The overreaching goal of this project is to couple thermal-hydraulics, neutronics, and fuel performance codes together to predict the distribution of hydrogen and hydrides in the cladding as a function of time and space.
A constitutive model is constructed and solved numerically to predict the stress distribution and variation in the cladding under normal operating conditions.
The second step develops a semi-analytical model and experimentally tests the temperature and/or stress dependent hydrogen pick-up, diffusion, and precipitation in the cladding.
The loss-of-flow transient after a trip time of 4.08 s at 85% of loss of normal flow for the TRIGA core shows a peak temperature of 709.22 °C in the fuel centreline and 131.94 °C in the clad and 46.63 °C in the coolant exit of the hottest channel.
It was found that chemical reactions took place between Ti and SiC in the clad layers, and the reaction products included TiC, Ti5Si3, Ti5Si4, TiSi2, and Ti3SiC2.
Finally, an FEM model is employed to investigate the addition of material and thermal history in the cladding structure.
The emergence of β-Ti, TiC and W in the clad resulted in enhanced hardness values.
However, corrosion resistance of the laser cladded alloy was reduced by almost an order of magnitude compared to that of the as-cast alloy mainly due to the presence of cracks and pores in the cladded layer.
From Poisson's ratio and the proportionality between the thickness of individual layers in the cladding and the spectral band-gap position, the reflection peak center wavelength λpeak is predicted to follow the relation λpeak = λpeak(1 + ε) − v, where λpeak represents the reflection peak centre wavelength at zero axial strain, ε the applied axial strain and v the fibre's Poisson's ratio.
Three rings of uniform elliptical air holes are arranged in triangular lattice in the cladding and an extra small defected hole is introduced in the fiber core.
