Thermal diffusivities of W-Re alloys were examined before and after neutron
irradiation by a laser-flash method. W and W-Re alloys (up to 25 mass% Re)
were irradiated in the Japan materials test reactor (JMTR) reactor at 330
K to thermal and fast neutron fluences of 1.03 x 10(20) and 3.37 x 10(19) (
E>1 MeV), respectively. After irradiation thermal diffusivities of W and W-
5% Re decreased, while those of W-10% Re and 25% Re increased. In the unirr
adiated condition, though the diffusivities of W and W-5% Re decreased with
an increase of temperature, those of W-10% Re and W-25% Re increased. Thes
e temperature dependencies were the same after the irradiation. After annea
ling at 973 K for 10 min, the thermal diffusivity was restored for W-5% Re
at room temperature, while a difference still existed between those of the
irradiated and unirradiated W and W-25% Re. The observed changes are discus
sed in terms of lattice constant measurements and precipitation behavior. (
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