Status of Studies on HLW Glass Performance for Confirming Its Validity in Assessment

Changes in surface structure of sodium aluminoborosilicate glasses during aqueous corrosion analyzed by using NMR

“…Table 1 summarizes the compositions of the prepared glasses under study. The molar ratios of SiO 2 , B 2 O 3 , and Al 2 O 3 were calibrated to be the same as that of a Japanese reference nuclear waste glass of P0798 [27]. The three glasses with different Na 2 O content denoted as R03, R08, and R20 with different Na/B ratios were prepared to investigate the effects of alkali content.…”

“…However, detailed solid reactions on the glass surfaces have been unclear. To understand the solid reaction on these surfaces, we employed solid-state NMR spectroscopy for 11 B, 29 Si, 27 Al, and 23 Na nuclei.…”

“…All spectra from pristine and altered glasses were acquired on a JEOL NMR spectrometer (Delta) at 11.75 T. 29 Si, 11 B, 27 Al, and 23 Na NMR experiments were conducted using a Varian/Chemagnetics 4-mm T3-HXY triple-resonance MAS NMR probe with a ZrO 2 rotor. To avoid signal saturation, relaxation delay for NMR signal acquisition was determined from longitudinal relaxation time of each nuclide.…”

“…11 B MAS spectra were corrected and referenced against a saturated H 3 BO 3 aqueous solution at 19.49 ppm. 27 Al MAS NMR spectra were obtained with a pulse delay of 2 s and a pulse width of μ 0.6 s with a tip angle of 15°at 130.32 MHz and spinning at 18 kHz. The chemical shift was referenced to a 1 M aqueous AlCl 3 solution at À0.10 ppm.…”

“…Structural analyses are conducted by employing solid-state NMR techniques such as 11 B, 29 Si, 27 Al, 23 Na MAS, → H S i 1 29 , → H N a 1 23 CPMAS, 23 Na triple-quantum magic-angle spinning (3QMAS), and 11 B{ 23 Na} rotational echo double-resonance (REDOR) NMR.…”