Calculations of safe distance from the point of a severe accident during transportation of a package containing spent nuclear fuels

This paper shows our calculations with a diffusion calculation code, HotSpot, on the effects of a radiological release of fission products by assuming a severe accident in transportation of spent nuclear fuel. Two main conclusions of the calculations were:1. By assuming that 5% of spent PWR fuel rods contained in a transport package TN12 were damaged and entire gaseous fission products were released in to the air, a French paper derived the safe distance as 450 m, whereas our calculations to replicate it estimated the safe distance of 33 m. The large discrepancies were ascribed to differences in source terms.2. Nuclear emergency preparedness and response for nuclear facilities (May 2000) suggested a safe distance of 15 m with an assumption of a release rate of A2 value per week for 10 hours. Our calculations to replicate the description showed a consistent result with it.