Strategy to safely enable X-ray computed tomography examination of highly radioactive tristructural isotropic nuclear fuel

Nondestructive post-irradiation examination of nuclear fuels and materials is useful in collecting data to inform commercial licensing of new nuclear concepts. This work details the planning, shielding design, and workflow of an X-ray computed tomography examination of an irradiated AGR-5/6/7 tristructural isotropic fuel compact with a dose rate of 1318 R/hr on contact from both β and ɤ-ray radiation with 120 R/hr of the dose rate coming exclusively from ɤ-rays. Rather than waiting for radioactive decay to reduce the dose rate from the sample, careful implementation of specially developed shielding and work controls enabled some examinations of the irradiated fuel in a timelier manner, which benefits the ongoing qualification and commercialization cases for this fuel by reducing the timeline from irradiated to examination. This timeframe reduction is important as data from these experiments can be more quickly available to inform modeling efforts and subsequent experiments. While this work represents the hottest radiological sample that has been openly transported and examined at Idaho National Laboratory’s Irradiated Materials Characterization Laboratory to date, it is anticipated that this work and its lessons learned will facilitate future examinations of similar or even more radioactive specimens.