Structural integrity of heavy liquid-metal target installed in neutron spallation facility. Pt. 1. Preliminary study on stress wave generated by irradiating pulsed-proton beam

JAERI has planned to construct a neutron spallation facility connected with a high-intensity proton accelerator under the neutron science program. A success of this plan depends on establishing a technology of the target as a neutron generator. To make clear engineering problems in developing the target, a numerical calculation was conducted on the heavy liquid-metal target container by using the structural analysis code ABAQUS-Explicit, focusing on dynamic stress which results from an injection of a pulsed-proton beam from the accelerator. The following results were obtained: (1) A stress wave occurred in a beam window was formed by a thermal stress caused by volumetric heat generation in the window and an internal pressure increase caused by rapid thermal expansion of mercury; an amplitude of the wave attained up to 1000MPa. (2) A stress wave occurred in a drum of the target container was ruled by the rapid increase of the internal pressure, and the amplitude attained up to 400MPa. These results agreed well with those of the ESS target calculated in PSI using the ANSYS code. To keep a structural integrity, it is indispensable for optimizing a target structure so as to reduce the stress above mentioned below a yield stress of a container material. (author)