Chapter One: To the Chernobyl Sarcophagus
On the Saturday morning in April 1986 when the alarms went off at the Institute for Nuclear Power Engineering of the Byelorussian Academy of Sciences, in a forest outside Minsk, the nuclear physicist Stanislav Shushkevich thought the institute's reactor was bleeding radiation. Its fuel assemblies, sealed inside aluminum cassettes at the bottom of a deep, stainless-steel tank full of distilled water, might have sprung a leak. Or something might have spilled in the institute's radiochemistry lab. Dosimeter operators began working their way methodically through the labs and offices and found radiation everywhere. It was in people's hair and clinging to their clothes. It registered two hundred times normal on the air filters. It was near danger levels at the front door.
The dosimetrists moved outside and discovered it there as well: on the sidewalk, on the grass, on the periwinkle crocuses pushing up through the dark litter of the forest floor. So the institute wasn't the source. An order over the public-address system warned everyone to stay indoors. Someone called the Lithuanian nuclear-power complex at Ignalina, one hundred miles northwest, and radiation was everywhere there too. Chernobyl, in the Ukraine, was farther away, two hundred miles southeast, where four big RBMK* thousand-megawatt reactors were lined up end to end in a building almost a mile long. Hundreds of people worked there, but the phones rang unanswered. Something was wrong at Chernobyl.
By afternoon, institute chemists had found radioactive iodine in the fallout, which confirmed that a reactor had exploded. For radioactive gas and smoke from Chernobyl to have reached Minsk, the explosion must have occurred sometime during the night. How much radioactivity had been released? How much more would follow? Why had no one warned them?
Shushkevich, fifty-two, a solid, ample man with a ruddy face and a high, domed forehead fringed with graying brown hair, was friendly and avuncular but shrewdly intelligent. He was vice-provost of the Byelorussian University in Minsk, a liberal humanist in the tradition of Andrey Sakharov. The Soviet Union's change of direction since the death of Konstantin Chernenko in March 1985, just thirteen months before, had filled him with hope. Chernenko, an emphysemic general secretary with the soul of a retired file clerk, had served as a placeholder between the reform-minded but ailing former KGB chief Yuri Andropov and his vigorous young heir apparent, Mikhail Gorbachev. At Chernenko's death his private safe had turned up no personal diary or other intimate record, only a large cache of money no one could account for. Good riddance, Shushkevich had thought: "I was the first at the university to put a portrait of Gorbachev on the wall."
The night of Chernenko's death, Raisa Maksimovna, Mikhail Gorbachev's wife and partner, pacing beside him in the garden of their country house near Moscow, heard him say resolutely, "We just can't go on like this." The next day, 11 March 1985, Gorbachev had been elected general secretary at a meeting of the Communist Party Central Committee. In his acceptance speech immediately after his election he had called for open government and accountability: "I emphasized the need for transparency (glasnost) in the work of Party, Soviet, state and public organizations," he wrote later. He had laid out in detail his other fundamental goal, perestroika—economic restructuring, salvaging the nearly moribund Soviet economy—at a Central Committee plenum the following month, stressing "the elimination of everything that interferes with development."
The huge Soviet military-industrial complex, which insinuated itself into every corner of the Soviet economy and consumed at least 40 percent of the state budget, headed his list for cutbacks, and in a letter delivered to President Ronald Reagan on 15 January 1986 he had broached a proposal without precedent across the four dangerous decades of the U.S.-Soviet nuclear-arms race: "A concrete program," as he described it during a press conference in Moscow later that day, ". . . for the complete liquidation of nuclear weapons throughout the world . . . before the end of the present century." Opening to such unprecedented initiative, 1986 had seemed a year of immense possibility. Now a disaster loomed, of consequences yet unknown, and radiation blew north from Chernobyl.
At 2:30 on Saturday afternoon someone finally called the institute to report an accident at Chernobyl. In the early hours after midnight, Chernobyl Reactor Number Four had run away in four seconds from 7 percent of maximum rated power to about one hundred times maximum rated power, an event called a prompt critical excursion that had flashed the reactor's thousands of gallons of circulating water to high-pressure steam. The graphite core of the massive concrete-encased reactor was an enclosed cylinder forty feet in diameter and twenty-three feet tall, set on end, with blocks of concrete and a water pool beneath it to absorb the fierce radiation its zirconium-clad uranium fuel elements produced, and a two-million-pound, disk-shaped upper biological shield of concrete blocks set over it like a lid to protect workers from radiation exposure. In the same spirit of bravado that had prompted the scientists at Los Alamos during the Second World War to nickname the atomic bomb they were building the "gadget," the men who operated the RBMKs called the upper biological shield the pyatachok, Russian for one of the smallest Soviet coins, the five-kopek piece.** When the water flashed to superheated steam and the reactor's steam pipes started exploding, an eyewitness reported later, the pyatachok "began to bubble and dance."
Then two explosions in the space of less than four seconds tore open the reactor and blew out the building. The reactor core was sealed within a metal tank filled with a mixture of helium and nitrogen to prevent the graphite moderator—four million pounds of pure carbon—from burning. The prompt critical excursion had heated the graphite red hot. The first steam explosion lifted the two-million-pound pyatachok. At the same time the steam burst down through the metal tank and penetrated the red-hot graphite. Steam combines ferociously with hot carbon to make carbon monoxide, liberating hydrogen; the second and more powerful explosion combined steam and exploding hydrogen gas, tilted up the pyatachok nearly vertical, shattered the upper half of the reactor core, and blew tons of its red-hot radioactive debris—a rubble of highly irradiated uranium-oxide fuel as well as radioactive graphite and zirconium—past the pyatachok, through the roof, and half a mile into the air.
It fell out by size. Big blocks of hot graphite landed on the roofs of Number Four's turbine hall and Reactor Number Three. To lower construction costs, the roofs had been covered with flammable asphalt; the hot graphite set them on fire. Blocks and smaller pieces of graphite landed on the grounds around the building and splashed hissing into the four-mile-long cooling pond that lay between the plant and the Pripyat River. The cooling pond was fed by and drained into the river, which drained in turn into the big reservoir downstream that stored the water supply of the city of Kiev, the Soviet Union's third-largest city, with a population of some 2.5 million people.
Graphite pieces and soot-like particles scattered across a stand of pines southeast of the complex; several weeks later, when the radiation had killed the trees and their chlorophyll had faded, people started calling the dead stand "the Red Forest." About half the total radioactive fission products jettisoned from the reactor fell within a two-mile radius of the building. The gases released in the explosion diluted and dispersed into the upper atmosphere, but the wind carried the finest aerosols and hot, intensely radioactive particles (which lofted on their own heat like microscopic hot-air balloons) northwest toward Minsk, on to Ingalina and then across the Baltic Sea to Finland and Sweden. The explosions also blew out the shield elements below the reactor; with the water channels through the graphite blocks drained, the hot graphite chimneyed air up the channels through the remaining lower half of the reactor core and the graphite began to burn. It burned efficiently, the soot and ash carrying more and more radiation high into the air.
A containment structure such as the concrete-and-steel dome that protects all Western and Japanese power reactors would probably have confined the Chernobyl explosions and their radioactivity, but Soviet reactors of the RBMK type lacked such containment.
In the 1950s, when the RBMK design was developed and approved, Soviet industry had not yet mastered the technology necessary to manufacture steel pressure vessels capacious enough to surround such large reactor cores. For that reason, among others, scientists, engineers, and managers in the Soviet nuclear-power industry had pretended for years that a loss-of-coolant accident was unlikely to the point of impossibility in an RBMK. They knew better. The industry had been plagued with disasters and near-disasters since its earliest days. All of them had been covered up, treated as state secrets; information about them was denied not only to the Soviet public but even to the industry's managers and operators. Engineering is based on experience, including operating experience; treating design flaws and accidents as state secrets meant that every other similar nuclear-power station remained vulnerable and unprepared.
Unknown to the Soviet public and the world, at least thirteen serious power-reactor accidents had occurred in the Soviet Union before the one at Chernobyl. Between 1964 and 1979, for example, repeated fuel-assembly fires plagued Reactor Number One at the Beloyarsk nuclear-power plant east of the Urals near Novosibirsk. In 1975, the core of an RBMK reactor at the Leningrad plant partly melted down; cooling the core by flooding it with liquid nitrogen led to a discharge of radiation into the environment equivalent to about one-twentieth the amount that was released at Chernobyl in 1986. In 1982, a rupture of the central fuel assembly of Chernobyl Reactor Number One released radioactivity over the nearby bedroom community of Pripyat, now in 1986 once again exposed and at risk. In 1985, a steam relief valve burst during a shaky startup of Reactor Number One at the Balakovo nuclear-power plant, on the Volga River about 150 miles southwest of Samara, jetting 500-degree steam that scalded to death fourteen members of the start-up staff; despite the accident, the responsible official, Balakovo's plant director, Viktor Bryukhanov, was promoted to supervise construction at Chernobyl and direct its operation.
Now in the night someone called Bryukhanov from the power plant to tell him that "something awful has happened—some sort of explosion." He rushed to the scene thinking he would have to deal with another steam-valve rupture, but when he saw Number Four ruined and smoking, fires burning on the roof, fire trucks everywhere, he said later, "my heart stood still." He claimed he called Moscow for permission to order an immediate evacuation, without finding anyone in authority willing to believe that such an accident could happen to an RBMK. Whether he contacted Moscow or not, he waited until four in the morning—three and a half hours after the explosions—to alert the authority nearest the plant, Kiev Regional Civil Defense, and then reported only the roof fires, which he told Kiev would soon be extinguished.
They were, by firemen from Pripyat and from Chernobyl town, eleven miles from the power station. Firemen arrived within seven minutes of the explosions; by four a.m. eighty-one engines and 186 firemen had joined the first responders, most of the men working on the roof in ordinary fireman's gear, directing water onto the fires and moving intensely radioactive blocks and chunks of graphite over the side with wheelbarrows, shovels, and their bare hands. Despite the danger, no one ordered Reactor Number Three shut down. Doing so might have been unsafe. It continued operating through the night, the control-room operators wearing respirators for the little protection they gave. Saving Number Three's roof from collapse became the firefighters' first priority. By seven a.m. they had extinguished all the roof fires, but Number Four was still a red-hot crater, billowing smoke.
The first information known to have reached Moscow was a coded signal, "1-2-3-4," sent to Soviet civil-defense headquarters about two hours after the explosions. The numbers invoked the highest state of emergency, an accident involving nuclear, radiation, fire, and explosion effects. The Soviet nuclear-power industry was managed by the Ministry of Medium Machine Building, the branch of the Soviet military-industrial complex that was also responsible for producing nuclear weapons. That ministry contacted Nikolai Ivanovich Ryzhkov, the Politburo member responsible for Soviet industry, and he in turn alerted Gorbachev. Gorbachev hastily assembled the Politburo in an emergency meeting. By noon on Saturday, just as Shushkevich, in Minsk, was learning that a reactor had exploded, the Politburo had appointed a government fact-finding commission whose members—scientists, physicians, engineers, and high Party officials—were instructed to meet at Moscow's Vnukovo Airport at four p.m. From there they flew to Kiev, where a long line of black government ZIL limousines waited to deliver them to Pripyat. It was eight o'clock Saturday evening before they arrived. A member of the commission, a fifty-year-old physicist named Valery Legasov, the first deputy director of the Kurchatov Institute of Atomic Energy in Moscow and a former member of the RBMK reactor design team, described the conditions they found: "The reactor premises were destroyed, several hundred people had received radiation injuries, two people had been killed and the remainder of the shift of workers on duty at the time of the accident were hospitalized."
Legasov was detailed by the commission leader to organize putting out the reactor fire. He saw immediately that the station managers and local officials were unprepared for a disaster on such a major scale and had no idea what to do; "they had no guidelines written earlier and were incapable of making any decisions on the spot." The government commissioners improvised, discussing options among themselves and consulting by phone with the Kurchatov Institute and the Ministry of Energy in Moscow. With the roof fires out, they could confirm that the reactor itself was burning, "a white pillar several hundred meters high," Legasov emphasized, "consisting of burning products constantly flying from the crater of the reactor," and down in the reactor itself "individual spots of deep crimson luminescence." A large mass of graphite burns at the rate of about 2,200 pounds per hour; since there were about 5.5 million pounds of graphite in the reactor, if it was allowed simply to burn itself out it would continue to spew its radioactivity into the environment for more than ten days.
In some desperation, lacking any other means of limiting the fire—water would dissociate in the intense heat into oxygen and hydrogen, feeding combustion—Legasov and his colleagues decided to try to smother it from the air. The only immediately available material with which to do so was sand from a riverside quarry. The Pripyat town committee was delegated to round up 150 spades and an equivalent number of local young people. At around eleven on Saturday evening a truckload of sacks arrived at the quarry, but the load included no twine for tying the sacks once they were filled. Someone remembered a stock of red calico the town kept for festival decorations, and strips of red calico soon brightened the mounting pile of sandbags.
*In Russian, an acronym for "reactor, high-power, boiling, channel type." The RBMK reactor is essentially a large block of graphite drilled with hundreds of channels into which uranium fuel elements are inserted. Water also circulates through the channels to cool the fuel elements and transfer heat out of the block. Reactors use light elements to slow and reflect neutrons to sustain a slow-neutron fission chain reaction, the source of their energy; in the RBMK design, both the graphite (carbon) and the circulating water (hydrogen) moderate the reaction.
**One hundred kopeks equal one ruble.
From the Hardcover edition.