Assessment of the consequences of the radioactive contamination of aquaticmedia and biota for the Chernobyl NPP cooling pond: model testing using Chernobyl data

The 'Cooling Pond' scenario was designed to test models for radioactive con tamination of aquatic ecosystems, based on data from the Chernobyl Nuclear Power Plant cooling pond, which was heavily contaminated in 1986 as a resul t of the reactor accident. The calculation tasks include (a) reconstruction of the dynamics of radionuclide transfer and bioaccumulation in aquatic me dia and biota following the accident; (b) assessment of doses to aquatic bi ota; and (c) assessment of potential doses and radiation risks to humans fr om consumption of contaminated fish. Calculations for the Scenario were per formed by 19 participants using 6 different models: LAKECO-B (Netherlands); LAKEPOND (Romania); POSOD (USA); WATER, GIDRO and ECOMOD-W (Russia). For a ll endpoints, model predictions were compared with the test data, which wer e derived from the results of direct measurements and independent dose esti mates based on measurements. Most of the models gave satisfactory agreement for some portions of the test data, although very few participants obtaine d good agreement with all criteria for model testing. The greatest level of difficulty was with the prediction of nonequilibrium radioecological proce sses in the first year after the accident (1986). The calculations for this scenario gave modellers a unique opportunity to test their models using an independent data base and to analyse the advantages and weaknesses of diff erent model approaches. The use of post-Chernobyl data in such a scenario i s also recommended for use in training students in the held of radioecology and environmental protection. (C) 1998 Elsevier Science Ltd. All rights re served.