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Title: Glass-bonded iodosodalite waste form for immobilization of 129 I

Abstract

Immobilization of radioiodine (e.g., 129I, 131I) is an important need for current and future nuclear fuel cycles. For the current work, iodosodalite [Na8(AlSiO4)6I2] was synthesized hydrothermally from metakaolin, NaI, and NaOH. Following hydrothermal treatment, dried unwashed powders were used to make glass-bonded iodosodalite waste forms by heating pressed pellets at 650, 750, or 850 °C with two different types of sodium borosilicate glass binders, i.e., NBS-4 and SA-800. These heat-treated specimens were characterized with X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, thermal analysis, porosity and density measurements, neutron activation analysis, and inductively-coupled plasma mass spectrometry. The pellets mixed with 10 mass% of NBS-4 or SA-800 and heat-treated at 750 °C contained relatively high percentage iodine retention (~44-47 % of the maximum iodine loading) with relatively low porosities, while other pellets with higher percentages iodine retention either contained higher porosity or were not completely sintered. ASTM C1308 chemical durability tests of monolithic specimens showed a large initial release of Na, Al, Si, and I on the first day, possibly from water-soluble salt crystals or non-durable amorphous phases. Release rates of Na and Si were higher than for Al and I, probably due to a poorly durable Na-Si-Omore » phase from the glass bonding matrix. The cumulative normalized release of iodine was 12.5 g m-2 for the first 10 1-d exchanges, suggestive of coherent dissolution. The average release rate from 10-24 days during the 7-d exchange intervals was 0.2336 g m-2 d-1.« less

Authors:
; ; ORCiD logo; ; ; ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1434845
Report Number(s):
PNNL-SA-130829
Journal ID: ISSN 0022-3115; 830403000
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 504; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
sodalite; iodosodalite; waste forms; iodine

Citation Formats

Chong, Saehwa, Peterson, Jacob A., Riley, Brian J., Tabada, Diana, Wall, Donald, Corkhill, Claire L., and McCloy, John S. Glass-bonded iodosodalite waste form for immobilization of 129 I. United States: N. p., 2018. Web. doi:10.1016/j.jnucmat.2018.03.033.
Chong, Saehwa, Peterson, Jacob A., Riley, Brian J., Tabada, Diana, Wall, Donald, Corkhill, Claire L., & McCloy, John S. Glass-bonded iodosodalite waste form for immobilization of 129 I. United States. doi:10.1016/j.jnucmat.2018.03.033.
Chong, Saehwa, Peterson, Jacob A., Riley, Brian J., Tabada, Diana, Wall, Donald, Corkhill, Claire L., and McCloy, John S. Fri . "Glass-bonded iodosodalite waste form for immobilization of 129 I". United States. doi:10.1016/j.jnucmat.2018.03.033.
@article{osti_1434845,
title = {Glass-bonded iodosodalite waste form for immobilization of 129 I},
author = {Chong, Saehwa and Peterson, Jacob A. and Riley, Brian J. and Tabada, Diana and Wall, Donald and Corkhill, Claire L. and McCloy, John S.},
abstractNote = {Immobilization of radioiodine (e.g., 129I, 131I) is an important need for current and future nuclear fuel cycles. For the current work, iodosodalite [Na8(AlSiO4)6I2] was synthesized hydrothermally from metakaolin, NaI, and NaOH. Following hydrothermal treatment, dried unwashed powders were used to make glass-bonded iodosodalite waste forms by heating pressed pellets at 650, 750, or 850 °C with two different types of sodium borosilicate glass binders, i.e., NBS-4 and SA-800. These heat-treated specimens were characterized with X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, thermal analysis, porosity and density measurements, neutron activation analysis, and inductively-coupled plasma mass spectrometry. The pellets mixed with 10 mass% of NBS-4 or SA-800 and heat-treated at 750 °C contained relatively high percentage iodine retention (~44-47 % of the maximum iodine loading) with relatively low porosities, while other pellets with higher percentages iodine retention either contained higher porosity or were not completely sintered. ASTM C1308 chemical durability tests of monolithic specimens showed a large initial release of Na, Al, Si, and I on the first day, possibly from water-soluble salt crystals or non-durable amorphous phases. Release rates of Na and Si were higher than for Al and I, probably due to a poorly durable Na-Si-O phase from the glass bonding matrix. The cumulative normalized release of iodine was 12.5 g m-2 for the first 10 1-d exchanges, suggestive of coherent dissolution. The average release rate from 10-24 days during the 7-d exchange intervals was 0.2336 g m-2 d-1.},
doi = {10.1016/j.jnucmat.2018.03.033},
journal = {Journal of Nuclear Materials},
number = C,
volume = 504,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2018},
month = {Fri Jun 01 00:00:00 EDT 2018}
}