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Intermediate level waste often contains residual water or other liquids. The liquids can be decomposed due to radiolysis and can also vaporize especially under fire impact. These pressure generating processes are described. One example for the pressure determination inside a closed cask is discussed using two different approaches: analytical and CFD
Effective assessment and management of railway infrastructure for competitiveness and sustainability
(2018)
In this chapter the challenges facing railways have been illustrated through the description of two important events occurring in different geographical areas. While the explosion in Quebec, Canada, points out the importance of taking away the transportation infrastructure from highly populated areas; the disruption of the European railway network in Rastatt, Germany, describes the importance of designing alternative routes to critical railway segments, together with the need to have contingency plans to face extraordinary situations regarding the connectivity in a given transport network.
Future research efforts are recognized in relation with the railway car – track interaction, as the dynamic loads derived from such interaction could be reducing the life of such infrastructure. It is particularly important for infrastructures dedicated to the transportation of liquid hazardous substances.
Elastomers are widely used as the main sealing materials in Containers for low- and intermediate-level radioactive waste and as an additional component fo metal seals in spent-fuel and high-level waste containers. According to appropriate guidelines and regulations, safe enclosure of the radioactive container contents has to be guaranteed for lengthy storage periods of at least 40 years. Therefore, the understanding of seal ageing behaviour is of high importance and has to be considered with regard to possible dynamic events taking place during transport after storage. An accelerated ageing approach for compressed seals is presented, as well as some first results.
The safety of any transport system depends on a multitude of conditions, parameters and circumstances. In this regard, the interaction of the carried Cargo with the carrying vehicle represents a factor influencing the overall safety of any transport. The effects of cargo on the vehicle have to do with the vibration or shifting of the cargo, affecting the lateral stability of the vehicles and the braking performance.
Such interaction has been associated to road crashes and maritime vehicles capsizing. Simulation of cargo-vehicle interaction thus represents an interesting Topic when a reduction in transport accidents is pursued. In this paper, the fundamentals principles for simulating the interaction of the liquid cargo and the carrying vehicle, is presented. In the case of a road transportation, the proposed simplified Simulation methodologies, show good agreement with a full-scale test.
The interaction between the package lid system and internal Content during mechanical drop testing is a decisive matter in evaluating Impact loads and the safety of the package. In the case of movable contents ist impact onto the inner side of the package lid can cause additional load peaks on the lid and the lid bolts. Some aspects of this issue were discussed on the basis of experimental results from instrumented drop tests with transport casks and on the basis of analytical approaches.
For the long-term storage of spent nuclear fuel and other high-Level radioactive waste, dual purpose casks for the transportation and storage are widely used. Usually, these casks consist of a thick-walled monolithic cask body and a bolted double barrier lid System equipped with metal seals (consisting of an inner helical spring and two outer metal layers with a total cross-section diameter between 5 and 10 mm) to ensure the long-term safe confinement of the radioactive inventory.
Based on analytical and experimental studies, such metallic Systems have been qualified of storage periods of up to four decades so far as long as proper manufacturing and assembling conditions are met. More than 20 years of Operation experience with a permanently increasing number of casks has shown full compliance with the expectations.
In the meantime many countries have to face a significant delay of establishing a high-level radioactive waste repository what leads to Need for extending interim storage periods for probably 60, 80 or 100 years.
For that reason the long-term performance of metal seals for such time periods is of specific internst to demonstrate their sufficient safety function and specific investigations have already been launched, e.g. by BAM, to gain more experimental data and to develop validated models to extrapolate the seal performance to longer periods of time and or requested temperature levels.
Turning maneuvers performed by railway cars, imply the development of steering forces at the wheel-track interface, whose magnitude depends on a set of properties and operating conditions related to the vehicle and to the infrastructure, including track´s turning radius and vehicle´s yaw resistance.
Yaw resistance integrates two components. On the one hand, there is the yaw stiffness, as a function of the different vehicle suspension components. On the other hand, there is the dry friction at the centre plate. Such yaw resistance of the car´s bogies, has a two-contradictory effect on railway performance, as a flexible bogie reduces the level of the steering forces, but at the same time, it increases the probability of having hunting instability. A variable yaw resistance, with high values at straight track segments and low values at curved tracks, seems to be an interesting design. In this paper, a variable friction Center plate is proposed, aiming at maximizing the yaw resistance on straight track segments, and minimizing such resistance at curved tracks. The conceptual design of this device is described, together with its ability to reduce the yaw torque. Benefits of this device, regarding the transport energy consumption and the magnitude of the steering forces, are estimated on the order of 1 to 10, when comparing the proposed design with the standard center plate design.
The magnitude of the steering forces at the wheel-track Interface depends on different properties and operational conditions linked to the vehicle and to the track, with the bogie´s yaw stiffness/resistance and the friction at the centre plate being recognized as the most influential vehicle factors. In this respect, the negative consequences of high values for yaw resistance have been recognized in terms of the railway accelerated deterioration and on the possibility for derailment. While some theoretical models have been proposed to simulate the effects of the centre plate friction on the railway damage, and experimental measurements have been reported of the turning resistance, no experimental data is available regarding the effect of the friction at the centre plate on the wheel-track forces. In this paper the conceptual design of a testing rig is presented for assessing such forces as a function of the center plate friction. The testing rig quantifies the effects of the friction forces developed at the centre plate, in terms of the loss of potential energy when a scaled-down vehicle travels downwards and tries to return upwards in a “U turn” maneuver. A simplified mathematical model is also proposed in this paper, whose Outputs suggest a significant effect of the dry friction on the magnitude of the steering forces.
Braking-in-a-turn maneuvers represent a critical operational condition for any vehicle, due to the associated longitudinal and lateral perturbations to which it is subjected, which maximize the load transfer among the different wheels, and result in vehicle´s poor lateral stability and deficient braking performance.
In this paper, a suspended vehicle supporting a partially filled 10 litter-capacity container, is set on a tilt table at oblique angles, in order to simulate a braking-in-a-turn maneuver. The measurements are assessed in the time and frequency domains, on the basis of the lateral load transfer ratio and the infrastructure fatigue damage. The outputs from the experiment show that the Minimum fill level (one-quarter), generates the larger lateral load transfer (0.45). Such fill level also causes the greatest ratios for the alternate stress over the mean stress on the infrastructure. The spectral analysis reveals the dominance of one of the sloshing frequencies during such combined perturbation condition.