Abstract: The feasibility to cool component cooling water with refueling water storage tank through the containment spray test line, spray pump and spray heat exchanger in the event of loss of essential service water in nuclear power plant is analyzed. It is (concluded) that after a loss of essential service water, the cooling component cooling (water) system with containment spray system is difficult to succeed in summer, but it is successful in winter if only operator switches off the unnecessary heat loads within (8 min).