Following a LOCA, large flow paths are established interconnecting the fuelling machine vaults and SG enclosures with the rest of the reactor building. These flow paths allow natural circulation flows to prevent formation of regions of locally high temperature and/or hydrogen concentration to protect the integrity of containment.

For LOCA events with the LTC system available, the LTC system alone is capable of removing decay heat and maintaining indefinitely the integrity of the reactor building.

If the LTC system fails, steam will be discharged to the reactor building both from the break and eventually, from the moderator system as well (see the discussion for the broken HTS loop above). In this case, either the LACs or the containment cooling spray will suppress the pressure and temperature inside containment. If the LACs are unavailable to provide forced circulation, the natural circulation airflows will prevent regions of locally high temperature and/or hydrogen concentration inside containment.