During the month of May, everyone who lives within 25 kilometers of the nuclear power plants Forsmark, Ringhals and OKG in Oskarshamn will receive a map of iodine tablets and an information letter.
Eventually, radio receivers will also be sent out, who can warn in the event of an accident.
Iodine tablets should be taken to reduce the radiation dose in the event of a nuclear accident.
Previously, only households within the internal emergency preparedness zone were included in the authorities' mailings, but following an investigation by the Swedish Radiation Safety Authority, an external emergency preparedness zone and planning zone have also been created.
The map shows what the contingency zones look like at Sweden's nuclear power plant.
Green field is the planning zone, yellow field is the outer contingency zone, and red is the inner contingency zone.
Thousands of households
In Kalmar County, the County Administrative Board estimates that 22,000 households are covered by the internal and external emergency preparedness zone.
Previously, just over 2,000 households were included in the close contingency.
At Forsmark in Uppland, the County Administrative Board estimates that 19,000 households are within the 25-kilometer limit, and in Halland around Ringhals, just over 130,000 people are affected by the external and internal emergency preparedness zone.
See in the clip above if your home is within the boundaries of the zones.