Post-test of the sgtr experimental tests carried out in the LIFUS facility

The steam generator tube rupture (SGTR) accident is considered by the International Regulatory Bodies a design basis event in HLM technology because of its safety concerns in terms of impulsive dynamic load caused by the thermal interaction between the lead/lead-bismuth-water. Aim of this study is to investigate, through numerical analyses, the dynamic response induced in LIFUS5/Mod2 facility during a SGTR. In particular it is intended to furnish a post-test evaluation of the structural effects caused by the interaction between water and lead-bismuth (during a SGTR accident event) with reference to the experimental tests carried out at the ENEA Brasimone Research Centre. The interacting fluids are Lead Bismuth Eutectic (LBE) at 0.1 MPa and 400°C and water at 4 MPa and 200°C. After a briefly description of Test A1.3 and A1.4, executed at the ENEA Brasimone Research Centre in the LIFUS 5/Mod 2 facility, the result of the numerical FEM analyses are presented and discussed. The propagation of the pressure wave was simulated by 3-dimensional Finite Element Method (FEM) models implemented in suitable FEM structural codes. The obtained results, validated by a comparison with the experimental data results, indicate that no significant dangerous effects on the LIFUS test vessel occur - as stress levels are below the allowable limit value - with the assumed geometry and in the testing conditions. The present work may also provide an useful contribution to the development of lead reactor technology by means of the test programme to be carried out in the LIFUS experimental facility (work performed in the framework of the 7th FP THINS).