RADIATION DAMAGE TO BERYLLIUM UNDER LOW-TEMPERATURE NEUTRON IRADIATION

Abstract

In this work, to assess the radiation damage of beryllium under low-temperature neutron irradiation, samples from beryllium grade TShG-200 with an oxide phase concentration of about 1 wt % were studied, which were kept in the IVG.1M research reactor for a long time and were irradiated to fluences 0.8–4·1020 neut./cm2. Also, unirradiated original witness samples of the same brand were tested to compare the results.The aim was to establish the level of radiation degradation of beryllium samples during their tests in the IVG.1M reactor. Mechanical tests for three-point bending and tension were performed to determine the strength of beryllium samples, and their microhardness was also measured. To determine the degree of swelling of the beryllium samples their densities were measured by the method of hydrostatic weighing in the medium of distilled water.According to the results of short-term bending and tensile tests, it was found that the beryllium material after reactor irradiation softens in the range of 9.3–16.7%. And the results of measuring the microhardness showed an increase of up to 23%. Density results did not reveal swelling of the samples after low-temperature neutron irradiation.After mechanical tests, special studies of fractures and microstructural analysis were carried out, which did not reveal noticeable changes in the microstructure of beryllium after irradiation.