Coresoar Update Of The Core Degradation State-Of-The-Art Report: Status September 2016

In 1991 the CSNI published the first State-of-the-Art Report (SOAR) on In-Vessel Core Degradation, updated in 1995 under the EU 3rd Framework programme. These reports covered phenomena, experiments, material data, main modelling codes and their assessments, identification of modelling needs, and conclusions with needs for further research. This is relevant to such safety issues as in-vessel melt retention of the core, recovery of the core by water reflood, H-2 generation and fission product release.In the following 20 years, there has been much progress in understanding, with major experimental programmes finished, such as the integral Phebus FP tests, and others with many tests completed, e.g. QUENCH, on reflooding degraded rod bundles, and LIVE, on melt pool behaviour, and more generally in EU Framework projects such as COLOSS and ENTHALPY. A similar situation exists regarding integral modelling codes such as MELCOR (USA) and ASTEC (Europe) that encapsulate current knowledge in a quantitative way. After the two EU-funded projects in the SARNET network of excellence, now continuing in the NUGENIA association, it is timely to take stock of the knowledge gained.The NUGENIA/TA2 SARNET CoreSOAR project combines the experience of 11 European partners to update these SOARs over the next two years. This paper as an example indicates progress in small-scale material interaction tests by IRSN and KIT providing data covering knowledge gaps identified in the integral tests. Detailed examination of post-test samples at JRC Karlsruhe for example elucidates the mechanisms involved. Also considered are advances in thermodynamic databases needed to model the formation and relocation to the lower head of the complex corium compositions involved, relevant to lower head retention. The main report will serve as a reference for ongoing research programmes in NUGENIA, in other EU research projects such as in Horizon2020, and in CSNI, e.g. the Fukushima benchmark BSAF.