The Chernobyl Disaster
—Chrissie

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            At 1:23 am on 26 April 1986, two successive explosions rocked the Vladimir I. Lenin Nuclear Power Plant (better known as Chernobyl) near the city of Pripyat in Ukraine, which was then a part of the Soviet Union. It is considered to be one of the worst nuclear accidents, to this day, and is widely seen as a major factor contributing to the collapse of the USSR.

In an example of irony that would be rejected in a fiction manuscript, the explosion occurred during a safety test. The test was intended to determine if the reactor could take over powering the emergency cooling system for a short time in the event of a complete power failure while backup generators came online. It was planned to coincide with a maintenance shutdown, which allowed for a controlled reduction in the reactor’s power without the need to immediately ramp it up again. The test was scheduled for the afternoon of 25 April but was delayed due to an outage at another plant. By the time the delay was arranged, the emergency cooling system had already been shut down; it was not turned back on. While this is not considered a causal factor in the accident, it is indictive of the lack of attention to safety measures. The test was also left to the unprepared and smaller staffed night shift, but this was not seen as a problem as it was to be overseen by the deputy chief engineer of the plant and one of the coauthors of the test procedure, Anatoly Dyatlov.

The explosion, and subsequent meltdown, was caused by a combination of unlikely elements and a lack of needed safety procedures and information. In dropping the power level of the reactor in preparation for the test, the operators did not realize that there was a buildup of the element Xenon, which caused the nuclear reactions to slow. This prompted an unexpected drop in power, which was met with the removal of some of the control rods, in order to increase the reaction and the power being produced. At the same time, coolant water was added to the system, but the tanks were so hot that it was boiling almost immediately, causing a great deal of steam. Another power drop prompted the operators to remove more control rods, allowing the nuclear reaction to increase beyond safe levels. The operators had no way of knowing this because this type of nuclear reactor, the RBMK, had no sensors monitoring the percentage of the rods in the reactor. When the test began, a massive spike in power prompted an emergency shutdown, which dropped all of the control rods back into the reactor, stopping the nuclear reaction. A flaw in the reactor design was the ultimate cause of the explosion: reinserting all of the control rods briefly displaced coolant, which caused an uncontrolled increase in reactions before stopping them. This increased the pressure of the superheated steam to the point that broke open the reactor casing in a great explosion. The core itself exploded seconds later, igniting the graphite from the rod assemblies and blasting it through the now-open roof. It ignited the tar and bitumen on the roof of the buildings near the reactor and sprayed radioactive debris all over the site. It also ignited a fire in the reactor core itself. Local firefighters were brought in to deal with the roof fires; they were not told about or equipped against potential radiation. The roof fire was extinguished within a few hours, the fire in the core continued for fifteen days.

The crew involved in the reactor test did not immediately realize the drastic nature of the accident. The dosimeters available to them maxed out long before they showed the actual amount of radiation in the area, contributing to an assumption that the core was still intact; an assumption which delayed appropriate action to protect both the people in the plant itself and in the local area. The key members of the crew who were involved, led by shift supervisor Alexandr Akimov, did everything they could to keep the reactor under control, even manually opening water valves to assure coolant water was flowing. Most of them died of severe radiation poisoning within a few weeks. Seeking to present the appearance of control over the situation, the government first told people there was no danger, but then decided to evacuate the city of Pripyat the next afternoon. People were told to bring only essentials with them and that they would be able to return within a few days; they never did.

An investigation to determine the cause was begun immediately alongside the mitigation efforts. Once the fire was extinguished, the site had to be cleaned up and a method designed to contain the radiation that would continue to be released for centuries. This was all made more difficult by the attempts of the Soviet government to keep the information about the accident secret. Their efforts were stymied by the detection of the radiation by the Swedish Radiation Safety Authority, who were first offered denials by the Soviet government, but also forced the issue by threatening a report to the International Atomic Energy Commission (IAEA) without Soviet contributions. An official announcement about the accident was made, which both downplayed its severity and attempted to create false context by discussing nuclear accidents in the United States and western Europe.

The first mitigation efforts were to reinforce the foundation under the plant, to make sure that nuclear material and radiation did not poison the groundwater. This turned out to be less of a concern than originally thought because the core material stopped and cooled earlier than expected. Next, before a protective dome could be constructed over the building, the nearly 100 tons of debris had to be cleared from the roof. This work was begun with robots, but the radiation so damaged the controls that they added to the debris. Five thousand people, referred to at the time as “bio-robots,” donned heavy protective gear to spend 60 to 90 seconds on the roof pushing debris into the hole where the core had been and then dash back to the relative protection of the building. There, they removed the protective gear, cleaned themselves as thoroughly as they could, and were thanked for their service to the state. Each person could only do this once, as during those brief seconds they were exposed to more radiation than would be safe over an entire lifetime.

            Work on the protective structure, which came to be known as the Sarcophagus, began in late May and was completed by November. At the same time, investigators entered the reactor to determine the state of the remaining fuel. They determined that there was no longer a risk of explosion, even though there was still a great deal of heat coming from it.

            Soviet investigations focused on placing blame. A trial held in July of 1987 ended with five of the men involved sentenced to labor camps and/or prison for criminal mismanagement and negligence. The USSR collapsed before their sentences were completed. Investigations by the IAEA found a lack of safety consideration combined with fatal flaws in the reactor design to be the ultimate cause. In the end, it was a very particular set of circumstances that led to the accident, ones that are, thankfully, not easily duplicated.

            The other three reactors at the plant remained in operation until 2000, but were still in process of being completely decommissioned as of 2021. The area around it of approximately 2600 km2 (1000 square miles) is the Chernobyl Exclusion Zone, in which no one is supposed to live. Short visits are allowed, however, and it has become an important site for research about the effects of radiation and of re-wilding in areas formerly inhabited by people. It has also become a tourist location. The area was taken by Russian forces on 24 February 2022 and its status is unknown as of this writing.