The U.S. Nuclear Regulatory Commission (NRC) is amending its spent fuel storage regulations by revising the Holtec International ("Holtec," or "the applicant") HI-STORM 100 Cask System listing within the "List of Approved Spent Fuel Storage Casks" to include Amendment No. 9, Revision 1, to Certificate of Compliance (CoC) No. 1014. Amendment No. 9, Revision 1, changes cooling time limits for thimble plug devices (TPDs), removes certain testing requirements for the fabrication of Metamic HT neutron-absorbing structural material, and reduces certain minimum guaranteed values (MGV) used in bounding calculations for this material. Amendment No. 9, Revision 1, also changes fuel definitions to classify certain boiling water reactor (BWR) fuel within specified guidelines as undamaged fuel.