Pilot implementation of the Rodos system in Ukraine

Full text: In the frame of the EC Tacis project TA REG 02/3 'Implementation in Ukraine of the RODOS system for off-site emergency preparedness and response' the RODOS system was installed, adapted for the local conditions of the Zaporizhje NPP and tested for preoperational use in 2002. RODOS was connected with two radiation monitoring systems of Zaporizhje NPP an the basis of the developed software interfaces. The GAMMA-1 system includes a number of gamma dose-rate monitors and a meteorological station near the Zaporizhje NPP. The Remote Monitoring System (RMS) provides real-time measurements of plant parameters of the Zaporizhje NPP, as well as site meteorological and radiological data. Currently RODOS system uses GAMMA-1 and RMS meteorological information for diagnose of the atmospheric dispersion of radionuclides and radiological data for visualization. To calculate prognoses of the atmospheric dispersion the Atmospheric Dispersion Module of the RODOS system needs results of a Numerical Weather Prediction (NWP) model. Before start of the RODOS project NWP models were not used by the National Weather Service. IMMSP in co-operation with the UkrHydrometcenter took over the task to customize the NWP model MM5 of the Penn State University/UCAR (USA) for the Ukrainian region. The developed software MM5-IIVIh4SP provides meteorological forecasting for the Ukrainian territory in resolution 30*30 km an the basis of the rare gridded forecasting data from the German Weather Service (DWD) center Offenbach and the operational data from Ukrainian meteostations processed by UkrHydrometcenter. For the vicinity of NPP the NWP model an the nestled embedded grid 22x22 nodes of the resolution 9*9 km was implemented. RODOS customization to the Zaporizhje NPP site-specific conditions was made as follows. A digital multi-layered map of Ukraine of 1:200 000 scale was used as a basis for the RODOS geo-information system. The map was used to derive gridded data on population, surface elevation, land use and other geo-spatial data. Three scenarios of accidental releases from VVER-1000 type reactor are available in the RODOS database; two of them are being supplied as a part of the standard RODOS software package. The third scenario was developed under the project on basis of the Technical Safety Assessement Validation Report for Zaporizhje NPP. The Hydrological Dispersion Module of RODOS was customized to simulate radionuclide transport in the Kakhovka Reservoir following the radioactive fallout to its surface. Both the terrestrial and aquatic food chain and dose modules, as well as the countermeasure modules were adapted and customized to the Zaporizhje NPP site specific data. The assessment of the radionuclide fluxes into the Black Sea in a case of the accidental fallout on the surface of the Kakhovka reservoir has been provided using the atmospheric and hydrological chain. Since the RODOS system was implemented in Ukraine it was used in DSSNET RODOS training (April 2002) and in the National training an off-site emergency management of Zaporizhje NPP (August, 2002). These trainings showed a strong need for simultaneous use of meteorological information from the site and NWP data in the forecasting of atmospheric dispersion of the radionuclides. The software interface between MM5 and the Atmospheric Dispersion Module, developed during RODOS implementation in Ukraine, can be used in other countries which would use MM5 as Numerical Weather Prediction tool. figs. 2 (author)