Gas Release and Compression Properties in Beryllium Irradiated at 600 and 750 C

Effects of Neutron Radiation on Structural Materials.

“…Irradiation at 600 and 750 C resulted only in minor changes in compression properties, as indicated in Table 8. (19) These results, which show no changes in compressive properties, agree with tensile data obtained on beryllium irradiated at the sajne temperatures.…”

TEM investigation of long-term annealed highly irradiated beryllium

“…Small faceted bubbles are formed, which themselves are still sessile. The mobility of the gas atoms increases with higher temperature and the saturation of the swelling at 750°C suggest that all 4 He is present in bubbles. The small faceted bubbles are mobile above 825°C and contribute to the further growing of the large grain boundary bubbles, but this does not induce a further significant swelling of the beryllium.…”

“…As a consequence, the 3 H migrates faster towards the grain boundaries and a higher fraction is released at lower temperature [10]. The gas in the bubbles will be a mixture of mainly 4 He atoms and a small amount of 3 H. Therefore, in the remainder of the paper, only the 4 He atoms will be mentioned, but it should be remembered that the gas also contains 3 H and 3 He atoms.…”

“…The production and diffusion of gases like helium and tritium is an important issue. High quantities of these gases are produced as a result of the neutron multiplication reaction 9 Be(n,2n)2 4 He and the reaction chain 9 Be(n,a) 6 He(b À ) 6 Li(n,a) 3 H.…”

“…The diffusion of 4 He and 3 H atoms as created by neutron irradiation of beryllium has been discussed in the literature [2][3][4][5]. The solubility of both elements in beryllium is very low and they will easily precipitate into small gas bubbles.…”