The U.S. Nuclear Regulatory Commission NRC is proposing to amend its spent fuel storage regulations by revising the NAC International Inc. MAGNASTOR Storage System listing within the List of approved spent fuel storage casks to include Amendment No. 13 to Certificate of Compliance No. 1031. Amendment No. 13 would revise the certificate of compliance to add a new type of radioactive contents to be stored inside the MAGNASTOR transportable storage canister add a new design configuration for the canister to accommodate the fuel bearing material and new canister components and use an alternate compressive strength for concrete cask number 6 of 6000 psi.