Design optimization of multi-layer Silicon Carbide cladding for light water reactors

- SiC cladding designs are optimized with a multi-layer structural analysis code.
- Layer radial thickness fraction that minimizes cladding fracture probability exists.
- The demonstrated procedure is applicable for multi-layer SiC cladding design.
- Duplex SiC with the inner composite fraction ∼0.4 is optimal in a reference case.
- Increasing composite thermal conductivity markedly decreases SiC cladding stress.

A parametric study that demonstrates a methodology for determining the optimum bilayer composition in a duplex SiC cladding is discussed. The structural performance of multi-layer SiC cladding design is significantly affected by radial thickness fraction of each layer. This study shows that there exists an optimal composite/monolith radial thickness fraction that minimizes failure probability for a duplex SiC cladding in steady-state operation. An exemplary reference case study shows that the duplex cladding with the inner composite fraction ∼0.4 and the outer CVD-SiC fraction ∼0.6 is found to be the optimal SiC cladding design for the current PWRs with the reference material choice for CVD-SiC and fiber reinforced composite. A marginal increase in the composite fraction from the presented optimal designs may lead to increase structural integrity by introducing some unquantified merits such as increasing damage tolerance. The major factors that affect the optimum cladding designs are temperature gradients and internal gas pressure. Clad wall thickness, thermal conductivity, and Weibull modulus are among the key design parameters/material properties.