Part 17 (1/2)

”You'll be sorry,” he called over his shoulder at the sullen group who had gathered to see him on his way down the trail. ”It won't do you any good to come chasing after me and telling me you've changed your minds when winter comes. The price to you will have gone out of sight.”

”a.s.shole!” Ug shouted back. ”I told you you'd blow it.”

Over the months that followed, Og traveled the length and breadth of the valley trying to interest the other tribes in his discovery. The Australopithecines were too busy training kangaroos to retrieve boomerangs as a result of not having got their design calculations quite right yet. The tribe of h.o.m.o erectus (famous for their virility) were preoccupied with other matters and didn't listen seriously, while A.

robustus declared that they had no intention of becoming A. combustus by being ignited and becoming extinguished at the same time. And so Og found himself at last in the remote far reaches of the valley where dwelt the H. saps, who were known for their strange ways and whom the other tribes tended to leave to their own devices.

The first Sap that Og found was sitting under a tree, staring thoughtfully at a thin slice of wood sawn from the end of a log that was lying nearby.

”What's that?” Og asked without preamble. The Sap looked up, still wearing a distant expression on his face.

”Haven't thought of a name for it yet,” he confessed.

”What is it supposed to do?”

”Not sure of that either. I just had a hunch that it could come in useful . . . maybe for throwing at hyenas.” The Sap returned his gaze to the disk of wood and rolled it absently backward and forward in the dust a couple of times. Then he pushed it away and looked up at Og once more. ”Anyhow, you're not from this end of the valley. What are you doing on our patch?” Og unslung an armful of sticks from his pack for the umpteenth time and squatted down next to the Sap.

”Man, have I got a deal for you,” he said. ”You wait till you see this.”

They spent the rest of the afternoon wheeling and dealing and ended up agreeing to joint management of both patents. The Sap had got a good deal, so it followed that Og must have got a wheel-which was what they therefore decided to call it. The chief of the Saps agreed that Og's trick with the sticks const.i.tuted a reasonable share-transfer price, and Og was duly installed as a full member of the tribe. He was content to spend the remainder of his days among the Saps and never again ventured from their end of the valley.

The winter turned out to be a long one-over twenty-five thousand years, in fact. When it at last ended and the ice sheets disappeared, only the Saps were left. One day Grog and Throg were exploring far from home near a place where the Neanderthals had once lived, when they came across a large rock standing beside a stream and bearing a row of crudely carved signs.

”What are they?” Grog asked as Throg peered curiously at the signs.

”They're Neanderthal,” Throg said.

”Must be old. What do they say?”

Throg frowned with concentration as he ran a finger haltingly along the row.

”They're like the signs you find all over this part of the valley,” he announced at last. ”They all say the same thing: OG, COME HOME. NAME YOUR OWN PRICE.”

Grog scratched his head and puzzled over the revelation for a while. ”So what the h.e.l.l was that supposed to mean?” he mused faintly.

”Search me. Must have had something to do with the guys who used to live in the caves behind that terrace up there. Only bears up there now though.” Throg shrugged. ”It might have had something to do with beans. They were always counting beans, but they were still lousy traders.”

”Weirdos, huh? It could have meant anything then.”

”Guess so. Anyhow, let's get moving.

They hoisted their spears back onto their shoulders and resumed picking their way through the rocks to follow the side of the stream onward and downward toward the river that glinted through the distant haze.

KNOW NUKES.

Before the 1940's, the future confronting the human race was bleak. With the global population increasing and becoming ever more dependent on energy-dense technologies to sustain its food supplies and rising living standards, there seemed no escape from the catastrophe that would come eventually when the coal and the oil ran out. But few worried unduly. It was only after an escape from the nightmare presented itself-suddenly and unexpectedly, with the harnessing of nuclear power and the prospect of unlimited energy-that people began to worry. People can be very strange.

My own position on this subject is that nuclear power is cheaper, cleaner, and safer than any other source of energy that the human race has so far come up with. To see why, let's set to rest some of the myths that it has become fas.h.i.+onable to repeat, and consider the facts.

The first fact is that there cannot be an absolutely safe energy source. By definition, ”energy” is the capacity to do physical work. Whether the results are considered beneficial or otherwise involves only a value judgment, hence, no energy technology can be risk-free. Attempting to judge the acceptability of any particular risk in isolation is meaningless. Society must weigh it against the benefits obtained in return, and compare the result with those obtained with the alternatives.

Despite the hysterical media reactions to Three Mile Island and Chern.o.byl, nuclear power remains the least threatening to human life of all the major energy technologies. The energy yields of processes involving the atomic nucleus are orders of magnitude greater than anything attainable from rearrangements of the outer electron sh.e.l.ls of atoms, which is the basis of all conventional chemical combustion. This means that nuclear fuels are enormously more concentrated, and far smaller quant.i.ties are needed. Over five thousand times as much coal, for example, has to be mined, transported, and processed as uranium to deliver the same amount of energy-two hundred trains per year, each consisting of over a hundred cars, for each one-thousand-megawatt plant, compared to a single carload of uranium oxide-which entails an enormous supporting network of heavy industries with all their attendant risks and hazards.

Two to three hundred fatal accidents happen annually among U.S. coal miners alone, but like automobile accidents they occur in one's and two's spread through the year in different places, and remain largely invisible. Airplane crashes kill far fewer people than automobiles do, but when they happen they are sensationalized. In the Western world, nuclear power generation has never killed anybody.

Chern.o.byl didn't say anything new about nuclear engineering. A plant that is ineptly designed and recklessly operated can be dangerous, as is equally true of bridges, dams, high-rise buildings, or any other kind of heavy engineering. It did say something about a political and economic system run by an incompetent bureaucracy, in which the wishes and safety of the people don't figure into policy-making.

It's difficult to see how the same kind of thing could occur in Western light-water reactors as some critics claim. The accident at Chern.o.byl was due to the graphite core of the reactor catching fire after the cooling system failed. Western models don't possess a graphite core-in fact such a basis for design was expressly rejected by the U.S. in 1950, precisely because of this risk. Furthermore, the cooling water in Western systems is also the ”moderator,” needed to keep the chain reaction going. Hence, if the coolant flow fails for any reason, the reaction automatically stops, leaving only the residual fission products in the fuel as sources of heat to be disposed of, which represents typically about 5 percent of the reactor's normal output. But with the design used at Chern.o.byl, where the graphite is the moderator, operation continues at full power if the cooling water fails. The two designs are about as comparable to each other as the Hindenburg and the Goodyear blimp. Saying that we should shut down our industry because of what happened at Chern.o.byl makes as much sense as calling for the dismantling of the U.S. farming system because the Soviets have made a mess of theirs.

The facts of Three Mile Island were that no one was killed, no one was hurt, and no member of the public was ever in the slightest danger. TMI did not bring us to the brink of a major catastrophe. Some bizarre circ.u.mstances occurred and there were operator errors in responding to them, which led to loss of coolant and damage to the core that included melting of some fuel. However, the safety systems responded in the way they were supposed to by shutting the system down. The outer layers of containment were never challenged, let alone breached, putting the conditions well within the worst-case design accident that the plant had been built to withstand. For some time there was speculation that an acc.u.mulation of hydrogen gas might explode. But this would have been simply a chemical detonation, certainly nothing of a thermonuclear nature as was suggested by the headline H-BLAST IMMINENT that appeared on at least one newspaper. It was established later that the hydrogen couldn't in fact have exploded since there was no oxygen present; but even if it had, the shock would have been comparable to that imparted by a handheld sledgehammer-hardly enough to damage a reactor-vessel with steel walls twelve inches thick. The engine block of a car absorbs more stress thousands of times per minute.

And even if the vessel had cracked, any radioactive material released would still have had to get through a four-foot concrete s.h.i.+eld and a steel containment sh.e.l.l outside that to reach the environment. Yes, some radioactive gas did fill the containment building and was subsequently vented to the outside. But the dire warnings of the tens of thousands of cancer deaths that we heard would follow as a consequence are ridiculous. The maximum increase in radiation dose that would have been experienced by somebody immediately above the plant was measured by EPA, HEW, and NRC as eight millirems at most in the course of several days; a routine dental X-ray delivers twenty-five millirems in seconds. When a dam bursts, a drilling platform collapses, or a gas storage tank explodes, you don't get three days for the luxury of holding press conferences or to talk about evacuating. To me that makes nuclear-properly respected and implemented-a very benign and forgiving technology.

More people seem to be realizing at last that a nuclear power plant can't explode like an atom bomb.

The mechanism that enables a bomb to detonate has to be built with extreme precision to work at all, and a power plant contains nothing comparable. And besides that, the uranium used in each is quite different.

Natural uranium contains about 0.7 percent of the fissionable 235 isotope, which is enriched to more than 90 percent for bomb-grade material. For the slow release of energy required in power reactors, by contrast, the fuel is enriched only to 3.5 percent. It's simply not an explosive. A power plant is about as close to a bomb as a barrel of damp sawdust without a detonator.

So, what about a meltdown? Even if TMI wasn't one, couldn't next time be? Yes, it could. The chance has been estimated-using the same methods that have worked well in other areas of engineering, where there have been sufficient actual events to verify the procedures-to be about the same as the chance of a major city being hit by a meteorite one mile across. And even if it were to happen, the result wouldn't automatically be the major catastrophe that many people think. Computer simulations suggest that if the fuel did melt its way out of the reactor vessel, it would sputter about and solidify around the ma.s.sive supporting structure rather than continue reacting and burrow its way down through the floor. For over twenty years the British have been testing an experimental reactor in an artificial cave in Scotland and subjecting it to every conceivable failure of the coolant and safety systems. In the end they switched everything off and sat back to see what happened. There was no meltdown, nothing very dramatic. The core quietly cooled itself down, and that was that.

But what if the computer simulations turn out to be flawed, and what if the British experience was a fluke? Then mightn't the core turn into a molten ma.s.s and go down through the floor? Yes, it might. And then what would happen? Nothing much. We'd have a lot of mess down a hole in the ground, which is probably the best place for it. But what if there was a water table near the surface? In that case we'd create a lot of radioactive steam, which would blow back up the hole into the containment building, which again would be the best place for it. But what if some kind of geological or structural failure caused it to come up outside the containment building?

Now we are beginning to see the kinds of improbability chains that have to be constructed to produce disaster scenarios for scaring the public with. Remembering the odds against any major core disintegration in the first place, then if, on top of that, there was a water table below the plant, and if the steam burst through the ground outside the building . . . it would most likely expand high into the sky and dissipate. But beyond that, if there happened to be an atmospheric thermal inversion to hold the cloud down near the ground, and if there was a wind blowing toward an urban area, and if the wind happened to be just strong enough to move the cloud without disrupting the inversion layer, then yes, you could end up killing a lot of people. The statistical predictions worked out at about 400 fatalities per meltdown-perhaps not as bad as you'd guess. And that's if we're talking about deaths that couldn't be attributed to the accident as such, but would materialize only as slight increases in the cancer rate in a large population, over many years, i.e., increasing an individual's risk from something like 20.5 percent to 21 percent. Since air pollution from coal burning is estimated to cause 10,000 deaths per year in the U.S., for nuclear power to be as dangerous would require a meltdown somewhere or other every two weeks.

But if we are talking about directly detectable deaths-from acute radiation sickness within a couple of months-it would take 500 meltdowns to kill one hundred people. On this basis, even having twenty-five meltdowns every year for 10,000 years would cause fewer deaths than automobiles do annually.

Very well, that puts major accidents more in perspective. But what about the hazards a.s.sociated with normal operation? What about the thing that has become a new fad phobia word: radiation?

Yes, it's true that even an unmelted-down nuke in proper working order releases some radiation into the environment. In the units used to measure radiation dosage, a person sitting on the boundary fence of a large plant for a year would soak up about a tenth of a millirem above what he'd get from the natural background anyway. An average year's TV-watching incurs ten times as much as this, and a coast-to-coast jet flight-because of the increased intensity of cosmic rays at alt.i.tude-fifty times as much in five or six hours.

In fact there's hardly anything in the environment that doesn't emit some radiation. The rocks under our feet, the air we breathe, everything we eat and drink, and even our body tissues all contain traces of radioactive elements, the dose from all of which adds up to several thousand times anything contributed by the nuclear industry. The emission from the granite that Grand Central Station is built from, for example, exceeds the permissible NRC limit for industry. Grand Central Station wouldn't get a license as a nuclear plant.

This is in no way meant to suggest that ma.s.sive doses of radiation aren't dangerous. Napalm bombs and blast furnaces aren't very healthy, either, but it doesn't follow that heat in any amount is therefore harmful-you wouldn't last long at a temperature of absolute zero. The science of toxicology has long recognized the phenomenon of ”hormesis”-in which substances that are lethal in high doses turn out to be actually beneficial in small doses, by stimulating the body's defense and repair mechanisms (all medicines become toxic at high enough doses.) In his book Hormesis With Ionizing Radiation, Professor T.D. Luckey of the University of Missouri, an internationally recognized expert on the subject, lists twelve hundred references to experimental evidence acc.u.mulated on organisms of every description, supporting the contention that the effect is true of radiation as well.

Nevertheless, we're constantly hearing that any level of radiation is harmful, however small. A simple prediction from this hypothesis is that cancer rates in areas with higher backgrounds ought to be greater.