Thirty-five years after the Chernobyl Nuclear Power Plant in Ukraine exploded in the world’s worst nuclear accident, nuclear reactions are again being detected in an inaccessible basement room called 305/2.
Room 305/2, located below the Unit Four reactor is now a vat containing tons of semiliquid nuclear mush, made up of uranium, zirconium, graphite, and sand that oozed into the plant’s basement like lava, before hardening into formations called fuel-containing materials (FCMs).
The FCMs are laden with about 170 tons of irradiated uranium—95 percent of the original fuel, reports Science Magazine. “It’s like the embers in a barbecue pit,” says Neil Hyatt, a nuclear materials chemist at the University of Sheffield.
Ukraine’s Institute for Safety Problems of Nuclear Power Plants (ISPNPP) is currently responsible for securing Chernobyl. The New Safe Confinement (NSC) covering the old Shelter Structure (sarcophagus) was originally intended to be completed in 2005, but the project suffered lengthy delays, not being completed until 2017.
The NSC was supposed to keep the existing remains of the reactor stable for eventual dismantling, and also to keep the site dry. Ever since the meltdown and initial cleanup, engineers have worried that rainwater leaking into the building could cause another nuclear event.
As it turns out, keeping the FCMs dry might create an even worse scenario, seeing as neutron levels have doubled in the past four years, according to ISPNPP scientists. According to ExtremeTech, there is speculation that some property of the mixture causes it to generate more neutrons as it dehydrates.
Over time, that could increase the risk of another self-sustaining nuclear reaction, which could breach the NSC and spread fallout across the region again. Maxim Saveliev, a senior researcher with the ISPNPP says the neutron levels could continue to rise over a period of several more years.
Saveliev adds that it’s possible these nuclear nuggets will fizzle out on their own in that time. But if neutron levels keep rising, scientists will have to intervene, according to Live Science.
Any remedy Saveliev and his colleagues come up with will be of keen interest to Japan, which is coping with the aftermath of its own nuclear disaster 10 years ago at Fukushima, Hyatt notes. “It’s a similar magnitude of hazard.”
