SKB is preparing a license application for the construction of a final repository for spent nuclear fuel in Sweden. This application will be supported by the safety assessment SR-Site for the post-closure phase. As a preparation for SR-Site SKB has recently produced the SRCan safety assessment, which is currently in review. The assessment of long-term safety is based on a broad range of experimental results from laboratory scale, intermediate scale and up to full scale experiments. It is essential that there is a satisfactory level of assurance that experiments have been carried of with sufficient quality, so that results can be considered to be reliable within the context of their use in safety assessment. SKI has initiated a series of reviews of SKB’s methods of quality assurance and their implementation. This project in particular addresses SKB’s quality assurance of experiments related to the buffer and backfill. These include characterisation of material properties in small scale experiments (Clay Technology AB in Lund Sweden), intermediate scale experiments addressing various aspects of buffer evolution as well as experiments with full-scale canister and buffer components mainly for confirmation and demonstration (Äspö Hard Rock Laboratory).