Standard Code Description

1. Coding Language and Computing Platforms
   DASSH is written in Python 3.6+ and therefore can be run on any computer or operating system on which a compatible version of Python has been installed. For coupling with the ARC codes, DASSH requires a Unix/Linux workstation that runs the ARC code suite.
2. Description of Purpose
   The coolant temperature distribution in fast reactors is critical to reactor design, informing core restraint and flow orificing calculations. DASSH is a reduced-order subchannel code being developed at Argonne to perform steady-state thermal fluids calculations that determine coolant flow and temperature distributions in ducted, hexagonally arranged assemblies typical of liquid metal fast reactors. DASSH avoids solving coupled energy and momentum equations through the use of correlations based on pin bundle geometry and flow conditions. DASSH includes models for inter-assembly heat transfer and calculation of pin temperatures. Power distributions for DASSH are obtained via user input or by coupling with the DIF3D-VARIANT neutronics software from the ARC code suite.
3. Typical Running Time
   On the order of minutes to hours, depending on the size and complexity of the calculation.
4. References
   M. Atz, M. A. Smith, F. Heidet, ​“DASSH software for ducted assembly thermal hydraulics calculations – overview and benchmark,” Transactions of the American Nuclear Society 123 pp. 1673-1676 (2020).
5. Primary Authors
   M. Atz, Nuclear Science and Engineering Division, Argonne National Laboratory
6. Materials Available
   The Python source code is openly available. Documentation includes a theory manual and user guide.
7. Sponsor
   U.S. Department of Energy, Office of Nuclear Energy