Frederik Pohl - Chernobyl

Then the alarm bell stopped in mid-clang. From outside, almost drowned in the hideous crackle and crash of the burning reactor building, Sheranchuk could hear the lesser sirens of the plant's fire brigade racing to the disaster point. "Do you hear?" he yelled. "The firemen are coming! Help them, get back to your work, make sure the other reactors are safe!" And then, abandoning the effort, he pushed past the dazed ones and hurried through choking smoke and alarming sounds of crash and rumble to the stairs. He was hardly aware of the long climb, and when he reached the control room for Reactor No. 4, he could not believe his eyes. Below the window, the entire turbine room was in flames. The top of the reactor building was simply gone. He could not see the burning core itself- that saved his eyes, as well as his life-but there were fires everywhere, everywhere, and the world had without warning come to an end.

What went wrong at 1:23 a.m.on that Saturday morning in Chernobyl occurred in four separate stages, but they followed so closely on each other that they were only seconds from beginning to end.

First, there was the power surge in one little corner of the vast graphite and uranium core. Although the reactor had been throttled back almost to extinction, a small section went critical; that was the atomic explosion.

The second stage was steam. The nuclear blast blew the caps off the 1,661 steam tubes. All of them blew out at once, and the broken tubes of water were exposed to naked, violently hot fuel material. The water squeezed under sixty-five atmospheres of pressure was suddenly under no pressure at all. It flashed into steam, and the steam explosion shattered the containment vessel. At that point the disaster was completely out of control and everything that followed was inevitable.

The next explosion was chemical. The terrible heat and pressure caused the steam from the ruptured pipes to break down into its gaseous elements, hydrogen and oxygen; the zirconium in which the steel pipes were clad helped the process along as a catalyst. That produced a hydrogen-oxygen explosion, the powerful reaction that drives spacecraft into orbit. The wreckage of the immense steel and concrete containment box was hurled into the air. The refueling floor, just above the reactor, was tossed aside, along with the forty-ton crane that transported the fuel rods. Fiercely radioactive material was thrown in all directions. Anything nearby that could burn was ignited. Major fires began on the tarred roofs of the building complex, and that was the third stage.

All of those things happened in an instant, and then the fourth stage completed the holocaust.

The graphite that contained the core was now exposed to the open air, with its containment shattered. Graphite is carbon. Carbon burns, even (though with more difficulty) when it is in the dense, poreless form of graphite. Moreover, thick steam from ruptured water pipes now roiled over the hot graphite. This is a classical chemical reaction that is demonstrated every day in high school chemistry labs all over the world; it is called the "water gas" process. Chemistry teachers write the equation C + H 20 = CO +H 2on the blackboard for their students, meaning that the carbon and the water combine to produce carbon monoxide and free hydrogen. The carbon monoxide is quite combustible when exposed to air. The hydrogen is explosively so.

At that point the basic event was complete. The edge of the graphite blocks had begun to burn. All the fires together produced a vertical hurricane of hot gases that carried along with it a soup of fragmentary particles and even ions of everything nearby… including the radionuclides of the core. Lanthanum-140, ruthenium-103, cesium-137, iodine-131, tellu-rium-132, strontium-89, yttrium-91-they laced the soot of the smoke, mingled with the plutonium and uranium of the fuel elements, spread out in a cloud that ultimately would cover half a continent. The first three explosions wrecked Reactor No. 4 of the Chernobyl Power Station, but it was the fire that carried the calamity over a million square miles.

There was no longer anything that anyone could do in the main control room for Reactor No. 4. There was nothing left of Reactor No. 4 to control. The wall of meters showed readings that were reassuringly staid or wildly impossible, but they were no longer registering any reality. The only person left in the room was the shift chief, who said, "There's nothing to do here. Everybody else has gone; you might as well get out too."

"But then, why are you still here?" Sheranchuk asked.

The man did not look well at all; he was sweating and rubbing at his mouth.

"Because I haven't been relieved yet," he said.

Halfway down the stairs again it occurred to Sheranchuk that he could simply have said the words, I relieve you, then, and the man might have accepted the release. But, after all, he was as safe there as anywhere else, Sheranchuk reasoned. In any case, he would not go back.

At the ground level he could not resist another look outside. There were plenty of firemen present now, from the town of Pripyat as well as the plant's own brigade, and yellow militia cars were arriving with their green lights flashing. Searchlights paled the flames from burning debris and picked out the shapes of firemen on the roofs of some of the buildings. Beyond the milling firemen on the ground was the dark hulk of the plant's office block, looking curiously deserted-because, Sheranchuk saw, all of its windows had been blown out in the force of the explosion.

Somebody was shouting at him-a militiaman, face black with smoke and sweat. "Hi, you there! Are you all right? Give a hand with these people!"

Sheranchuk did not stop to think about whether that was what he should be doing, he simply obeyed. He was glad for the order, because an order to follow was better than helplessly trying to decide what to do. For what that was he simply could not guess.

He helped a fireman to stumble toward the waiting ambulance; the man limped and held one hand to his face. He was not the only casualty already. The doctor who had given him a lift was loading a bundle of charred rags into his ambulance that Sheranchuk would not have thought human if it hadn't been cursing steadily in a faint, high-pitched voice. Three other firemen were coughing as they sat on the cement roadway, waiting for someone to bring them oxygen, or, better still, new lungs to replace the ones filled with smoke. (Why weren't they wearing respirators? Sheranchuk asked himself. But, for that matter, why wasn't he?) Glazouva, the tough old woman who ran the plant's night coffee stand, had managed to stay together long enough to help two of her customers to safety, but when Sheranchuk saw her, she was collapsed under the plaque of Lenin at the plant entrance, sobbing helplessly, not responding to anyone's attempts to talk to her. A militiaman lay stunned on the ground, his hair scorched where a bit of flaming debris from the sky had knocked him out and, likely enough, cracked his skull.

There was room for only two in the ambulance, but the doctor promised to send more from the Pripyat hospital as he got in to drive away. "And hurry, please!" Sheranchuk shouted after him.

The next ambulance to arrive, though, didn't come from Pripyat. It was from the town of Chernobyl, thirty kilometers away, and with it came half a dozen new fire trucks. There were more than a hundred firemen on the scene already, the stentorian throbbing of pumps adding to the shouts and the ominous thuds and snaps and crackling sounds from the fires; and in the center of it all, stark and incredible, the splintered walls of what had once been Reactor No. 4.

Burns, bruises, cuts, contusions, smoke inhalation, heat fatigue, simple exhaustion-put them all together and there were forty or fifty people lined up to be taken away in the ambulances shuttling between the Chernobyl Nuclear Power Station and the hospital in Pripyat, just a few kilometers away. Sheranchuk thought it strange that when the ambulances left the plant they went without sirens or bells, and seemed to take a roundabout way that circled the town before heading directly for the hospital. Was it possible they were being considerate about waking the townspeople up? He stood amid a tangle of hose lines, his mind weary of questions, pondering that irrelevant one.