scholarly journals Characteristics of Hydride Precipitation and Reorientation in Spent-Fuel Cladding

Author(s):  
HM Chung ◽  
RS Daum ◽  
JM Hiller ◽  
MC Billone
Author(s):  
Jesus Ruiz-Hervias ◽  
Miguel Angel Martin-Rengel ◽  
Francisco Javier Gomez-Sanchez

The ring compression test applied to nuclear fuel cladding is relatively easy to perform but difficult to interpret. It can be representative of the loading state associated to a hypothetical spent fuel assembly drop accident. This is particularly important for spent fuel cladding subjected to drying operations previous to storage and transportation, because they may produce hydride reorientation along the radial direction of cladding. In this paper, experimental testing and numerical simulations are combined to obtain operative failure criteria from the results of the ring compression tests on unirradiated pre-hydrided samples with radial hydrides, simulating drying, storage and subsequent transport conditions.


Author(s):  
He Kai ◽  
Song Zifan ◽  
Zheng Yuntao ◽  
Jiang Xiaochuan ◽  
Yang Changjiang ◽  
...  

Author(s):  
Yoshiyuki Nemoto ◽  
Yoshiyuki Kaji ◽  
Toru Kanazawa ◽  
Kazuo Nakashima ◽  
Masayuki Tojo

Author(s):  
Ahmed Aly ◽  
Victor Petrov ◽  
Maria Avramova ◽  
Annalisa Manera ◽  
Kostadin Ivanov

The fuel cladding is an important barrier to the release of fission products to the environment. Its integrity must be conserved during the in-reactor lifetime and during the spent fuel pool and dry cask storage. The corrosive interaction between the cladding and the water coolant in light water reactors leads to the oxidation of the zirconium-based cladding. A fraction of the hydrogen released due to those corrosive interactions or the radiolysis of the water coolant is picked-up by the fuel cladding. It diffuses inside the cladding driven by the concentration and temperature gradients. Eventually, its concentration can increase beyond a certain limit above which hydrogen precipitates as hydrides. The formation of hydrides can embrittle the cladding and leads to micro-cracks that can compromise the cladding integrity. At the spacer grids locations, the mixing vanes will create swirl flow and mixing of the coolant leading to a high temperature gradient on the fuel rod cladding. This temperature gradient is a strong driving force for hydrogen to diffuse from high to low temperature locations. Therefore, the hydrogen behavior around the spacer grids with mixing vanes is important to model. In this work, the computational fluid dynamics code START-CCM+ is used to model the effect of the mixing vanes on the temperature profile on the cladding outer surface. It ws coupled with the transport code MPACT and the fuel performance code BISON. The computational model consisted of a 5 × 5 fuel rods subassembly with a guide tube in the central location. The obtained cladding temperature profile on a fuel rod of interest was applied as a boundary condition to BISON to model the hydrogen behavior around the spacer grids in a three-dimensional manner. Three spacer grids were modeled at elevations of 217.9 cm, 270.14 cm and 322.35 cm. The hydrogen behavior at each of those locations is evaluated and compared to assess the importance order of those locations.


Estimates are given of the total quantities of radioactivity, and of the contribution from different isotopes to this total, arising in the wastes from civil nuclear power generation; the figures are normalized to 1 GW (e) y of power production. The intensity of the heat and y-radiation emitted by the spent fuel has been calculated, and their decrease as the radioactivity decays. Reprocessing the spent fuel results in 95% or more of the fission products and higher actinides being concentrated in a small volume of high-level, heat-emitting waste. The total decay curve of unreprocessed spent fuel or of the separated high-level waste is dominated by the decay of some fission products for a few hundred years and then by the decay of some actinide isotopes for some tens of thousands of years. The residual activity is compared with that of the original uranium ore. Some of the long-lived activity will appear in other waste streams, particularly on the fuel cladding, and the volumes and activities of these wastes arising in this country are recorded. The long-lived activity arising from reactor decommissioning will be small compared with the annual arisings from the fuel cycle.


2011 ◽  
Vol 34 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Ching-Kong Chao ◽  
Kuo-Ching Yang ◽  
Chin-Kun Chen ◽  
Che-Chung Tseng

1972 ◽  
Author(s):  
J. O. Blomeke ◽  
J. J. Perona
Keyword(s):  

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