Quality assurance via internal tests in a newly setup laboratory for environmental radioactivity

The development of an environmental program on NORM radionuclides in former mining areas in Sweden implied the assessment of alpha emitter elements (U, Th and Po) measured for the first time in a Laboratory in different matrices. The first stage of this program is devoted to the Quality Assurance. The present work shows one way to apply inner Control Tests to produce reliable results based on (a) the combination of different techniques (alpha vs. Gamma spectrometry, alpha spectrometry vs. ICP-MS or gamma spectrometry vs. XRF) and (b) on the performance of intercomparison exercises with another laboratory with a wider experience in the field. After a positive feedback in these previous steps, the laboratory took part in an external validation exercise: IAEA Proficiency test in 2015 with a good degree of performance. In conclusion, a laboratory starting with radiometrical techniques based on alpha spectrometry can develop its own inner quality control program with the main aim to enhance the Quality Assurance of the delivered results without using reference material and based on regular samples results. This goal is achieved mainly via internal validation exercises and the final competence is gained through regular participation in external validation exercises (IAEA, Almera network or European Commission's Joint Research among others).