Progress in the benchmark exercise for analyzing the lithiate breeder pebble bed thermo-mechanical behaviour

Status of ceramic breeder pebble bed thermo-mechanics R&D and impact on breeder material mechanical strength

“…After cooling, the pebble beds were subjected to the another thermal ramp and the process was repeated. DIN reports [29] that the pebble bed temperatures exhibited cyclical behavior. FZK simulated two cycles of the HELICA test and an example of the calculated results and experimental data are shown in Figs.…”

“…The experiments investigated the thermo-mechanical behavior of pebble beds within geometry much more representative of current breeder designs. These include the medium-scale mock-up exercises of HELICA (HE-FUS3 lithium cassette) and HEXCALIBER (HE-FUS3 experimental cassette of lithium beryllium pebble beds) [29,14]. For those experiments, the pebble layers are heated by electric heaters, and temperature and displacement were measured.…”

“…Additional details on modeling steps can be found in Refs. [13,14,[19][20][21]29]. The two most developed models, from FZK and DIN, have had their results compared to experimental data and have thus far shown great promise.…”

A constitutive model for the thermo-mechanical behaviour of fusion-relevant pebble beds and its application to the simulation of HELICA mock-up experimental results

“…EFDA has recently launched a benchmark exercise to select which thermo-mechanical constitutive model(s), among those assessed by EU Associations and Universities (ENEA-DIN, FZK, NRG), has to be adopted for the prediction of the HCPB-TBM pebble bed thermo-mechanical performances [18].…”

“…The temperature distributions across the beds are measured by 9 thermocouples located in the beds, 12 on the heaters and 6 on the CP surfaces also by means of a proper supporting frame (Fig. 2) [18].…”