The Nuclear Regulatory Commission (NRC) is amending its regulations by revising the Holtec International HI-STORM 100 cask system listing within the "List of approved spent fuel storage casks" to include Amendment No. 5 to Certificate of Compliance (CoC) Number 1014. Amendment No. 5 includes deletion of the requirement to perform thermal validation tests on thermal systems; an increase in the design basis maximum decay heat loads, namely, to 34 kilowatts (kW) for uniform loading and 36.9 kW for regionalized loading, and introduction of a new decay heat regionalized scheme; an increase in the maximum fuel assembly weight for boiling water reactor fuel in the Multi- Purpose Canister (MPC)-68 from 700 to 730 pounds; an increase in the maximum fuel assembly weight of up to 1,720 pounds for assemblies not requiring spacers, otherwise 1,680 pounds; changes to the assembly characteristics of 16 x 16 pressurized water reactor fuel assemblies to be qualified for storage in the HI-STORM 100 cask system; a change in the fuel storage locations in the MPC-32 for fuel with axial power shaping rod assemblies and in the fuel storage locations in the MPC-24, MPC-24E, and the MPC-32 for fuel with control rod assemblies, rod cluster control assemblies, and control element assemblies; elimination of the restriction that fuel debris can only be loaded into the MPC- 24EF, MPC-32F, MPC-68F, and MPC-68FF canisters; introduction of a requirement that all MPC confinement boundary components and any MPC components exposed to spent fuel pool water or the ambient environment be made of stainless steel or, for MPC internals, neutron absorber or aluminum; the addition of a threshold heat load below which operation of the Supplemental Cooling System would not be required and modification of the design criteria to simplify the system; minor editorial changes to include clarification of the description of anchored casks, correction of typographical/editorial errors, clarification of the definitions