Evaluating Type B package responses to impacts onto different targets

Abstract

The International Atomic Energy Agency (IAEA) regulations for the safe transport of radioactive materials require a 9 m free drop onto an unyielding target to demonstrate the robustness of the package design to accident loads. This drop results in an impact velocity of 13˙3 m s^–1 (30 mph), which is considerably lower than typical transport speeds for both truck and rail. This leads to the concern that the regulatory impact is not sufficiently severe to assure protection of the public and environment. Sandia National Laboratories and others have conducted both experimental and analytical research in the attempt to demonstrate the severity of the 9 m impact onto an unyielding target by comparing this impact with higher velocity impacts onto other types of targets. Targets investigated have included soil, concrete roadways, concrete runways, bridge columns, sand, water and other transportation vehicles. Impact velocities have ranged up to 110 m s^–1 (246 mph). Two important conclusions can be drawn from this body of research: the hardness of a yielding target depends on the stiffness of what is impacting it and that for most target types and most radioactive material packages the regulatory impact encompasses nearly all 'real' impacts. This paper provides an overview of past research in the area of impacts onto yielding targets. A methodology for comparing these impacts to the regulatory impact is presented and several examples are given.

Keywords:

• IMPACT TESTING
• TARGET HARDNESS