Nuclear reactions detected under debris of destroyed Chornobyl reactor – Scientists

The Institute for Safety Problems of Nuclear Power Plants (ISP NPP) of the National Academy of Sciences of Ukraine says scientists have detected fission reactions are smoldering again in uranium fuel masses under debris of the destroyed reactor at the Chornobyl power plant (ChNPP) since the installation of a new safe confinement there.

That is according to a statement published by the ISP NPP's press service on its website on May 12.

Read alsoThirty-fifth anniversary of Chornobyl NPP tragedy: "Data on radiation doses was grossly manipulated. Among those who used to work here, only a few are still alive""After the establishment of the new safe confinement (NSC) [New Shelter] Arka in the design position, sensors are indeed tracking a rising number of neutrons at the periphery of formations of fuel-containing materials (FCM), which is localized in one of the reactor hall's basement rooms inside the Shelter," the report said.

At the same time, the neuron counts are rising slowly, the background remains within the established safety limits controlled by the standard nuclear safety control system, it said.

According to predictive estimates, the neutron counts are expected to further increase there, which will be determined by a loss of moisture in the waterlogged layer of lava-like FCMs

"Therefore, ISP NPP experts are focusing on the need for an in-depth study of fuel-containing materials and factors affecting the state of nuclear safety at the Shelter facility. To this end, they have developed the FCM monitoring program for the Shelter," the press service said.

Realizing the complexity of the problem the ChNPP is facing amid the transformation of the Shelter into an environmentally safe system providing for the handling of nuclear hazardous materials, the institute in 2016 developed a special program for monitoring of the Shelter's FCMs.

However, the ChNPP is not provided with adequate resources for the implementation of this program, the experts say.

Transforming Shelter into an ecologically safe area

In March 2021, Ukraine's Cabinet of Ministers allocated almost UAH 1.4 billion (US$50.6 million) to decommission the Chornobyl NPP and transform the Shelter into an ecologically safe area.

In July 2019, a new safe confinement worth EUR 1.5 billion was commissioned over the ChNPP's fourth reactor, with a service life of at least 100 years.