Evaluation of the stability of protective coatings on microfuel in a vapor-gas medium with interaction with structural materials

The serviceability of unirradiated microfuel with protective silicon carbide cladding in contact with corrosion-resistant 08Kh18N10T and EI-847 (05Kh15N16M3B) steels in a vapor-gas medium at 1100-1450°C has been investigated under bench conditions in application to emergency operating regimes of the core of a light-water reactor with loss of coolant in the first loop. It has been established that the cladding of microfuel tested at ~1200°C for 2-4 h in a medium consisting of the products of combustion of propane in oxygen in contact with austenitic steel remained completely sealed and whole. Under these conditions, this temperature is the maximum admissible temperature for microfuel with a protective silicon carbide outer layer. Under the conditions studied at 1300-1450°C, the 08Kh18N10T and EI-847 steels possess the same and comparatively low corrosion resistance. The corrosion depth over 2 h exceeds 0.5 mm or they melt. At 1100-1210°C the corrosion depth in these steels lies in the range 0.15-0.2 mm.