@article{oai:repo.qst.go.jp:00077550,
 author = {Kim, Jaehwan and Nakamichi, Masaru and Kim, Jaehwan and Masaru, Nakamichi},
 journal = {Journal of Materials Science},
 month = {Nov},
 note = {Beryllium and beryllium intermetallic compound (beryllide) pebbles have been
regarded as a neutron multiplier in an international thermonuclear experimental
reactor (ITER), as well as a demonstration (DEMO) fusion reactor.A novel fabrication
process of the beryllide pebbles has been successfully established by
combining the plasma sintering and rotating electrode processes. However,
owing to the brittleness of beryllides, their granulation yield is approximately
70%, which does not generally satisfy the requirement, whereas the fragments
(designated to be not spherical) with 30% are generated as by-products. To
improve the granulation yield and in considering a new recycling process, a novel
step on fundamental experiments was adopted to confirm feasibility on the
recycling process using the same plasma sintering and rotating electrode processes.
Because the formation of oxidized surface and neutron-induced defects in
these materials is anticipated, these defects should be eliminated during the
recycling process. The plasma sintering process is known to remove impurities on
powder surfaces by applying a pulse current, whereas the rotating electrode
process (REP) is a granulation process that uses arc melting at a temperature
higher than the melting point. Hence, a feasibility test on the recycling process
was performed by applying this process with the fragments for the pebbles
simulated as the used pebbles. In the case of mixture ratios of 1:1 and 2:1 for the
mixed powders and fragments, respectively, and the powders pulverized by
100% fragments, the rods produced through plasma sintering were successfully
fabricated even if several areas with low density are identified. Not all rods were
broken during the REP, indicating granulation results with similar size distribution
and yield. Regarding the oxygen contents of as-received pebbles, fragments,
and rod and pebbles produced with 100% fragments, the plasma sintering
effect on impurity cleaning is therefore not significant, whereas the REP evidently
leads to remarkable reduction of oxygen as impurity.},
 pages = {2454--2461},
 title = {Optimization on producibility improvement and the recycling process of neutron multipliers for fusion applications},
 volume = {55},
 year = {2019}
}