Effects of external energetic factors on tritium release from the EXOTIC 8-3/13 neutron-irradiated beryllium pebbles

Tritium release from samples of 9-13 mg of the EXOTIC 8-3/13 neutron-irradiated beryllium pebbles under the separate and simultaneous action of temperature 490-770 K, 5 MeV fast-electron radiation 14 MGy h^-1 for 3 h and magnetic field (MF) of 1.7 T was investigated. The pebbles were found to be very dissimilar with respect to their total tritium content-2.5-9 MBq g^-1. The batch contained also some coarse agglomerates of the pebbles containing 10-19 MBq g^-1 of tritium having also a high tritium release. For the pebbles having the total tritium 2.5-5.3 MBq g^-1, the electron radiation for 3 h caused the fractional tritium release 17-26% (B = 0) and 21-29% (B = 1.7 T), the temperature of the pebbles being <550 K. The annealing of the pebbles at the temperature ramp at 5 K/min to 553 K and at 553 K for 3 h caused the fractional tritium release 10-19% (B = 0) and 14% (B = 1.7 T). For the pebbles having the total tritium 3.6-5.8 MBq g^-1, the annealing of the pebbles at the temperature ramp at 5 K/min to 770 K and at 770 K for 1 h caused the fractional tritium release 17-24% (B = 0) and 25% (B = 1.7 T), but with the simultaneous additional action of the electron radiation for 3 h the fractional tritium release was 24-42% (B = 0) and 32-37% (B = 1.7 T).