SAS4A/SASSYS-1: Fast Reactor Safety Analysis Code

Tests carried out by Argonne were used to perform validation for advanced safety simulations, such as the one shown here from SAS4A/SASSYS-1. This image shows the calculated fuel, cladding, coolant, and structure temperatures for the XX09 experimental assembly and its six neighbors one minute into a full-power protected loss of flow accident.

Tests carried out by Argonne were used to perform validation for advanced safety simulations, such as the one shown here from SAS4A/SASSYS-1. This image shows the calculated fuel, cladding, coolant, and structure temperatures for the XX09 experimental assembly and its six neighbors one minute into a full-power protected loss of flow accident.

Argonne’s SAS4A/SASSYS-1 safety analysis code system is a simulation tool that can perform deterministic transient safety analysis of anticipated operational events, as well as design-basis and beyond-design-basis accidents for advanced nuclear reactors. The original code development was for sodium-cooled fast reactors, and sodium boiling can be modeled. However, basic core thermal-hydraulics and systems analysis features are applicable to other liquid-metal cooled reactor concepts.

Applications

  • Safety analysis of fast reactors
  • Simulations for operational, design-basis and beyond-design-basis events
  • Passive heat removal and natural circulation flow predictions
  • Severe accident modeling with sodium boiling, fuel melting and pin failure

Features

The current version (version 5) features:

  • Detailed code manual
  • Single-pin assembly models for rapid evaluation of transients
  • Detailed thermal-hydraulic sub-channel models for subassembly pin bundles
  • Support for three-dimensional visualization of sub-channel temperatures
  • Support for liquid-metal coolants such as sodium, NaK, lead and LBE, as well as other single-phase coolants
  • Full-plant coolant system models to simulate passive heat removal and natural shutdown
  • Oxide fuel models for fuel melting, in-pin motion, pin failure, and ex-pin fuel dispersal and freezing
  • Metal fuel models for fuel-clad eutectic formation and cladding failure
  • High-fidelity decay heat models
  • Built-in support for ANS standard decay heat properties
  • Built-in support for alternative coolants in decay heat removal loops
  • Support for line-based comments in input files
  • Support for an unlimited number of time steps
  • Support for coupling to third-party computational fluid dynamics tools (such as STAR-CCM+) for representing thermal stratification in large volumes
  • Support for coupling to DIF3D-K for reactor spatial kinetics

Technical Details/Requirements

  • Executable versions are available for Linux, Mac OS X and Windows
  • Source code is compliant with Fortran 90/95 free-formatted source format and can be compiled on a variety of operating systems including Unix, Linux, Mac OS X and Windows. A standards-compliant Fortran compiler is required.