Shielding the BR-100 spent-fuel shipping cask

The B and W Fuel Company, under contract to the Department of Energy, is developing a US Nuclear Regulatory Commission certified cask (the BR-100) for shipping spent nuclear fuel from utilities by either rail or barge to a licensed repository. The BR-100, is a spent-fuel shipping container capable of handling both pressurized water reactor (PWR) and boiling water reactor (BWR) fuel by utilizing specially designed baskets. The limiting dose rate criterion as specified by 10CFR71 is 10 mrem/h, 2 m from the personnel barrier of the BR-100 cask. This criterion is met for all locations around the cask with the maximum, dose rate being 9.6 mrem/h at the radial midplane. Based on the conservative nature of the source, i.e., high burnup/low enrichment and axial shape at peak burnup, this represents a conservative dose rate. The BR-100 cask shield design successfully meets both the 100-t weight limitation and the 10CFR71 dose rate limitations with a loading of either 21 PWR or 52 BWR fuel assemblies