JASPER: A joint U.S.-Japan program of experimental shielding research

A cooperative shielding research program between the U.S. Department of Energy and Japan's Power Reactor and Nuclear Fuel Development Corporation has been initiated. The program includes six specific shielding integral experiments to be performed at the Oak Ridge National Laboratory Tower Shielding Facility and analyzed by both U.S. and Japanese participants. Planned experiments include studies of (1) attenuation in radial shield mockups, (2) neutron streaming in a fission gas plenum, (3) shield effectiveness of different axial shield designs, (4) neutron streaming in narrow gaps, (5) source multiplication effects within in-vessel stored fuel assemblies, and (6) sodium activation in an intermediate heat exchanger mockup. The first experiment, which included numerous configurations containing steel, graphite, and boron carbide, has been completed and initial results are presented. The remaining four experiments, which are in various stages of planning, fabrication and execution, are described briefly