The need to see train engines crash together may have played out in the 1930s, but the specter of exploding locomotives would affect engineering for generations. Even today, in the 21st century, most of the safety design effort in a nuclear power plant is devoted to preventing a steam catastrophe. A nuclear plant is, after all, just another steam engine, heating water to a temperature beyond the boiling point and using the resulting vapor to rotate a shaft. The main difference between a nuclear generating station and its equivalent 100 years ago is that disintegrating uranium has replaced burning coal as the source of heat.
Numerous substitutes for steam as the prime mover in a power plant have been tried, but nothing has proven more reliable, efficient, or economical than boiling water. The task of converting heat into electrical current is not straightforward, but using steam as the transfer medium means that a large-output plant can be compact, and the working fluid is neither toxic nor flammable. Sitting on a small plot of land next to a river, a four-boiler steam plant can light up everything for a hundred miles, and if it is nuclear-powered then there is not even a pile of coal cinders and a mile-long line of rail cars waiting to be unloaded. Still, there is the fear of a steam explosion, something that impressed itself on both the public and the technical acolytes long ago.
In the early years of nuclear power development, in the technology scramble after World War II, early experiments and some small disasters pointed out the dangers of a runaway nuclear reaction. In practice, it was possible to increase the power output of a nuclear reactor not as a gradual heat transfer, like boiling water on the stove to make tea, but as a step function, or an abrupt increase in the blink of an eye. If you were standing near such an occurrence, you died, and it had the potential of flashing water directly and promptly into steam. The possibility of a runaway reaction and a resulting steam explosion was seen as the most critical safety concern in nuclear power development. If only this worst possible accident could be designed out of nuclear reactor plants, then everything else would be taken care of. All we had to do was keep the steam from exploding, and nuclear power would be stable enough to unleash on a safety-conscious public.
And so it was. With testing, accident simulations, well-thought-out engineering effort, and unusually robust building standards, the possibility of an explosive steam release was forcibly eliminated from nuclear power plants. In 56 years of commercial nuclear power generation in the United States, there has never been a steam explosion, and not one life has been lost.[4]
No dreaded boilers coming apart, ripping holes in buildings and sending shrapnel into the crowd to worry about, but everything else in the history of nuclear accidents has happened for what seem to be the most insignificant, unpredictable reasons, much to the consternation of engineers everywhere. Entire reactor plants, billions of dollars of investment, have been wrecked because a valve stuck open or an operator turned a switch handle the wrong way. Some water gets into a diesel engine cooling pump, and six reactors are wiped out. Imagine the frustration of having built an industry having the thickest concrete, the best steel, meticulously inspected welds, with every conceivable problem or failure having a written procedure to cover it, and then watch as three levels of backup fail one at a time and the core melts. Obviously, the machinery was more sensitive to simple error than anyone could have thought, and thicker concrete is needed.
All the issues to be addressed concerning accident avoidance are not technical. Some are deeply philosophical. It is painful to notice, but some of the worst nuclear accidents were caused by reactor operator errors in which an automatic safety system was overridden by a thinking human being. Should we turn over the operation of nuclear power plants to machines? Would this eliminate the strongest aspect of human control, which is the ability to synthesize solutions to problems that were never anticipated? The machine thinks in rigid, prescribed patterns, but in dealing with a cascade of problems with alarms going off all over the place, has this proven to be the better mode of thought? Should operators be taught to think like machines, or should they be encouraged to be creative? Study the history of nuclear disasters, and you will have this subject to ponder.
There is also the elephant in the room: ionizing radiation. Nuclear engineers are acutely aware of this elephant and have designed it out of the way. Concrete thickness helps a lot to keep radiation away from all workers at the plant and certainly out of the public. The human fear of radiation is special and pervasive. As you will see, it originates in the initial shock of discovery, when we were introduced to the unsettling concept of death by an invisible, undetectable phenomenon. We have never quite gotten over it, and, in fact, all the fear of a steam explosion is not connected to the problem of hurtling chunks of metal or the burning sensation, but directly to the problem of radiation dispersal into the public. Steam, when it escapes in an unplanned incident at the reactor plant, takes with it pieces of the hot nuclear fuel. It floats in the air and blows with the wind, transporting with it the dissolved, highly radioactive results of nuclear fission. This undesirable process is at the root of accident avoidance in the nuclear power industry. Employee safety is, of course, very important, but public safety is even more so. To keep the industry alive, thriving, and growing, it is imperative that the general population not feel threatened by it.
Feeling threatened is not the same as being threatened, but the difference gets lost. The danger from low levels of radiation is quite low, as expressed as morbidity statistics or probabilities, but there is an unfortunate lack of connection to probability in the average person. Low probabilities are a particular problem of perception. If they were not, then nobody would play the lottery and the gambling industry would collapse. The impression of radiation, and even the science, can get lost in the numbers. In reading these chronicles of nuclear incidents big and small, I hope that you can develop a sense for the origins and the realities of our collective dread of radioactivity. Will this universal feeling prevent the full acceptance of nuclear power? Will we develop a radioactivity vaccine, or will we gradually evolve into a race that can withstand it? Perhaps.
There is also the problem of the long-term radiation hazard. People do not mind a deadly threat so much if it leaves quickly, like an oil refinery going up in a fireball or a train-load of chlorine gas tankers crashed on the other side of town. For some reason, a cache of thousands of rusting, leaking poisonous nerve-gas cylinders in Aniston, Alabama, does not scare anyone, but the suggestion of fission products stored a mile underground at Yucca Mountain, Nevada, causes great concern.
In this book we will delve into the history of engineering failures, the problems of pushing into the unknown, and bad luck in nuclear research, weapons, and the power industry. When you see it all in one place, neatly arranged, patterns seem to appear. The hidden, underlying problems may come into focus. Have we been concentrating all effort in the wrong place? Can nuclear power be saved from itself, or will there always be another problem to be solved? Will nuclear fission and its long-term waste destroy civilization, or will it make civilization possible?
Some of these disasters you have heard about over and over. Some you have never heard of. In all of them, there are lessons to be learned, and sometimes the lessons require multiple examples before the reality sinks in. In my quest to examine these incidents, I was dismayed to find that what I thought I knew, what I had learned in the classroom, read in textbooks, and heard from survivors could be inaccurate. A certain mythology had taken over in both the public and the professional perceptions of what really happened. To set the record straight, or at least straighter than it was, I had to find and study buried and forgotten original reports and first-hand accounts. With declassification at the federal level, ever-increasing digitization of old documents, and improvements in archiving and searching, it is now easier to see what really happened.[5]
4
I have to be careful here not to fall into the usual pro-nuclear trap of overstating a concept. Several people have been killed in nuclear industry accidents, and many of those incidents will be discussed here. The worst nuclear accident in American history was a steam explosion, but it was a military reactor. So far, every death that can be positively linked to nuclear activity has been of military personnel, government workers in the atomic bomb industry, or a civilian working in fuel reprocessing. Nobody has died because he or she was working in a commercial nuclear power plant in the United States. The Soviet Union is another matter.
5
A good example of this enhanced document availability is in my search for the original report, “The Accident to the NRX Reactor on December 12, 1952, DR-32,” by W. B. Lewis. This was a very important accident. It was the world’s first core meltdown, and it happened at the Chalk River facility in Canada. I had heard about it many times, but I wanted the raw document. It seemed that every nuclear data repository I could think of, even in Canada, had an abstract of the paper, but not the paper itself. After a lot of digging I found it. The Russians had it, possibly recovered from the old KGB archives. This turned out to be a gold mine of information, including such things as accounts of the “Castor and Pollux” vertical assembly machines used in the development of the French atomic bombs.