The aim of the study is to investigate the structural effects induced by a beyond design basis earthquake on the main safety relevant structures and components of an isolated liquid metal reactor, such as the European Lead-cooled SYstem (ELSY) or ALFRED projects. An extensive R&D program related to heavy-metal cooled systems was recently carried out as Euratom projects of the 6th and 7th Framework Programmes, addressing many of the most important issues related to the viability of a lead-cooled fast reactor. The importance of seismic effects is mainly related to the high inertial forces of the primary coolant (liquid metal) and associated with the impact of the liquid waves on the reactor structures. The isolation devices considered for the design were represented by means of an iso-elastic approach. Moreover, the influence of isolator failure was also evaluated. The fluid-structure interaction and the sloshing phenomenon, characterized by hydrodynamic and impact forces, were numerically investigated, since an explicit analytical solution for structures of such complex geometiy is not possible. Numerical calculations (i.e., dynamic nonlinear analyses) were carried out with appropriate finite element method codes and external coupling. A validation analysis was further pei formed to check the consistency and adequacy of the method used with respect to the American Society of Civil Engineers (ASCE) 4-98 rules. The accelerations propagated in the reactor building confirmed the favorable effect of the seismic isolation, even with 2% faulted isolators. The results indicated that the stress state, in the reactor internals, is not sufficient to impair their structural integrity, although there is localized plastic deformation.
|Autori:||Lo Frano R|
|Titolo:||Preliminary Evaluation of the Fluid-Structure Effects in a LFR|
|Anno del prodotto:||2015|
|Digital Object Identifier (DOI):||10.13182/NT14-23|
|Appare nelle tipologie:||1.1 Articolo in rivista|