Rejecting nuclear power will push the world into an economic abyss, a Russian scientist warned here Monday. \"I believe that nuclear energy to a certain extent is an absolutely essential part of the power tool set,\" Yevgeny Velikhov told a seminar. \"We simply cannot maintain the pace of the economic development and keep today\'s world as we know it without nuclear energy. The world will plunge into an economic abyss, let alone the environment,\" said Velikhov, member of the Russian Academy of Science. He said he has not changed his mind about nuclear power. Yet he also expressed concerns about the way Japan has handled the nuclear radiation leak after a major earthquake in March, saying that Japan has made many mistakes. \"In some ways, Japanese management is brilliant, giving the world cars, electronics and so on, but they could not cope with the challenge presented by Fukushima (nuclear accident). Six months passed and nobody knows where the fuel is and in what form it exists,\" he added.