The U.S. Nuclear Regulatory Commission (NRC) is amending its spent fuel storage regulations by revising the TN Americas, LLC Standardized NUHOMS[supreg] Horizontal Modular Storage System for Irradiated Nuclear Fuel listing within the "List of approved spent fuel storage casks" to include Renewed Amendment No. 18 to Certificate of Compliance No. 1004. Because this amendment was submitted subsequent to the renewal of the TN Americas, LLC Standardized NUHOMS Horizontal Modular Storage System for Irradiated Nuclear Fuel Certificate of Compliance No. 1004 and, therefore, subject to the Aging Management Program requirements of the renewed certificate, NRC is referring to it as "Renewed Amendment No. 18." Renewed Amendment No. 18 amends the certificate of compliance to provide an improved basket design, revise technical specifications, and incorporate administrative controls during short duration independent spent fuel storage installation handling operations. The amendment also includes a change to the horizontal storage module concrete to allow use of a blended Portland cement that meets the requirements of American Society for Testing and Materials standards.