The use of one- and three-dimensional shielding codes for dose calculations in spent-fuel storage casks

This paper compares radial and axial dose rates outside a spent nuclear fuel storage cask calculated by one- and three-dimensional shielding codes. The techniques used for axial dose rate calculations with the one-dimensional codes were previously developed and tested with a transport cask. The storage cask analyzed in this paper has a 2.5-m o.d. (D), is 5 m high (H), with a resulting height-to-diameter ratio (H/D) of 2. The transport cask previously analyzed had a H/D of 3.4. This paper also investigates the appropriateness of using one-dimensional codes for radial dose rate calculations in casks with three-dimensional factors. The storage case is analyzed when fully loaded with 26 pressurized water reactor assemblies with 40,000 MWd/tonne U burnup and 5-yr cooling time before being stored in the cask. 10 refs., 2 tabs