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Simulation Results by SPEEDI*
(System for Prediction of Environmental Emergency Dose Information) of MEXT
SPEEDI is a system for predicting the airborne concentration of radioactive materials and the dose rates in case of large release, either ongoing or imminent, from a nuclear facility. SPEEDI predicts such quantities by simulating the atmospheric dispersion of radioactive materials based on the release information (time-dependent release rate for each nuclide) from the facility, the meteorological forecasts and the topographic information for the areas around the plant. In the accident at the Fukushima Dai-ichi nuclear power station, however, the release information has been unavailable from the plant instruments or from plant simulations based on measurements. Consequently, SPEEDI has been unable to demonstrate its intended function of quantitative prediction.
The results shown below have been obtained under such constrictions.
--> (1)Simulation based on an emission per unit volume by SPEEDI (hourly predictions performed to date)
--> (2)Simulation results of accumulative dose by SPEEDI
--> (3)Simulation results by SPEEDI based on various assumptions
* SPEEDI is operated by operators belongs to NUSTEC (Nuclear Safety Technology Center)
who have been dispatched to NSC office by MEXT.
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