| ATHLET, CATHARE, CATHENA, RELAP, TRAC | Well-known thermal-hydraulic codes (on the basis a separate-phase approach) |
| BC, SC | Basic(=coolant) channel subdivided into subchannels (=regions of different flow types) |
| CCF | Counter-current flow |
| CCM | Coolant channel model and module (established on the basis of a separate-region approach) |
| GCSM | General Control Simulation Module (Part of ATHLET) |
| GRS | Gesellschaft für Anlagen- und Reaktorsicherheit |
| HETRAC | Heat transfer coefficients package |
| HTC | Heat transfer coefficients |
| MDS | Drift flux code package |
| MPPWS, MPPETA | Thermodynamic and transport property package |
| NPP | Nuclear power plant |
| PAX (PAXDRI) | Quadratic polygon approximation procedure (with driver code) |
| PDE, ODE | Partial and ordinary differential equation |
| UTSG | U-tube steam generator code |