Beyond spreadsheets:next-generation evacuation modelling at Koeberg nuclear power station

Abstract

The Koeberg Nuclear Power Station (KNPS) Traffic Evacuation Model (TEM) plays a crucial role in ensuring the safety and efficiency of emergency responses, as well as evaluating the effectivity of the transport network to accommodate further development, in the effective evacuation area of the KNPS located near Cape Town, South Africa. The purpose of the overall study was to evaluate the City of Cape Town’s documented emergency procedures for testing and estimating evacuation times, of which the TEM is a key component. The existing spreadsheet-based methodology which employs a simplified road capacity evaluation has indicated that the time for full evacuation of the evacuation area is approaching the 16-hour limit stipulated by the National Nuclear Regulator (NNR). With the simplified methodology and input estimates, it has become necessary to bring the evaluation methodologies in line with the state of the art and to update input information while developing a streamlined approach to updating input data. Additionally, the evaluation of expected evacuation time required extension to multiple scenarios representing different incident, population, infrastructure and traffic management scenarios. In its latest redevelopment, modern transport modelling software was used to transform the TEM from a basic spreadsheet-based tool to a cutting-edge, integrated traffic and land use model. This advanced model employs a simulation-based assignment algorithm, enabling enhanced traffic flow analysis and evacuation route optimization. The integration

of a user-friendly graphical user interface (GUI) is a notable advancement, allowing real- time user interaction with the model for proposing changes and simulating evacuation

scenarios. This innovative tool is pivotal for evacuation planning and regulatory compliance. The intention moving forward is that the utility of the streamlined methodology is extended to urban planning and development assessment in the study area. The approach adopted exemplifies the successful application of technology in addressing complex transportation and land use challenges, setting new standards in evacuation modelling and urban planning. This paper outlines the methodology employed in creating the state-of-the-art model, including the lessons learnt in acquisition, processing and ongoing maintenance of the required input data. It demonstrates the model output and evacuation scenario evaluation and details the way forward in incorporating the model into existing statutory processes.