Description
Chairs: Frederic Serre and Shigenobu Kubo
In the frame of France-Japan collaboration, one of the objectives is to define and assess the calculation methodologies, and to investigate the phenomenology and the consequences of severe accident scenarios in sodium fast reactors (SFRs). A methodology whose purpose is to assess the loadings of the structures induced by a Fuel Coolant Interaction (FCI) taking place in the sodium plenum of SFR...
A large 3600 MWth European Sodium Fast Reactor (ESFR) design was proposed in 2000s. It is studied now in the EURATOM ESFR-SMART project. A new core configuration with several new safety measures, including a reduced to a near-zero value coolant void reactivity effect, mainly due to introduction of a sodium plenum above the core and core flattening, has been established recently. We investigate...
The CEA, together with the NNC, has carried out a feasibility study with regard to conducting an in-pile test program - the future SAIGA program (Severe Accident In-pile experiments for Gen-IV reactors and the Astrid prototype) - on the degradation of a SFR fuel bundle with molten fuel discharge device which are planned to be housed in the IGR reactor (Impulse Graphite Reactor operated by...
To achieve in-vessel retention for mitigating the consequences of core disruptive accidents (CDAs) of sodium-cooled fast reactors, controlled material relocation (CMR) has been proposed as an effective safety concept. CMR is not only aiming at eliminating the potential for exceeding prompt criticality events that affect the integrity of the reactor vessel, but also enhancing the potential for...
Safety studies of fast reactors are carried out on a medium sized core and found that, under Unprotected Transient Over Power Accidents (UTOPA) there is fuel melting and there is feedback due to in pin fuel motion. From the UTOPA analyses it is found that, the in pin fuel motion feedback reduces the peak reactor power and hence it reduces the hot spot clad and coolant temperatures at the end...
Fuel-coolant interactions (FCI) are important phenomena occurring in the event of core disruptive accidents in sodium-cooled fast reactors (SFR). A new phase of experimental research into FCIs has been launched through a collaboration between French and Japanese organisations. Bespoke high-speed, high-resolution X-ray imaging at the JAEA MELT facility has enabled successful visualisation, in...
An Unprotected Loss Of Flow transient (ULOF) in the 1500MWth Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) reactor is investigated with SIMMER-IV, a 3D multi-phase, multi-velocity and multi-component fluid-dynamics and neutronics code. The 2D RZ code version, SIMMER-III, is a working horse for fast reactor severe accident studies at KIT and other institutions, but...
An In-vessel core catcher located in European type SFR is a safety design feature to guarantee the integrity of the SFR during a core-melting accident. The core catcher collects and distributes the relocated melt from the core region via discharging tubes to avoid firstly a significant molten pool in the core, and secondly the local thermal attack on bottom part of the vessel. The heat...
