SAFETY EVALUATION REPORT FOR THE STANDARDIZED NUHOMS® SYSTEM CERTIFICATE OF COMPLIANCE NO. 1004 RENEWAL DOCKET NO. 72-1004 Office of Nuclear Material Safety and Safeguards United States Nuclear Regulatory Commission May 2017 CONTENTS Section Page INTRODUCTION .......................................................................................................................... v 1 GENERAL INFORMATION ................................................................................................. 1-1 1.1 CoC and CoC Holder Information .............................................................................. 1-1 1.2 Safety Review ............................................................................................................ 1-1 1.3 Application Content ................................................................................................... 1-1 1.4 Interim Staff Guidance ............................................................................................... 1-2 1.5 Evaluation Findings ................................................................................................... 1-2 2 SCOPING EVALUATION .................................................................................................... 2-1 2.1 Scoping and Screening Methodology ........................................................................ 2-1 2.1.1 Scoping Process ............................................................................................ 2-3 2.1.2 Structures, Systems, and Components Within Scope of Renewal ................ 2-7 2.1.3 Structures, Systems, and Components NOT Within Scope of Renewal ....................................................................................................... 2-17 2.2 Evaluation Findings ................................................................................................. 2-20 3 AGING MANAGEMENT REVIEW ...................................................................................... 3-1 3.1 Review Objective ....................................................................................................... 3-1 3.2 AMR Process ............................................................................................................. 3-1 3.3 Aging Management Review Results: Materials, Service Environment, Aging Effects, and Aging Management Programs ............................................................... 3-2 3.3.1 Spent Fuel Assembly (SFA) ........................................................................ 3-14 3.3.1.1 Materials and Environments .......................................................... 3-15 3.3.1.2 Aging Effects/Mechanisms for the Spent Nuclear Fuel Assemblies During the Period of Extended Storage...................... 3-19 3.3.1.3 Evaluation of the Proposed Aging Management Activities ............ 3-21 3.3.2 Dry Shielded Canisters (DSC) ..................................................................... 3-21 3.3.2.1 Materials and Environments .......................................................... 3-22 3.3.2.2 Aging Effects/Mechanisms for the Dry Shielded Canisters During the Period of Extended Storage ......................................... 3-25 3.3.2.3 Evaluation of the Proposed Aging Management Activities ............ 3-35 3.3.3 Horizontal Storage Modules (HSM) ............................................................. 3-37 3.3.3.1 Materials and Environments .......................................................... 3-38 3.3.3.2 Aging Effects/Mechanisms for the Horizontal Storage Modules During the Period of Extended Storage .......................... 3-41 3.3.3.2.1 Reinforced Concrete Structure ...................................... 3-41 3.3.3.2.2 Steel and Aluminum Subcomponents ........................... 3-42 3.3.3.3 Evaluation of the Proposed Aging Management Activities ............ 3-48 3.3.4 Storage Pad (Basemat) ............................................................................... 3-48 3.3.4.1 Materials and Environments .......................................................... 3-49 3.3.4.2 Aging Effects/Mechanisms for the Storage Pad (Basemat) During the Period of Extended Storage ......................................... 3-49 3.3.4.3 Evaluation of the Proposed Aging Management Activities ............ 3-49 3.3.5 Transfer Cask (TC) ...................................................................................... 3-50 ii 3.3.5.1 Material and Environments ............................................................ 3-51 3.3.5.2 Aging Effects/Mechanisms for the Transfer Cask During the Period of Extended Storage .......................................................... 3-52 3.3.5.3 Evaluation of the Proposed Aging Management Activities ............ 3-56 3.3.6 Evaluation Findings ..................................................................................... 3-57 3.4 Time-Limited Aging Analyses Evaluation ................................................................ 3-57 3.4.1 Fatigue Evaluation of the Dry Shielded Canisters ....................................... 3-58 3.4.2 Fatigue Evaluation of the Transfer Casks .................................................... 3-60 3.4.3 Horizontal Storage Module Concrete and Dry Shielded Canister Steel Support Structure Thermal Fatigue, Corrosion, and Temperature Effects Evaluation ........................................................................................ 3-62 3.4.4 Dry Shielded Canister Poison Plates Boron Depletion Evaluation .............. 3-64 3.4.5 Evaluation of Neutron Fluence and Gamma Radiation on Storage System Structural Materials ......................................................................... 3-65 3.4.6 Confinement Evaluation of 24P and 52B Non-Leaktight DSCs ................... 3-66 3.4.7 Thermal Performance of Horizontal Storage Modules for the Period of Extended Operation ................................................................................. 3-68 3.4.8 Evaluation of Additional Cladding Oxidation and Additional Hydride Formation Assuming Breach of Dry Shielded Canister Confinement Boundary ..................................................................................................... 3-69 3.4.9 Evaluation of Cladding Gross Rupture during Period of Extended Operation ..................................................................................................... 3-70 3.4.10 Structural Assessment of High Burnup Cladding Performance during Period of Extended Operation ..................................................................... 3-70 3.4.11 Defense-in-Depth Evaluation of Dry Shielded Canister Internal Pressures Assuming High Burnup Fuel Cladding Failure during Period of Extended ...................................................................................... 3-72 3.4.12 Defense-in-Depth Structural Evaluation of Dry Shielded Canister Confinement and Retrievability Assuming High Burnup Fuel Cladding Failure during Period of Extended Operation .............................................. 3-73 3.4.13 Bounding Evaluation of Dry Shielded Canister with Reduced Shell Thickness Due to Chloride-Induced Stress Corrosion Cracking under Normal and Off Normal Conditions of Storage during Renewal Period ....... 3-75 3.4.14 Evaluation Findings ..................................................................................... 3-76 3.5 Lead Canister Inspection ......................................................................................... 3-76 3.6 Aging Management Programs ................................................................................. 3-79 3.6.1 High Burnup Fuel Aging Management Program .......................................... 3-79 3.6.2 DSC External Surfaces Aging Management Program ................................. 3-81 3.6.3 DSC Aging Management Program for the Effects of CISCC ....................... 3-83 3.6.4 Horizontal Storage Module Aging Management Program for External and Internal Surfaces ................................................................................... 3-86 3.6.5 HSM Inlets and Outlets Ventilation Aging Management Program ............... 3-87 3.6.6 Transfer Cask Aging Management Program ............................................... 3-92 3.6.7 Evaluation Findings ..................................................................................... 3-97 4 CHANGES TO CERTIFICATE OF COMPLIANCE AND TECHNICAL SPECIFICATIONS 4-1 5 CONCLUSION .................................................................................................................... 5-1 6 REFERENCES ................................................................................................................... 6-1 iii TABLES Table Page 1.6-1 Existing Interim Staff Guidance Relevant to ISFSI Renewal .......................................... 1-3 2.1-1 SSCs Within and Not Within Scope of Renewal ............................................................ 2-3 2.1-2 SSC Subcomponents Within Scope of Renewal SNF Assemblies ................................ 2-7 2.1-3 SSC Subcomponents Within Scope of Renewal 24P DSC ............................................ 2-8 2.1-4 SSC Subcomponents Within Scope of Renewal 24P Long Cavity DSC ........................ 2-8 2.1-5 SSC Subcomponents Within Scope of Renewal 24PT2 DSC........................................ 2-9 2.1-6 SSC Subcomponents Within Scope of Renewal 52B DSC ............................................ 2-9 2.1-7 SSC Subcomponents Within Scope of Renewal 24PHB Long Cavity DSC