Impact-Limiting Materials Characterization·

Packagings for the shipment of radioactive materials are required to survive a sequence of hypothetical accident conditions. Regulatory requirements for Type B packages are specified in the United States Code of Federal Regulations (10 CFR 71, \"Packaging and Transportation of Radioactive Materials\"). The regulatory sequence consists of a free drop onto an unyielding target followed by a puncture and then a fire. Impact limiters are often used in packages designed to survive this hypothetical accident sequence. The primary goal in the design of an impact limiter is to minimize the deceleration loads that the package and contents experience during the drop. Minimizing the decelerations enhances packaging performance by reducing loads in critical areas such as the closures, containment boundaries, and shielding. A secondary goal for impact limiter design is to reduce the thermal assault on the package due to the regulatory thermal event A final objective in impact limiter design is to minimize the weight or size of the impact limiter consistent with the other design constraints. This requires materials, such as foams and honeycombs, which have a high energy absorption per unit weight or per unit volume. Characterization of the responses of the impact-limiting materials to the impact and fire events provides the design parameters required for selection of materials for the impact limiter.