Civil & Hydraulic Engineering Rationale (Paks NPP Cooling Intake)
In midsummer heatwaves, drought-induced Danube river levels drop to historic minimums (near 60 cm on the Paks gauge). The 2000 MW Paks Nuclear Power Plant relies on open-cycle Danube cooling requiring ~100 m³/s flow. When river stages plunge, suction head decreases, risking vortex ingestion, pump cavitation, and breaching environmental 30°C thermal discharge limits.
Submerged Weir Deflection
By ballasting (flooding) two 70-meter barges onto prepared riverbed bathymetry, engineers create an artificial submerged groin. This obstructs bypass velocity and forces mainstream hydraulic head into the intake canal mouth.
Vortex & Cavitation Prevention
Low water depths cause surface depression vortices that ingest atmospheric air into the primary cooling pumps. Sinking the barges raises local canal stage by 15–35 cm, maintaining required Net Positive Suction Head (NPSH).
Thermal Recirculation Guard
Deflected cooler bottom currents prevent warm downstream plume recirculation, ensuring cooling intake water remains below critical safety margins without reactor power curtailment.