Fluxes and enhancement of natural radionuclides in a pulp mill factory located in the south-west of Spain

摘要

Activity concentrations of several naturally occurring radionuclides (with ~(226)Ra as a key radionuclide) have been determined by different radiometric techniques in samples representatives of the raw material (eucalyptus wood, fresh water), industrial process (liquors) and wastes (sludges, ashes) of a pulp-mill factory located in the south-west of Spain. This facility follows the so-called alkaline process for the production of cellulose pulp, and especially in several steps of its recycling line (in the so-called Ca-cycle) tends to concentrate several natural radionuclides. Annually in this factory, 725 000 m3 of wood are treated and 241 404 t of cellulose are produced. Radiometric determinations have allowed us to evaluate the fluxes of several natural radionuclides throughout the process and to determine their enrichment factors. In this sense, we can indicate that, annually, more than 200 MBq of ~(226)Ra enters the process associated with the raw material, about 160 MBq leaves the production process associated with wastes, while annual fluxes ranging from 1200–1800 MBq have been found in the Ca-cycle of the recycling line.