ML21098A128
| ML21098A128 | |
| Person / Time | |
|---|---|
| Issue date: | 04/06/2021 |
| From: | Gabe Taylor Office of Nuclear Regulatory Research |
| To: | |
| Kenneth Hamburger | |
| Shared Package | |
| ML21098A124 | List: |
| References | |
| Download: ML21098A128 (7) | |
Text
Modeling Overview Gabriel Taylor, P.E.
Office of Nuclear Regulatory Research
Overview of ZOI development Current Duration Scenario Equipment Config.
Material Modeling + Fragility = ZOI Tables Incident Energy Target Vulnerability Zone of Influence (ZOI)
Heat Flux Threshold HEAF Research Working Group Update - April 6th, 2021 2
Flashback : April 2018 Merging with incorporation of CFD modeling insights HEAF Research Working Group Update - April 6th, 2021 3
Modeling Approaches
- SNL SIERRA Suite
- Multi-physics coupled model
- Focus on modeling arc (source term)
- CFD modeling
- Focus on modeling thermal transport to target
- Empirical
- Data fit
- Focus on specific phenomena; enclosure breach, arc voltage HEAF Research Working Group Update - April 6th, 2021 4
Modeling Scenarios
- Medium Voltage, Non-segregated phase bus duct
Enclosure:
Steel or Aluminum
- Conductors: Aluminum or Copper
- Medium Voltage Switchgear
- Configuration: Supply, Main, Load
- Energy Profile: Stiff, Decay, or Stiff + Decay
- Conductors: Aluminum or Copper
- Low Voltage Switchgear
- Conductors: Aluminum or Copper HEAF Research Working Group Update - April 6th, 2021 5
Scenario Consolidation
- PRA document covers over 300 scenarios for just aluminum
- Low energy scenarios are being removed from initial list using empirical correlations and slightly conservative fragility thresholds
- Reduces scenario list by 88%
- Some scenarios have similar or identical hazard and can be consolidated even further HEAF Research Working Group Update - April 6th, 2021 6
Summary
- Overall approach to decouple modeling and fragility efforts remains intact
- Modeling approach has evolved into a hybrid between category and dynamic
- PRA guidance document supports defining model scenarios
- Modeling appears to provide reasonable estimates to inform the working groups ZOI determination. However, areas for uncertainty reduction exist.
HEAF Research Working Group Update - April 6th, 2021 7