Chernobyl 2019 ‧ Historical period drama ‧ 1 season In April 1986, the city of Chernobyl in the Soviet Union suffers one of the worst nuclear disasters in the history of mankind. Consequently, many heroes put their lives on the line to save Europe. No. of episodes: 5
The #Chernobyldisaster was a nuclear accident that occurred on Saturday 26 April 1986, at the No. 4 nuclear reactor in the #Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR.[1][2] It is considered the worst nuclear disaster in history and is one of only two nuclear energy disasters rated at seven—the maximum severity—on the International Nuclear Event Scale, the other being the 2011 Fukushima Daiichi nuclear disaster in Japan. The accident started during a safety test on an RBMK-type nuclear reactor, which was commonly used throughout the Soviet Union. The test was a simulation of an electrical power outage to aid the development of a safety procedure for maintaining cooling water circulation until the back-up generators could provide power – there is a time gap between the moment of power outage and the moment at which the back-up generators reach full power.
This operating gap was about one minute and had been identified as a potential safety problem that could cause the nuclear reactor core to overheat. Three such tests had been conducted since 1982, but they had failed to provide a solution. On this fourth attempt, the test was delayed by 10 hours, so an unprepared operating shift had to perform it.[3] During a gradual decrease of reactor power that was done in preparation for the test, the power unexpectedly dropped to a near-zero level at one moment. The operators were able to partially restore power, but this put the reactor in a highly unstable condition. The risks were not made evident in the operating instructions, despite a similar accident occurring years before, and the test proceeded even though the power was still lower than prescribed. Upon test completion, the operators triggered a reactor shutdown, but a combination of unstable conditions and reactor design flaws caused an uncontrolled nuclear chain reaction instead.[4]:33 A large amount of energy was suddenly released, vapourising superheated cooling water and rupturing the reactor core in a highly destructive steam explosion. This was immediately followed by an open-air reactor core fire that released considerable airborne radioactive contamination for about nine days that precipitated onto parts of the USSR and western Europe, before being finally contained on 4 May 1986.[5][6] The fire gradually released about the same amount of contamination as the initial explosion.[7] As a result of rising ambient radiation levels off-site, a 10-kilometre (6.2 mi) radius exclusion zone was created 36 hours after the accident. About 49,000 people were evacuated from the area, primarily from Pripyat. The exclusion zone was later increased to 30 kilometres (19 mi) radius when a further 68,000 people were evacuated from the wider area.[8][8]
