ATHLET models for the Emergency Condenser and the Containment Cooling Condenser of the INKA test facility

The ATHLET code (GRS®) has been used for the numerical analyses of the EC (Emergency Condenser) and the CCC (Containment Cooling Condenser) performance at the INKA (INtegralversuchsanlage KArlstein) test facility. Three ATHLET 2.2 Cycle A models have been developed: EC, CCC and Integral model.
The EC model predictions for the postulated steady state scenario (EC characteristic curves) were compared with the old simulations (ATHLET 2.1 Cycle A model for of the EC). INKA EC transient run at 45 bar primary pressure was used as second validation step for the assessment of the different ATHLET versions influence on the numerical predictions. The EC ATHLET Cycle 2.2 A model validation was extended further with the transient EC INKA experiment at 80 bar primary pressure.
Technically, the CCC ATHLET model was based on the old CCC ATHLET 2.1 Cycle A one. However, significant improvements have been accomplished in order to make it capable of adequately representing the INKA CCC experimental layout and conditions. Two models have been developed to account for the different sparger designs. Experimental data (information) analyses have been in addition carried out due the initial poor model performance. The CCC ATHLET 2.2 Cycle A model ability to correctly capture the CCC heat transfer and in general the process has been demonstrated. Second CCC ATHLET model has been developed to incorporate the new sparger design. The model has been partly validated against the provided experimental data. While it was able to calculate well the initial stage of the experiment, it failed to represent the final one.
An integral INKA ATHLET model, which includes both the EC and the CCC, has been developed. This model incorporates the CCC one with new sparger design. Two LOCA scenarios have been postulated for the investigation of the EC-CCC performance under the INKA configuration. These scenarios include RPV (Reactor Pressure Vessel) and RSL (Reactor Steam Line) break. The EC – CCC joined operation under the break scenarios has been analysed.

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