Safety Analysis for Nuclear Power Plants has been the most significant application of Apros. For example, the Finnish Radiation and Nuclear Safety Authority (STUK) has approved accident analyses made with Apros as official licensing analyses for Finnish NPPs.
Apros includes physical models to model the whole nuclear power plant, both BWR and PWR types (boiling and pressurised water reactors). The calculation models include: 1D and 3D reactor neutronics, two-phase thermal hydraulics, containment, I&C systems, electrical systems and process components.
Apros calculation models are extensively validated in many projects during the last decades.
Examples of safety analysis cases calculated with Apros:
- LOCA, loss of coolant accidents, even 2*100% LOCA
- SGTR – Steam generator tube rupture (primary – secondary leaks)
- DEC (Design Extension Condition) analyses
- PTS (Pressurised Thermal Shock) analyses
- Validation of emergency and shutdown procedures
- Containment DBA analysis
- Uncontrolled withdrawal of a control rod
- PCP trips
- Overpressure protection analysis
- Loss of feed-water
- Decrease of feed-water temperature
- Closure of main steam isolation valve(s)
- Inadvertent opening of one steam generator safety valve
- Trip of external grid
- Analyses of the emergency systems at high sump temperatures
- Behaviour of boron concentration in primary system coolant loop (SBLOCA)
- Feed-water pump cavitation analyses
- ATWS-analysis: steam line break, main steam header break, erroneous starting of PCP
- Analyses of the secondary circuit breaks