The technical feasibility of short-term storage and retrieval of spent nuclear fuel assemblies has recently been demonstrated in a test of deep geologic storage at the U.S. Department of Energy Nevada Test Site (NTS). Handling systems and procedures developed and deployed on this test functioned safely and reliably to emplace eleven intact spent-fuel assemblies and retrieve them three years later. Three exchanges of spent fuel were conducted at regular intervals during the storage period to maintain the proficiency of personnel and the readiness of the handling system.
Technical data was collected using nearly 1,000 instruments. These data show that the mechanical and thermal properties of granites are compatible with nuclear waste isolation objectives. Measured and calculated temperatures are in excellent agreement, confirming the adequacy of available heat transfer codes. Radiation transport calculations were of high quality, exceeding the accuracy of available long-term dosimetry techniques which were used on the test. We also found good agreement between measured and calculated displacements within the rock mass.