Scientists have put forward another idea of what caused the unusual spike of radiation recorded near Chernobyl during the opening days of the Russian invasion of Ukraine. Instead of tanks kicking up contaminated soil or the leak or deliberate release of radioactive material, they suspect the rising radiation levels might have been created by unidentified Russian military equipment messing with sensors in the area. 

On February 24 and 25, as Russia advanced into the abandoned city of Pripyat and the Chernobyl Nuclear Power Plant, a notable spike in gamma radiation was reported by Ukraine's nuclear agency and the interior ministry. 

A team of scientists from the UK has taken a close look at the situation by analyzing the readings taken from a network of 67 gamma detectors placed around the grounds of the ruined nuclear power plant, known as the Comprehensive Radiation Monitoring and Early Warning System (CRMS).

Their work — which has not yet been peer-reviewed — can be read on the preprint server arXiv.

Modeling of how contaminated soil might react to being driven over suggested that vehicle movements disturbing the soil wouldn’t result in such high levels of radiation to be recorded. They attempted to track the movement of the Russian military in the area using Sentinel satellite imagery, but found that the images were too low quality to gain any real insight. 

Furthermore, the location of the high radiation levels does not appear to be linked to the location of areas where radioactive debris is being contained, suggesting that a leak or deliberate release is also an unlikely explanation.

After excluding these two explanations, the researchers argue that the answer might lie in how Russian military communication equipment was meddling with the sensors, which wirelessly send data back to the central hub at the plant. 

“Military electro-magnetic frequency interference may potentially cause reporting anomalies from detectors, but again this would be expected to follow a spatial pattern and to be observed for gamma dose rate detectors at other locations in Ukraine where military activity has taken place. A more plausible explanation may be that reception of wireless signals by the CRMS network base-station in Chornobyl was disrupted,” the researchers write. 

As a counterargument, there have been unverified reports that some Russian soldiers had to be pulled out of the Chernobyl area after falling sick from radiation poisoning, suggesting there was a genuine rise in contamination levels. The troops allegedly drove through a highly contaminated portion of forest near the ruins of the power plant without wearing any protective equipment.  

It’s worth noting that this is still very early work and the scientists don’t have much data to play with. Given the ongoing conflict in Ukraine, it’s impossible to send researchers into the field and gather real on-the-ground data. Further blurring the situation, the team noted that the CRMS network has been offline since early March, so they’re currently being left in the dark about radiation levels in the area. 

“The CRMS, and other monitoring networks, need to come back online urgently so that the radiological situation in Ukraine, where intense military activity continues in some areas, can be monitored,” the team concluded

[H/T: New Scientist]