Study on structural integrity of C/C composite using as core restraint mechanism in HTGR

High temperature gas cooled reactor (HTGR) with higher outlet coolant temperature nearly 1000 C is expected for direct utilization of process heat to hydrogen production. The thermal analysis of reactor internals with 3 dimensional, flow paths coupled model was conducted to demonstrate how strictly PSR block gaps must be closed to limit core bypass flow rate ratio lest fuel temperature should exceed admissible level, and the highly heat resistant core restraint mechanism must be developed in consequence. Potential applicability of the core restraint mechanism made of C/C composite, the attractive candidate material, was demonstrated by point design with adequate thickness and FEM stress analysis for material with orthotropic anisotropy. (orig.)