Chernobyl: The old plant in Chernobyl, Ukraine, is increasing nuclear fission reactions in one of its chambers, with emission levels 40% higher since its construction in 2016. The observation occurred during a routine monitoring of the ruins, which recorded the radiation leaving an inaccessible place inside the complex due to the explosion of reactors in the 1986 disaster.
In this case, the sub-reactive room is called 305/2 and its access was prevented due to the fall of walls after the accident. In that event, radioactive substances were spread throughout the installation, taking a material formed by the melting of concrete and steel from the building to the lower floors. Scientists and officials are evaluating whether the problem should stabilize or whether intervention is needed to prevent a catastrophic nuclear reaction.
If mediation is required on site, the process should require a lot of effort to drill and release access. There, they would apply substances, such as gadolinium nitrate, capable of absorbing excess neutrons and inhibiting a fission reaction.
Experts believe that the process is taking place due to a structure built on the ruins in 2016, which may be consuming part of a water flow used to hinder the emergence of neutrons. The technique is based on providing large amounts of water to slow down a fission reaction generated from the decay of radioactive fuels, such as uranium and plutonium.
In an interview with New Scientist magazine, nuclear waste disposal researcher Neil Hyatt – from the University of Sheffield (UK) – says that the situation can be compared to “embers on a barbecue grill” and “is a reminder for us that [the Chernobyl case] is not a solved problem, but a stabilized one ”.
Despite the warning, “we’re talking about very low fission rates, it’s not like a nuclear reactor is running at full speed. We are confident with our estimate that the amount of fissile material in that room will not cause an explosion. But we are not sure ”, he added.
“We have already seen cases like this with other fuel residues. The basic neutron rate has increased, stabilized and decreased again. Obviously, this is what we hope will happen now. It is a matter of concern, but not of alarm ”, he added.
However, there is no consensus among experts on the real situation. For Maxim Saveliev, who has worked on recent containment actions in Chernobyl and a member of the Nuclear Power Plant Safety Problems Institute – of the Ukrainian National Academy of Sciences -, he says it is difficult to determine a precise level of danger.
He says that because there is no neutron sensor in the vicinity of the sub-reactive room 305/2, it is not possible to have an idea of the amount of radioactive material present inside it and the exact scale of the problem. “We only have assumptions,” he commented. Thus, he defends the use of robots to get as close to the area as possible, collect samples and install sensors and devices to contain greater risks.