with Cajuput leaves at five proportions by weight of Teak sawdust 100%, Cajuput leaves 100%, Teak sawdust 75% +Cajuput leaves 25%, Teak sawdust 50% +Cajuput leaves 50%, Teak sawdust 25% +Cajuput leaves 75% . The pellets were produced by a grinding and pelleting machine at three different speeds of 200, 250, and 300 rpm. After that, the quality of fuel pellets was evaluated by the physical properties as pellet dimensions, particles and bulk density, as well as moisture content and durability. The results show that blending proportion of Teak sawdust 75% and Cajuput leaves 25% provided the appropriate fuel pellet properties.

scholarly journals Analysis of temperature distribution in the heating boiler equipped with afterburning chamber

2019 ◽  
Vol 128 ◽  
pp. 01009
Author(s):  
Wojciech Judt ◽  
Bartosz Ciupek ◽  
Rafał Urbaniak
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Distribution ◽  
Transfer Process ◽  
Solid Fuel ◽  
Heat Transfer Process ◽  
Heating Device ◽  
Afterburning Chamber ◽  
Vertical Tubes ◽  
Heating Boiler

Analysis of a heat transfer process for construction of solid fuel heating boiler equipped with additional afterburning chamber is presented. Analyzed construction of the heating device is intended for shouse heating and preparation of hot utility water. A heat exchanger in the analyzed boiler is composed of vertical tubes divided into three boiler draughts. Afterburning chamber connects main combusting chamber of the heating boiler with second and third boiler draught. The aim of this analysis is to identify the character of heat transfer through the heating boiler

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