Plan of a Shaking Table Test on a Piping System Model for Verifying the Fracture-Control Concept

Abstract

To mitigate the severe effects in the beyond design basis accident (BDBA), the concept of fracture control was proposed in the previous study. The idea of the fracture control is to manage the accident consequence by controlling to cause minor failure prior to the fatal failure. Taking the piping system as an example, boundary failure should be prevented under the BDBA condition, whereas the minor failure, such as support failure which does not affect the function of the piping system, can be acceptable. To realize the fracture control concept on piping system, shaking table tests on piping systems with support are planned. As the first step of the attempt, fundamental experiment on relatively simple piping system and support configuration was conducted. In this experiment, pipe elbows made of simulation material (lead-antimony alloy) were used, and the support was modeled by a plate. Through the experiments, the fracture of support successfully occurred prior to the large deformation of pipe itself. The results showed that the fracture control may be possible when the fracture of support occurred prior to the failure of pipe itself, and the ratio of the input frequency to the specimen’s natural frequency (fR) be over 1.0 after the support failure. The test results demonstrated the possibility of fracture control concept by support failure. As the next step of the attempt, shaking table test on more realistic piping system, which is named as validation test, is now prepared. The preliminary analysis shows that the inelastic behavior of support is expected.