The NEA Rod Bundle Heat Transfer (RBHT) project focused on reflood thermal hydraulics. The project generated new and unique reflood experimental data and provided these data to the participants, who included members from 20 organisations from 12 countries. Simulations of the reflood experiments were performed and compared to the data, providing a useful and important assessment of the several different analytical codes involved.
Reflood thermal hydraulics remains a difficult and complex subject. Understanding the physical phenomena that occur during reflood is important to nuclear safety. Simulations of hypothetical large break loss-of-coolant accidents (LOCAs) often determine the core management strategies with respect to the sufficiency of the emergency core cooling system (ECCS). Inaccurate prediction of reflood thermal hydraulics can lead to an unnecessary restriction or critical operation of the reactor, or an unreliable expectation of ECCS performance.
The RBHT project was conducted to provide participants with new reflood data to assess analysis codes and improve their accuracy.