James P. Hogan Mind, Machines and Evolution

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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
massive 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 mass
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 associated 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
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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 altitude 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 massive 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
accumulated 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. But the fact is they're
not. Colorado, for example, with double the average radiation, due mainly to
altitude but also because of its soil composition, has a cancer rate only 68
percent the national average. The correlation remains negative (i.e., the
higher the radiation background, the lower the cancer rate) across the country
as a whole with a spectacular -39 percent correlation coefficient. (Judging
from their previous statistical manipulations, antinuclear groups wouldn't
hesitate to use such a correlation to "prove" that radiation prevents cancer.)
And then, of course, there's the waste. Well, after the foregoing heresies
about accidents and radiation, would it come as a complete surprise if I
suggest that the ease of getting rid of the waste is one of nuclear power's
major advantages? This is another consequence of its being so much more
concentrated than conventional sources: because the amount of fuel required to
release the same amount of energy is so much smaller, so is the amount of
waste produced. And the waste that is produced isn't as hazardous as most
people imagine. It's considerably less dangerous, in fact, than many other
substances that are handled routinely in far greater quantities with far less
care, which we accept as a matter of course.
Over 90 percent of the spent fuel that comes out of a power reactor can be
reprocessed into new fuel and put back in (saving in a plant's typical forty- [ Pobierz całość w formacie PDF ]

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