The IAEA is launching a four-year Coordinated Research Project (CRP) on In-Vessel Melt Retention (IVMR), a severe accident mitigation strategy for nuclear power plants. IVMR consists of cooling the melted reactor core material (i.e. corium) from outside the reactor vessel in order to avoid reactor vessel failure and retain the corium inside the reactor vessel.
In IAEA meetings that took place since the 2011 accident at the Fukushima Daiichi Nuclear Power Plant, IVMR was confirmed to be one of the highest research and development priority areas for the mitigation of severe accidents at nuclear power plants. This CRP will commence later in 2020.
Although there already are considerable methodological developments, as well as experimental and numerical simulation works, meetings on IVMR organized by the IAEA and other organizations have concluded that further work would be beneficial on various aspects including: the quality of numerical simulations, experimental data needed for validating individual models; and, the identification of most pertinent acceptance criteria to be considered in the safety demonstration of IVMR.
All of these aspects support the safety demonstration of IVMR, which aims at proving that this strategy effectively retains the corium inside the reactor vessel, hence ensuring the containment integrity and confinement of radioactive materials.
The IAEA held an international experts meeting, which was followed up by specific technical meetings, which provided an opportunity to exchange perspectives and strengthen research and development strategies on severe accidents at nuclear power plants. This CRP will provide a platform to continue facilitating interactions among experts from Member States and international organizations to advance the knowledge on and build more robust technical bases for the IVMR strategy.
