ACCIDENT OPERATING CONDITIONS .
Emergency core cooling.
Nuclear reactor injection.

1)Improving the boron concentration in the attempt to reduce the neutron reaction. 2)Compensating for the loss of primary loop coolant in the attempt to ensure the removal of heat from the core.

There are limitations about the flow rate and the total amount of coolant which can be injected. In addition to that, the heat must be removed from the reactor building.

These are some of the reasons why the injection need to be complemented with other emergency operations, such as recirculating the coolant and spraying inside the containment.