Nuclear dynamics consequence analysis of SNF disposed in volcanic tuff

This paper describes criticality analyses for spent nuclear fuels in a geologic repository. The analyses investigated criticality potential, criticality excursion consequences, and the probability frequency for nuclear criticality. Key findings include: expected number of fissions per excursion range from 1017 to 1020, repeated rate of criticalities range from 3 to 30 per year, and the probability frequency for criticality initiators (based on rough-order-of-magnitude calculations) is 7x10-7. Overall results indicate that criticality consequences are a minor contribution to the biological hazards caused by the disposal of spent nuclear material