Testing of High Damping Rubber Bearings and Lead Rubber Bearings for Nuclear Power Plants

The paper describes a wide testing campaign carried out on full scale prototypes of elastomeric isolators – both high damping rubber bearings (HDRB) and lead rubber bearings (LRB) – within the framework of the EC-funded SILER research project. The prototypes tested were designed for two reference nuclear power plants, the ELSY reactor and the MYRRHA reactor. Due to the typical huge masses of NPP, the related isolators often have large sizes. HDRB prototype is circular, with a diameter of 1350 mm; LRB prototype is square, with a side of 1250 mm, and four lead cores. The prototypes were subjected to different tests. One prototype was subjected to a complete type test campaign according to the European Standard EN 15129:2009, as well as to 3-D tests applying contemporarily displacement time-histories in two horizontal axes and vertical load time-history. Failure and post-failure tests were also performed, showing that the isolator, even after failure, is still able to sustain the vertical load and the horizontal displacement.