Abstract
A nondestructive neutron scattering method to precisely measure the uptake of hydrogen and the distribution of hydride precipitates in light water reactor (LWR) fuel cladding was developed. Zircaloy-4 cladding used in commercial LWRs was used to produce hydrided specimens. The hydriding apparatus consists of a closed stainless-steel vessel that contains Zr alloy specimens and hydrogen gas. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentrations were selected for the neutron study. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall thickness. Small angle neutron incoherent scattering was performed in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Our study demonstrates that the hydrogen in commercial Zircaloy-4 cladding can be measured very accurately in minutes by this nondestructive method over a wide range of hydrogen concentrations from a very small amount (≈20 ppm) to over 1000 ppm. The hydrogen distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor determined by a calibration process using standard, destructive direct chemical analysis methods on the specimens. This scale factor can be used in future tests with unknown hydrogen concentrations, thus providing a nondestructive method for determining absolute hydrogen concentrations.
Original language | English |
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Pages (from-to) | 114-121 |
Number of pages | 8 |
Journal | Journal of Nuclear Materials |
Volume | 460 |
DOIs | |
State | Published - May 2015 |
Funding
This research was sponsored by the Laboratory Directed Research and Development ( LOIS-6502 ) Program of Oak Ridge National Laboratory , managed by UT-Battelle, LLC, for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725), and EBSD through a user project supported by ORNL’s Center for Nanophase Materials Sciences (CNMS) , which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy . Beamline CG3 is supported by the Office of Biological and Environmental Research of the U.S. Department of Energy Research through ORNL Center for Structural Molecular Biology . The High Flux Isotope Reactor and beamline CG2 of ORNL was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy . We are grateful to Dr. Jeremy Busby for his technical inputs and stimulating discussions.