Radioactive fallout and the lessons of Chernobyl

We cannot see radioactive contamination without the help of specialised equipment, but the mere risk of it being present is nevertheless enough for the authorities to evacuate inhabitants within a certain radius of the stricken plant.

The International Atomic Energy Agency defines an exclusion zone as the area surrounding a reactor in which the power plant’s operator has the authority to determine “all activities including exclusion or removal of personnel and property” and all nuclear plants are built with this worst-case scenario in mind.

The most famous exclusion area is the one around the Chernobyl nuclear power plant in Ukraine, which in 1986 became the site of the world’s worst nuclear accident.

Radioactive fallout and contamination is still present within the 30km exclusion zone around Chernobyl, but by and large this only poses a limited hazard to living things. In fact, the absence of people has caused wildlife in the area to thrive – some rare species have even returned to breed.

Some of the radioactive isotopes released into the atmosphere at Chernobyl – notably Strontium-90 and Caesium-137 – still linger in random “hot spots” on the ground. Radiation exposure may be tolerable for short periods, but living for long periods poses an unacceptably high risk to health.

Authorities in Japan have studied how Ukraine has monitored and policed the Chernobyl exclusion zone, which resulted in the evacuation of about 116,000 inhabitants. The greatest source of radioactive contamination was from radio-iodine in the food and milk, which is quickly taken up by the thyroid gland – thyroid cancers over the coming decades are expected to be higher than normal as a result.

Fortunately, thyroid tumours are treatable if caught in the early stages. But the physical effects of radiation are possibly not as damaging as the psychological impact of losing your home, your livelihood and the community where you once lived.