Effect of grain size on recrystallization in high burnup fuel pellets

1997 ◽  
Vol 248 ◽  
pp. 196-203 ◽  
Author(s):  
K. Nogita ◽  
K. Une ◽  
M. Hirai ◽  
K. Ito ◽  
K. Ito ◽  
...  
Keyword(s):  
Grain Size ◽  
Fuel Pellets ◽  
High Burnup

Grain Subdivision Fission Gas Swelling Model for UO2

MRS Advances ◽  
2016 ◽  
Vol 1 (35) ◽  
pp. 2465-2470
Author(s):  
Thomas Winter ◽  
Richard Hoffman ◽  
Chaitanya S. Deo
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Gas Diffusion ◽  
Fine Grain ◽  
Fuel Pellets ◽  
Model And Simulation ◽  
Nucleation Sites ◽  
Fission Gas ◽  
High Burnup ◽  
Swelling Model

ABSTRACTUnder high burnup UO2 fuel pellets can experience high burnup structure (HBS) at the rim also known as rim effect. The HBS is exceptionally porous with fine grain sizes. HBS increases the swelling further than it would have achieved at a larger grain size. A theoretical swelling model is used in conjunction with a grain subdivision simulation to calculate the swelling of UO2. In UO2 the nucleation sites are at vacancies and the bubbles are concentrated at grain boundaries. Vacancies are created due to irradiation and gas diffusion is dependent on vacancy migration. In addition to intragranular bubbles, there are intergranular bubbles at the grain boundaries. Over time as intragranular bubbles and gas atoms accumulate on the grain boundaries, the intergranular bubbles grow and cover the grain faces. Eventually they grow into voids and interconnect along the grain boundaries, which can lead to fission gas release when the interconnection reaches the surface. This is known as the saturation point. While the swelling model used does not originally incorporate a changing grain size, the simulation allows for more accurate swelling calculations by introducing a fractional HBS based on the temperature and burnup of the pellet. The fractional HBS is introduced with a varying grain size. Our simulations determine the level of swelling and saturation as a function of burnup by combining an independent model and simulation to obtain a more comprehensive model.

scholarly journals Grain size and phase purity characterization of U3Si2 fuel pellets

2018 ◽  
Vol 512 ◽  
pp. 199-213 ◽  
Author(s):  
Rita E. Hoggan ◽  
Kevin R. Tolman ◽  
Fabiola Cappia ◽  
Adrian R. Wagner ◽  
Jason M. Harp
Keyword(s):  
Grain Size ◽  
Phase Purity ◽  
Fuel Pellets

Development of the MFPR/R code for characterization of the rim zone and high burnup structure evolution in UO2 fuel pellets

2019 ◽  
Vol 517 ◽  
pp. 214-224 ◽  
Author(s):  
V.I. Tarasov ◽  
P.V. Polovnikov ◽  
V.E. Shestak ◽  
M.S. Veshchunov
Keyword(s):  
Structure Evolution ◽  
Fuel Pellets ◽  
High Burnup

Identification of Radial Position of Fission Gas Release in High-Burnup Fuel Pellets under RIA Conditions

2010 ◽  
Vol 47 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Hideo SASAJIMA ◽  
Tomoyuki SUGIYAMA ◽  
Toshinori CHUTO ◽  
Fumihisa NAGASE ◽  
Takehiko NAKAMURA ◽  
...  
Keyword(s):  
Radial Position ◽  
Gas Release ◽  
Fuel Pellets ◽  
Fission Gas ◽  
High Burnup ◽  
Fission Gas Release

Development and characteristics of the rim region in high burnup UO2 fuel pellets

1992 ◽  
Vol 188 ◽  
pp. 19-27 ◽  
Author(s):  
M.E. Cunningham ◽  
M.D. Freshley ◽  
D.D. Lanning
Keyword(s):  
Fuel Pellets ◽  
High Burnup

Fracture Toughness of VVER and PWR Uranium-Dioxide Fuel Pellets with Different Grain Size

Atomic Energy ◽  
2015 ◽  
Vol 118 (2) ◽  
pp. 117-123 ◽  
Author(s):  
V. V. Novikov ◽  
R. B. Sivov ◽  
E. N. Mikheev ◽  
A. V. Fedotov
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Uranium Dioxide ◽  
Fuel Pellets ◽  
Different Grain Size

Preparation of UCO Microspheres by Internal Gelation Process

2016 ◽  
Vol 697 ◽  
pp. 831-834
Author(s):  
Xing Yu Zhao ◽  
Jing Tao Ma ◽  
Yong Gao ◽  
Shao Chang Hao ◽  
Chang Sheng Deng ◽  
...  
Keyword(s):  
Grain Size ◽  
Carbon Black Content ◽  
Internal Gelation ◽  
Sintering Atmosphere ◽  
Gelation Process ◽  
Cladding Layer ◽  
High Temperature Reactor ◽  
High Burnup ◽  
And Performance ◽  
Microstructure And Performance

UCO kernels were used for High Temperature Reactor (HTR) fuel, which can restrain kernels migration and avoid corrosion of cladding layer under the high burnup compared with UO2 or UC kernels. In this paper, UCO kernels were prepared by internal gelation process containing dissolving, broth preparation, dispersing, AWD (aging, washing and drying) and sintering procedures. The broth composition was studied based on the fabrication of UO2 kernels before. Effects of the carbon black content and sintering atmosphere on the microstructure and performance of microspheres were mainly studied. Surface morphology of dried microsphere was observed by integrated microscope. Grain size and the degree of densification of UCO microspheres were observed by SEM.

Model for evolution of grain size in the rim region of high burnup UO2 fuel

2016 ◽  
Vol 471 ◽  
pp. 74-79 ◽  
Author(s):  
Hongxing Xiao ◽  
Chongsheng Long ◽  
Hongsheng Chen
Keyword(s):  
Grain Size ◽  
High Burnup

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

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