Zoning in the vicinity of the nuclear power plants

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The zoning in the vicinity of the nuclear power plants is the planning for alarm zones created as part of the emergency planning for nuclear power plant accidents in Switzerland . It is also used to some extent in the event of chemical accidents.

The alarm zones are divided into three areas:

  • Zone 1: It covers a radius of 3 to 4 kilometers around a nuclear power plant. In this area, it is expected that serious accidents with release can lead to early deaths due to radiation sickness : In extreme cases, the radiation dose ( whole-body dose ) can be so intense that, with little protective measures and a relatively short exposure duration, death within occurs for a few weeks or months (see firefighters in the Chernobyl disaster ).
  • Zone 2: Covers a 20-kilometer radius around the NPP. Early deaths are no longer accepted here.
  • Zone 3: Basically comprises the entire country outside Zone 2. Here, the slowly thinning radioactive cloud is not assumed to be an immediate hazard, provided that the area is largely in the course of the accident (which may extend over several days, possibly even weeks) lies in the slipstream . If, on the other hand, it is brushed by the wind, long-term consequences to the extent of zone 2 can occur for the unprotected whole body. The contamination of food is also of concern in this zone; consumption bans for milk and free-range products may be issued.

The population living in zones 1 and 2 is alerted by sirens when required, and if necessary, parts of the population in zone 3. In addition, sheltered areas are available to the majority of the population in Switzerland . Critics complain, however, that this reference to the shelter would not function smoothly due to organizational problems if there was a short time window between the start of the accident and the release of radioactivity. In Zone 1 and Zone 2, iodine tablets were distributed to households as a preventive measure , which, if taken early (but not too soon), prevent thyroid cancer. It should also be added that a wash-out from the radioactive cloud through precipitation (rain, snow) can considerably increase the dose intensity for the unprotected whole body; this also for areas in zone 3.


  • Federal Office of Public Health: Radioactivity and Radiation Protection , 1999
  • Federal Commission for NBC Protection: Emergency protection in the vicinity of nuclear power plants. Standard documentation and checklists for cantons, regions, municipalities and companies in Zone 1 + 2 around the nuclear power plants, 1.2. Zoning in the vicinity of the nuclear power plants , p. 4 ( pdf , Federal Office for Civil Protection FOCP, babs.admin.ch)

Individual evidence

  1. ^ Alarm brochure Radioactivity / Chemistry of the Canton of Solothurn , 1991