ML21252A490
| ML21252A490 | |
| Person / Time | |
|---|---|
| Site: | 07109386 |
| Issue date: | 08/31/2021 |
| From: | Holtec |
| To: | Christopher Regan Division of Fuel Management |
| P Saverot NRC/NMSS/DFM/STLB 3014157505 | |
| Shared Package | |
| ML21252A489 | List: |
| References | |
| Download: ML21252A490 (13) | |
Text
www.holtecinternational.com HI-STAR PBT (TPBAR)
Pre-Application Meeting August 31, 2021 Holtec Information for Public Release
Holtec Proprietary Information l Page 2 Presentation Agenda Introduction Design Overview Acceptance Criteria and Overview of Safety Analysis Approach Structural Safety Overview Thermal Safety Overview Containment Safety Overview Shielding Safety Overview Summary and Proposed Licensing Schedule
Holtec Proprietary Information l Page 3 Introduction PNNL has procured the design, fabrication, and certification of a TPBAR transportation cask and dedicated trailer on behalf of Tritium Modernization Program (NNSA NA-19) for transporting Tritium Producing Burnable Absorber Rods (TPBARs) from Watts Bar Nuclear (WBN) Units 1 and 2 in Tennessee to the Tritium Extraction Facility (TEF) in South Carolina (Savannah River Site) to Improve Operational Efficiencies and Asset Assurance A pre-application meeting to present the HI-STAR PBT cask was held on March 31, 2021. NRC provided comments during this meeting that were documented in April 9, 2021 memorandum to Christopher M. Regan (ML21098A213)
Purpose of todays meeting:
Provide additional information and discussion on HI-STAR PBT cask design and analysis
Address comments provided during March 31, 2021 pre-application meeting
Holtec Proprietary Information l Page 4 HI-STAR PBT Design Overview Intended to hold 1-4 Consolidation Canisters, each containing up to 300 individual TPBARs Cask is designed for a minimum operational life of 20 years.
Maximum Heat Load of Cask: 1.753 kW Maximum Allowable TPBAR Temperature: 650°F No credible hydrogen generation due to cavity dryness criteria, bolted lid design, and max. TPBAR temperature
Holtec Proprietary Information l Page 5 HI-STAR PBT Design Overview Dunnage Dunnage is credited for:
Restricting axial movement of Consolidation Canisters & TPBARs
Additional shielding Dunnage has been evaluated to remain in place post-HAC Bolted connection, may be replaced if necessary
Holtec Proprietary Information l Page 6 HI-STAR PBT Design Overview Impact Limiter Identical top and bottom Protects cask against HAC Pour-in-place, closed-cell polyurethane foam crush material fills interior cavity
Holtec Proprietary Information l Page 7 Structural Criteria, Modeling, Methodology Acceptance Criteria General Criteria: Type B(U) Provisions of 10CFR71 Containment Integrity: ASME B&PV Code Section III, Division 1, Subsection NB Closure Lid Seal Joint: Remains leaktight under NCT and HAC per NUREG-1609, Suppl. 2 Basket: Maintains cell configuration w/o gross plastic deformation after impactive events Shielding Components: Remain functional after impactive events Impact Limiter: Sufficient energy absorption to protect TPBARs, basket and cask containment boundary and to maintain attachment to the cask Safety Analysis Approach Finite element method and hand calculations summarized in SAR with supporting calculation packages Dynamic Analysis: LS-DYNA explicit FEM analyses for 10CFR71.71 and 10CFR71.73 drop and puncture accidents Static Analysis: ANSYS FEM analyses and hand calculations for design pressure, lifting, immersion, fire accident and fatigue.
Holtec Proprietary Information l Page 8 Major Structural Analyses Lifting and tie-down analysis for top and bottom trunnions per NUREG-0612 and 10CFR71.45.
Structural evaluation for normal conditions of transport
- Static stress analyses of the cask subject to pressure, temperature, and closure lid bolt pre-loading
- Fatigue considerations of the cask and its contents
- Vibration considerations of the cask and its contents
- Dynamic stress analysis of package 0.3-m drop accident Structural evaluation for hypothetical accident conditions of transport
- Dynamic stress analyses and containment integrity evaluation for 9-m drop accident and 1-m drop puncture accident
Holtec Proprietary Information l Page 9 Thermal Criteria, Modeling, Methodology
Acceptance Criteria General Criteria: Type B(U)F Provisions of 10CFR71 All component temperatures and pressures meet their respective limits under all conditions of transport
Safety Analysis Approach Thermal analyses similar to prior HI-STAR applications For normal conditions of transport, a heat event consisting of an ambient temperature of 38°C (100°F) in still air and prescribed insolation is evaluated [10 CFR 71.71(c)(1)]
For normal conditions of transport, a cold event consisting of an ambient temperature of -40°C (-40°F) in still air and shade is evaluated [10 CFR 71.71(c)(2)]
For hypothetical accident conditions, a thermal event consisting of a fully engulfing hydrocarbon fuel/air fire with an average emissivity coefficient of at least 0.9, with an average flame temperature of at least 800°C (1475° F) for a period of 30 minutes [10 CFR 71.73(c)(4)]
Decay heat is 1.461W/TPBAR or 1.753kW per cask.
Holtec Proprietary Information l Page 10 Thermal Criteria, Modeling, Methodology Hypothetical fire accident (HAC) evaluation purported to occur after, and therefore accounts for structural damage caused due to, the 9m drop followed by 1m drop onto a 6-inch diameter bar.
Foam combustion modeling during HAC based on test data from General Plastics.
Steady state results from normal transport conditions are used as the initial conditions for the fire phase of the transient HAC analysis.
Tritium release per year in the consolidation canister is found to be about 1.4%, and therefore, flammability is not a concern.
Combustion of foam is modeled based on the available test data from General Plastics.
Holtec Proprietary Information l Page 11 HI-STAR PBT Containment Acceptance Criteria Design and Testing to ANSI N14.5 (2014) reference leakage rate of Leaktight Package maintains leaktightness under normal and accident condition events Structural and thermal evaluations confirm containment boundary integrity under normal and accident conditions of transport Evaluated against increased internal pressures during accident events due to rod rupture All containment boundary welds to be pressure (hydro) tested to ASME BPVC Section III NB-6000
Holtec Proprietary Information l Page 12 Shielding Criteria, Modeling, Methodology Acceptance criteria Normal conditions of transport: 10CFR71.47 2 mSv/h on the external surface of the package 0.1 mSv/h at any point 2 meters from the outer lateral surfaces of the vehicle 0.02 mSv/h in any normally occupied space (dose not apply to private carriers, if personnel wearing radiation dosimeters)
Hypothetical accident conditions: 10CFR71.51(a)(2) 10 mSv/h at any point 1 meter from the external surface of the package Safety Analysis Approach MCNP5 dose rate calculations
Holtec Proprietary Information l Page 13 HI-STAR PBT Summary Date (on or before)
Tritium Program Critical Activity Holtec Deliverable September 2021 Submit SAR to NRC Submit SAR to NNSA/NRC September 1, 2022 Window for trial load/unload shakedown at WBN and TEF Cask Unit 1 and dedicated trailer May 1, 2023 Support Cycle 18 transport from WBN to TEF Cask Unit 2 and dedicated trailer May 31, 2023 Support critical window to transport Cycle 18 TPBARs from WBN to TEF Finalization of safety documentation to support NRC award of CoC