Thermodynamic descriptions of oxygen redistribution in a nuclear fuel pellet: Heat of transport of oxygen in mixed conductors

1994 ◽  
Vol 24 (5) ◽  
Author(s):  
M. Kamata ◽  
T. Esaka
Keyword(s):  
Nuclear Fuel ◽  
Fuel Pellet ◽  
Mixed Conductors ◽  
Heat Of Transport

scholarly journals Properties of the high burnup structure in nuclear light water reactor fuel

2017 ◽  
Vol 105 (11) ◽  
Author(s):  
Thierry Wiss ◽  
Vincenzo V. Rondinella ◽  
Rudy J. M. Konings ◽  
Dragos Staicu ◽  
Dimitrios Papaioannou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Nuclear Fuel ◽  
Experimental Studies ◽  
Fuel Pellet ◽  
Extended Defects ◽  
Safety Margins ◽  
Fission Gas ◽  
High Burnup ◽  
Formed Structure

AbstractThe formation of the high burnup structure (HBS) is possibly the most significant example of the restructuring processes affecting commercial nuclear fuel in-pile. The HBS forms at the relatively cold outer rim of the fuel pellet, where the local burnup is 2–3 times higher than the average pellet burnup, under the combined effects of irradiation and thermo-mechanical conditions determined by the power regime and the fuel rod configuration. The main features of the transformation are the subdivision of the original fuel grains into new sub-micron grains, the relocation of the fission gas into newly formed intergranular pores, and the absence of large concentrations of extended defects in the fuel matrix inside the subdivided grains. The characterization of the newly formed structure and its impact on thermo-physical or mechanical properties is a key requirement to ensure that high burnup fuel operates within the safety margins. This paper presents a synthesis of the main findings from extensive studies performed at JRC-Karlsruhe during the last 25 years to determine properties and behaviour of the HBS. In particular, microstructural features, thermal transport, fission gas behaviour, and thermo-mechanical properties of the HBS will be discussed. The main conclusion of the experimental studies is that the HBS does not compromise the safety of nuclear fuel during normal operations.

Defect inspection system of nuclear fuel pellet end faces based on machine vision

2020 ◽  
Vol 57 (6) ◽  
pp. 617-623
Author(s):  
Bin Zhang ◽  
Mengmeng Liu ◽  
Yongzhi Tian ◽  
Ge Wu ◽  
Xiaohui Yang ◽  
...  
Keyword(s):  
Machine Vision ◽  
Nuclear Fuel ◽  
Fuel Pellet ◽  
Inspection System ◽  
Defect Inspection

scholarly journals Thermal Conductivity Measurement of Zr-ZrO<sub>2</sub> Simulated Inert Matrix Nuclear Fuel Pellet

2013 ◽  
Vol 03 (02) ◽  
pp. 46-50 ◽  
Author(s):  
Dong-Joo Kim ◽  
Young Woo Rhee ◽  
Jong Hun Kim ◽  
Jang Soo Oh ◽  
Keon Sik Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Nuclear Fuel ◽  
Conductivity Measurement ◽  
Thermal Conductivity Measurement ◽  
Fuel Pellet ◽  
Inert Matrix

Review about the Effect of He on the Microstructure of Spent Nuclear Fuel in a Repository

MRS Advances ◽  
2016 ◽  
Vol 1 (62) ◽  
pp. 4147-4156 ◽  
Author(s):  
C. Ferry ◽  
J. Radwan ◽  
H. Palancher
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Critical Concentration ◽  
Fuel Pellet ◽  
Spent Fuel ◽  
Operational Model ◽  
Matrix Microstructure ◽  
Natural Analogues ◽  
Order Of Magnitude ◽  
Radionuclide Release

ABSTRACTHelium is produced in spent nuclear fuel by α-decays of actinides. After 10,000 years, the concentration of He accumulated in UO2 spent fuel is about 0.23 at.%. For direct disposal of spent nuclear fuel, consequences of helium build-up on the fuel matrix microstructure must be evaluated since it can modify the radionuclide release when water comes into contact with the spent fuel surface, after breaching of the disposal canister. An operational model has been proposed in order to evaluate the effect of helium on the microstructure of spent fuel in a repository. Based on conservative assumptions and different scenarios of bubble population, the calculated helium critical concentration, that could lead to a partial loss of integrity of the spent fuel pellet, is 0.37 at.%. However, observations on He-implanted UO2, α-doped UO2 pellets and natural analogues evidence a macroscopic damage only for He concentrations, which are more than one order of magnitude higher.

scholarly journals Isotopic and Compositional Variations in Single Nuclear Fuel Pellet Particles Analyzed by Nanoscale Secondary Ion Mass Spectrometry

ACS Omega ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 296-303 ◽  
Author(s):  
Connaugh M. Fallon ◽  
William R. Bower ◽  
Ian C. Lyon ◽  
Francis R. Livens ◽  
Paul Thompson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Fuel ◽  
Secondary Ion Mass Spectrometry ◽  
Fuel Pellet ◽  
Ion Mass Spectrometry ◽  
Compositional Variations ◽  
Secondary Ion

FRACTAL MODEL OF FISSION PRODUCT RELEASE IN NUCLEAR FUEL

2012 ◽  
Vol 23 (09) ◽  
pp. 1250057
Author(s):  
GEDIMINAS STANKUNAS
Keyword(s):  
Diffusion Process ◽  
Nuclear Fuel ◽  
Functional Dependence ◽  
Experimental Studies ◽  
Fractional Diffusion ◽  
Fractal Model ◽  
Fuel Pellet ◽  
Operation Conditions ◽  
Fuel Burn ◽  
Fission Gas

A model of fission gas migration in nuclear fuel pellet is proposed. Diffusion process of fission gas in granular structure of nuclear fuel with presence of inter-granular bubbles in the fuel matrix is simulated by fractional diffusion model. The Grunwald–Letnikov derivative parameter characterizes the influence of porous fuel matrix on the diffusion process of fission gas. A finite-difference method for solving fractional diffusion equations is considered. Numerical solution of diffusion equation shows correlation of fission gas release and Grunwald–Letnikov derivative parameter. Calculated profile of fission gas concentration distribution is similar to that obtained in the experimental studies. Diffusion of fission gas is modeled for real RBMK-1500 fuel operation conditions. A functional dependence of Grunwald–Letnikov derivative parameter with fuel burn-up is established.

Cost Saving When Using Enhanced Conductivity Nuclear Fuel Containing BeO in WWER-1000 Reactors

2014 ◽  
Author(s):  
Tomáš Zahrádka ◽  
Radek Škoda
Keyword(s):  
Thermal Conductivity ◽  
Nuclear Fuel ◽  
Fuel Pellet ◽  
Internal Stresses ◽  
Fuel Temperature ◽  
Pressurized Water ◽  
Adverse Conditions ◽  
Advantages And Disadvantages ◽  
Fuel Pin ◽  
Water Reactors

Current pressurized water reactors utilize sintered UO2 that has a number of advantages and disadvantages. Uranium Dioxide’s low thermal conductivity results in a large thermal gradient within the fuel pellet corresponding to higher centerline temperatures compared to other potential fuel forms. These gradients result in non-uniform thermal expansion leading to large internal stresses resulting in cracking of the pellet and fuel-clad interaction, which can lead to loss of the integrity of the fuel pin. Higher fuel temperatures also increase the release of fission gases. Fuels with higher thermal conductivity may alleviate or reduce the severity of these adverse conditions. It is shown that higher thermal conductivity can be obtained by adding BeO to the basic UO2 matrix. This paper focuses on WWER1000 hexagonal fuel geometry. Improvements when using 10% of BeO, as proposed in this paper, reduce the centerline nuclear fuel temperature by 234°C and improve the fuel economy while reducing its cost by 7%. The study was done for NPP Temelín which has two units WWER1000/320.

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