Availablity of alternative sources for heat removal in case of failure of the RHRS during midloop conditions addressed in LPSA

In general, in the case of closed primary, the residual heat generated in the core, causes an increase in the coolant temperature and a subsequent steam formation that causes a rise of reactor pressure, while when the primary is open, the primary system pressure is maintained stabilized around the atmospheric pressure (except for determinate local effects). In both cases it is necessary to remove the residual heat to guarantee the plant safety.