[en] Density change measurements have been completed on the Ispra second generation AMCR alloys irradiated in MOTA-2A. The various compositional modifications induce a wide variation of swelling behavior in the range 423-600 degree C at 32-36 dpa

[en] This is the fourteenth in a series of semiannual technical progress reports on fusion reactor materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Depart of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Separate abstracts were prepared for each individual section

[en] Irradiation continues in the EBR-II and DR-3 reactors of pure copper and GlidCop CuAl25 in the form of subsize tensile fatigue specimens. The first phase of the EBR-II irradiation sequence has been completed. A size effects experiment on unirradiated CuAl25 fatigue specimens is nearing completion. Early results on the fatigue behavior of subsize specimens are presented in this report

[en] Microstructurally-oriented irradiation experiments are shown in this paper to be strongly dependent on details of reactor history that frequently are not brought to the experimenter's attention. In some cases, these details can dominate the experiment so as to produce very misleading results. To aid in the design and interpretation of microstructurally-oriented experiments, a number of studies are reviewed to highlight history effects and then guidelines are presented to minimize the impact of reactor history in new experiments

[en] Tungsten has been used in a variety of low activation ferritic alloys and also in copper composite alloys, both currently being irradiated in various fusion materials experiments. It has been proposed as an armor material also. Tungsten transmutes strongly to rhenium and then osmium, however, in a manner that is strongly dependent on neutron spectra. This adds significant complexity to the interpretation of data developed in one spectral environmental but intended for application to another environment

[en] Present knowledge of the processes involved in creating defects during cascade-producing irradiations is reviewed. Molecular dynamics simulations within the past few years have led to an understanding of the creation and survival of point defects in the critical first picoseconds of the cascade process, through the quenching of the thermal spike. The concept that 'freely migrating defects' arise only from isolated Frenkel pairs produced in a cascade is critically discussed

[en] The final measurements of helium generation in specimens used in the ⁵⁹Ni isotopic tailoring experiment have been completed. The results show that the target generation rates were sustained throughout the experimental series. It was also demonstrated that helium generation rates grow continuously in undoped specimens, reaching levels substantially larger than usually quoted in most other studies

[en] New nuclear cross section libraries (known as USACT92) have been created for activation calculations. A point-wise file was created from merging the previous version of the activation library, the U.S. Nuclear Data Library (ENDF/B-VI), and the European Activation File (EAF-2). 175 and 99 multi-group versions were also created. All the data are available at the National Energy Research Supercomputer Center

[en] Irradiation has been completed in MOTA-2B for creep tubes constructed from a candidate reduced activation austenitic alloy supplied by the Baikov Institute in Moscow. The total strains are strongly dependent on irradiation temperature in the range 425-600 degrees C, but are not completely linear with stress level

[en] Proper assessment of the mechanical properties along interfaces of bonded structures currently used in many fusion reactor designs is essential to compare the different fabrication techniques. A Mechanical Properties Microprobe (MPM) was used to measure hardness and Young's modules along the interfaces of Be/Cu bonded structure. The MPM was able to distinguish different fabrication techniques by a direct measurement of the hardness, Young's modules, and H/E² which reflects the ability of deformation of the interfacial region