“‘The Shelter is not hermetic and was never intended to be,’ [Oleg] Goloskokov explained. ‘There are about 100 square meters of cracks and openings.’
“These cracks serve as a way for dust to get out into the environment. Birds fly in, get sprinkled with dust, and then fly out, carrying the contamination great distances. Such vectors are minor, however. But if one of the large, unstable objects inside—such as the 200-ton core cover that was blown on its side and hangs over the empty reactor vault—falls, it would raise a significant cloud of radioactive dust that could drift out into the environment.
“The cracks also allow precipitation to get inside. In the early postdisaster period, the FCMs [Fuel-Containing Materials] were hot and glass-like, so the water merely evaporated on contact. But now that the FCMs have cooled, the water no longer evaporates. Shelter experts—and an entire interdisciplinary institute of the Ukrainian Academy of Sciences is devoted to Shelter science—estimate that there are now from 2,000 to 3,000 cubic meters of water inside the structure. In comparison, an Olympic-sized pool holds 4,000 cubic meters.
“This ‘unit water,’ as it is known, affects electrical and diagnostic systems, corrodes metals, and deteriorates concrete. In the winter it freezes, cracking FCMs, and creating dust. Most dangerously, it also leaches out water-soluble forms of enriched uranium and transuranic elements such as plutonium and then trickles and flows into the reactor’s basements, where it is ankle-deep in places. And the amount of transuranic elements in it is increasing with time. This means that the water poses a nuclear risk.
“In contrast to fission products such as cesium-137 and strontium-90 that are merely radioactive, transuranic elements such as uranium and plutonium are also capable of fission. Since water is a moderator, slowing neutrons so that they are more likely to hit other atomic nuclei in a chain reaction, the transuranic soup accumulating in the bowels of the reactor poses the risk of starting an uncontrolled nuclear reaction.
“This is why pumping that radioactive water out for processing is a top priority. It is also a huge undertaking. Although the plant has facilities for processing liquid waste created in the course of normal reactor operations, it is not suited for the dangerous job of removing the transuranic elements in the unit water. The problem is that when radioactive materials are separated from water, they are usually concentrated to take up less space for storage. But concentrating transuranic elements could create a critical mass that will sustain fission. So the decontamination facility must somehow ensure that such accumulations do not occur.
“I swept my arm towards the Shelter, ‘So will it ever be clean?’
“‘A green field?’ Goloskokov smiled and shook his head. ‘I doubt it. You see, the Shelter Object itself is radioactive waste that should be processed and safely stored.’
“Goloskokov laughed at the notion of such a mind-boggling task. ‘We’re talking about hundreds of thousands of tons. That is more radioactive waste than exists in the entire world! Disposing of it is simply unrealistic.’”
—Mary Mycio, Wormwood Forest: A Natural History of Chernobyl (p. 223-4)