| Popis: |
We present the main features of code system AC² developed by GRS for the mechanistic integral simulation of severe accidents. AC² uses ATHLET-CD, an extension of ATHLET, for relevant processes in the cooling circuit or spent fuel pool and COCOSYS (COntainment COde SYStem) for processes in the containment. We briefly explain the main models and approaches used in these codes for the core degradation and melt relocation, lower plenum processes, including reactor pressure vessel failure and ex-vessel cooling, molten corium–concrete interactions, iodine chemistry, hydrogen deflagration, and source term prediction. Moreover, we briefly discuss code validation matrices and give examples from recent validation calculations. This shows that ATHLET-CD and COCOSYS are well suited to simulate accident progression in light-water reactor designs, including water–water energetic reactor. Finally, we give a brief outlook on current lines of development for both codes. |
