Monitoring local dose rate
Several networks exist for monitoring and measuring radioactivity levels in Switzerland.
NADAM monitoring network
The NEOC operates the NADAM network, which continuously monitors local radioactivity levels. The network consists of 76 stations, located at the MeteoSwiss weather stations throughout Switzerland, that transmit radioactivity levels and other parameters back to the NEOC at ten-minute intervals. If the threshold value (1000 nanosievert per hour [nSv/h]) is exceeded, an alarm is automatically raised. The NEOC evaluates the data from the NADAM network on a daily basis and uses it for the large-scale monitoring of external radiation.
MADUK monitoring network
The Swiss Federal Nuclear Safety Inspectorate (ENSI) operates the MADUK network for the small-scale monitoring of radioactivity levels in the vicinity of nuclear power facilities. Local radioactivity levels are measured at 57 locations, each within a radius of about five kilometres around the respective nuclear facility. The network is also equipped with an alarm system. All recorded data and reports of a possible incident are sent to the NEOC.
Air and water monitoring networks
The URAnet Aqua network monitors the concentration of gamma radiation in the Rivers Aare and Rhine downstream from nuclear power facilities at ten-minute intervals using four automatic sensors. The network contains an alarm system based on two threshold values. The NEOC is notified if these values are exceeded. The URAnet Aero network continuously monitors radioactivity levels in the air at 15 stations located across Switzerland. Readings are taken every five minutes. At five of these stations (Aarau, Bellinzona, Geneva, Liebefeld, Paul Scherrer Institute), gaseous iodine is also measured every 30 minutes using separate air sample collectors. The NEOC is notified if the two pre-defined threshold values are exceeded. In addition to the URAnet Aero network, six highly sensitive mobile air sample collectors (high-volume samplers) are in use, which can detect even the smallest traces of radioactivity. The aerosol filters are changed weekly and analysed in the FOPH laboratory.