Waste Package Filler Material Testing Report

As part of the Mined Geologic Disposal System Waste Package Development design activities, it has been determined that it may be beneficial to add material to fill the otherwise free spaces remaining in waste package after loading high-level nuclear waste. The use of filler material will benefit criticality control in spent nuclear fuel waste packages, by the moderator displacement method. Another objective of adding filler would be to enhance long term containment and isolation by inhibiting release of radionuclides, for both the cases of spent nuclear fuel and of high-level waste glass.
This Waste Package Filler Material Testing Report presents results of a development test program for placement of filler material within a loaded waste package containing spent nuclear fuel assemblies. Two simulated/dummy nuclear fuel assemblies were fabricated to support this filler placement test program. Additionally, experimental determination of selected physical properties was performed for the candidate filler materials, as needed to support the Management and Operating Contractor (M&O) Waste Package Development design activities.