LOCA analysis is composed of two parts: blowdown phase and reflood phase. As an example of SCWR, the blowdown analysis model is shown in Fig. 2.47 in which valves and systems able to simulate cold-leg break and hot-leg break are implemented into the abnormal transient and accident analysis model of Fig. 2.46.

The reflood phase can be analyzed by modeling the LPCI in the calculation code as shown in Fig. 2.48. In the practical analysis of plant safety, general — purpose codes are used to describe more detailed models and to calculate the blowdown and reflood phases as one body.