Many Sources of Radioactivity Between 1987 and 1991, Ukrainian and Russian scientists conducted research at the sarcophagus to determine the location and physical state of the irradiated fuel. A number of fuel assemblies were ejected from the reactor, falling up to one-quarter mile away. Some were bulldozed up and moved to the sarcophagus, and some were buried where they landed. Over this period, the Ukrainians mapped the location of radiation fields within the unit, measured radiation and temperature levels within the sarcophagus, monitored site ground water and nearby rivers, and reinforced internal structures that had been badly damaged by the accident to prevent further failures. The sarcophagus is not leak tight.
Rainwater can enter and radionuclides can escape.
The 10 metric tons of radioactive dust within the sarcophagus represent a major threat to public health and the environment. In 1988, for instance, drilling equipment was accidentally dropped, sending up a thick cloud of dust and forcing the evacuation of the sarcophagus. The Ukrainians have installed a system for sprinkling resins to control dust within the structure, and it reportedly works. The high radiation levels within the sarcophagus contribute to the problems with dust and structural integrity. The magma containing molten fuel is disintegrating in the high radiation fields, providing even more radioactive dust.