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Title: Using Finite Model Analysis and Out of Hot Cell Surrogate Rod Testing to Analyze High Burnup Used Nuclear Fuel Mechanical Properties

Based on a series of FEA simulations, the discussions and the conclusions concerning the impact of the interface bonding efficiency to SNF vibration integrity are provided in this report; this includes the moment carrying capacity distribution between pellets and clad, and the impact of cohesion bonding on the flexural rigidity of the surrogate rod system. As progressive de-bonding occurs at the pellet-pellet interfaces and at the pellet-clad interface, the load ratio of the bending moment carrying capacity gradually shifts from the pellets to the clad; the clad starts to carry a significant portion of the bending moment resistance until reaching the full de-bonding state at the pellet-pellet interface regions. This results in localized plastic deformation of the clad at the pellet-pellet-clad interface region; the associated plastic deformations of SS clad leads to a significant degradation in the stiffness of the surrogate rod. For instance, the flexural rigidity was reduced by 39% from the perfect bond state to the de-bonded state at the pellet-pellet interfaces.
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  1. ORNL
Publication Date:
OSTI Identifier:
Report Number(s):
AF5865010; NEAF346
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
Oak Ridge National Laboratory (ORNL); High Temperature Materials Laboratory (HTML)
Sponsoring Org:
NE USDOE - Office of Nuclear Energy
Country of Publication:
United States
Spent nuclear fuel; transportation; fuel-pellet interface