Mechanical and Environmental Testing [Slides]
Summary of recent developments for mechanical testing irradiated materials at INL.
11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
SEARCH · Search NASA
Results for “Irradiation Testing”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Microstructurally validated stable and predictable swelling in low-enriched uranium monolithic U-10Mo fuel mini-plates
Qualification of the low-enriched uranium (LEU) monolithic U-10 wt%Mo (U-10Mo) plate-type fuel system requires a demonstration of a stable and predictable fuel swelling behavior over the anticipated operating conditions of the United States high-performance research reactors (USHPRRs) selected for conversion to LEU operation. This will allow each reactor to develop appropriate safety margins that will retain fuel element lifetime coolability. Additionally, the fuel system must maintain performance attributes when fabricated at a commercial scale. The Mini-plate 1 experiment represents the first irradiation test of commercially fabricated miniaturized monolithic LEU U-10Mo fuel plates. Here, the swelling behavior within this experiment was compared against that of historical fuel developmental tests to reveal that the commercially fabricated fuel performed within the current recommended U-10Mo swelling model's predictions. Additionally, the fuel microstructural evolution was evaluated to link initial conditions to subtle variations detected in the swelling response, providing validation and confidence that the fuel system is robust.
11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Silicon Carbide Composite Cladding Qualification
This report examines the process to qualify a new fuel-cladding type focusing on the data requirements and types of irradiation testing necessary to meet the regulatory burden and related guidance applicable to fuel qualification of accident-tolerant fuel. The report considers the use of accelerated fuel qualification techniques and lead-test specimen programs that may shorten the timeline for qualifying fuel for use in a nuclear reactor at the desired burnup. The assessment framework particularly emphasizes the identification of key fuel manufacturing parameters, the specification of a fuel performance envelope to inform testing requirements, the use of evaluation models in the fuel qualification process, and the assessment of the experimental data used to develop and validate the empirical models and empirical safety criteria.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Van de Graaff Irradiation Studies of Oxygen Sensor and Hydrated Zirconia Sorbent
Commercial-scale production of Mo-99 demands a facility-wide assessment of radiation-induced degradation across process equipment, instrumentation, and purification media. Key factors— total ionizing dose, dose rate, radiolysis-driven chemistry, thermal loads, activation, and any neutron-related effects—should inform material selection, shielding, and component layout. Purification materials (sorbents, resins, filters, seals, housing) require particular attention to ensure that irradiation does not alter selectivity or capacity, generate fines, or introduce leachables that could compromise Mo-99 purity or downstream Tc-99m generator performance. Dose mapping, accelerated irradiation testing, and studies of extractables/leachables together provide the basis for setting maintenance, calibration, and replacement intervals and for qualifying materials that retain mechanical integrity, chemical compatibility, and radiopurity over their service life.
36 MATERIALS SCIENCE↗
Capsule Design and Preparation for YH x Specimen Irradiation in the High Flux Isotope Reactor
Advanced nuclear systems for terrestrial microreactors and space applications require moderator materials with high thermal stability, hydrogen retention, and efficient neutron moderation. Yttrium hydride (YH x ) is a promising candidate, but its irradiation performance and hydrogen stability remain insufficiently understood. To address this, Oak Ridge National Laboratory (ORNL) and Los Alamos National Laboratory, supported by the US Department of Energy’s Nuclear Science User Facilities program, have initiated an irradiation campaign in ORNL’s High Flux Isotope Reactor. The experiment employs six irradiation capsules containing YH x specimens (H/Y ≈ 1.9) designed for three target temperatures (300°C, 400°C, and 500°C) and two distinct neutron fast fluence levels. This report documents the irradiation test matrix, capsule design, specimen precharacterization, and experiment readiness for insertion. Planned postirradiation examinations will provide new insights into hydrogen retention and microstructural stability, advancing the understanding of YH x as a moderator for compact reactor applications.
36 MATERIALS SCIENCE↗
Capsule Design and Preparation for YH x Specimen Irradiation in the High Flux Isotope Reactor
Advanced nuclear systems for terrestrial microreactors and space applications require moderator materials with high thermal stability, hydrogen retention, and efficient neutron moderation. Yttrium hydride (YH x ) is a promising candidate, but its irradiation performance and hydrogen stability remain insufficiently understood. To address this, Oak Ridge National Laboratory (ORNL) and Los Alamos National Laboratory, supported by the US Department of Energy’s Nuclear Science User Facilities program, have initiated an irradiation campaign in ORNL’s High Flux Isotope Reactor. The experiment employs six irradiation capsules containing YH x specimens (H/Y ≈ 1.9) designed for three target temperatures (300°C, 400°C, and 500°C) and two distinct neutron fast fluence levels. This report documents the irradiation test matrix, capsule design, specimen precharacterization, and experiment readiness for insertion. Planned postirradiation examinations will provide new insights into hydrogen retention and microstructural stability, advancing the understanding of YHx as a moderator for compact reactor applications.
36 MATERIALS SCIENCE↗
Measurement of mean excitation energies of neutrino-relevant materials
Modern neutrino experiments require precision reconstruction of events. A crucial component of this reconstruction is the stopping power for charged particles, calculated using the Bethe equation. The main free parameter of the Bethe equation is the mean excitation energy (the "I-value"), which in most cases cannot be calculated, but must be measured for each substance. In many cases, the values are derived from very old experiments with large quoted uncertainties, or worse, small quoted uncertainties and inadequate treatment of systematics. Even if the tabulated values were reliable to the necessary degree, the I-value is affected by the phase of the substance and by chemical bonding, and only rough heuristics have been developed to convert measurements of single elements into I-values for compounds or from one phase to another. Modern neutrino experiments which need to measure an absolute energy scale, while lacking calibration sources, suffer the most from uncertainties in the I-value. DUNE is a primary example. We are performing measurements with the 400MeV Fermilab LINAC beam at the Irradiation Test Facility. We describe our efforts to measure the I-value of liquid argon, as well as those for several other materials used in past, present and potential future neutrino experiments, including water, NOvA scintillator, MINOS steel, zirconium, and molybdenum. These measurements use a set of degraders to scan the beam energy around the Bragg peak for each substance to determine the proton range. Experimental results are compared to results from Geant4 and FLUKA to determine the I-value.
Strait, Matthew L. [Fermilab] (ORCID:0000000157088↗
UN Synthesis, Fabrication, and Characterization and UC Oxidation Study in support of Advanced LEU Fuel Concepts
Uranium nitride and carbide-based fuels are proposed for use in advanced LEU fuel systems. This report details recent development work to study synthesis, sintering and fabrication methods for single phase UN in monolithic geometries. These samples were intended to support a variety of irradiation testing conditions by tailoring enrichment, geometry, and compositional requirements. Two methods were under evaluation for synthesizing uranium nitride powder – carbothermic reduction-nitridation (CTR-N) of UO 2 powder feedstock and hydride-dehydride/nitridation (HDN) of uranium metal feedstock. Pellets were fabricated from powder feedstocks via conventional pressing and sintering methods. As-fabricated feedstocks and pellets were evaluated via X-ray diffraction (XRD) for phase purity and sintered materials were characterized for density. Both the CTR N and the HDN methods were successfully demonstrated as an effective process for fabricating phase pure UN. Additionally, results from machining efforts for UN are detailed. This report also contains information on a study trying to elucidate the oxidation mechanisms of sintered uranium carbide samples fabricated from feedstock synthesized via an arc-melting method.
11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Predictive equations for thermal neutron flux perturbation effects in cylinders
Prediction of thermal neutron flux perturbation effects in cylinders during irradiation tests
Lynch, J. H.↗
Replica grating study, phase 7 Interim report, 1 Jul. 1969 - 30 Jun. 1970
Particle irradiation tests on concave and Pyrex gratings
Gunter, R. C., Jr.↗
Materials technology program for a compact fast reactor for space power
Materials technology of Ta-W-Hf clad uranium mononitride fuel for lithium cooled compact fast space power reactor, including irradiation tests
Gluyas, R. E.↗
Fabrication of fuel pin assemblies, phase 3
Five full size and eight reduced length fuel pins were fabricated for irradiation testing to evaluate design concepts for a fast spectrum lithium cooled compact space power reactor. These assemblies consisted of uranium mononitride fuel pellets encased in a T-111 (Ta-8W-2Hf) clad with a tungsten barrier separating fuel and clad. Fabrication procedures were fully qualified by process development and assembly qualification tests. Detailed specifications and procedures were written for the fabrication and assembly of prototype fuel pins.
Keeton, A. R.↗
Fission-gas-release rates from irradiated uranium nitride specimens
Fission-gas-release rates from two 93 percent dense UN specimens were measured using a sweep gas facility. Specimen burnup rates averaged .0045 and .0032 percent/hr, and the specimen temperatures ranged from 425 to 1323 K and from 552 to 1502 K, respectively. Burnups up to 7.8 percent were achieved. Fission-gas-release rates first decreased then increased with burnup. Extensive interconnected intergranular porosity formed in the specimen operated at over 1500 K. Release rate variation with both burnup and temperature agreed with previous irradiation test results.
Weinstein, M. B.↗
Integrally covered silicon solar cells.
The electron-beam technique for evaporating dielectric materials onto solar cells has been examined and developed. Titanium oxide cell antireflection coatings have been obtained which compare to silicon monoxide in environmental capabilities and which provide 3 to 4% improvement over SiO for glass covered cells. Evaporation processes have been obtained which provide a 50 to 100 micromil thick transparent (0.5 to 1.0% absorption per mil), low stressed integral cover capable of surviving space type qualification testing. Irradiation with 10 to the 15th power 1-MeV electrons shows 2% darkening, and long term UV irradiation incurs approximately 1.3% cover darkening for 50 micromil thick covers.
Stella, P. M.↗
Development of space stable thermal control coatings for use on large space vehicles
The development of a large scale manufacturing method for the production of a stable zinc orthotitanate pigment is discussed. Major emphasis was placed on the evaluation of the radiation stability of Tektronix, Inc. pigments and of the conditions (time and temperature) leading to high reflection and high optical stability. Paints were formulated in OI-650 and in OI-650G vehicles from pigments which were prepared at various temperatures, some of which were chemically treated to remove ZnO. Ultraviolet irradiation tests of these paints were performed, and observations made regarding optimum pigment preparation parameters.
Gilligan, J. E.↗
Large area, low cost space solar cells with optional wraparound contacts
Design parameters for two large area, low cost solar cells are presented, and electron irradiation testing, thermal alpha testing, and cell processing are discussed. The devices are a 2 ohm-cm base resistivity silicon cell with an evaporated aluminum reflector produced in a dielectric wraparound cell, and a 10 ohm-cm silicon cell with the BSF/BSR combination and a conventional contact system. Both cells are 5.9 x 5.9 cm and require 200 micron thick silicon material due to mission weight constraints. Normalized values for open circuit voltage, short circuit current, and maximum power calculations derived from electron radiation testing are given. In addition, thermal alpha testing values of absorptivity and emittance are included. A pilot cell processing run produced cells averaging 14.4% efficiencies at AMO 28 C. Manufacturing for such cells will be on a mechanized process line, and the area of coverslide application technology must be considered in order to achieve cost effective production.
Michaels, D.↗
Uranium nitride fuel fabrication for SP-100 reactors
Fuel pins of uranium mononitride clad in Nb-1 percent Zr were fabricated for irradiation tests in EBR-II. Laboratory scale process parameters to synthesize UN powders and fabricate UN pellets were developed. Uranium mononitride was prepared by converting UO2 to UN. Fuel pellets were prepared by communition of UN briquettes, uniaxial pressing, and high temperature sintering. Techniques for machining, cleaning, and welding Nb-1 percent Zr cladding components were developed. End caps were electron beam welded to the tubing. Helium back-fill holes were sealed with a laser weld.
Mason, Richard E.↗
Prediction of error rates in dose-imprinted memories on board CRRES by two different methods
An analysis of the expected space radiation effects on the single event upset (SEU) properties of CMOS/bulk memories onboard the Combined Release and Radiation Effects Satellite (CRRES) is presented. Dose-imprint data from ground test irradiations of identical devices are applied to the predictions of cosmic-ray-induced space upset rates in the memories onboard the spacecraft. The calculations take into account the effect of total dose on the SEU sensitivity of the devices as the dose accumulates in orbit. Estimates of error rates, which involved an arbitrary selection of a single pair of threshold linear energy transfer (LET) and asymptotic cross-section values, were compared to the results of an integration over the cross-section curves versus LET. The integration gave lower upset rates than the use of the selected values of the SEU parameters. Since the integration approach is more accurate and eliminates the need for an arbitrary definition of threshold LET and asymptotic cross section, it is recommended for all error rate predictions where experimental sigma-versus-LET curves are available.
Brucker, G. J.↗