An even better development is the Generation IV International Forum, a coalition of nine countries, including the United States, which was brought together by the Department of Energy in January 2000. The purpose of this group of scientists and engineers is to identify realistic targets for research and development of a new generation of nuclear power plants, using all that we learned in 50 years of experimentation and experience. The goal is to develop and build these new power plants by the year 2030, without discouraging the building of Generation III reactors, such as the Westinghouse AP1000s now under construction in Georgia.
The list of exotic reactors being studied by the Forum includes sodium-cooled, gas-cooled, and lead-cooled fast reactors, supercritical water reactors, and very high temperature reactors, but right at the top of the pile is the molten-salt thorium-fueled reactor. The old, nearly forgotten concept of constantly melted fuel may find a new, productive life in the 21st century. It and the other revived reactor designs could help save us from packing more carbon dioxide into the atmosphere than nature can handle. The dangers of atomic bomb fabrication, flying nuclear weapons around in airplanes, Soviet engineering and bureaucracy, and ingesting radium will be in history books, along with the curious recreation of crashing train locomotives into each other.
As the nuclear engineering community lifts its graying head and looks to the future, remember one thing. If the person sitting next to you seems concerned with the radioactive fish from Japan, the air over the Tokyo Olympics heavy with fallout, or the contaminated junk that washes ashore in Oregon, then caution him or her not to eat a banana. It is crawling with potassium-40, a naturally occurring radioactive nuclide that spits out an impressive 1.46 MeV gamma ray. Neither radiation dose, from eating a banana or a bluefin tuna contaminated with cesium-137 (0.662 MeV gamma), is considered to be the slightest bit dangerous. In fact, tuna fish have been contaminated with radioactive cesium for the past 60 years or so, ever since the oceanic nuclear weapons tests from long ago, and it is used as a radioactive tag to trace migratory routes. The destruction of the Fukushima I nuclear plant may have added to the countdown period when all the detectable cesium-137 will have decayed away, but the danger remains indetectably slight.
The real danger is that any engineering discipline can fall into its own Rickover Trap. We do not, for example, necessarily burn gasoline at the rate of 134 billion gallons per year in the United States because it is the best way to power an automobile: we do so because we have been doing it a long time, and the infrastructure is in place. As is the case of pressurized water reactors, it has worked well for us for a long time, but there could be a better way to do it.
The dangers of continuing to expand nuclear power will always be there, and there could be another unexpected reactor meltdown tomorrow, but the spectacular events that make a compelling narrative may be behind us by now. We have learned from each incident. As long as nuclear engineering can strive for new innovations and learn from its history of accidents and mistakes, the benefits that nuclear power can yield for our economy, society, and yes, environment, will come.
Chapter 1. Tho-Radia was one of many radioactive cosmetic lines promising to cure boils, pimples, redness, pigmentation, and the increasing diameter of pores. This particular product, “RACHEL No. 1” face powder, contained both thorium chloride and radium bromide, both radioactive and nothing that one should rub into the skin. Dr. Alfred Curie, named on the can, was not related to Pierre or Marie Curie, co-discoverers of radium, but the name recognition helped sell the product. Tho-Radia face cream, powder, and soap were introduced in France in 1933, and these products were sold in Europe until the early 1960s.
Chapter 1. A magazine ad for Undark radium-charged luminous material. It suggests that radium would be good on your bedroom slippers as well as the push-button light switch on the wall in your bedroom. The use of radium in consumer products is now banned in most countries.
Chapter 2. This is a mock-up of the Mk-2 bomb-core setup that Harry Daghlian was testing in 1945. The shiny, rectangular blocks of material surrounding the plutonium sphere are tungsten carbide (WC) bricks, and Daghlian was stacking them around the center-mounted sphere to see how much WC the assembly could stand before the neutron-reflection effect caused it to go critical. He accidentally dropped a brick right on top, and the plutonium went prompt supercritical. This was not an atomic bomb configuration, where the plutonium sphere would be crushed down to the size of a large marble, but it was a functioning nuclear reactor, out of control.
Chapter 2. Not long after Daghlian’s accident, Louis Slotin was demonstrating the criticality effect to his replacement. The screwdriver, shown in the mock-up picture, shimming up the hemispherical reflector on top, slipped, and the assembly came together suddenly. Slotin died from the radiation pulse caused by the prompt startup of the nuclear reactor that he had accidentally assembled. The mock-up was as accurate as possible, down to Slotin’s empty Coke bottle on the setup table.
Chapter 2. This is a rarely seen shot of the entire space around Slotin’s setup table, showing many interesting details. Note the old bank vault at the left, used to store the plutonium sphere, the radiation-counting equipment racked up on the left, the welder’s helmet on the floor, and the 400 Hz motor-generator in the foreground. The motor-generator was used to simulate the power environment on a B-29 strategic bomber, for testing equipment that would be attached to the bomb and using aircraft power. The gliders on the floor are piled with lead bricks for radiation shield applications, and there is an active neutron source atop the brick pile closest to the motor-generator set. I’m not sure what the welder’s helmet was for.
Chapter 3. The Castle Bravo test in the Pacific in 1954 used this ground-level thermonuclear device, named “Shrimp” for its modest size. It was a new bomb design, using a stock RACER IV plutonium atomic bomb adjacent to a cylindrical assembly containing lithium deuteride powder. It was predicted to yield 5 megatons of explosive energy, but gave 22 instead. It was a surprise. Note the NO SMOKING sign at the lower left.
Chapter 3. The NRX heavy-water reactor in Chalk River, Canada, in 1955, after a complete rebuild due to the unfortunate incident in 1952. The world’s first reactor core meltdown occurred accidentally in this reactor, soon after which the first radiation-induced hydrogen explosion happened. Ensign James Earl Carter from Plains, Georgia, participated in the cleanup of the site.
Chapter 3. Samples of various materials were placed in the radiation environment of the NRX reactor core to be tested for stamina under high-flux conditions. The sampling ports on test reactors are usually driven by compressed air and controlled remotely, but the NRX system, called the “self-serve unit,” seemed to be manually operated. A health physicist is holding a “cutie pie” ion chamber to closely monitor the radiation during this operation.
Chapter 3. The NRU heavy-water reactor under construction at Chalk River, Canada, in 1956. This reactor was used to test concepts that are in use today in CANDU reactors all over the world. It is in use today, and it may be the oldest reactor in the world that is still running. If you have had a medical test performed using technetium-99m, then that nuclide was produced in this reactor.
