The MacArthur Maze Fire and Roadway Collapse: A “Worst Case Scenario” for Spent Nuclear Fuel Transportation?

Abstract

In 2007, a severe transportation accident occurred near Oakland, California, at the interchange known as the “MacArthur Maze.” The accident involved a double tanker truck of gasoline overturning and bursting into flames. The subsequent fire reduced the strength of the supporting steel structure of an overhead interstate roadway causing the collapse of portions of that overpass onto the lower roadway in less than 20 minutes. The US Nuclear Regulatory Commission has analyzed what might have happened had a spent nuclear fuel transportation package been involved in this accident, to determine if there are any potential regulatory implications of this accident to the safe transport of spent nuclear fuel in the United States. This paper provides a summary of this effort, presents preliminary results and conclusions, and discusses future work related to the NRC’s analysis of the consequences of this type of severe accident.

A streamlined framework for calculating the response of steel-supported bridges to open-air tanker truck fires

“…The first span of the eastbound overpass collapsed approximately 17 min following the start of the fire, and a second adjacent span in that overpass also collapsed about 5 min following the first collapse [14,19,40]. According to observations and subsequent forensic analysis, the presumed mode of failure was the loss of strength in the supporting steel girders [14,15,19]. The streamlined framework proposed in this paper is used to perform a forensic simulation of the MacArthur Maze fire event to demonstrate its ability to predict the observed time to failure.…”

“…(1)) and an assumed fuel consumption of 75% of the 32.6 m 3 total volume of gasoline (i.e. 25% of the fuel spills over the side of the bridge or is captured by the drainage system [15]). Note that Choi [14] assumes 10% of the fuel spills over the side of the bridge.…”

“…As shown in Table 1, CFD analysis has been implemented for several forensic studies of the aforementioned MacArthur Maze [14,15] and Birmingham, AL bridge fire events [5,16], as well as for the evaluation of a new steel bridge design [17]. These tools are robust and generate significant levels of numerical resolution; however, they are also computationally expensive and may not be practical in many applications due to budgetary and scheduling constraints.…”

“…The summary of these studies in Table 1 shows that although high-fidelity CFD modeling was used to calculate the heat transfer from the fire to the structural elements, the fire intensity was often represented very simply using either a constant maximum fire temperature [15], a constant maximum heat release rate per area [14,16], or a heat release rate time history from previously published references [5,17]. The proposed framework uses both semiempirical and analytical calculations in its approach to modeling the fire itself, thereby allowing the user to tailor the overall analysis of the bridge's response to a variety of fuel types, spill footprints, and other fire scenario parameters.…”

“…Because there is no consistent pool size agreement between existing case studies [14,15,19,20], the width of the fire was calculated based on typical lane widths of 3 m to 4.5 m and shoulder widths of 1 m to 2 m. The length of the pool size was taken as double the width, because anything larger would not affect the fire model height. Schematics of the overpass bridge were obtained from a 2008 Caltrans report [42].…”