Summary and conclusions from the International Seminar on In-Vessel Retention Strategy

On the 6-7 June 2016, IRSN hosted an international workshop about the « Strategy of In-Vessel Melt Retention: Knowledge and Perspectives ». The workshop was co-organized by JRC and IRSN, with the sponsorship of ETSON. With panel discussions and technical sessions, the workshop covered all the important issues related to in-vessel corium retention, from the physical understanding to regulatory frames. The major points of the safety demonstration were discussed. Some industrial aspects were also addressed. One of the objectives was to provide an orientation of R&D projects to strengthen IVR strategies, such as the H2020 IVMR project, coordinated by IRSN. The current approach followed by most experts for IVR is a compromise between a deterministic approach using the significant knowledge gained during the last two decades and a probabilistic approach to take into account large uncertainties due to lack of data for some phenomena and due to excessive simplifications of models. It was concluded that a harmonization of the positions of safety authorities on the IVR strategy is necessary to allow decision making based on scientific knowledge. For this, a consensus on several issues should be reached between R&D experts. This includes in particular the issues of the transient evolution of oxide and metal layers in the lower plenum and of the long term mechanical behavior of the thin “cold shell” resulting from vessel ablation.

FICHOT F.;  RAIMOND E;  HERMSMEYER Stephan;  CHAUMONT Bernard; 

2017-12-20

IAEA

JRC104855