VERA DevelopmentKevin ClarnoOak Ridge National LaboratoryPHI Focus Area Lead

Tom DownarUniversity of MichiganPHI Focus Area Deputy Lead

CASL Joint Industry Council/Science Council MeetingOak Ridge National Laboratory

October 10, 2017

Representing the contributions of many researchers across all focus areas, includingORNL, INL, LANL, SNL, UM, UTK, UTA, NCSU, MIT, EPRI, and Westinghouse

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Virtual Environment for Reactor Applications

VERA

Fuel PerformanceBISON

VeraIn/Out

Common I/O & Visualization

Trilinos

DAKOTA

MOOSE

PETSc

Solvers / UQ

COBRA-TFThermal-Hydraulics

STAR-CCM+

VERAView

Shift

Neutronics

MPACT

ORIGEN

SCALE/AMPX

ChemistryMAMBA

External Codes that

Support CASL

Research

Mesh / Solution Transfer

Potential Interoperability

with Reactor Systems Codes

(as needed)

RETRAN

TRACE

RELAP-7

VisItParaView

DTK

libMesh

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MPACTAdvanced pin-resolved 3-D whole-core

deterministic neutron transport in 51 energy groups

CTFSubchannel thermal-hydraulics with transient two-fluid, three-field solutions in 14,000 coolant channels with crossflow

ORIGENIsotopic depletion and decay in

>2M regions tracking 263 isotopes

WB1C11 End-of-Cycle Pin Exposure Distribution

WB1C11 Beginning-of-Cycle Pin Power Distribution

WB1C11 Middle-of-Cycle Coolant Density Distribution

VERA Core Simulator Virtual Environment for Reactor Applications

Control rod ejection

demonstration

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Evaluation of PCI Risk Virtual Environment for Reactor Applications

CTFSubchannel thermal-hydraulics with

transient two-fluid, three-field (i.e., liquid film, liquid drops, and vapor) solutions in 14,000 coolant channels with crossflow

ORIGENIsotopic depletion and decay in

>2M regions tracking 263 isotopes

BISONFuel performance code modeling

thermo-mechanics of standard and advanced fuel and cladding for

every rod in the core

WB1C2 Middle-of-Cycle Clad Hoop Stress

MPACT

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Fuel-Clad Gap Thickness

Evaluation of PCI Risk Virtual Environment for Reactor Applications

Clad Hoop Stress (MPa)

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Integrated ex-core modeling Virtual Environment for Reactor Applications

• Shift integrated with VERA to:– Predict fluence in vessel, core pads, and core barrel– Model ex-core detectors, including relative response from

secondary sources

• Simplicity:– Single execution with VERA input– Full resolution with no homogenization– Monte Carlo (n,γ) with no discretization error– Automated adjoint for variance reduction

• Status:– Initial capability with AMA for testing:

• Demo of quarter-core cycle depletion– Capability enhancements:

• Incorporating the full isotopic inventory, IFBA depletion, moveable geometry, and multi-cycle accumulation

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CRUD PredictionsVirtual Environment for Reactor Applications

• MAMBA– Surface chemistry modeling of CRUD– Microstructural chemistry and heat transfer

• CFD-Informed Subchannel– Mapping of CFD to CTF for resolved flow– High-resolution prediction of threshold physics

• CRUD Source-terms– Metal ion pickup throughout primary loop– Calibration based on plant measurements

• CILC “Plug-in” for STAR-CCM+– Models heat transfer and clad corrosion behind CRUD– Uses DTK with MAMBA for conjugate heat transfer– Uses VERAout for accurate local state during cycle– Also used to quantify CTF error for nominal operation

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VERA Input, Output, and VisualizationVirtual Environment for Reactor Applications

VERAin VERAout• Simple, intuitive format enables engineers to

build complex models• One input for all multiple physics codes • Free format, minimum characters, and credit

for symmetry• ASCII text

• Open-source hierarchical binary format (HDF5)• Accessible by many languages such as Fortran,

C/C++, Python, etc.• Free utilities for viewing and manipulation• Post-processors for code comparisons,

sensitivity studies, and visualization

VERAView• Nuclear reactor data analysis tool• Designed specifically for VERA users • Leverages knowledge of VERAout• Compares codes to codes/experiments

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Application Tested Releases via RISCC Virtual Environment for Reactor Applications

Key VERA Advancements V3.6 (Feb ‘17) V3.7 (Oct ‘17) V3.8 (March ‘18)

ReleasedCross section library update1st release with new AMA evaluation process

Shift coupling in VERA-CS Non-source distribution

Inline VERA-CS then BISONTransient VERA-CS

Being Tested

Shift coupling in VERA-CSNon-source distributionVERA-CS and Bison for load-follow operation

StarCCM+ plug-in for CILC Inline VERA-CS then BISONTransient VERA-CS

Advanced CRUD ModelingStarCCM+ plug-in for CILCCoupled VERA-CS and BisonVERA-CS and Bison for ATF

In Development

Transient VERA-CSStarCCM+ plug-in for CILC Integrated VERA-CS and BisonAdvanced CRUD Modeling

Advanced CRUD ModelingBISON performance and robustnessIntegrated UQ with VERAVERA-CS for BWRs

Integrated UQ with VERAVERA-CS for BWRs

All software in development is consistently verified with multiple levels of unit and regression tests

Each code is updated nightly from every institution, unless it would

break any test in VERA

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FY18 PlansVirtual Environment for Reactor Applications

• VERA-CS Fidelity and Usability – Integration of pre- and post-processors – Improved robustness of thermal expansion and auto-meshing

• Application of CILC plug-in– Modeling experiments for validation, calibration, & UQ of MAMBA– Enhancement and calibration of CTF models using CFD

• Enhanced CIPS modeling– Calibrated CRUD models with sources tunable to plant data– Enhanced physics and heat transfer within CRUD layer

• Integration of Bison and ATF– Significant improvement in Bison performance and enhanced consistency of physics transfers– Support for modeling of accident tolerant fuel and demonstration of LTAs

• Demonstration and support of RIA analyses – Incorporation of time-dependent fuel solver in CTF with dynamic gap– Improved usability for input and output processing

• Re-ignition of BWR modeling– CTF has continued to improve in FY17, but all else was on hold– Complete MPACT development, verification of coupling with CTF, and coupling strategies

• Incorporation of embedded UQ– Inlet flow anomaly optimization for Watts Bar Unit 1– Quantification of error in power and fuel temperature during cycle depletion

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Pulling it all together…Virtual Environment for Reactor Applications

• Easy to Use:– Single execution with single VERA input– Integrated, automated, mesh generation – Single output, processed with VERAView

• Capability:– Fully-coupled neutronics, TH, CRUD, and fuel performance– Modeling in-core and ex-core detector prediction of axial-offset due to CRUD deposition– Identification of PCI failure risk during load follow operation with accident tolerance fuel and cladding– Accumulation of radiation damage in the reactor vessel due to neutron fluence– Prediction of cladding integrity during reactivity-initiated transient using coupled neutronics, TH, and fuels.

• Resolution:– Pin-resolved radiation transport throughout the core with a 2 cm axial mesh– Transmutation of 263 isotopes in 3 radial rings and 50 axial segments of every rod in the core– Subchannel two-phase thermal-hydraulics of every coolant channel with crossflow– Fuel performance thermo-mechanics of standard & advanced fuel & clad for every rod in the core– CRUD growth and erosion on at least 4 azimuthal segments about each fuel rods with 2 cm axial resolution– Account for the thermal expansion of the reactor core plate and grid spacers– Validation of the solution with over 40 cycles of operational data

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