The Nuclear Regulatory Commission (NRC) is amending its regulations revising the Holtec International HI-STORM 100 cask system listing within the list of approved spent fuel storage casks to include Amendment 1 to Certificate of Compliance (CoC) Number 1014. This amendment will modify the present cask system design, under a general license, to: add four new multipurpose canisters; add new containers for damaged fuel; add the HI-STORM 100S overpack and the 100A and 100SA high-seismic anchored overpacks; allow the storage of high-burnup fuel; delete the Technical Specifications for special requirements for the first systems in place and for training requirements and relocate these requirements to the main body of CoC 1014; and allow the storage of selected nonfuel hardware. The amendment will also use revised thermal analysis tools to include natural convection heat transfer, revise the helium backfill requirements to allow a helium density measurement to be used, allow a helium drying system rather than the existing vacuum drying system, and require soluble boron during canister loading for certain higher enriched fuels. In addition, modifications will be made to applicable CoC conditions and sections of Appendix A and Appendix B to the CoC to reflect the changes.