Combustion and Disintegration of Zirconium Hydride-Uranium Fuel Rods During Atmospheric Re-Entry

Author(s):  
F.E. Littman ◽  
A.E. Levy-Pascal ◽  
N.A. Tiner
Author(s):  
G.J.C. Carpenter

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.


1964 ◽  
Vol 25 (5) ◽  
pp. 451-453 ◽  
Author(s):  
S.W. Peterson ◽  
V.N. Sadana ◽  
W.L. Korst

2011 ◽  
pp. 107-114
Author(s):  
B. Lacroix ◽  
T. Martella ◽  
M. Pras ◽  
M. Masson-Fauchier ◽  
L. Fayette

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