INVESTIGATION AND DESIGN OF ENERGY-ABSORBING STRUCTURE IN NUCLEAR FUEL CASK

High Temperature Gas Cooled Reactor is considered as one of the most advanced reactors in the GEN-IV reactor system with inherent safety and high generating efficiency. Now, the project of High Temperature Reactor Pebble bed Module (HTR-PM) designed by Tsinghua university is going to finish construction. The first products of nuclear fuel elements have been transported to the Shidao Bay NPP that is ready to provide fuel power for a subsequent grid-connected generation. HTR-PM employs spherical fuel elements instead of common fuel assemblies. They have significant differences in geometry, structure, and mechanical property. The existing transfer cask for fuel assemblies doesn't seem appropriate anymore. Therefore, it is necessary to find a new cask to meet this demand for nuclear fuel. One of the most important things is the application of lightweight technology which can promote transport efficiency and enhance the economy. Besides, referring to the safety code required by IAEA, the procedure of radioactive material transportation is strictly controlled, hence we should pay attention to both lightweight and safety. Research has focused on the new energy-absorbing structure and performance. In this paper, we concentrate on cushioning effect of the thin-walled metal box with foam, rather than the normal structure of metal tube filled with foam. This structure will be assembled in one special type of nuclear fuel container to provide energy-absorbing and cushioning effect. The shape of foam specimen is cuboid, and the metal material is attached to it. First of all, we investigate the drop ball test. This study takes two sets of control group. One is a thin-walled box without foam, the other only has foam. Compared with the control group, the cushioning effect of energy-absorbing box is investigated. Secondly, the energy-absorbing structure is tied with the steel block and drop them from 9m height. Then sensitive analysis has been conducted to study the effect of design parameters and multi-work condition, to reveal some empirical regularities. This paper intends to provide important design experiences and references for energy-absorbing structure of nuclear fuel cask.