[en] Full scale testing to date has verified that current analytical tools and the use of scale model testing are both accurate methods for predicting shipping cask response to severe accident conditions. The containers tested are capable of surviving severe transportation accidents

[en] In 1977 and 1978, five first-of-a-kind full scale tests of spent-nuclear-fuel shipping systems were conducted at Sandia Laboratories. The objectives of this broad test program were (1) to assess and demonstrate the validity of current analytical and scale modeling techniques for predicting damage in accident conditions by comparing predicted results with actual test results, and (2) to gain quantitative knowledge of extreme accident environments by assessing the response of full scale hardware under actual test conditions. The tests were not intended to validate the present regulatory standards. The spent fuel cask tests fell into the following configurations: crashes of a truck-transport system into a massive concrete barrier (100 and 130 km/h); a grade crossing impact test (130 km/h) involving a locomotive and a stalled tractor-trailer; and a railcar shipping system impact into a massive concrete barrier (130 km/h) followed by fire. In addition to collecting much data on the response of cask transport systems, the program has demonstrated thus far that current analytical and scale modeling techniques are valid approaches for predicting vehicular and cask damage in accident environments. The tests have also shown that the spent casks tested are extremely rugged devices capable of retaining their radioactive contents in very severe accidents

[en] This report described structural analyses of a high-speed impact between a locomotive and a tractor-trailer system carrying a nuclear-spent-fuel shipping cask. The analyses included both mathematical and physical scale-modeling of the system. The report then describes the full-scale test conducted as part of the program. The system response is described in detail, and a comparison is made between the analyses and the actual hardware response as observed in the full-scale test. 34 figures

[en] In an attempt to understand the dynamics of extra severe transportation accidents and to evaluate state-of-the-art computational techniques for predicting the dynamic response of shipping casks involved in vehicular system crashes, the Environmental Control Technology Division of ERDA undertook a program with Sandia to investigate these areas. This program, which began in 1975, encompasses the following distinct major efforts. The first of these utilizes computational methods for predicting the effects of the accident environment and, subsequently, to calculate the damage incurred by a container as the result of such an accident. The second phase involves the testing of ¹/₈-scale models of transportation systems. Through the use of instrumentation and high-speed motion photography, the accident environments and physical damage mechanisms are studied in detail. After correlating the results of these first two phases, a full scale event involving representative hardware is conducted. To date two of the three selected test scenarios have been completed. Results of the program to this point indicate that both computational techniques and scale modeling are viable engineering approaches to studying accident environments and physical damage to shipping casks

[en] Static and dynamic analyses of an impact limiter for a spent fuel cask have been performed using the finite element analysis code PRONTO2D (Taylor and Flanagan, 1987). The impact limiter contained wood as the energy absorbing material, with the wood confined by a cylindrical metal outer skin and sixteen metal stiffeners (gussets). The object of these analyses was to determine how the wood interacts with the metal stiffeners and to determine if the impact limiter would behave differently under static versus dynamic loading conditions. Originally, the metal gusset strength was assumed to be limited by the elastic buckling load. Further analysis showed that the gusset strength was not limited to the elastic buckling load and that each gusset contributed significantly to the impact limiter's strength. The current analyses investigated the strength of a flat plate or gusset used in impact limiter systems. 3 refs., 6 figs

[en] Results are presented of two full-scale tests simulating the impact of turbine disk fragments on simple ring and shell structures that represent the internal stator blade ring and the outer housing of an 1800-rpm steam turbine casing. The objective was to provide benchmark data on both the energy-absorbing mechanisms of the impact process and, if breakthrough occured, the exit conditions of the turbine missile. A rocket sled was used to accelerate a 1527-kg (3366-lb) segment of a turbine disk, which impacted a steel ring 12.7 cm (5 in.) thick and a steel shell 3.2 cm (1.25 in.) thick. The impact velocity of about 150 m/s (492 ft/s) gave a missile kinetic energy corresponding to the energy of a fragment from a postulated failure at the design overspeed (120% of operating speed). Depending on the orientation of the missile at impact, the steel test structure either slowed the missile to 60% of its initial translational velocity or brought it almost to rest (an energy reduction of 65 and 100%, respectively). The report includes structural and finite element analysis and data interpretation, estimates of energy during impact, missile displacement and velocity histories, and selected strain gage data

[en] Postmortem examination of a large rail-transported spent fuel shipping cask which had been exposed to a JP-4 fuel fire revealed the presence of two macrofissures in the outer cask shell. One, a part-through crack located within the seam weld fusion zone of the outer cask shell, is typical of hot cracks found in stainless steel weldments. The other, a through-crack, was apparently initiated during the formation of a copper-stainless steel dissimilar metal joint, with crack propagation through the cask outer shell having occurred during the fire-test. 8 figures

[en] Nuclear power plant designers are required to provide safety-related components with adequate protection against hypothetical turbine-missile impacts. In plants with a ''peninsula'' arrangement, protection is provided by installing the turbine axis radially from the reactor building, so that potential missile trajectories are not in line with the plant. In plants with a ''non-peninsula'' arrangement (turbine axis perpendicular to a radius), designers rely on the low probability of a missile strike and on the protection provided by reinforced concrete walls in order to demonstrate an adequate level of protection USNRC Regulatory Guide 1.115). One of the critical first steps in demonstrating adequacy is the determination of the energy and spin of the turbine segments as they exit the turbine casing. The spin increases the probability that a subsequent impact with a protective barrier will be off-normal and therefore less severe than the normal impact assumed in plant designs. Two full-scale turbine-missile casing exit tests which were conducted by Sandia Laboratories at their rocket-sled facility in Albuquerque, New Mexico, are described. Because of wide variations in turbine design details, postulated failure conditions, and missile exit scenarios, the conditions for the two tests were carefully selected to be as prototypical as possible, while still maintaining the well-controlled and well-characterized test conditions needed for generating benchmark data

[en] In an attempt to understand the dynamics of extra severe transportation accidents and to evaluate state-of-the-art computational techniques for predicting the dynamic response of shipping casks involved in vehicular system crashes, the Environmental Control Technology Division of ERDA undertook a program with Sandia to investigate these areas. The program encompasses the following distinct major efforts. The first of these utilizes computational methods for predicting the effects of the accident environment and, subsequently, to calculate the damage incurred by a container as the result of such an accident. The second phase involves the testing of ¹/₈-scale models of transportation systems. Through the use of instrumentation and high-speed motion photography the accident environments and physical damage mechanisms are studied in detail. After correlating the results of these first two phases, a full scale event involving representative hardware is conducted. To date two of the three selected test scenarios have been completed. Results of the program to this point indicate that both computational techniques and scale modeling are viable engineering approaches to studying accident environments and physical damage to shipping casks

[en] This paper reviews numerical analysis and scale modeling techniques used to analyze the response of spent-nuclear-fuel shipping containers in severe impact environments. Illustrations of how these techniques have been utilized to analyze two extremely severe hypothetical accident environments are presented. The accident environments include the headon impact of a tractor trailer system and cask into a rigid barrier at 129 km/h (80 mph) and the broadside impact of a cask by a locomotive traveling at 129 km/h (80 mph). The results of the analysis techniques are discussed and compared to results of full-scale tests of the accident scenarios conducted subsequent to the analyses. It is shown that the analyses successfully predicted the response of the full-scale hardware