Comparative Structural Testing of ‘Type C’ Radioactive Materials Transportation Packages and Aircraft Flight Data Recorders

A major regulatory issue raised during the development of IAEA Regulations for the Safe Transport of Radioactive Material No. ST-1 was the impact test velocity requirement of the newly designated Type C radioactive material transportation package. Several international bodies suggested that the impact test velocity requirement of 90 m/s for the Type C package, intended for air transport of large quantities of radioactive materials, may be less stringent than the aircraft flight data recorders and cockpit voice recorders (FDR) impact test requirements. The Canadian Nuclear Safety Commission (then called Atomic Energy Control Board), sponsored a research project to investigate this issue with the objective of obtaining a better understanding of the differences between the impact test requirements of a Type C packages and an aircraft flight data recorder. A FDR rated for 3500 ‘g’ was propelled at 90 m/s, impacting onto an essentially unyielding target. A second recorder was tested for the other series of mechanical tests required for the Type C package to withstand accident conditions. This consisted of the 9 m drop test, followed by the dynamic crush test (500 kg mass drop from a height of 9 m onto the specimen) and then the puncture test (250 kg probe drop from a height of 3 m above the intended impact point of the specimen). The enhanced thermal test was not performed. A test was then carried out on internal components of a Type B radioactive material package according to the FDR impact shock test performance specification. The impact shock test specification for flight data recorders requires that an impact shock be applied so that the energy content of the impact shock shall be equivalent to a half-sine wave shock of 6.5 milliseconds and a peak acceleration of 3400 'g'. This acceleration pulse is equivalent to an impact velocity of 138 m/s. This paper presents and discusses the results of tests done on the flight data recorder using the Type C package impact testing requirements and the results of impact tests done on a Type B package according to the flight data recorder impact shock test specification. Based on the test results, FDR may not survive the Type C test requirements, however, Type C packages would likely survive the FDR crash survival testing requirements.