Influence of high dose neutron irradiation on thermal conductivity of beryllium

The thermal conductivity of beryllium is a very important physical characteristic, which considerably determines the serviceability of fusion reactor components where this material is supposed to be used. The neutron irradiation leads to a decrease of the thermal conductivity, the quantitative characteristic of the effect considerably depending upon the irradiation temperature and dose. So, after the irradiation in the SM reactor at a temperature of 70 °C up to neutron fluence of (1–6)×1022 cm−2 (E>0.1 MeV) the effect reaches hundreds of percents, after irradiation in the BOR-60 reactor at a temperature of 400 °C up to fluence of 1.6×1023 cm−2 (E>0.1 MeV) the effect reaches only tens of percents. One hour annealing of beryllium at 500 °C after the low temperature irradiation leads to a partial thermal conductivity recovery.