One of the advantages of having a father who was a nuclear safety researcher is that I had a chance to look at nuclear safety from the inside rather than from the outside. Most of my father’s work during his twenty-nine year Oak Ridge career was either directly or indirectly related to nuclear safety. My father made significant contributions to the safety of reactors in several respects. He also made contributions to the study of the release of radioisotopes in the environment through a number of sources including natural gas. He concluded that radioisotopes from natural gas could be far more dangerous to customers than radioisotopes from nuclear power plants because some radioisotopes are delivered to homes through natural gas pipes. Needless to say, people who are frightened about radiation from nuclear power plants steadily ignore the far more dangerous problem of radio active materials traveling into the home through natural gas pipes. My father estimated that there were as many as ten thousand causalities in the US every year due to breathing radioisotopes transmitted to the home by natural gas. Critics of nuclear power do not worry about the radiation safety problems of natural gas even though they may be far more serious.
The first commercial reactors were far less safe than the current generation of reactor design. Reactor scientists expressed their concern during the 1960s and early 1970, although the nuclear establishment in Washington D.C. steadfastly refused to acknowledge the problem. Eventually, this refusal led to the Three-Mile Island accident, but subsequently great strides were made in improving nuclear safety. The accident at Fukushima was the result of human error as well as huge and unexpected natural events. The human error was not anticipating a natural event; a forty-five foot tsunami that overwhelmed the backup generation system of the Fukushima reactors. This deprived the reactors of coolant water and eventually led to partial core meltdowns. Despite these catastrophic accidents, no one was killed by core meltdowns or the radiation released as a consequence. The truth is, that no one has ever been killed as a result of a commercial reactor core meltdown.
In contrast, construction and maintenance workers have fallen to their death from wind generator towers making wind far more dangerous than a nuclear power plant. There have also been causalities in relationship to both solar voltaic installations and concentrated solar energy facilities. Despite this evidence, some claim that nuclear power is more dangerous. When asked to explain this claim, they say that accidents will happen because we are human and human beings always make mistakes, however there is one way to avoid human mistakes leading to serious nuclear accidents. That is to take human judgment out of the equation. Reactors can be designed so that they will be safe by nature.
Nuclear accidents in the past have been the consequence of human errors, but if you take the safety out of the hands of human operators and place it in the hands of Mother Nature you can avoid accidents. How do you put nuclear safety in the hands of Mother Nature? In a West African nation called Gabon in a place called Okla there is a Uranium mine. Scientist exploring the Uranium mine discovered evidence that ore in the Uranium deposit had gone critical spontaneously some two billion years ago and continued to go critical at times over a period of several million years. The criticality came about as underground water seeped into the ore and, as in Light Water Reactors, it moderated neutron speed thus stimulating a chain reaction.
There were as many as twenty separate natural reactors uncovered in the mine none of which had what could be called a nuclear accident. As the temperature of water in the ore went up, it boiled away and as it boiled away the chain reaction slowed and then stopped. The heat was not great enough to melt the ore and most of the nuclear byproducts did not leave the locality. Eventually, as the natural reactor cooled, water seeped back into it and the chain reaction commenced again. Finally, the amount of U-235 in the ore became too low to sustain further chain reactions and the natural reactors died. The Okla events tell us that by following the laws of nature nuclear safety is possible. Furthermore, if we are only following the laws of nature, it is not possible for mistakes in human judgment to produce major accidents. We need only trust the laws of nature to establish safe nuclear power. Unfortunately, safety of Light Water Reactors is not based on the laws of nature. Their safety is based on multi layered defense systems.
The latest generation of reactors is designed to partially use natural safety, but still has to go on the multi layered defense system in order to make them safe enough. The next generation of reactors called generation IV includes a number of designs that are even safer than the most recent water cooled reactor designs. These include both the Integral Fast Reactor and all forms of Molten Salt Reactors including LFTRs. Critics of nuclear safety often fail to recognize the evolution of reactor safety design and further fail to recognize the potential for developing even safer reactors. Given that nuclear power is now the safest form of energy and that very great improvements in nuclear safety are possible, the arguments against nuclear power for safety reason are absurd. The critics of nuclear power have been informed of the actual situation of nuclear safety. The source of information is science, thus the attacks on the safety of nuclear power are attacks on science.
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