Developing High-Energy Laser-Driven Bremsstrahlung Radiation Sources for Imaging and Analysis of Nuclear Waste Packages - 17300

Radiographic imaging of small scale simulated nuclear waste packages (a 28 mm uranium penny encapsulated in grout) was achieved using a single pulse exposure from an x-ray source driven by a high-power laser. The high-energy laser pulse was generated at the Vulcan laser facility, which focused the photon burst onto a tantalum target foil in order to produce a bright burst of highly penetrating x-rays (with energy >500 keV) from a source size less than 0.5 mm. The sample was imaged using BAS-TR and BAS-SR image plates alongside a Thallium doped Caesium Iodide scintillator-based detector coupled to CCD chips for rapid image acquisition. The penny was resolved to sub-mm accuracy over a 30 cm² scan area from a single shot. In addition, on a parallel beamline, neutron generation (of 10⁷-10⁹ neutrons per steradian per pulse) was achieved, thereby demonstrating the potential application for criticality testing of waste packages. The principle concern regarding intermediate level waste (ILW) containers is the internal volumetric expansion due to the formation of corrosion products. Therefore, simulated waste samples with hydride corrosion have been formed and characterised in order to emulate this phenomenon. In addition, samples containing controlled isotopic ratios have been formed. This next generation of simulated waste samples have been produced in preparation for a second phase of analysis at the Vulcan laser facility to quantify the identification ability of radiographic imaging and characterisation accuracy of neutronics measurements. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material and this paper details the next phase of technological development. (authors)