Introduction of a New Structural Material for Spent Nuclear Fuel Transportation Casks

The From-Reactor Transportation Cask Initiative of the DOE Office of Civilian Radioactive Waste Management (OCRWM) has, since 1988, supported the development of cask systems for the shipment of spent nuclear fuel by both legal weight truck (LWT) and rail or barge. The design basis fuel to be transported would be 10 years out-of-reactor with maximum burnups of 35 and 30 GWD/MTU for PWR and BWR assemblies, respectively. Westinghouse's work on the program led to the development of a common use LWT cask design capable of transporting either three PWR or seven BWR assemblies. This payload in a common use cask is achieved by the use of depleted uranium for the gamma shielding material and Grade 9 titanium as the principal structural material. The use of Grade 9 titanium for cask structures has no certification precedent. This paper describes the work performed to characterize the material and the status of steps taken to gain its acceptance by the NRC, which includes ASME approval of its use in the construction of Section 3 Class 1 components.