'Complementary safety indicators (endpoint) for the best analysis of the radiological impacts during the safety assessment to radioactive waste disposal facilities'

摘要

The paper shows the implementation of the concentrations and fluxes of naturally occurring radioactivematerials (NORM) as new safety indicators on risk assessment (safety assessment) to radioactive wasteenvironmental management. These obtained endpoint, allow the best analysis of the radiological impactassociated to radioactive waste isolation system. The common safety indicators for safety assessment purpose,dose and risk, are very time dependent, increasing the uncertainties in the results for long term assessment. Thecomplementary and new proposed endpoints are more stable and they are not affected by changes in the criticalgroup, pathways, etc. Therefore, it could be the basis to enhance the safety assessment results. The NORMvalues on facility site were obtained as result of national surveys, the natural concentrations of U, Ra, Th, K hasbeen associated with the variation of the lithologies in 3 geographical areas of the Country (Occidental, Centraland Oriental). The results obtained are related with the safety assessment topics and allowed to apply the newcomplementary safety indicators, by comparisons between the natural concentrations and fluxes on site and itscalculated values for the conceptual repository design. In order to normalize the concentration results, theanalysis was realized adopting the criteria of the Repository Equivalent Rock Volume (RERV). The preliminarycomparison showed that the calculated concentrations and fluxes in the Cuban conceptual radioactive wasterepository are not higher than the natural values in the host rock. According to the application of new safetyindicators, the reference disposal facility does not increase the natural activity concentration and fluxes in theenvironment. In order to implement these new safety indicator it has been used the current ~(226)Ra inventory of theRepository and the ~(226)Ra as natural concentration on the site. In Cuba, it is the first application of other safetyindicators for safety assessment of radioactive waste disposal facilities, evidencing that those endpoints are veryuseful tool to support all study about the risk and safety analysis of the radioactive waste disposal System.