Pressurised Thermal Shock Analyses

Pressurised Thermal Shock (PTS) denotes the occurrence of thermal loads on the Reactor Pressure Vessel (RPV) under pressurised conditions. These thermal loads may lead to very large stresses and to the instability of possible flaws present inside the vessel wall. Assessment of PTS is therefore important for long term operation, since the integrity of the RPV must be assured throughout the lifetime of the reactor.

The most severe PTS scenario limiting the RPV lifetime is a cold water Emergency Core Cooling (ECC) injection into the cold leg during a Loss-Of-Coolant Accident. The injected cold ECC water mixes with the hot fluid and the resulting mixture flows towards the downcomer where further mixing takes place. Using LES techniques validated by experiments performed in the ROCOM facility of HZDR in Germany, NRG is at the forefront of companies employing advanced numerical methods to analyse PTS.