THE CASE OF A LOSS OF VHLW CARGO AT SEA: TOWARDS A RISK ANALYSIS PERSPECTIVE

Recently, the sea transport of vitrified high level radioactive waste (VHL W) between Europe and Japan has been a subject of public concern. Some anxiety and strong request for more information has been expressed by several en-route states, especially with respect to hypothetical accidents along the coasts, that might result in significant consequences. Namely, the safety of such shipments was questioned by state representatives, journalists and academists. Although several factors have to be considered at the root of the public concern, the two of them addressed here are closely connected with the available scientific knowledge supporting the safety assessment of such industrial operations and with the way to inform the public of this knowledge. Namely, the public perception of risks may be twisted by : • catastrophic presentation of the safety case ; a \"worst case\" scenario, well beyond design basis, can always be imagined without any consideration of probability : for instance ship collisions with consequent hypothetical waste immersion and huge dispersion of radionuclides into the sea ; • apparent or overemphasized discrepancies between published results from different sources, that might suggest poor knowledge of the involved phenomena : for instance, between published evaluations of the potential impact of radionuclides associated with the dispersion into the sea. Both sources of potential public distrust call for a well balanced and extended elaboration of scenarios, displaying the intervening features, events and processes, that will clarify the real significance of extreme hypothetical scenarios (i) and of residual scientific uncertainties (ii). In this perspective, it seems helpful to apply extended risk analysis approach and particularly to put into perspective the influence of the various assumptions adopted in the analysis of scenarios.