Application of data assimilation techniques to post accident management, assessment and presentation of uncertain environmental and radionuclide data

National Radiological Protection Board, Environmental Assessments Department, Chilton, Didcot OX11 0RQ, U.K.

Abstract

A major collaboration between IPSN and NRPB has recently commenced with the intention of developing and implementing practical data assimilation techniques. This joint work builds on the CITRAME and SECTAR projects of IPSN and NRPB respectively. The tools developed through the collaboration will assist decision-makers after an accident to protect the public more effectively. They will clarify the state of knowledge available through the display of map based estimates of the likely environmental concentrations of radioactivity and the uncertainties in those concentrations. Considerable attention will be paid to the development of risk maps that show clearly the current uncertainties in the estimated concentrations in a range of foods and the predicted uncertainties at different times arising from the migration of radioactivity through the food chain. The estimates of radioactivity concentration and its temporal development in different foods, together with the associated uncertainties, will change as more measurement information becomes available. The maps will therefore help decision-makers to allocate resources more effectively by concentrating measurement effort in areas of high uncertainty. A discussion of the role these techniques might play in the management and selection of intervention strategies is given together with an initial progress report on their development.