About five years ago, a sensor tracked a gradual increase in activity deep in the rubble of the Chernobyl nuclear power plant. This sensor tracks neutron emissions in the plant. And it has been increasing the last five years, making the experts worry about it.
The truth is that the count up might mean nothing, it might even go down again. However, scientists won’t take any risks. The chances of a new nuclear fission reaction in the future cannot be discarded until they know what’s going on.
But it is more challenging than you might imagine. The precise location of decaying material under rubble and heavy concrete slabs is uncertain, making it more difficult for scientists to make detailed investigations and thus possible solutions.
Over the decades, uranium isotopes have continued to fire occasional neutrons from their nuclei. Those who get close enough to the nucleus of another isotope take the risk of upsetting their own delicate balance, releasing more neutrons.
Given a sufficiently high concentration of atoms, the chain reaction of the stray neutrons can generate enormous amounts of energy in a short period of time, with potentially explosive consequences. It is not surprising that fission rates increase each time they get wet.
“There are many uncertainties. But we cannot rule out the possibility of [an] accident”, say Maxim Saveliev a scientist at the Institute for Nuclear Power Plant Safety Problems (ISPNPP) in Kiev, Ukraine.
The risk of hazards in the near future appears low. Nonetheless, the worst scenarios would also fall far short of the 1986 catastrophe. For now, little can be done but watch and count on, hoping that in time, the ticking of Chernobyl will subside once more.
