Non-destructive Preirradiation Assessment of UN / U-Si “LANL1” ATF formulation

Status Report on Development of a Cask to Enable Pulsed Neutron Characterization of Irradiated Fuel

“…The first step in this project is to "benchmark" the initial condition of candidate materials before irradiation [3]. The second step will be to make comparable non-destructive measurements on irradiated rodlets prior to their destructive examination in INL hot cells.…”

“…The second step will be to make comparable non-destructive measurements on irradiated rodlets prior to their destructive examination in INL hot cells. Neutron, proton and (synchrotron) X-ray scattering as well as radiography/tomography techniques all pose opportunities for this endeavor [3]. By virtue of their stand-off capability and ability to probe materials despite an intense gamma field, neutrons and protons both offer potential for study of highly radioactive materials.…”

“…This cask is a key component of a pathway to characterize irradiated materials with pulsed neutrons at LANSCE described previously [14]. While in previous reports [2,3,15,16,17] these pulsed neutron techniques were described in detail and applied to un-irradiated materials, application to irradiated materials promise the highest return. These methods probe the bulk of a material and are applicable to actual fuels rather than custom-made demonstration samples and are based on energy-resolved neutron imaging (ERNI) and neutron diffraction.…”

“…In the first phase a set of mock-up rodlets were examined containing pellets of depleted uranium dioxide (dUO 2 ) with defects similar to that seen in irradiated fuel rodlets [20]. After these first measurements over the last years, measurements have demonstrated the applicability of neutrons, protons and synchrotron X-rays to a range of ceramic and metallic fuels [3,11,12,17,17,26], including the ability to measure fission gas pressures [21,25] and measurements to complement modeling [11]. Several terabytes of imaging and scattering data have been collected on various fuel types.…”

Event Centroiding Applied to Energy-Resolved Neutron Imaging at LANSCE

“…By measuring full transmission spectra, i.e., with the ability to record thousands of TOF channels in each pixel as provided by modern neutron imaging detectors [8][9][10] installed at modern intense pulsed neutron sources [11][12][13][14][15], data analysis codes such as Oak Ridge National Lab's SAMMY [16] can quantify the areal density of several isotopes measured simultaneously with the known cross sections. Based on pioneering neutron cross section measurements demonstrated at Los Alamos Neutron Center (LANSCE) [17][18][19][20], this technique has been developed over the past years at LANSCE with applications to nuclear fuels [6,7,21] and scintillators [22][23][24]. Using tomographic reconstruction methods, this technique allows non-destructive spatially resolved measurements of isotope densities.…”