Cascading disasters of earthquake and tsunami gave rise to blackout and further nuclear leakage in East Japan in 2011. Cognitive deficiencies on small probability events with very high risk are introspected from a viewpoint on risk. Principles coping with such incidents are also proposed. The construction， operation and management of integrated defense systems are discussed， as well as the improvements urgently needed. Finally， the important roles played by strong smart grid in energy security and ecological security are well indicated.