Large-reactor safety

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ATLAS: LWR Thermal Hydraulic Safety Research



  • Support to resolve safety issues and concerns of LWRs
  • Simulation of transients/accidents of LWRs for assessment and validation of system-scale safety analysis codes
  • Confirmation of design concept and operational performance of new safety systems

Design Features of ATLAS

  • Multi-purpose thermal-hydraulics safety validation test loop
  • Scaling based on APR1400:
  • 1/2 Height & Length
  • 1/12 Diameter
  • 1/288 Volume
  • Loop configurations:
  • 2 Hot legs x 4 Cold legs
  • Integrated annulus downcomer
  • Safety injection systems: DVI & CLI
  • Operating conditions:
  • Full pressure/temperature
  • Maximum 10% of scaled power
  • Number of measurements: > 1,600

R&D Status

  • Safety evaluation of multiple failure bDBAs
  • RCS-CTMT integrated safety evaluation
  • Validation and development of multi-D models which will be implemented to CUPID and CAP
  • Validation of M/E evaluation methodology and P/T analysis for reactor containment
  • Confirmation of design concept of passive cooling systems
  • Resolution of safety issues and safety enhancement
  • Evaluation of the long-term coolability with partial core blockage
  • Evaluation of the shutdown coolability w/o RHRS
  • Evaluation of effectiveness of ECC injection during IBLOCA
  • Operation of OECD-ATLAS-II international cooperation project and domestic standard problem (DSP)

Outcomes & Perspectives

  • Resolution of safety issues related with DBAs and bDBAs
  • LBLOCA tests: contribution to resolving the licensing issues of APR1400
  • Other major DBAs have been simulated for understanding of phenomena and code validation
  • Reinforced safety standards after Fukushima accident: contribution to resolving safety issues related to SBO scenarios
  • Validation of system analysis codes and new safety systems
  • SPACE code validation for major DBAs: SBLOCA, SGTR, FLB, SLB, IBLOCA
  • Establishment of IET DB for validation of operational & cooling performance of APR+ PAFS
  • Operation of International & domestic cooperation
  • Successful completion of the ISP-50 exercise and the OECD-ATLAS project
  • Successful completion of the domestic standard problem (DSP): DSP-01/02/03/04
  • Enforcement of Defense-in-Depth concept and advancement of safety validation technology
  • Safety evaluation of DECs (Design Extension Conditions)
  • RCS-CTMT integrated safety evaluation
  • Validation of innovative new safety systems: H-SIT, PCCS, PECCS