Topical report on tests on vitrified (V)HLW waste in Supercontainer disposal conditions (status 2014): Topical report for research plan RP.W&D.0061 (O/N references), research programme 2012-2014 Version 1.0

mainly devoted to the study of the effect of a cement buffer on glass dissolution as foreseen in the Supercontainer Design and was performed by SCK•CEN for NIRAS/ONDRAF as client, in the period 2009-2014. The context, requirements, and objectives of the programme, and the technical content are given in the mentioned research plan. The experiments performed in the period 2009-2011 were described in the SCK•CEN -ER-195 external report [1]. In this report, we briefly describe the experiments for the period 2012-2014. The experiments planned for 2012-2014 were described in the technical annex (2011-12-08) of the research plan. They included glass leach tests with isolated C-S-H phases but also tests at a high ratio of glass surface area to solution volume (SA/V) to determine the Si saturation level of SON68 and SM513 glasses in synthetic cementitious waters (YCWCa, ECW), and to support the geochemical modeling. During the technical meetings with NIRAS/ONDRAF, it was decided to postpone the tests with the C-S-H phases to a next programme, and to include extra tests with an International Simplified Glass (ISG) composition. As these tests are continued in the new research programme for NIRAS/ONDRAF in the period 2015-2020 according to the SCK-15-HLW-03 specification sheet, this report presents the results obtained until 433 days but without any discussion. More interpretation will be given in a topical report including all the raw data, for which the deadline is fixed at 31 December 2016.