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On September 29, 1966, the Soviet Union’s Council of Ministers approves a new generation of water-and-graphite reactors known as RBMK reactors. During development, at least one scientist at the Kurchatov Institute, the Soviet Union’s leading nuclear research institute, warns that the positive void coefficient makes the RBMK too dangerous, but his superiors dismiss these concerns. Under the leadership of Kurchatov Institute head Anatoly Aleksandrov, designers build the RBMK reactors and put them into mass production without bothering with a prototype. In what Higginbotham refers to as “a triumph of Soviet gigantomania” (61), the RBMK is 20 times larger than Western reactors, making it more difficult to regulate, particularly during startup and shutdown periods.
But the most dramatic flaw involves the emergency shutdown mechanism. By pressing the reactor’s AZ-5 button, workers can insert all 211 neutron-absorbing boron carbide rods into the core at once. But to avoid a grid failure, scientists design the mechanism for a gradual shutdown that takes between 18 and 21 seconds, “a long time in neutron physics” (66). Even worse, the RBMK designers choose to coat the tips of the rods in graphite in an effort to “save neutrons” while the rods go through extraction. As a result, reactivity spikes for a brief moment with the rods’ insertion. As long as there are at least 30 inserted rods when the AZ-5 button activates, the shutdown will proceed as planned. Between seven and 30 rods inserted, however, will significantly delay shutdown. And if there are fewer than seven, pushing the AZ-5 button can result in a runaway chain reaction followed by a core meltdown or explosion.
Researchers at NIKIET, the Soviet reactor design agency, realize the AZ-5 design flaws as early as 1983. While NIKIET’s chief designer Nikolai Dollezhal orders some updates to the already-massive reference materials associated with the RBMK reactors, few modifications take place to the reactors themselves to correct the flaws. And while senior plant managers occasionally learn of serious design flaws, reactor operators are largely in the dark and furthermore forced to work under conditions that are hardly conducive to safety because “The staff of Soviet nuclear power plants […] had long become accustomed to bending or ignoring the rules in order to get their work done” (68).
In the years prior to the Chernobyl explosion, the Soviet Union experiences a series of incidents involving RBMK reactors, including the ones at the Chernobyl power station. In 1982, Chernobyl Unit One actually suffers a partial meltdown after a cooling valve ruptures, but the Soviet government makes the results of the inquiry classified as top secret. This is only one of many nuclear incidents the Soviet government suppresses, including a 1985 accident at the Balakavo plant in Russia in which superheated steam from a burst relief valve boils 14 men alive.
By the beginning of 1986, the only nuclear accident the world is aware of belongs to the United States. On March 28, 1979, the reactor at the Three Mile Island power station near Harrisburg, Pennsylvania suffers a partial meltdown, resulting in a significant release of radiation. While there are no injuries, deaths, or illnesses directly connected to the Three Mile Island incident, the panic caused by the event contributes to the United States’s decision to wind down its nuclear power ambitions. But in the Soviet Union, the incident becomes symbolic of the failings of capitalism. In a January 1986 article in Soviet Life published just months before the Chernobyl explosion, first deputy director of the Kurchatov Institute Valery Legasov writes, “In the thirty years since the first Soviet nuclear power plant opened, there has not been a single instance when plant personnel or nearby residents have been seriously threatened” (74).
Prior to going online for the first time, the Unit Four reactor at Chernobyl is supposed to successfully complete a test on its backup generator mechanisms. In the event of a blackout, it takes up to three minutes for emergency diesel generators to turn on, a dangerously long interval for the water pumps to go without power. The plant is supposed to convert the existing momentum from turbines to power the water pumps during the gap, but all previous attempts to complete the test fail. In order to meet the Soviet Union’s extraordinary power demands, Chernobyl director Viktor Brukhanov repeatedly approves lengthy delays to the test which is now two years overdue. With a scheduled maintenance on the horizon for Unit Four, if the plant doesn’t conduct the test soon, there won’t be another opportunity for at least a year. Without alerting NIKIET, the Kurchatov Institute, or even Brukhanov himself, deputy director Nikolai Fomin orders the test for April 25, 1986, mere hours prior to its scheduled maintenance shutdown.
The test is to take place by the end of the afternoon. But the central power dispatcher in Kiev intervenes, instructing Chernobyl operators to delay the test until at least 9:00 pm because the city needs every kilowatt of power it can get ahead of the May Day weekend. Under normal circumstances, a reactor control engineer like Toptunov with only two months experience on the job would not work the control board during such a precarious test. But Anatoly Dyatlov, the plant’s prickly and demanding deputy chief engineer for operations, is determined to go through with the test.
Around midnight, following a long controlled descent in power beginning as soon as the Kiev dispatcher gives permission, the reactor output hovers at 720 megawatts, near the minimum level required for the test. Perhaps working under the assumption that a lower power level will be safer, Dyatlov insists that they reduce power to 200 megawatts. Akimov, the shift foreman, adamantly disagrees. He points out that one of the many noted flaws of the RBMK reactors is that they are notoriously difficult to control at low power levels. After a heated argument, Akimov relents and orders Toptunov to gradually reduce power. But here, the relatively inexperienced Toptunov makes a serious error. Before initiating the system’s automatic controls, he forgets to set a minimum power level the system must maintain, causing core reactivity to enter a freefall, bottoming out at 30 megawatts in just two minutes. In this state of extreme low power, the neutron-scavenging gas xenon 135 builds up in the core, poisoning the reactor. Under such circumstances, the nuclear safety procedures indicate a clear course of action: Immediately shut down the reactor.
Although Dyatlov would later claim he was not in the control room at this time, the testimonies of Toptunov and Akimov tell a different story. According to Toptunov, Dyatlov orders him to withdraw control rods to increase reactivity for the test. Worried that this will make the reactor dangerously unmanageable, Toptunov refuses. Over the next six minutes, the two argue until Toptunov—knowing Dyatlov will simply get someone else to withdraw the rods—finally obeys the order. Over the next 30 minutes, Toptunov manages to increase the power back up to 200 megawatts. But because of the buildup of xenon gas which poisons reactivity, he must withdraw a whopping 203 of the unit’s 211 rods to reach this threshold. This leaves behind only 8 rods, making the chances of an AZ-5-induced runaway chain reaction very high. Complicating matters further, two more giant water pumps come online as part of the test program. The extra pumps, combined with the low power level, makes the system more susceptible to the effects of the positive void coefficient.
At 1:22 am, most of the operators are nervous, but Dyatlov is ready for the test to begin. “What are you waiting for?” (83) he asks Akimov. As the test commences and the turbines begin to slow, more and more water turns to steam, kicking the positive void coefficient into effect. “A deadly feedback loop had begun” (85). When the turbines reach the desired speed, Akimov orders an AZ-5 shutdown to end the test. After Toptunov presses the AZ-5 button, the remaining rods enter the core all at once. As soon as the rods’ graphite tips reach the lower part of the core, there is a massive surge of reactivity, helped along by the positive void effect. In three seconds, thermal power reaches more than a 100 times its maximum, peaking at more than 12 billion watts. “The temperature inside the reactor rose to 4,650 degrees centigrade—not quite as hot as the surface of the sun” (87). The walls of the control room shake, and the operators hear a loud bang followed by a huge roar. An explosion of ignited hydrogen and oxygen tosses the reactor’s 2,000-ton concrete-and-steel lid into the air “like a flipped coin” (88). Twenty-five to 30 tons of uranium and radioactive graphite scatter around Unit Four. An additional seven tons of tinier radioactive fragments enter the atmosphere, forming a gaseous mixture made up of “the most dangerous substances known to man” (88).
Senior coolant pump operator Valery Khodemchuk, from his post near the main circulation pumps, is either vaporized or crushed instantly during the explosion—the first, but not the last, to die as a result of the Chernobyl disaster.
Here, Higginbotham begins to explore in more detail the stark differences between the Soviet nuclear industry and that of its counterparts in the United States and Western Europe. Aside from the West’s mandate to use safer—though less efficient—PWR reactors rather than the dangerously unstable RBMK reactors, the most dramatic divide can be found in the United States’s relative transparency in the wake of the Three Mile Island partial meltdown and the Soviet Union’s obsessive dedication to secrecy around multiple nuclear accidents, most of which result in far more damage than the Three Mile Island incident. That incident is largely the result of human error, as plant operators take various actions in violation of US Nuclear Regulatory Commission rules. The fact that the United States even has a dedicated federal governing body overseeing the activity in its nuclear plants is itself a significant divergence from the Soviet Union, where around a half-dozen agencies enforce rules with little consistency or efficiency.
In the wake of the US accident—during which nobody gets hurts and operators quickly contain the radiation—anti-nuclear activists see their credibility and political influence increase as they effectively advocate for a slowdown in the United States’s nuclear ambitions. “In the United States, the development of the nuclear power industry, already dogged by rising construction costs and growing public apprehension, halted almost overnight” (73). The mere existence of anti-nuclear groups is something that differentiates the United States from the Soviet Union, where political repression—though somewhat on the decline by the 1980s—is still a powerful force in Soviet society. Beyond that, the Soviet Union works hard to maintain the myth that the heroic men in charge of its nuclear program are the closest thing the fiercely atheist Community Party had to gods. “Alongside the cosmonauts and martyrs of the Great Patriotic War, according to historian Paul Josephson, the nuclear scientists became ‘near-mythic figures in the pantheon of Soviet heroes’” (34).
To maintain this myth, the Soviet Union goes to great lengths to conceal the increasing number of accidents plaguing its reactor plants. Only around a year before the Chernobyl explosion, a burst relief valve at the Balakavo plant in Russia boils 14 men alive in a far more damaging accident than Three Mile Island. And yet the Soviet Union suppresses reports of the incident—like the Mayak explosion—and even operators at other Soviet nuclear plants are unaware of the accident. Perhaps the most absurd example of Soviet secrecy in regard to plant accidents happens at Chernobyl itself, four years prior to the explosion. In 1982, the Unit One reactor actually suffers a partial meltdown. While the vague existence of a problem is impossible to conceal from the workers there, the fact of the meltdown itself becomes classified as a state secret by the KGB. The technician who first reported the problem “would wait years before learning the truth about what happened” (70).
And yet, when the Three Mile Island disaster occurs—one that, again, pales in comparison to the Soviet Union’s own secret history of nuclear accidents—the USSR is quick to frame it in terms that speak highly not only of its own nuclear industry but also Communism in general, revealing the persistent theme of how Party ideology always supersedes truth and safety.
Having set the stage and establishing the factors of secrecy, ideology, recklessness, and over-confidence that all conspired to create a dangerous set of conditions, Higginbotham finally depicts the night of the accident itself. Here, the demands of the Soviet energy apparatus begin to play a major role. The fact that the turbine generator test is two years overdue and therefore a point of urgency is the result of numerous delays approved by Brukhanov in order to meet centralized power demands. Even on the scheduled day of the test, further delays ensue because the energy dispatcher in Kiev insists he needs all the power Unit Four can muster ahead of the long May Day weekend. This has the unintended effect of putting Leonid Toptunov—a reactor control engineer with only two months experience in that position—in charge of managing the power during the test, despite the fact that the task would have generally gone to a more senior operator. And it is Toptunov who commits one of the only errors that night that can truly fit the characterization of “innocent,” rather than borne out of recklessness or willful denial. As the systemic factors like these pile up ahead of the explosion, Higginbotham’s argument that the Chernobyl accident is a bureaucratic disaster as much as a technical disaster becomes even more persuasive.
Less innocent are the errors committed by Dyatlov the night of the explosion. In addition to advising Toptunov to lower the power needlessly in the first place—which leads to the sequence in which Toptunov’s error causes reactivity to bottom out—Dyatlov insists that the operators continue to conduct the test, despite the fact that the conditions of the reactor necessitate a full shutdown. A less stubborn man might have listened to Toptunov’s and Akimov’s very reasonable objections to these directives. But Dyatlov possesses an arrogance and disdain toward less senior plant workers that Higginbotham suggests is also a product of the Soviet Union and its dictates regarding following orders without question. “By crushing dissent and conjuring an air of infallibility, Dyatlov—like the Soviet state itself—expected his underlings to carry out his commands with robotic acquiescence, regardless of their better judgment” (78).
The overall takeaway from Higginbotham’s minute-by-minute depiction of the events leading up to the explosion suggests that despite numerous instances in which Chernobyl might have averted catastrophe, the plant’s operators continue to hurtle toward disaster, driven forward by a kind of institutional inertia endemic to the Soviet Union.



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