The interaction of helium and displacement damage in inertial confinement fusion reactors
Abstract Helium is thermodynamically insoluble in metals and tends to form cavities if the conditions are appropriate for its migration. The processes of helium migration and interaction with point defects are strongly influenced by the level and the mode of displacement damage production. In this paper, we present an application of the rate theory for helium cavity formation in Inertial Confinement Fusion Reactors (ICFR's). A new computer code “EXPRESS” has been developed for the solution of the time-dependent rate equations describing the evolution of the space-averaged damage state of an ICFR first wall. An optimal algorithm was developed for the long-term solution of the rate equations (10 5 pulses) with modest computational requirements. It is shown that the timefluctuations in point defect and helium concentrations due to ICF-type pulsing lead to an overall reduction in the swelling of ICF materials.
Nuclear analysis of a laser fusion reactor, SENRI-I
A neutronic analysis of the laser-driven inertial-confinement fusion reactor SENRI-I is presented. Three-dimensional Monte Carlo calculations were performed to examine the effects of laser beam ports on the flux distribution, tritium breeding ratio, thermal energy deposition in the blanket, and radiation streaming. A Monte Carlo code was also used for the time-dependent radiation-damage analysis accounting for the time of the flight spread of neutrons and the results are compared to the analysis for the HIBALL design. Induced radioactivity was estimated, based on the one-dimensional transport calculation and depletion analysis. The calculated results reveal the advantages of the SENRI-I design with a thick Li layer compared to other reactor systems employing a dry-wall scheme.
On the location and motion of rare gas atoms in metals
Abstract Using potentials of about 40 kV, rare gas ions were accelerated into metal films and foils. In spite of the fact that as much as 2 at % argon was loaded into the metal lattice, little or no X-ray effect due to lattice distortion was observed. This result suggests that rare gas atoms coming to rest in a metal lattice capture vacancies. When rare gas loaded metal foils are heated in a vacuum system connected to a mass spectrometer, the evolution of the gas can be measured. The evolution of argon from foils of silver, gold, aluminum, and lead and krypton from uranium has been studied with interesting variations from metal to metal. Exploratory experiments with other rare gases indicate similar results. The combination of the ion bombardment and mass spectrometer techniques appears very promising for the study of the behaviour of rare gases in crystals.