Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster

by Adam Higginbotham

On the night of November 30, 1975, just over a year after it had first reached full operating capacity, Unit One of the Leningrad nuclear power plant was being brought back online after scheduled maintenance when it began to run out of control. The AZ-5 emergency protection system was tripped, but before the chain reaction could be stopped, a partial meltdown occurred, destroying or damaging thirty-two fuel assemblies and releasing radiation into the atmosphere over the Gulf of Finland. It was the first major accident involving an RBMK reactor, and the Ministry of Medium Machine Building set up a commission to investigate what had gone wrong. Afterward, the official line was that a manufacturing defect had led to the destruction of a single fuel channel. But the commission knew otherwise: the accident was the result of the design faults inherent in the reactor and caused by an uncontrollable increase in the steam void coefficient. Sredmash suppressed the commission’s findings and covered up the accident. The operators of other RBMK plants were never informed of its true causes. Nevertheless, the commission made several important recommendations, to be applied to all RBMK-1000 reactors: develop new safety regulations to protect them in the event of coolant loss; analyze what would happen in the event of a sharp rise in steam in the core; and devise a faster-acting emergency protection system. Despite their apparent urgency, the reactor designers failed to act on a single on...