1. 1 Computer Codes and Applications in the Regulatory Process Dr. Ralph R. Landry Senior Level Advisor Office of New Reactors

2. 2 Purpose of Code Application Confirmation of Submittals –Are licensee/applicant analyses reasonable? –Have submittals captured the phenomena? Exploratory –Are there any hidden “cliffs” that have not been discovered? Resolution of Generic Issues

3. 3 Fluid Code Types DNS – Direct Numerical Simulation –Micro scale, only practical for low Re LES – Large Eddy Simulation –Direct solution for large scale, models smallest scale CFD – Computational Fluid Dynamics –Local and component scale –Turbulence models for closure System Codes – TRACE, RELAP5 –Reliance on models and correlations

4. 4 Codes Used for Regulation System Level – TRACE and RELAP5 Containment and Severe Accident – MELCOR Component Level - FLUENT

5. 5 TRACE EPR Results - LBLOCA

6. 6 TRACE ESBWR Results - LBLOCA

7. 7 TRACE – GSI-191 Core Blockage

8. 8 FLUENT – GSI-191 Core Blockage

9. 9 FLUENT – ESBWR Contours of Stream Functions

10. 10 FLUENT – ESBWR Contours of Axial Velocity

11. 11 FLUENT ESBWR – Boron Injection

12. 12 FLUENT ESBWR – Boron Injection

13. 13 Regulatory Applications of Codes Systems codes have assisted in confirming behavior of licensee/applicant submittals System codes have assisted in exploring generic issues and their resolution CFD codes have given valuable insights into component-level behavior