The recent nuclear disaster in Japan has resurrected the memories of Chernobyl in the public’s imagination. The 1986 disaster of the Ukrainian reactor at the Chernobyl nuclear power plant is still regarded as the worst nuclear disaster in history, although the Japanese crisis is still unfolding. The Chernobyl disaster “was the product of a flawed Soviet reactor design coupled with serious mistakes made by the plant operators. It was a direct consequence of Cold War isolation and the resulting lack of any safety culture” (“Chernobyl,” WNA, 2011). In 1987 an important article appeared in the Journal of the American Medical Association. The author, Roger E. Linnemann, MD, had this to say about the accident:
The four operating units were graphite -moderated, water cooled reactors... unlike the water-moderated, water-cooled reactor favored in the West. Because of their confidence in the design of the reactor, the Soviets did not enclose the entire unit with a containment structure and had not developed either an off-site emergency plan or employed an off-site monitoring system. (637)
Additionally, contrary to safety regulations, a combustible material called bitumen had been used in the construction of the roofs on the reactor building and the turbine hall. The uncontained explosion of a nuclear reactor from the safety test had just impacted the world, and the resulting roof fires threatened the adjacent reactor.
The incident occurred when the reactor crew attempted to carry out a safety test involving one of the plant's eight turbine-generators. The specific test the crew was conducting was to “determine how long turbines could spin and continue to supply power following loss of the primary electrical power supply. Similar tests had already been carried out at Chernobyl and other plants, despite the fact that these reactors were known to be very unstable at low power settings” (Kubiszewski & Cleveland 2009). During the test the operators had also disabled automatic shutdown mechanisms.
The crew unintentionally let steam voids form in the reactor's cooling water as it passed through the core. One of the flaws of the reactor design was its tendency to generate a sudden and uncontrollable burst of power if large steam voids are allowed to form in the reactor core, as happened during the test (Gillette 1986). In addition to the documented problem of the steam voids inherent in the design, poor manual operation of the reactor had caused the reactor to be in an even more unstable state than usual.
As the fission accelerated, the reactor's heat output rose 330 million watts within three seconds. This triggered explosions of steam and hydrogen gas in the core that destroyed the reactor, blew the roof off the building, and started a graphite fire in the core that spewed radioactive wastes into the atmosphere for the next 11 days. (Gillette 1986)
After the dramatic power surge occurred, and the ensuing steam and hydrogen explosion that...