THERMAL MODELING OF CRUSHED IMPACT LIMITERS

In the certification process, packages used for the transportation of large quantities of radioactive materials must be shown to survive a hypothetical accident sequence consisting of a 9-meter free drop onto an essentially unyielding target, a 1-meter drop onto a 15-centimeter diameter puncture probe, and a 30-minute exposure to a 800°C fire environment. The sequential nature of these tests implies that the impact limiters will be damaged during the fire test. The 9-meter drop provides for large scale crushing, while the puncture test can result in more severe local damage. To accurately determine the response of the package to the fire test, it is important to understand how much thermal protection the deformed impact limiters would provide to the package if it were exposed to a post accident fire. Thermophysical properties of aluminum honeycomb and high-density foam were collected for different crush levels. The collected data was then used in finite element computer simulations to study the effect that crushed impact limiters have on the thermal performance of a container used for the transportation of hazardous material.