Project Presentation: WP2
SYSTEMS MODELLING (EA, ENEA, SCK•CEN, ANSALDO, NUMERIA, SRS)WP2 activities are subdivided in the following 3 tasks:
Task 2.1: System description: LFR and ADS
The general data on the considered systems design are collected and made available for realizing detailed numerical models: general layout of the plant, mass distribution, geometrical and mechanical description of the most critical components will be made available for modelling the reactor systems for the numerical simulations. Detailed information on the design of specific, representative components (i.e., vessel, steam generators, pipelines) are collected for a detailed investigation of the effects of earthquakes on the behaviour of components that could particularly suffer dynamic loads. The components requiring a specific design due to seismic isolation are considered for a detailed design in task 5.1.
Task 2.2: Reactor systems modelling
Computationally efficient but reasonably accurate models of the heavy liquid metal cooled reactor designs considered in the project are realized.
A refined numerical model of the LFR reactor system, moving from the previous experience and the data available in ELSY and LEADER Projects, is realized and its dynamic response is evaluated . Specific attention is paid to beyond-design seismic motions. The reactor systems models are integrated with the isolator models realized in task 2.3. A Response spectra are generated for critical component locations within the reactor building to provide inputs to WP3 for the study of sloshing effects and for fragility evaluations. A numerical model of the MYRRHA reactor is realized , with particular attention to the proton beam and the target. Response spectra will be generated for critical locations within the reactor building to provide inputs to WP3 to analyze the behaviour of the reactor/accelerator coupling for two different isolation solutions (isolated vessel or isolation of part of the reactor building).
Task 2.3: Design and modelling of the seismic isolators
Simplified models of the isolators are developed for addressing the analyses of the whole isolated model. These models should be simplified enough to permit the performance of a large number of simulations, as required for fragility analysis purposes, but should correctly reflect the mechanical behaviour under combined 3D horizontal and vertical loadings. Detailed models will be realized to support the experimental activity, to optimize the isolator layout and evaluate internal stress/strain distributions.
In particular, for LRBs suitable mathematical models are set up to:
1) investigate the interaction among lead core, steel reinforcing sheets and elastomeric layers;
2) calculate the main mechanical characteristics (initial stiffness, post-elastic stiffness and yield deformation) to substantiate or disprove the discordant relevant formulae given in the European Standards EN 1337: Structural Bearings and EN15129: Anti-seismic Devices.