[en] Nuclear power plants continue to experience intake cooling water blockage events that adversely affect safety-related systems and plant reliability world-widely. To prevent such blockage events, Monitoring techniques and prediction methods should provide sufficient early warning to manage intake cooling water blockage scenarios. Thus the design requirements and operation methods for the early warning system should be developed to manage intake cooling water blockage scenarios. The Scope and Contents of this report is as the following: - Analysis for the world-wide blockage events in NPPs - Review of the monitoring techniques for marine organism - Review of the prevention techniques for massive ingress - Establishment of the design requirements As results, early warning and prevention strategy and the design requirements based on the effective monitoring techniques and remotely operated robotic system have been developed