Experimental tests and thermo-mechanical analyses on the HEXCALIBER mock-up

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

“…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.…”

“…These models deduce a set of constitutive equations to be implemented in the framework of a finite element code. There are two major variants of phenomenological modeling approaches developed among institutions, including: (1) a non-linear elastic model and a modified Drucker-Prager-Cap theory for plastic strain [10,11]; and (2) a hyperporous non-linear elastic model and a Gurson model for plastic model [12][13][14]. The readers are referred to the additional efforts used in a third method [11] which employed two different elasticity laws for the loading and unloading branches but will not be discussed here.…”