Tritium analysis in building dismantling process using digital autoradiography

The aim of our study was to develop a sensitive analytical technique to investigate tritium traces on concrete floor, ceiling and walls of a laboratory under dismantling process. In dismantling process, the behaviour of tritium must be followed very closely and in particular releases to atmosphere and exposure to public must be prevented. The investigations were carried out using liquid scintillation counting (LSC) and digital autoradiography techniques. The LSC investigations were carried out using wipe tests. It was concluded that even though LSC technique provided accurate information on the level of contamination, the loss of exact localisation of contamination spots was considered to be a major disadvantage in this application. The digital autoradiography was shown to provide both quantitative information and localisation of contamination spots. The exposure time on the digital autoradiography films were optimized, the matrix effect and the selectivity of the films were studied using polymethylmethacrylate standards. The studies showed that the digital autoradiography technique can give quantitative results, especially if standards of the investigated material (concrete) are used.