In many senses nuclear energy is clean. It does not produce emissions such as greenhouse gases, which are harmful either to the population or to the environment. It is unclean in that it does produce radioactive waste, but this is better to have than what burning fossil fuels produces. Since radioactive waste is in solid form it can be dealt with much more easily and stored away from centers of population. It could even be stored in space or on moons some time in the future. When radioactive waste was dumped into the ocean, that was a mistake due to lack of knowledge and we know better now. The damage caused to the environment and populations due to the burning of fossil fuels is far in excess of the damage done to the environment due to the nuclear industry, including any of the nuclear plant catastrophes. In this sense nuclear energy is quite preferable to the burning of fossil fuels. Furthermore, as new technology becomes available to allow the more efficient use of nuclear fuel, less nuclear waste will be produced. A recent example that was in the news is the development of the fast breeder reactor, which uses fuel much more efficiently. However, this increase in development will only continue with investment. Judging from the pace of development of nuclear technology since its start, it is a good bet that with more investment nuclear energy will become an even more desirable source of energy with many of its current drawbacks a thing of the past.