Drop Tests of the HI-STAR ATB-1T Cask for Radioactive Materials

Holtec International is developing a transport package for radioactive materials, the HI-STAR ATB-1T. It is designed to transport existing rectangular containers with radioactive materials, hence the HI-STAR ATB-1T is also rectangular. The maximum weight is about 112 metric tons, and due to dimensional restrictions, large impact limiters cannot be used. The package design therefore imposes the technical challenge to withstand the regulatory 9 m drop scenarios without the use of large impact limiters.Holtec has conducted a benchmark test program to support the qualification and licensing of the Package. The test was primarily designed to benchmark the analytical code (LS-DYNA), and not necessarily as the integral test of the entire containment boundary. The regulatory confirmation that the cask withstands the 9-m drop conditions is therefore still performed based on analyses with critical details benchmarked by the tests. Nevertheless, a quarter (1/4) scale model of the package was used in the tests. The test program was carried out at a test facility at the Sandia National Laboratory in New Mexico in September 2016. The following three critical drops where performed, all with a single cask:- 9-m flat drop onto the closure lid (expected to maximize acceleration and load on the closure system)- 9-m CG over bottom corner (expected to maximize local deformation)- 1-m puncture drop in the trunnion area (expected to maximize impact from pin)Overall, the comparisons between the tests and calculations showed very good agreements, with maximum deformations practically identical between tests and calculations.It is therefore concluded that the non-linear analytical code is highly capable of predicting the dynamic response and large deformations of the transport package when subject to highly impulsive loads such as those imparted from the package drop tests in compliance with 10CFR71 regulations. It is also demonstrated that the dynamic simulation approach, using a carefully constructed LS-DYNA model, can be used in lieu of physical testing for safety demonstration. For a video of the tests see https://holtecinternational.com/news/videos/hi-star-atb-1t-drop-test/