Radiation monitoring programme in a university hot laboratory

The Department of Radiochemistry in the University of Helsinki is the only institute teaching radiochemistry at the university level in Finland. The research programme of the Deparment must therefore include the uses of radiation and radionuclides in many branches of science. The students must receive adequate instruction in radiation protection for safe work in laboratories. This also has the educational benefit that the radiochemists will subsequently be able to observe the necessary safety precautions when employing ionizing radiation professionally. The Department of Radiochemistry consists of the following laboratories: a radiotracer laboratory, a neutron/electron and a gamma irradiation laboratory, an environmental low activity level laboratory, a whole-body counting laboratory, a reactor chemistry laboratory and a waste-treatment facility. The radiation protection organization of the Department is presented. Various methods of monitoring, including advantages and disadvantages are discussed. Emphasis is placed on the reactor chemistry laboratory where transuranic elements are utilized. These elements are highly radiotoxic and their monitoring in most cases requires destructive analysis. Different methods of determining external and internal doses are evaluated with regard to sensitivity and accuracy. Detection limits for radionuclides utilized in the laboratory are presented for different measurement systems, including non-destructive monitoring, spectrometry after chemical analysis, liquid scintillation counting and low-energy gamma spectrometry using a CsI-NaI scintillation detector. The guidelines laid down in the IAEA Safety Series Manuals are discussed in the light of practical experience. (author)