Compression properties of neutron irradiated beryllium pebbles

Compression properties of neutron irradiated beryllium pebbles manufactured by the rotating electrode method and the Mg reduction method were evaluate d from compression load tests at 10% deformation. Neutron irradiation was c arried out up to a total fast neutron fluence of about 4 x 10(25) n/m(2) (E > 1 MeV, about 8 dpa) at 400, 500 and 600 degreesC. There was no significa nt difference for the two kinds of beryllium pebbles. Additionally, it beca me clear that not only helium concentration, but also dpa value is an impor tant factor which might influence the compression properties, because the c ompression load at 10% deformation for the present specimens irradiated at high dpa was smaller than that of the specimens, with similar helium concen tration, irradiated at low dpa. (C) 2000 Elsevier Science B.V. All rights r eserved.