ESTABLISHMENT OF NEW CONSEQUENCE ASSESSMENT SYSTEM FOR EMERGENCY RESPONSE OF COMPETENT AUTHORITY TO MARITIME TRANSPORT ACCIDENTS INVOLVING RADIOACTIVE MATERIAL

National Maritime Research Institute has developed and maintained a supporting system for emergency response of competent authority to maritime transport accidents involving radioactive material since 2005. The supporting system for emergency response has functions of air diffusion simulation, marine diffusion simulation and radiological impact evaluation to grasp potential hazard of radioactive material caused by the falling to the ocean of the package or by the collision with other vessels. In response to this situation, the urgent need for the configuration of the new supporting system was recognized. The new supporting system contains functions as follows; the diffusion calculation of radioactive material can be performed not only in the open ocean but in local area around port and harbor for the sake of the employee and public to expose radiation which is as low as reasonably achievable. In order to prevent employee, who contributes to accident mitigation, from radiation exposure, it is necessary for the supporting system to calculate the current of air and in the ocean by practical forecast data including meteorological characteristics and sea states. In the supporting system, the diffusion calculation for radioactive material is performed by Lagrange model with consideration for current of air and in the ocean. The use of this model enables calculation in a short time which responds to emergency action. Additionally, the graphical user interface of the supporting system is enhanced to make it possible to evaluate rapidly the result which is obtained by the supporting system. This paper shows the principal improving point and the concrete method of utilization of the supporting system.