The U.S. Nuclear Regulatory Commission (NRC) is amending its spent fuel storage regulations to add Amendment No. 4 to the Certificate of Compliance (CoC) No. 1031 for the NAC International MAGNASTOR[supreg] System. Amendment No. 4 changes a limiting condition for operation (LCO) in the technical specifications for transportable storage canister (TSC) vacuum drying and helium backfill times, and corrects a typographical error. The NRC approval of this Amendment would not authorize transportation.