Uncle John's Endlessly Engrossing Bathroom Reader (71 page)

In addition to control rods, nuclear reactors need something called a
moderator
. It turns out that when all those U-235 atoms split, the neutrons are moving too fast to be absorbed by other U-235 atoms in great enough numbers for the chain reaction to take place. A moderator is simply a substance that slows, or moderates, those flying neutrons to enable them to run into and split other fuel atoms in sufficient numbers to cause the fission chain reaction.

Any number of substances could be used to moderate neutrons. The safest and most common is water. Water-moderated reactors are ideal because the water doubles as both moderator and coolant. The nuclear chain reaction produces such extreme temperatures that the reactor must have coolant constantly circulating through it to prevent the whole system from breaking down. And a water-moderated reactor has a basic built-in safety feature: Any sudden loss of coolant is also a sudden loss of the moderator—and without a moderator the chain reaction stops.

Chernobyl, however, did not use water as the moderator—it used giant blocks of solid graphite. Within the graphite blocks were channels containing nuclear fuel and water-circulating systems that both cooled the reactor and provided steam to turn the electricity-generating turbines. In such a reactor, a sudden loss of coolant wouldn’t stop the fission reaction, and it
could
lead to the worst-case scenario in a nuclear power plant: a core meltdown.

A core meltdown is what can happen if plant operators lose control of the nuclear chain reaction. With nothing to regulate the extreme heat produced by the fission process, the reactor fuel actually melts. The phrase “China Syndrome” was coined in the 1970s to describe the idea that a runaway core meltdown could burn through the floor of the reactor and on down through the Earth until it came out the other side—in China.

While the “China Syndrome” may be far-fetched, a molten reactor core certainly could breach whatever containment structure was beneath it and release significant quantities of radioactive
debris into the environment. Redundant safety mechanisms are typically built into nuclear power plants to prevent the possibility of a meltdown. Ironically, the disaster at Chernobyl began with a test of one such safety mechanism.

The Chernobyl reactors had an emergency cooling system specifically designed to regulate the reactor core temperature in case of an accident. It depended on electric-powered water pumps to maintain circulation. And during an emergency shutdown of the plant, diesel generators were supposed to provide the electricity needed to run the pumps. But the problem with relying on generators is that they take time to power up—as much as 60 to 75 seconds. In the event of an emergency reactor shutdown, the Soviet plants were designed to use the momentum of the steam turbines as they ran
down
to deliver electricity to the water pumps until the diesel generators could take over.

Problems started when the ill-fated test of this emergency run-down power system had to be postponed for almost 10 hours, and the night shift was working in the control room rather than the day shift. Why is that a problem? Because the day shift workers were familiar with the test procedures; the night shift hadn’t been prepared for it.

The plan was to reduce reactor power to a relatively low level and then cut off the steam supply to the turbines so that engineers could measure the amount of electricity generated as they powered down. Unfortunately, plant operators accidentally brought the reactor power down too low. Result: The turbines were spinning slower than they ever would be during normal plant operation. If the engineers wanted to complete their test, they had to get the turbines back up to speed.

This may sound obvious, but because nuclear fuel and the byproducts of the controlled chain reaction are so volatile, it is dangerous to fiddle around too much with a nuclear reactor. A Soviet report later issued to the International Atomic Energy Agency concluded that the operators should have aborted the test and shut down the reactor when the power output became too low.

Instead, determined to continue the test, the operators tried to increase power by removing most of the control rods. The computer system ordinarily would not have allowed this, but the automatic emergency shutdown systems had been disabled for the test. At 1:23 a.m. on April 26, 1986, with the reactor controls at inherently unstable settings, engineers began their test by shutting off the flow of steam to the turbines—and the cooling system overheated.

Realizing that the reactor was overheating and that too many of the control rods had been removed for them to manage the chain reaction, plant operators pushed a panic button to shut down the entire reactor just 36 seconds after closing the steam valves…but it was already too late. The graphite reactor core had become so hot that it began breaking apart. The fuel and control rod channels in the broken graphite became blocked, preventing the control rods from being inserted all the way. There was no way to stop the chain reaction. Twenty seconds after the panic button was pushed, a steam explosion blew apart the plumbing system that carried coolant into the core. A few seconds later another, larger explosion—this one caused by excess hydrogen that was most likely created by the chemical reaction of hot graphite and steam—blew the roof off of the building.

This second explosion sent burning graphite and nuclear fuel flying into the air. The debris started fires on the roofs of several adjacent buildings. It also let oxygen into what was left of the reactor core, which ignited the graphite. As this was going on, nuclear fuel within the burning core continued the runaway fission chain reaction. The core turned molten and began burning through the floor, creating a huge crater.

Local fire crews arrived quickly and began fighting the many fires. Amazingly, these emergency workers had no special equipment to protect themselves from the massive doses of radiation to which they were exposed. (Survivors later reported that smoldering chunks of graphite and fuel from the core were strewn all around the grounds of the plant.) One crew even went into the remains of the reactor hall and tried to pour water into the crater where
what was left of the reactor core continued to melt down. Most of the men who went into the damaged reactor building died of acute radiation sickness within weeks. All told, 31 people died containing the meltdown, including two plant workers killed in the initial blast.

Within four hours of the explosions, the fires surrounding the destroyed reactor were contained, but the reactor core itself was still burning—and the nuclear fuel inside
continued
to melt down. Over the next six days, Soviet helicopters dropped more than 5,000 tons of sand, clay, lead, and fission-inhibiting boron into the crater to put out the graphite fire and stop the runaway nuclear reaction.

Hundreds of thousands of emergency workers—many of them military personnel—were involved in the containment and cleanup of the disaster. Crews pumped liquid nitrogen into the ground beneath the reactor to freeze it solid in an effort to cool the molten core. Remote-control bulldozers were used to bury radioactive debris. And eventually, the entire reactor site was encased in a gigantic concrete and steel sarcophagus.

Years later, it is clear that one design flaw above all others made the accident worse than it needed to be. The Soviet reactors at Chernobyl lacked something that almost every other reactor in the world has: a sealed, concrete containment structure designed to prevent radiation from reaching the outside environment in the event of an accident. Following on the heels of the 1979 near-disaster at the Three Mile Island plant in Pennsylvania (in which a containment structure prevented most of the radiation from a partial core meltdown from entering the atmosphere), Chernobyl added momentum to the anti-nuclear power movement.

In general, pro-nuclear groups blame the dysfunctional Soviet system for the accident, while anti-nuclear groups contend that it could happen anywhere. Perhaps the only thing they do agree on: It is nearly impossible to calculate the full cost and long-term impact of the Chernobyl disaster.

According to the ancient Greek philosopher Plato, Atlantis was a continent larger than Asia and Africa combined, sitting on the western edge of the Mediterranean Sea. Its capital city was built in a perfect circle, composed of alternating bands of earth and water. At its center was a temple to the Greek god Poseidon, surrounded by walls of solid gold and coated in silver. The city was equipped with canals, tunnels, racetracks, and a prodigious merchant fleet, all remarkable achievements for more than 12,000 years ago and more than 9,000 years before the golden age of ancient Greece.

And then…it vanished. As the Atlantian army attempted to conquer the known world, having already enslaved much of Asia, Africa, and Europe, it was defeated by an early incarnation of Greece. In what the Greeks believed to be an act of divine intervention, the continent of Atlantis was destroyed in 24 hours by violent earthquakes and floods, sending it to the bottom of the sea.

There’s just one big problem with this story: It’s just a story. Everything “known” about Atlantis was laid out in two of Plato’s dialogues:
Timaeus
and
Critias
. The story may have been based on real events, such as the volcanic eruption on the Greek island of Thera. It may also have been inspired by older mythical tales such as the Trojan War. Or it may have been purely an invention of Plato’s imagination. We may never know for sure. No evidence of any civilization matching Plato’s description has ever been discovered, but his descriptions are so vivid that for centuries many have believed Atlantis to be real.

Plato may have started the legend, but it was popularized (and expanded on) in modern times by late 19th century Minnesota congressman, academic, and eccentric Ignatius Donnelly. He dabbled
in astronomy, geology, botany, religion, law, and science fiction, all in order to help him prove that Atlantis was real. Donnelly had two major pieces of “evidence.”

• The first was the Biblical story of the Great Flood and similar flood tales from around the world. That would explain how Atlantis sank and disappeared: It was the same flood that prompted Noah to build his ark.

• The second piece of proof: the banana. Since it’s seedless, Donnelly believed its propagation would require humans to plant the fruit as they migrated from one part of the world to the next. And since the banana is native to Africa, Asia, and South America, there would have to be some sort of land bridge that banana planters would have used. The land bridge: Atlantis, of course.

Based on Plato’s writings, Donnelly pinpointed Atlantis’s original location as just outside the Mediterranean Sea. The Azores Islands, west of Spain, would be the exposed portion of the highest peaks of the sunken continent. Donnelly’s addition to the myth: He proposed that Atlantians were technologically advanced, inventing the compass and gunpowder thousands of years before the rest of the world invented written language.

Rudolf Steiner, a 20th-century German philosopher, added more to the theory of Atlantis, suggesting it was the place where the actual physics of life on Earth developed. According to Steiner, millions of years ago on Atlantis, solid objects behaved more like liquids, liquids behaved more like gases, and humans had not yet split into two separate genders. The technologically advanced humanoids on Atlantis, located off the coast of India, drove flying cars, which they powered with “spiritual energy” and the life force found in plant seeds. And where did Steiner discover this? In his book
Cosmic Memory,
he claimed that he “was not at liberty to disclose” his sources, but his number-one source was clearly his own vivid imagination.

In the 1940s, German researcher Otto Muck joined Donnelly’s “theories” with a sprinkling of actual science. Muck theorized that a cataclysmic volcanic explosion, triggered by a hammering of
meteors, is what ultimately destroyed the Atlantian empire. Like Donnelly, Muck hunted down parallel tales of a big flood in many world mythologies. Unlike Donnelly’s, Muck’s description and dating of the event is much more exact. Using a calendar system inspired by the ancient Mayans (who Muck believed were colonists from Atlantis), he claimed to have calculated the destruction of Atlantis down to the hour: about noon on June 6, 8498 B.C.

While Donnelly looked to bananas, Muck’s preferred theory involved eels. In his book
The Secret of Atlantis,
he discusses the European eel, which hatches in an area of the mid-Atlantic Ocean called the Sargasso Sea, and migrates to freshwater streams all over Europe. Muck’s explanation: The eels used to migrate to Atlantis. When it disappeared, they had nowhere else to go, so they started migrating to Europe.

Modern geology and oceanography simply do not allow for the existence of a continent the size of Atlantis anywhere in the Atlantic Ocean. Bananas and eels notwithstanding, the thousands of years spent searching for evidence that proves the existence of Atlantis have yielded exactly…nothing. But that hasn’t stopped the true believers. Atlantis hunters like to get creative with Plato’s data, theorizing that he somehow fudged the location, which means that Atlantis could be
anywhere.
Theories have placed the lost continent near Ireland, near Bolivia, in the South China Sea, and in the Bahamas.

Or maybe Atlantis is right in front of us. In February 2009, British newspapers reported that Atlantis was visible on the Google Earth satellite imaging service. A look at the Atlantic Ocean off the coast of Morocco indeed yields a strange series of lines and angles. Google says the discrepancy is the result of an error in processing the satellite image. But this happens to be near Spain and the Mediterranean Sea—the exact spot where Plato said Atlantis was.