DCT-8 pumped limiter design considerations

Disruption erosion drives the life of the DCT-8 pumped limiter. This result came from an evaluation of beryllium (Be), beryllium oxide (BeO), and silicon carbide (SiC) as candidate surface tile materials. Beryllium oxide was selected as the reference tile material because it has the longest life: 13 full power hours (2300 burns a 20 s/burn) or 2.3 years of DCT-8 operation. The fabricability of any of the candidate materials and the ability to survive thermal shock conditions and electromagnetic loads imposed by disruptions are serious concerns. The most desirable materials from an engineering standpoint (graphite and high-Z, e.g., tantalum) were eliminated due to physics considerations. (orig.)