Download presentation
Presentation is loading. Please wait.
1
V&V Assessment for CASL/VERA
Milestone Number Key Staff CP Support L2:VVI.P15.01 Jones, Hetzler, Seiger, Dinh, Athe All Codes Involved Nature Status MPACT, CTF, BISON, Star CCM+, Tiamat Assessment Complete, w’ Follow-on
2
Introduction Scope of Assessment Challenge Problem Assessments (3)
Challenge Problems Capability vs Credibility PCMM and Evidence Challenge Problem Assessments (3) Capability Gaps PCMM Scores Conclusion Future Work
3
CASL Codes and Challenge Problems
Present assessment focuses on: CIPS PCI DNB Challenge Problem scope helps to define requirements Assess only the capability related to CPs
4
Capability vs Credibility
Capability refers to the presence of models (physics, numerics, etc.) used to solve the problem Assessed using Phenomena Identification and Ranking Tables developed with expert elicitation Credibility is loosely defined as how trustworthy/mature the predictions are We assess prediction credibility with the Prediction Capability Maturity Model1 (SNL VV/UQ and Credibility Processes Department does this primarily for ASC) Capability fidelity is included as part of credibility 1 Oberkampf, Pilch, Trucano, Predictive Capability Maturity Model for Computational Modeling and Simulation, SAND Albuquerque, NM, 2007.
5
Challenge Problem PIRT / Capability Assessment
For each CP, and abbreviated PIRT was conducted to define requirements Future assessments should include sensitivity studies to quantify phenomenological importance VERA Capability and gaps are qualitative opinions of the authors Physics Phenomena Importance for CIPS VERA capability Gap Gap Description Sub channel thermal hydraulics Steaming Rate 3.0 Subcooled Boiling on a clean metal surface Subcooled Boiling In CRUD 1.0 2.0 Lack of SET data under reactor prototypic CRUD Bulk Coolant Temperature Heat Flux Wall Roughness Lack of SET Data was the most common capability gap
6
PCMM and Evidence Six Elements of PCMM
Code Verification (Includes SQA/SQE) Geometry Fidelity Physical and Material Model Fidelity Solution Verification Validation (SET/IET) Uncertainty Quantification Mutually Exclusive & Collectively Exhaustive Each element is assessed using evidence (documentation) We recognize that there may be: relevant work that may not be documented, or may have been overlooked during this assessment We need help from the other Focus Areas and Code Teams ensuring we know what’s been done
7
PCMM Assessment for CP Varied maturity between codes
Overall CP predictive maturity heavily influenced by “weakest links” Validation is generally well developed across all codes Verification and UQ are weak UQ method and tool investments have been made, but little application CIPS PCMM attribute MPACT CTF MAMBA TIAMAT Representation and Geometric Fidelity 3 2 1 N/A Physics and Material Model Fidelity Software Quality Assurance Code Verification Solution Verification Separate Effects Validation Integral Effects Validation Uncertainty Quantification NOTE: The PCMM scores are “quantitative” yet are subjective. Furthermore, focusing on achieving a specific score or using PCMM scores for goal setting can be problematic. PCMM provides a systematic framework for discussing and assessing the multiple attributes that contribute to maturity
8
Sub channel thermal hydraulics
CIPS Capability Gaps Physics Phenomena Importance for CIPS VERA capability Gap Sub channel thermal hydraulics Subcooled Boiling In CRUD 3.0 1.0 2.0 Wall Roughness Mass Balance of Nickel and Iron CRUD Erosion 2.2 1.2 Initial CRUD Thickness (Mass) 2.5 1.5 Initial Coolant Nickel and Boron Concentration 2.7 1.7 CRUD Source Term from SGs and other Surfaces 0.0 CRUD Induced Change in Boiling Efficiency: Heat Flux Distribution (new phenomenon) Changes in Eff, CRUD Cond. due to Int. Fluid Flow & Boiling Coolant chemistry Local changes (near the rod) in the equation of state 2.4 1.4 Chemical reaction rates are based on lower T and P CRUD Porosity 2.8 1.8 CRUD Permeability CRUD Chimney Density 2.6 1.6
9
CRUD Induced Power Shift
CIPS PCMM Assessment CRUD Induced Power Shift PCMM attribute MPACT CTF MAMBA TIAMAT Representation and Geometric Fidelity 3 2 1 N/A Physics and Material Model Fidelity Software Quality Assurance Code Verification Solution Verification Separate Effects Validation Integral Effects Validation Uncertainty Quantification
10
PCI Capability Gaps Physics Phenomena Importance for PCI
VERA capability Gap Fuel Modeling Cladding Creep 2.8 1.0 1.8 Pellet Cracking Pellet Swelling Pellet Densification 2.4 1.4 Gap Model 2.5 2.0 0.5 Thermal Creep In the Pellet and Clad 2.6 1.6 Friction Between Pellet and Clad Microstructure Impacts on Stress Driven Cracking Material Properties for Time Varying Heterogeneous Fuel Pellet
11
Pellet Clad Interaction
PCI PCMM Assessment Pellet Clad Interaction PCMM attribute MPACT CTF BISON TIAMAT Representation and Geometric Fidelity 3 2 N/A Physics and Material Model Fidelity Software Quality Assurance 1 Code Verification Solution Verification Separate Effects Validation Integral Effects Validation Uncertainty Quantification
12
Sub channel thermal hydraulics
DNB Capability Gaps Physics Phenomena Importance for DNB CP VERA Capability Gap Fuel Modelling Cladding surface heat transfer 2.5 2 0.5 Fuel rod growth or densification 1 Fuel rod bowing Sub channel thermal hydraulics Turbulent mixing single phase flow two-phase flow 3 Cross flow Nucleate boiling Two-phase flow Critical Heat Flux Flow regime CFD (CMFD) Bubble break-up and coalescence Nucleation site density Nucleation site interaction Wall Heat Transfer Surface effects Microlayer dynamics Spacer grid, MV effect Bubble departure frequency Average dry area
13
Departure From Nucleate Boiling
DNB PCMM Assessment Departure From Nucleate Boiling PCMM attribute MPACT CTF Star CCM+ Representation and Geometric Fidelity 3 2 Physics and Material Model Fidelity Software Quality Assurance Code Verification 1 Solution Verification Separate Effects Validation Integral Effects Validation Uncertainty Quantification 0`
14
Conclusions Initial Credibility Assessment Completed
Question: how to respond to the initial assessment Low hanging fruit in multiple areas, heavier lifts in other areas We propose value driven prioritization of FY18 Activities (e.g. PICK) V&V, SQA Scope for Code Teams UQ/Sensitivity Scope for VVI/AMA
15
Future Work Initial CASL V&V Assessment conducted in 2017
Capability and credibility gaps assessed and documented Commitment to periodic assessment to track maturity change Future funding decisions can be driven by gaps Value driven assessment of investment based on required resources and predicted impact Improved documentation of V&V activities will naturally increase credibility Clear shortcomings in UQ and verification for all codes and CPs Improvements in the assessment process will be implemented QPIRT, Formalization of assessment feedback
17
Backup Slides
18
CIPS (1/2)
19
CIPS (2/2)
20
PCI
21
DNB (1/2)
22
DNB (2/2)
23
PICK Chart Implementation Pay-Off Easy Possible Implement
VERA-P4 VERA-P6 MAMBA-P2 MPACT-P2 Easy MPACT-P1 CTF-P1 MAMBA-P3 MPACT-P3 TIAMAT-P2 BISON-P1 Possible Implement Implementation Keep for Later Challenge MAMBA-P1 VERA-P1 VERA-P2 Hard TIAMAT-P1 Small Big Pay-Off
Similar presentations
