The operators ought to have cancelled the test at this point, and indeed they proposed doing so, but a supervisor overruled them. This decreased its output so much that there was not enough energy left over to power the water pumps when the switch-over occurred. They inserted the control rods-graphite-tipped cylinders of boron carbide that slow or stop a nuclear reaction-too far into the reactor. The operators made a critical error right at the start. These technicians disabled the reactor’s emergency-cooling system-not a mistake, exactly, since the system would otherwise have overridden the test, but also not a maneuver to be left in inexperienced hands. on April 25th, and left to the night crew. Rather than taking place under the supervision of the seasoned day crew, it was delayed ten hours, to 11 P.M. When the test finally did happen, it was poorly scheduled. This made the reactor’s operation less stable than usual, and much harder to control. The reactor, a Soviet-designed RBMK-1000, was coming to the end of its fuel cycle, meaning that the uranium in its core was mostly depleted, leaving behind a motley mix of radioactive by-products. ![]() The test was several years overdue, and it was performed at a particularly dangerous juncture. The Chernobyl meltdown originated in what was meant to be a demonstration of the plant’s safety, specifically of its ability to switch between these power sources. In the event that this external power fails, a backup system kicks in. Keeping the water moving requires pumps, which run on electricity from outside the reactor complex. In most plant designs, the flow of water around the core must be constant, because the heat of fission can damage the reactor if it is not sapped away. A reactor is an immensely convoluted machine, full of interlocking, non-linear systems. This is true only in a very basic sense, in the same way that a paper airplane and a Boeing 747 share certain aerodynamic properties. When people wish to downplay the strangeness and complexity of nuclear power, they sometimes argue that reactors are not much different from teakettles: both use a heating element to boil water and produce steam. The Battle of Chernobyl had a clear beginning, but what of its ending? Was the fight only against flame, fallout, and technological calamity, or was it a campaign against something broader? Thirty years after the fact, it’s worth reëxamining how the battle got started, and how it continues. A massive new steel shelter, designed to fit over the sarcophagus, is scheduled to be finished next year, but it is meant to contain the reactor for only another century-longer than the life of a person, but a fraction of the half-life of some of the contaminants present. It took half a million workers, the so-called liquidators, more than six months to cover the ruined reactor with a protective concrete dome, aptly known as the sarcophagus. All told, thirty people were killed in the explosion and the cleanup that immediately followed. In the ensuing days, helicopters flew sorties over the reactor, dropping sand to impede the fire and boron to slow the ongoing reaction. ![]() ![]() The Battle of Chernobyl, as the disaster came to be called by Soviet historians, had begun. Burning graphite, molten bitumen, and radioactive debris-the misshapen half-atoms left over when uranium is split apart-were launched into the night sky. A few seconds later, it exploded again, this time with the force of ten tons of TNT. ![]() Lenin Nuclear Power Station exploded, tearing the top off the reactor building and exposing the core to the Ukrainian wind. Photograph by Paul Fusco / MagnumĪt 1:23 in the morning on April 26, 1986, Unit 4 of the V. Workers tend flower beds near the Chernobyl nuclear power plant before the explosion.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |