Cerenkov radiation in a test reactor
I was recently talking with a group of friends who are intelligent, well-read, and historically minded. They were surprised to hear my views on nuclear power, and I was equally surprised that they were surprised. It seems that in the long lull since the last time people rallied in opposition to nuclear power, we have conveniently forgotten a thing or two. And now some of the advocates of clean energy are promoting new and presumably safer reactor designs in order to address greenhouse gas concerns.
It ain’t gonna happen. For a variety of very good reasons, just … no.
America’s use of nuclear power for generating electricity started in the 1950s with the Atoms for Peace program under the Atomic Energy Commission. The AEC was a booster. They promoted atomic energy to public utilities as being “too cheap to meter”—that is, energy so clean, efficient, and inexpensive it would be a waste of time making people pay for it. This was also the time when the USS Nautilus sailed under nuclear power and crossed the North Pole beneath the ice. Plans were even afoot for nuclear-powered aircraft.1 I remember seeing a magazine article describing the wonders of nuclear fuel: the picture showed just a handful of these little black pellets, leaving the impression that the power plant, ship, or whatever could operate for months or years at a time on just those few magic beans.
The first commercial nuclear generating station in the United States was at Shippingport, Pennsylvania, and ran from 1958 to 1982. Since then, public utilities have built more than a hundred other reactors at 65 plant sites, producing about 20% of the country’s power needs at their peak. But they ordered no new nuclear plants after 1974, and by that time they were converting many of the nuclear units they had in the planning or construction stages to other fuels.2
Many people think the 1979 accident and partial core meltdown at Three Mile Island was the death of nuclear power, but the nuclear enterprise was on the ropes five years before then. The utilities had discovered that—rather than being too cheap to meter—nuclear power was too expensive to build and operate.
The first I knew of the problem was an article I read in Fortune magazine in 1968.3 It suggested that the energy conversion efficiency of nuclear fuel is less than one. That is, if you divide the energy you can get out of a bundle of manufactured fuel rods by the energy you must put into making that bundle, the result is a fraction less than one. You’ve just discovered a way to go broke slowly.
Making nuclear fuel is a complicated process. You first have to mine the ore and remove the rocky waste, converting the remainder into pure uranium oxide, U3O8, or yellowcake. Then you move the yellowcake to a concentration facility where you turn it into a heavy gas, uranium hexafluoride, UF6, and run it though high-speed centrifuges to separate the fissionable isotope U-235 from the more stable isotope U-238. Since U-235 is only about 0.72% of most naturally occurring uranium, you have to do a lot of concentrating, which consumes a lot of electricity. Finally, you convert the enriched gas into uranium metal, mold it into pellets, insert them into stainless-steel tubes inside a clay matrix, and bind the tubes into bundles with a specific configuration of the enclosed pellets. Needless to say, shaping and handling enriched uranium must be performed under precisely controlled conditions and generate a lot of low-level waste.
By the time you’ve done all that, you have put more energy into mining, trucking, converting, centrifuging, and manufacturing than you get out by radioactively fissioning—also called “burning”—the pellets. The only advantage to this tradeoff is that the pollution from this invested energy is spread out. You are burning diesel in excavators and trucks at mines out in the desert or in transporting the interim products along country roads, rather than burning coal or oil at your nice, clean nuclear plant in or near town.
And that power plant doesn’t come cheap, either. A gas-powered turbine or a coal-fired boiler may put out carbon dioxide and, in the case of coal or oil, soot. But if it has a breakdown, you only lose some of the plant operating time and have to repair some damaged equipment. A nuclear reactor, on the other hand, can go bad in astounding ways—not the great, glowing gopher burning through bedrock of “China syndrome” fame—but a mess of radioactive materials and hot pieces and parts that take a lot of cost and effort to clean up. And if your containment is compromised, an accident can release radioactive materials to the surrounding countryside.
Public utilities discovered that nuclear plants were far more expensive to build and maintain than any other power source. To give just one example, the rebar in the containment structure has to be tracked stage by stage, from manufacture through storage and shipping down to installation on the site, with a level of documentation that approaches the chain of custody for evidence in a criminal trial. Every weld in the plant piping has to be x-rayed and documented. Safety measures are complex and narrowly scrutinized. And everything is subject to observation and adjustment by federal inspectors who don’t always agree among themselves about best practices and interpretation of the rules. A “nuke” can be five or six times as expensive to build as a fossil fuel plant of comparable capacity.
And yes, the nuclear fuel will power it at full capacity for a long time—usually about a year and a half—before it needs refueling. But during that time the operator must keep a log of the wear on every pump, valve, and pipe and track every reported issue and problem. Then, during refueling, the utility doesn’t just change out the fuel rods but generally takes down and rebuilds the whole steam supply system and other plant systems. And during that rebuild, all the original construction documentation requirements are still in force.
By 1974, the utilities themselves had figured out that nuclear power was hardly worth it. They only completed the plants on order because of their sunk investment costs. By that time, too, the Atomic Energy Commission had been abolished and its functions handed over to two different agencies: the Nuclear Regulatory Commission, to manage the nuclear power plants in existence; and the Energy Research and Development Administration, to investigate new energy technologies. Three years later ERDA became the U.S. Department of Energy.
France and Japan make nuclear power work economically because they reprocess their spent fuel. Exhausted fuel rods still contain fissionable material. Some of the U-235 atoms haven’t split during criticality. Some of the U-238 atoms that leaven the fissionable material have had a few neutrons knocked off and so become unstable U-235, and some have picked up a proton and become fissionable plutonium, Pu-239. Reprocessing closes the nuclear fuel cycle by extracting these unused and newly created fissionable materials and putting them to use in new fuel rods. That extends the energy capacity of the previously mined and processed uranium.4 Recycling also creates low-level wastes such as the steel and clay from the disassembled rods and high-level wastes from the fission products, mostly radioactive strontium and cesium. Low-level waste can be packaged and buried. High-level waste is normally mixed with molten glass to render these isotopes chemically inert and then disposed of by burying in geologically stable ground.5
France also maximizes the efficiency of its nuclear resource by using a standardized design in all of the country’s plants and servicing them during refueling with a flying team of experts trained in the special skills required. Compare this to the U.S. practice, where two different basic reactor designs—from either Westinghouse or Brown & Root—are used indiscriminately, and the plants built around them are designed according to the whims and specifications of the parent utility. Refueling in the U.S. is a matter of temporarily turning the operating staff that knows the plant best into refueling and reconstruction experts.
Without disassembly and reprocessing, spent fuel rods must be stored in their existing form. These rod bundles are both thermally hot, because their residual radioactivity is a form of energy, as well as radiationally hot. The low-level waste in the rods—the steel and clay—have a radioactive half-life of between five years and a few dozen years, depending on the material and its exposure to high-energy neutrons. If these wastes were removed in reprocessing, they would be packaged and buried at one of three registered disposal sites in South Carolina, Utah, or Washington state, which currently take wastes from fuel processing and handling. The high-level waste—the spent fuel isotopes—have half-lives on the order of tens of thousands of years. If these wastes were removed in reprocessing, they would be vitrified (i.e., mixed with molten glass) and stored deep inside a stable geological formation like Yucca Mountain in Nevada.
However, in 1977 President Carter issued an executive order that deferred indefinitely the reprocessing of spent nuclear fuel, because it would add to the world’s stock of plutonium and might lead to proliferation of nuclear weapons. Unprocessed spent fuel rods might once have been stored in back-filled pits deep in tunnels at Yucca Mountain, but work on that facility was terminated by an act of Congress in 2011.
So now all the spent fuel removed from America’s hundred or so power reactors sits waiting. Initially, the hot rods are stored on site in highly filtered “swimming pools” until they thermally cool down.6 After that—and here “cool” is still a relative term—they can be stored above ground in dry casks. Neither is a permanent solution. Either form of storage requires continuous monitoring. And of course, once the nuclear power plant itself is decommissioned, the reactor vessel and the “hot” side of the nuclear steam supply system and associated facilities must either be disassembled as hundreds of tons of low-level waste or put into some kind of continuously monitored mothball state for hundreds of years.
The people working on Yucca Mountain were grappling with how to warn future generations—50,000 or 100,000 years from now, or roughly ten or twenty times the length of recorded human civilization—about the dangerous wastes stored below ground. “Go away. This is not a place to be. If you do try to enter here, you will fail and also be accursed. If you somehow succeed, then do not complain that you entered unwarned, nor bother us with your deathbed prayers. [signed] The Gods.”7 Without such a long-term solution, the utilities that once owned and operated nuclear power plants will have to remain as functioning entities, or be acquired by governments or charitable organizations that will remain functioning entities, for the next 100,000 years or so in order to monitor and protect these abandoned sites. Any bets on that happening?
Before any public utilities succumb once more to the siren song of “safe and clean” nuclear power that is “too cheap to meter,” they will need some iron-clad, rock-hard—and made of rock more durable than Yucca Mountain—guarantees from federal regulators that a solution to the waste problem will be found and made economically viable for them. Otherwise, nuclear fission is a nonstarter in this country.
What about nuclear fusion? Physicists and engineers have been promising practical nuclear fusion “within the next twenty years”—for at least the past thirty years. Whether by magnetic bottles or laser-blasted glass pellets filled with deuterium and tritium, you still have to put more energy into compressing the fuel than you get out from the fraction of hydrogen isotopes that actually fuse. And whether you are dealing with lines of magnetic force or angled laser beams, the problem seems to be uniformity in heating the fuel. Nothing works as consistently as the pressure of gravity, which is how the only sustained fusion reactions we know—those taking place inside the Sun and other stars—actually work. And if the fire could be successfully lit in a reactor on Earth, there would still be the problems of feeding in more fuel and extracting heat energy to drive a working fluid. Fusion energy is a long way off—if it ever becomes practical.
No, the government can run all the reactors it needs for aircraft carriers and submarines and nuclear weapons development. They have ways of preparing and monitoring those wastes. But no commercial energy corporation operating under the profit motive and with shareholders to protect will lift a finger to play again with such a dangerous and politically volatile resource.
1. It was to have been powered by a gas-cooled reactor. The entire plane would be radioactively “hot,” and the pilot—sitting in a lead-lined capsule—would be inserted and extracted through a hatch in the belly. No one’s thinking got so far ahead as to imagine what would happen if the plane ever crashed. Thankfully, the project was mothballed at the conceptual engineering stage.
2. With the promise of new and “inherently safer” designs coming into parlance about 2002, five new reactors at existing plant sites were ordered. The first of these is scheduled to come on line in 2020. However, with new natural gas and oil resources flooding the North American market, whether the owners will actually complete these units or convert them to cheaper fuels remains open to question.
3. And no, I do not have a reference.
4. For a while the federal government also experimented with fast breeder reactors. These are reactors designed to create nuclear fuel by turning large amounts of stable U-238 into fissionable U-235 and plutonium. One of the drawbacks, however, is that using water as a coolant slows down the fast neutrons that accomplish this trick. So, for cooling, they would have circulated liquid sodium metal. Of course, hot liquid sodium is a stage prop from Hell, and the potential for damage in case of a coolant leak was too great to contemplate.
5. The difference between low-level and high-level waste is simple. Low-level waste is normal material—the rod’s clay and steel, plus any tools and equipment used to handle fissionable materials—which has been exposed to high-level radiation so that its atoms have become unstable. They now kick off alpha and beta particles and gamma rays. These materials are dangerous to be around and will make you sick with prolonged exposure, but they will not make you or anything else in their vicinity in turn become radioactive. High-level waste is radioactive isotopes—the unstable uranium, strontium, and cesium—which in addition to alpha, beta, and gamma kick off high-energy neutrons. They will not only make you sick but will make you glow in the dark.
6. The water must be continually filtered because, while water itself is relatively inert and a good source of radioactive shielding, any dust or debris circulating in the pool would become highly radioactive.
7. To borrow a warning from Roger Zelazny’s delightful novel of the Buddha, Lord of Light.