Cutting the Utility Power Cord

In the text of the book, I opined, "As far as I know, a low-power, inherently safe reactor has not been designed for community or home use" because of the risk to investors for such a project. That is no longer true. Toshiba calls its design the "4S reactor" for "super-safe, small and simple." It would be installed underground, and in case of a cooling-system failure, heat would be dissipated through the Earth. There are no complicated control rods to move through the core to control the flow of neutrons that sustain the chain reaction. If the reflective panels are removed, the density of neutrons becomes too low to sustain the chain reaction.

Toshiba has offered to provide a complete nuclear power plant if the residents of the ice-bound 7,000-person town of Galena, Alaska, will but pay the operating costs - far less than the cost of barging diesel fuel in for the town generator. Will the anti-nuclear, primitivist-environmentalists be joyful because the townspeople won't be spilling diesel fuel during its arduous journey and will pay only a fraction of what they would pay for petroleum power? And because they won't be creating any of that pesky carbon dioxide that the environmentalists claim is warming the earth? Will they be grateful for the lack of long electrical transmission lines that somehow are sterilizing the caribou and ruining the vista for the six people that visit each year?

Certainly not. If nuclear power is shown to be as safe as it really is, then the anti-industrializers lose the only weapon they have to prevent a dynamically progressing civilization: their lies about an environmental apocalypse. Let us work to bring out the truth and have nuclear power in this remote village by 2010.

Where the Terrorists Have Already Won

In 1978, Jimmy Carter reneged on the opening of a reprocessing plant that was nearing completion in Barnwell, South Carolina. This facility was to take "spent" fuel rods from power reactors owned by the utilities, dissolve them in acid, then separate the uranium and plutonium from the contaminants that would "poison" and eventually stop the chain reaction. The highly radioactive progeny of the energy-producing reactions - amounting to some 1% or 2% of the volume - would be disposed of by any one of a number of perfectly safe methods. The fuel portion would then be reformed into uranium or "MOX" pellets for insertion into fuel assemblies.

Hold on. Could one infer from this that these "spent" fuel elements contain in excess of 90% of their intial fuel? Yes, one could. Is this what we plan to bury under Yucca Mountain? Precisely.

Does this make sense to you? It certainly doesn't to the English, French, Japanese, Russians, and others who think we are absolutely nuts for planning to bury unbelievable amounts of readily obtainable energy. But it made sense to the Carter administration, and even though Reagan reversed the decision, there were no corporate takers who were willing to risk their shareholders' money on a project that could be changed by the whim of a government with a history of caving in to the slightest pseudo-environmentalist pressure. And there would certainly be pressure - since, as we "know," all radiation is dangerous, since any gamma ray could cause cancer... even though the odds against it are 30 quadrillion to one.

What was the reason - excuse, really - that the Carter administration used to stop reprocessing? It was the threat of terrorism. Let's consider briefly the problems from the standpoint of terrorists who are planning a heist of plutonium, with which they intend to make a bomb.

Under the Grandstand

The first man-made chain reaction occurred under the grandstand of the University of Chicago football field on December 2, 1942, in what was known as an atomic "pile." It was so named because it was constructed of a "pile" of 45,000 high-purity graphite bricks (250 tons), with 19,000 drilled holes to contain the approximately 93,000 pounds of uranium metal and uranium oxide along with the cadmium control rods. When operating at its design point, it generated a half watt of power - enough to almost power a pencil sharpener. (Fortunately, it was not designed as a power reactor, but as an experiment to prove the "chain reaction" hypothesis.)

Why the "high-purity graphite bricks?" It has to do with the statement a few paragraphs back about "... if the energy of the neutron is within a certain range." When we want to make little rocks out of big rocks, we are accustomed to using a bigger hammer and swinging hard. Not so in the nuclear world. In order for a neutron to have a decent chance at fissioning a U235 nucleus, it must be slowed down by the action of a moderator. Carbon - as long as it is of high enough purity to avoid absorbing the neutrons - is a good moderator, although, as Chernobyl demonstrated, it has a few potential problems - which is why U.S. power reactors never use this material... or this type of "graphite reactor." It is typically used in military reactors for the production of plutonium - which reportedly was one of Chernobyl's functions, in addition to generating power. [Other uses would be in research reactors, as well as in reactors for use in creating medical radionuclides.]

Footnote to chapter: There is much evidence that a natural reactor "happened" in Western Africa in the Republic of Gabon at Oklo some 1.7 billion years ago when the ratio of U235 to U238 was considerably higher. It appears to have operated in accordance with the Nuclear Regulatory Commission rules of that time and was safely shut down after several hundred thousand years of operation. See Oklo Reactor, Scientific American, August 1976.

Enter the Atom

Let's return for a short graduate course from Hormesis U. about "splitting the atom."

We've already seen that U238 is an isotope of uranium with a half-life of 4.5 billion years. [I realize I said I was going to refer to isotopes in the form of 238U or uranium 238. But U235 and U238 are such commonly used abbreviations to denote these isotopes that I will be using them in this chapter.]

With a lump of this element and the proper instruments, you would find there is another isotope, U235, which amounts to only 0.7% of the total mass. Yet it is this tiny fraction that makes uranium the tremendous source of safe and reliable energy - not to mention the fearful master - that it has become.

U235, like its more plentiful sibling, is an alpha emitter - but has a considerably shorter half-life... a mere 3,800,000 years, meaning that it was considerably more plentiful a billion or so years ago. [U235 is sometimes referred to as "actinium" or "uranoactinium."] It, along with plutonium 239 and U233, are the only isotopes that are fissionable - a phenomenon described below.

Under normal conditions, we can expect to see a U235 atom occasionally decay into an isotope of thorium and a helium nucleus (an alpha particle) similar to all radioactive isotopes experiencing alpha decay. ["Occasionally" takes on a new meaning in the atomic world. Our roughly penny-sized gram of U235 would experience approximately 80,000 nuclear disintegrations per second.]

But let us suppose that a stray neutron smacks into the nucleus of an unsuspecting U235 atom. If the energy of the neutron is within a certain range, our U235 target atom fissions, that is, breaks into pieces. [This was first observed by an unbelieving Lise Meitner in December 1938. She had observed barium, with an atomic number of 56, arising when she bombarded "actinium" with neutrons.]

It usually splits into two roughly equal parts, and most important, ejects about two neutrons. Obviously no atom could eject or emit about two neutrons, but, on average, that is what a fissioning U235 atom sends out of its nucleus.

Imagine, then, one of these neutrons hitting another U235 atom, which emits two neutrons with at least one of these splitting another atom... and so on, and so on. As you have no doubt already figured out, this is what is known as a chain reaction. When the ratio of fissioned atoms in successive generations is equal to one - that is, when one splitting atom causes exactly one more to split - the reaction is said to go critical. What happens to the other neutrons? They either escape from the volume of uranium, or they are absorbed - either unintentionally by structural material, or purposely by control rods made of boron, aluminum, cadmium, or several other neutron-absorbing materials - in order to keep the reaction under control (that is, to keep it from going super-critical). Does a super-critical reaction cause a bomb-like explosion? Not at all; if it did, bomb development by the Manhattan project would have been relatively simple rather than requiring the best theoretical physics minds on two continents. But super-criticality is no picnic. It causes rapid rises in fission reactions, leading to very high temperatures that cause structural damage, torrents of neutrons, and "steam explosions." Bad, yes, but still light years away from the mushroom-shaped cloud.

Let's look at a few different types of reactors, with an eye for those that might allow decentralization of electric power generation.