//Scientists detect dangerous nuclear reactions at Chernobyl NPP

Scientists detect dangerous nuclear reactions at Chernobyl NPP

Scientists have detected nuclear reactions taking place underneath the new confinement that isolates the destroyed reactor of the Chernobyl Nuclear Power Plant. Buried uranium fuel poses a potential hazard. Specialists are trying to establish whether the reactions stop on their own or require urgent action, an article posted on Science magazine says. 
According to Anatoly Doroshenko of the Institute for the Safety of Nuclear Power Plants, sensors track a growing number of neutrons, indicating nuclear fission reactions are underway. Experts can not rule out a new accident, but the neutron flux grows slowly, and it may take several years before the worst-case scenario occurs. Scientists will thus have time to come up with extraordinary measures to counter the threat.
On April 26, 1986, when part of the reactor core of the fourth block melted, uranium fuel rods, their zirconium cladding, graphite control rods and fire sand formed corium – a lava-like fuel-containing material (FCM) or nuclear lava. It flowed into the basement of the reactor hall, where it froze having formed an “elephant’s leg” – an extremely radioactive mass. Ten minutes near this substance is lethal. The Chernobyl corium contains 170 tons of radioactive uranium, but radioactivity decreases over time.