Chernobyl

Ukrainian city north of Kiev and site of a massive nuclear accident in April 1986. The explosion of Reactor Four at the Chernobyl nuclear power station marked a turning point for the fortunes of both atomic energy and the Soviet system. As a result of the accident, thirty-one people died outright, hundreds of thousands were exposed to high doses of radiation,rift gold and large areas of the Soviet Union were contaminated. Soviet mismanagement of the disaster damaged the USSR’s reputation at home and abroad. Chernobyl heightened public perceptions of nuclear risk and led many countries to reassess their atomic energy programs.

On April 25, 1986, a test was to be carried out at Reactor Four of the Chernobyl plant during a routine maintenance shutdown. The test program, which was to assess the viability of alternative electrical power supplies in the event of the loss of main power, included numerous actions that violated established nuclear safety regulations. Errors included the disabling of key components of the emergency shutdown system and the inadvertent lowering of reactor power to an unstable level. Flaws in the scheduled test were compounded by particular design features of the reactor itself, a light water-cooled RBMK1000 graphite-moderated unit, which was one of the most dangerous types of nuclear reactors.

During the experiment, plant technicians attempted to manually control the reactor after it reached a dangerous operating state. This intervention made matters worse, and at 1:23 A.M. on April 26, the reactor experienced a surge in power of one hundred times normal operating capacity. The result was a catastrophic steam explosion that blew off the top plate of the reactor, exposing the reactor core to the air. Seconds later, a hydrogen explosion ignited a graphite-moderator fire. Gases from the fire carried melted uranium fuel into the atmosphere. Meteorological and wind conditions transported the radioactive material over much of the Northern Hemisphere.

The causes of the Chernobyl accident and the series of events that led to the destruction of Reactor Four have been the subject of intense inquiry by international committees and individual scientists. Most investigations have pointed to an insufficient level of “safety culture” in both the Chernobyl plant and the Soviet nuclear industry. The reactor’s faulty design was unforgiving of operator error, while the technicians themselves betrayed a lack of respect for the potential dangers involved in deviating from established nuclear safety procedures. Moreover, the entire Soviet nuclear industry suffered from shoddy construction materials, chronic supply problems, and insufficient training of personnel. Much of the onus for Chernobyl must also rest on the Soviet Communist Party, which preferenced economic goals over responsible and safe energy production. In sum, the Chernobyl disaster was the product of the myriad curses of the Soviet system in its final stage of decay.

The magnitude of the accident was without precedent, and Soviet officials had no emergency plan in place to cope with such a disaster. Aggressive countermeasures at the plant were generally successful and reduced the threat of additional damage. To contain the graphite fires, helicopters dropped wet sand, boron carbide, lead, and dolomite on the burning reactor. Official Soviet reaction was characterized by delays in notification and underestimation of the scale of the danger. The evacuation of the nearby town of Pripyat and a thirty-kilometer zone around the reactor was delayed nearly thirty-six hours. For two weeks the Kremlin released only limited information about the disaster, and it was not until May 14 that General Secretary Mikhail Gorbachev addressed Soviet citizens on the matter.

The calculation of radiation dose estimates resulting from Chernobyl has sparked considerable controversy, but it is certain that most of the population of the Northern Hemisphere was exposed to some degree. Ey far the worst affected were the approximately 400 people on site at the time of the accident, including plant workers, firefighters, and medical crews. Of these, 31 died as a result of acute radiation syndrome. The 135,000 evacuees from the thirty-kilometer exclusion zone received significant doses, as did many of the 800,000 people involved in clean-up operations. About 270,000 people still live in contaminated areas, where radiocesium deposition is in excess of 555 kilobecquerels per square meter, the highest level considered safe. Populations outside the former Soviet Union received doses too low to be considered harmful.

The health implications of dose exposure from the Chernobyl accident vary. Those living in areas of contamination, especially children,rift gold have experienced increased incidence of carcinoma of the thyroid, which is expected to lead to many thousands of cancer deaths. The same areas have recorded no increases in leukemia, congenital abnormalities, adverse pregnancy outcomes, or any other radiation-induced disease. Over many years, however, public health officials expect increased incidence of genetic diseases, though these may not be statistically measurable or traceable to Chernobyl. The most serious longterm health impact continues to be psychological stress syndrome. Public fears about radiation, a mistrust toward public authorities, and the disruption of social networks and traditional ways of life has exacted a high psychological toll on populations in contaminated areas.

More serious than the direct health impact on humans is the long-term damage to food production and the environment. Large areas of agricultural land within the former Soviet Union must be excluded from productive use for many generations. Restrictions on animal slaughter and food distribution remain in place in some affected areas. Forest environments that lay in the path of fallout will constitute a radiological problem for many years. To date, contamination of ground water has been limited to the thirtykilometer exclusion zone.

The residual risks posed by the Chernobyl accident are considerable. Seven months after the event, Soviet authorities completed the construction of the “sarcophagus,” a massive concrete structure that encases the destroyed reactor. In recent years numerous cracks in the roof have allowed the penetration of rainwater, which is now radioactive. There is some concern that contamination of the water table in the thirty-kilometer zone could threaten the Dnieper River. An independent Ukraine awaits international assistance to repair the sarcophagus and eventually undertake the safe elimination of both the reactor and the large quantity of radioactive waste produced during postaccident countermeasures.

The destruction of the Chernobyl reactor, the worst industrial accident in European history, was and continues to be an event of far-reaching significance. Aside from health consequences and environmental, industrial, and economic damage, Chernobyl has had a profound impact worldwide on public perceptions of nuclear power. After the accident the transboundary implications of nuclear disaster were better understood, and a global campaign in favor of international nuclear regulation and cooperation was launched. The Chernobyl disaster was also a harbinger of the coming demise of the Soviet Union. At Chernobyl, as with the collapse and dissolution of the Soviet empire, a poorly conceived experiment on a faulty system led to the destruction of the entire machine.