The emergency core cooling subsystem has been designed to provide long term residual heat removal in case of a primary leak accident concurrent with a station blackout. The hydroaccumulators with nitrogen under pressure will provide the coolant injection during the first stage of such an accident. The active subsystem is connected before the hydroaccumulators are emptied.

XII — 4. Description of HA-2

The emergency core cooling subsystem has been designed to possibly provide a long term residual heat removal in case of primary LOCA concurrent with a station blackout.

The passive core flooding subsystem includes four groups of hydroaccumulators under atmospheric pressure (2nd stage HA) which are coupled with the pipelines connecting the ECCS hydroaccumulators and the reactor. The hydroaccumulators of the passive core flooding system are connected to the primary system at 1.5 MPa. The hydrostatic pressure of the water column will flood the core removing the residual heat at the last stage of a LOCA for at least 24 hours.