Part of the continuous nationwide monitoring of radionuclides in Finland. The dose rate monitoring network in Finnish Lapland comprise 32 automatic measurement stations (Finnish nation-wide monitoring network consists of about 257 stations equipped with GM tubes). Three of the stations are equipped with LaBr3-detectors measuring a gammaspectrum with 10 minute intervals. The network is intended for civilian defence and surveillance purposes, not for research. It is a good early warning system in radiation fallout situation. Every monitoring station have individual alarm level: 7 days average dose rate + 0.1 microSv/h. The dense network indicate also the extent of the radioactive contamination.
Precipitation sampling is performed using specially designed collectors made of stainless steel with a surface area of 0.07 m2. The deposition samplers do not separate wet or dry deposition, they are collected together. There is a light heating resistor inside the funnel to melt snow and ice gathered to the funnel to make the sampling more reliable in winter time. The sampling period is one month. Tritium samples are collected daily in a collector with a surface area 0.05 m2. The daily samples of one month are pooled and a 2 litre aliquot with a list of the daily precipitation is sent to STUK/Helsinki for analysis.
Known amounts of Sr, Cs, Ba and Ce carriers are added to the samples, which have already been acidified with nitric acid during the collection of the precipitation. The samples are concentrated by evaporation and ashing and thereafter analysed for gammaemitting radionuclides with gamma spectrometers. Measurement time >64 h. 90Sr is separated radiochemically either using the traditional fumic nitric acid method or with an ionchromatographic method. Thereafter 90Sr is determined via its daughter nuclide 90Y with alow background proportional beta counter. Tritium 3H distillation to dryness and electrolytic enrichment, determination using liquid scintillation counting.
Intercomparison IAEA and EPA. STUK is accreditated for gammaspectrometric measurements and 90Sr analyses (FINAS).
STUK reports doserate measurement information to European Comission under the article 35. STUK also reports doserate information to other Baltic Sea states.