German disaster sociologist - Rudiger Wolf Dombrowsky insisted that "Disasters do not cause effects. The effects are what we call a disaster:. Any act natural or man-made to the range which is sufficient warrant resulting in massive destruction, ecological damage, dent into the human life, and deterioration of public health is a disaster. From the flood-ravaged provinces of Pakistan and tsunami battered shorelines of Japan to the storms, floods, landslides and quakes that struck Australia, New Zealand and Spain, disasters have hogged theheadlines in the past 18 months. Many believe that catastrophes are the by-product of global climate change. These days, nuclear technology is used in several applications such as medicinal, power and off-course military, etc. Out of these, nuclear energy based power is getting popular. In any case, because of growth in applications, based on nuclear technology, there are several nuclear installationsbeing found at industrial scale. In spite of all industrial sophistications accidents still occurs. Theproblem with nuclear accidents is - though, less frequent (due to high degree of sophistication andcontrol measures), but, once an accident occurs, the impact is severe such as the Chernobyl disaster in Ukraine (Russia) 1986, Fukoshima meltdown in 2011, etc. In East Asia and the Pacific where risk is concentrated, the countries there have improved capacity in disaster response, preparedness and early warning systems which is announced by the Global Assessment Report on Disaster Risk Reduction in 2011, producedby the U.N.'s disaster management agency UNISDR. Since then even the Indian National Disaster Management Guidelines and Management of Nuclear and Radiological emergencies have passed out stringent laws for prevention of the disaster. The aim of the paper is to evaluate how the national and international polices are made for pre and post disasters specially focusing on nuclear disasters. The aim of the author is to analyse how far these legal regulations do and policies for prevention of disaster really helps in the present world.