>>144280
[reminder]
[28 April 1986]

"...during the weekend the wind had blown from the south-east and it had rained in the north-eastern parts of Sweden, depositing radioactive fall-out on the ground in that area. All the evidence was pointing towards one of the nuclear power plants in the Soviet Union. And late that evening, two days after the disaster, the Soviet Union declared that there had been an accident at Chernobyl in Ukraine, a republic of the Soviet Union at that time."

Forsmark: how Sweden alerted the world about the danger of the Chernobyl disaster

The alarm sounded at Forsmark, Sweden's second largest nuclear power plant, when one of the employees passed one of the radiation monitors on his way back from the restroom. When it showed high levels of radiation coming from his shoes, staff at first worried an accident had taken place at the power plant. However, a thorough scan discovered that the real source of the radiation was some 1,100 kilometres away in the Ukrainian town of Chernobyl.
The early detection by the Forsmark plant, one hour north of Stockholm, played a crucial role in forcing Soviet authorities to open up about the disaster that happened in Chernobyl in April 1986.
When the alarm sounded at Forsmark early in the morning of 28 April 1986, it was not immediately clear where the radioactive materials had been released despite staff scanning all the radiation detection instruments.

https://www.europarl.europa.eu/topics/en/article/20140514STO47018/forsmark-how-sweden-alerted-the-world-about-the-danger-of-chernobyl-disaster