HI-STAR 180D TYPE B(U)F TRANSPORTATION PACKAGE New … · 2012. 9. 28. · a generation ahead by...

a generation ahead by design

Pre-Application Presentation to NRC(Holtec Non-Proprietary Version)

September 5, 2012Holtec International

HI-STAR 180DTYPE B(U)F TRANSPORTATION PACKAGE

New License Application

Holtec Non-Proprietary PresentationThis document is copyrighted intellectual property of Holtec International. All rights reserved.


Pre-Application Meeting HI-STAR 180D

Agenda

• Introduction• Design Overview• Licensing• High Burnup Fuel• Criticality Safety• Shielding• Containment• Structural Analysis• Thermal Analysis• Summary

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Pre-Application Meeting HI-STAR 180DIntroduction

• Holtec is preparing to submit a license application for the new HI-STAR 180D Transportation Package

• The HI-STAR 180D package is a slight variant of the HI-STAR 180 package previously licensed under USNRC Docket 71-9325

• Holtec has prepared a safety analysis report on the HI-STAR 180D following essentially the same framework of SAR format, licensing approach, and safety analysis of the HI-STAR 180.

• This presentation discusses similarities and differences of the HI-STAR 180D and HI-STAR 180, in order to facilitate USNRC staff’s understanding of the design and to encourage feedback.

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HI-STAR 180D Design OverviewMajor Packaging Features HI-STAR 180/180D

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HI-STAR 180

BoltedDouble Lid Closure System

Fuel Basket

Basket Shims

MonolithicShieldCylinder

HI-STAR 180D



HI-STAR 180D Design OverviewHI-STAR 180D Comparison to HI-STAR 180

• Packaging Similarities– No separate fuel canister such as an MPC– Same cask cavity ID and only marginally larger in cask OD– Identical containment boundary construction and materials– Identical impact limiter construction and materials– Identical fuel basket cross-sections for 32 and 37 PWR assemblies and same Metamic-HT material– Identical double closure lid construction and materials

> Metal to metal contact joints provide maximum protection against leakage under impulsive loading> Each closure lid is equipped with two independent metallic seals and 68 bolts> All metallic seals are highly corrosion resistant and seat on stainless steel or nickel alloy surfaces

– Identical gamma and neutron shielding materials (same monolithic shield cylinder concept)

• Packaging Differences– Length: Shorter cask and package– Weight: Lighter cask and package– Other: Various minor customizations, including 4 vs 2 top trunnions

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HI-STAR 180D Licensing ApproachHI-STAR 180D Comparison to HI-STAR 180

• HI-STAR 180D equipment design and safety studies are based on HI-STAR 180

• Fabrication: No new equipment technologies - no new fabrication techniques

• Design Life: 50 yrs instead of 40 yrs

• License Life: 5 yrs same as HI-STAR 180 and other Part 71 CoCs

• Cask Contents:– Similar PWR UO2 fuel assemblies with high burnup and low cooling time– No damaged fuel, no non-fuel hardware

• Safety analysis methodology and approach is essentially the same

• Key acceptance criteria for safety analysis are the same

• HI-STAR 180D SAR format identical to HI-STAR 180 SAR– Reg. Guide 7.9– NUREG 1617

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HI-STAR 180D High Burnup Fuel Approach

• As was done for the HI-STAR 180, the HI-STAR 180D application requests package approval based on moderator exclusion under hypothetical accident conditions to address the criticality safety of high burnup fuel under accident conditions

• Consistent with 10 CFR 71.55(e) and ISG-19

• ISG-19 Options– Structural evaluation to determine reconfigured fuel geometries; or– Criticality evaluation of bounding reconfigured fuel geometries; or– No water inleakage under accident conditions.

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HI-STAR 180D Criticality Safety EvaluationsIntroduction

• HI-STAR 180D is essentially the same as HI-STAR 180 from a criticality safety perspective – Same methods used

• Criticality safety approach for the HI-STAR 180D is consistent with the new Draft ISG-8, Rev. 3 (April 2012)

• Overview– HI-STAR 180– Burnup Credit timeline, NRC and Holtec– HI-STAR 180D

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HI-STAR 180

• Criticality Control Features – Basket Designs – 32 or 37 assemblies, Flux Traps– Basket Material – Metamic HT

> Al + B4C Metal Matrix Composite

– 5% enrichment limit (both baskets)– F-32: 0 Burnup (fresh fuel)– F-37: several patterns with fresh (UO2 and MOX) fuel, and burned (UO2) fuel, burnup requirements

between 22 and 35 GWd/mtU depending on pattern

• Codes, Methods, Validations– CASMO-4, fuel depletion

> Validated by chemical assays

– MCNP4a> Validation by standard benchmarking experiments, including MOX criticals resembling spent fuel actinide

composition.

– Standard Studies – Moderation conditions; fuel eccentricity; clad gap flooding– Meets ISG-8, Rev. 2, with minor exceptions

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Burnup Credit Timeline USNRC / Holtec

• 2002: USNRC Interim Staff Guidance (ISG) 8, Rev. 2– Actinide-only Burnup Credit– Based on a extensive set of technical reports from Oak Ridge National Laboratory (ORNL), issued

by NRC as NUREG/CR reports– Benchmarks: Chemical Assays for depletion, Fresh and MOX fuel criticals for Criticality

• 2006: NRC approves Burnup Credit for HI-STAR 100 with MPC-32– Actinide and Fission Products

• 2009: NRC approved Burnup Credit for HI-STAR 180 with F-37– Actinide-only

• 2012: USNRC Interim Staff Guidance (ISG) 8, Rev. 3, Draft (April)– Actinide and Fission Products– Misloading evaluations as alternative to Burnup Measurement– Based on additional NUREG/CR ORNL Reports– USNRC Application for HI-STAR 180D will be based on this new ISG

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Limited Burnup Credit for HI-STAR 180D

• Same approach as for HI-STAR 180

• Principal Characteristics of Burnup Credit Approach– Major Actinides only: U, Pu and Am-241– Fully validated methodology– Burnup requirement lower than for HI-STAR 180– Misloading Accidents considered– Burnup Measurement not required (ALARA)– Various axial burnup profiles evaluated– 3-dimensional fuel and cask models– Conservative/bounding inputs/assumptions/modeling approaches– Meets USNRC Interim Staff Guidance (ISG) 8, Rev. 3, Draft (April 2012)

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HI-STAR 180D Criticality EvaluationsCodes and Code Validations

• Depletion analyses– Code: CASMO-5 with ENDF/B-VII Library– Chemical assays (fuel composition) of spent fuel samples irradiated under known

conditions are compared with corresponding CASMO results for the same irradiation conditions

• Criticality Analyses– Code: MCNP5, Version 1.51, with ENDF/B-VII Library– Critical Experiments

> MOX fuel resembling spent fuel> “HTC” critical experiments performed in France, simulating the actinide

composition of spent fuel of about 37.5 GWd/mtU burnup

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HI-STAR 180D Criticality EvaluationsMiscellaneous Evaluations

• Axial Burnup Distribution– Top and Bottom of the assembly are underburned compared to the center of the assembly– This can result in an increase in reactivity compared to an axially constant burnup, up to several

percent delta-k (e.g. 0.04 delta-k) at high burnups– At low burnups (below 30 GWd/mtU), the axially constant burnup is typically more reactive– There is no generic bounding axial burnup profile

• Misloading Analyses– ISG-8 Rev. 2 required burnup measurement– ISG-8 Rev. 3, permit a misloading analysis as an alternative to the burnup

measurement

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HI-STAR 180D Criticality Evaluations Summary

• HI-STAR 180D criticality safety evaluations essentially the same as for HI-STAR 180

• All results for the HI-STAR 180D application meets the regulatory limits with margin

• HI-STAR 180D criticality safety evaluations meet the draft ISG-8, Rev. 3

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HI-STAR 180D SYSTEM - Shielding

• The cask is designed to meet the criteria of the spent fuel packaging and transportation – 10 CFR 71

– Normal Conditions:10CFR 71.47– Hypothetical Accident Conditions:10CFR 71.51

• Same General Approach as for HI-STAR systems– SAS2H/ORIGENS (Scale 5) Source Term Calculations– MCNP (MCNP5) Shielding Calculations– Two different baskets, F-37 and F-32, are analyzed

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HI-STAR 180D SYSTEM - Shielding

Two approaches for dose rates calculations (adopted from the HI-STAR 180)

1. Design Basis Dose Rates • Conservative assumptions in transport model• Nominal depletion calculations

2. Alternative Dose Rate Calculations• Some of the conservative assumptions are replaced by more realistic

assumptions (same as in HI-STAR 180)• Depletion calculations with consideration for uncertainties.

Conclusion:– Dose rates are calculated for both normal and accident conditions. – For both design basis and alternative dose rates the HI-STAR 180D system

meets the regulatory limits.



HI-STAR 180D Containment Evaluation

• The containment boundary design of the HI-STAR 180D is identical to that of the HI-STAR 180 and other approved HI-STAR transport cask designs

• Structural (and thermal) evaluation confirms containment boundary integrity under normal and accident conditions of transport.

– Seals will maintain the necessary leaktightness under normal and accident condition events.

• Containment boundary and seals are test qualified to a leakrate criterion predetermined in the SAR by containment analysis using test methods consistent with ANSI N14.5

• Containment analysis is performed consistent with the requirements of:– NUREG/CR-6487, Containment Analysis for Type B Packages Used to Transport Various

Contents– Regulatory Guide 7.4 Leakage Tests on Packages for Shipment of Radioactive Materials– NUREG-1617, Standard Review Plan for Transportation Packages for Spent Nuclear Fuel

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• HI-STAR 180D Leakage Rate Acceptance Criterion at Reference Test Conditions (based on most stringent of normal or accident conditions per 10CFR71.51).

< 1.10x10-5 atm cm3/s, helium

• The HI-STAR 180 containment evaluation adopted the ANSI N14.5 reference leakage rate of “leaktight” (i.e. 2x10-7 atm cm3/s, helium).

• The containment analysis for HI-STAR 180D is performed with the same methodology that was used and approved in previous HI-STAR transportation cask safety analysis, HI-STAR 100 (71-9261) and HI-STAR 60 (71-9336).

Containment Acceptance Criteria



HI-STAR 180D Structural Evaluations Overview

TOPICS• ASME Code Division 1• HI-STAR 180D Analyses

– Acceptance Criteria– Analyzed Conditions– Methodology– Dynamic Model

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• The HI-STAR 180D uses the same design approach used for the HI-STAR 180 (i.e., ASME Section III, Division 1, Subsection NB), which has been accepted by the U.S. NRC

• Holtec has consistently used ASME Code, Section III, Division 1, Subsection NB to design, analyze, and fabricate the containment boundary system for its HI-STAR transportation casks, including the HI-STAR 180.

• NUREG-1617 (March 2000) states the following:– “ASME has published Section III, Division 3, ASME Boiler and Pressure

Vessel (B&PV Division 3) Code for the design and construction of the containment system of SNF transport packagings. NRC staff expects full compliance with the B&PV Division 3 Code for the containment system, including the services of an Authorized Inspection Agency. However, the SAR may justify alternatives as appropriate.”

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ASME Code Division 1



HI-STAR 180D Analyses - Acceptance Criteria

– Fuel Basket – Global average permanent deformation of panel below 0.5mm. Consistent with criticality analyses; ensures positive margin against loss of reactivity control after accident.

– Containment Boundary – ASME Sec. III, Subsection NB stress intensity limits; no loss of leaktighnessunder any event.

– Shielding Components – Remain functional after any drop event.

– Impact Limiters – Absorb sufficient energy to maintain sub-criticality and containment, and maintain positive attachment to cask after any event.

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HI-STAR 180D Analyses - Overview

• Dynamic Analyses– Utilizes benchmarked computer code and model

similar to that used in HI-STAR 180 submittal. – Comprehensive, robust LS-DYNA model includes

finite element representation of all components of cask including fuel, fuel basket, lid bolts and seals.

– Containment integrity, stress, and deformation evaluation from a single simulation of each event.

– Summary for each analysis provided in SAR; details provided in separate calculation package.

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HI-STAR 180D Analyses - Overview (Cont.)

• 10CFR71.71 Dynamic Analysis

– 0.3-meter free drop (cask horizontal)• 10CFR71.73 Dynamic Analyses

– 9-meter free drops (side, end, c.g-over-corner, slapdown). F-32 and F-37 basket configurations, top or bottom impact limiter initial impact location.

– 1-meter drop onto 15 cm diameter pin (puncture on secondary closure lid or on neutron shield)

• Static Analyses

– Lifting, immersion, component stability, fire accident, etc. summarized in SAR with separate supporting report (methodology used previously for HI-STAR 180).

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HI-STAR 180D Analyses - LS-DYNA Robust Model

• HI-STAR 100 (benchmark), HI-STAR HB, HI-STAR 60 and HI-STAR 180 all include impact limiter with internal backbone structure, ductile axial attachments to overpack, appropriate contact surfaces, and the same non-linear impact limiter crush material behavior.

• HI-STAR 180D model includes detailed representation of fuel, fuel basket structure, all lid bolts, and entire lid seal system (4-seal rings).

• Maximum possible clearance gaps between the stored fuel assemblies and the cask storage cavity are considered in the 9-meter drop analyses

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HI-STAR 180D Thermal Analyses Introduction

• Compliance of the HI-STAR 180D System to 10CFR Part 71 and ISG-11 thermal requirements is established for both normal and accident conditions of transport.

• Normal conditions of transport correspond to transport of a loaded HI-STAR 180D Package with an ambient temperature of 38C in still air and with prescribed 10CFR71 mandated solar insolation.

• Hypothetical accident conditions consists of a fully engulfing hydrocarbon fuel/air fire with an average emissivity coefficient of 0.9, with an average flame temperature of 800C for a period of 30 minutes.

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Analyzed Conditions

• Normal Transport Condition - Cask is in horizontal orientation

• Grid Sensitivity Studies

• Moisture Removal Operation

• Personnel Barrier Evaluation

• Fire Condition Evaluation

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Thermal Design Features

• Two basket designs, F-32 and F-37, for storing up to 32 and 37 PWR fuel assemblies.

• Design Features – The design features are similar to USNRC approved HI-STAR 180

transport Package– High conductivity, high emissivity Metamic-HT fuel basket– Minimum structural discontinuities (gaps)– Impact Limiters made of conductive crush material

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Thermal Acceptance Criteria

• Fuel Integrity (ISG-11, Rev. 3) – Cladding Temperature Limit Normal Transport Condition – 400°C Accident Condition – 570oC Short Term Operations – 400°C for HBF and 570oC for MBF

• All component temperatures must be below their respective material temperature limits

• Containment Boundary Integrity Rod Rupture Criteria

Normal Transport Condition – 3% rods rupture releasing 100% fill gas and 30%fission gas to containment

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Methodology

• The methodology used for normal condition of transport and fire accidentevaluations is the same as that used for the HI-STAR 180 system,licensed by the USNRC.

• A bounding fuel burnup profile is used to obtain a normalized burnupprofile in the thermal analysis with the peaking maintained in most of theactive region.

• All analyses are performed using three-dimensional Computational FluidDynamics (CFD) models.

• The thermal analyses are performed using the FLUENT CFD code.

• 3-D models in the HI-STAR 180D cask are modeled to determine the limiting fuel basket and fuel loading pattern.

• All the licensing basis calculations are performed for limiting scenario.

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Conservatisms in Thermal Analysis

• The conservatisms are exactly the same as that used in HI-STAR 180 System.

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Other Analyzed Conditions

• Cask Drying– For drying of casks one of the following two approaches may be used, to

ensure that the peak fuel cladding temperature remains below the 400oC limit:

> Vacuum Drying Process> Forced Helium Drying (FHD) Process

• Personnel Barrier Evaluation– To prevent access to the cask surface, an open lattice cage will be placed

around the HI-STAR 180D cask during the transport process– The personnel barrier design is the same as that approved for use with HI-

STAR 180 Package

• Hypothetical Fire Accident Condition– All engulfing fire with a temperature of 800oC and a duration of 30 minutes– Methodology is exactly the same as that approved for HI-STAR 180 cask.

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Summary

• The HI-STAR 180D is a variation of the HI-STAR 180 certified under USNRC Docket 71-9325

• Design details, materials and safety analyses approaches are essentially identical to those for the HI-STAR 180, which supports an efficient licensing process

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HI-STAR 180D TYPE B(U)F TRANSPORTATION PACKAGE New … · 2012. 9. 28. · a generation ahead by...

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