Summary Report on the Volatile Radionuclide and Immobilization Research for FY2011 at PNNL

Strachan, Denis M.; Chun, Jaehun; Matyáš, Josef; Lepry, William C.; Riley, Brian J.; Ryan, Joseph V.; Thallapally, Praveen K.

doi:10.2172/1031440

Cited by 16 publications

(22 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At Pacific Northwest National Laboratory (PNNL), we have made Pt-Ge-S (PtGe 2 S 5 ), Mo-Co-Ni-S (Mo 2 CoNiS 8 ), and Sn-S (Sn 2 S 3 ) chalcogels and the summary collages of methods are presented in Figure 2 (Ryan et al, 2009;Strachan et al, 2010;Strachan et al, 2011;Riley et al, 2011). We evaluated two casting techniques in which we cast the mixed precursors in either polymer vials or petri dishes.…”

Section: Overview Of Chalcogel Fabrication Methodsmentioning

confidence: 99%

Initial Assessment of Alternate Metals in Chalcogels

Riley¹,

Lepry²,

Chun³

et al. 2012

Self Cite

View full text Add to dashboard Cite

Section: Overview Of Chalcogel Fabrication Methodsmentioning

confidence: 99%

Initial Assessment of Alternate Metals in Chalcogels

Riley¹,

Lepry²,

Chun³

et al. 2012

Self Cite

View full text Add to dashboard Cite

“…Recently, studies have sought to develop alternative adsorbents and waste forms for 129 I in off-gas [11][12][13][14]. A bismuth-oxideiodine waste form was investigated to scavenge iodine contained in iodine scrubbing solutions [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Novel synthesis of bismuth-based adsorbents for the removal of 129I in off-gas

Yang

Shin

Park

et al. 2015

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…This novel sorbent has a high affinity for iodine at the low concentrations expected in the off-gas streams and a high sorption capacity, and, after loading with iodine, can be potentially consolidated into a dense, high-iodine-loaded and leach-resistant SiO 2 -based waste form. Previously, it was demonstrated to have a maximum sorption capacity for I 2 of 48 mass% (Strachan et al 2011), decontamination factors in excess of 10 000 (99.99 % of iodine removed) , good sorption performance after long-term exposure to dry air (simulating process idling) (Bruffey et al 2012, Matyáš et al 2012a, and retention of more than 92% of iodine in densified waste form after iodine-loaded aerogel was processed at 1200 °C for 30 min under low pressure . It is expected that iodine retention can be further improved by optimizing the sintering process through a simultaneous application of fast heating rates to temperatures above 1000 °C and pressures up to 210 MPa.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Methods to Consolidate Iodine-Loaded Silver-Functionalized Silica Aerogel

Matyáš¹,

Engler²

2013

Self Cite

View full text Add to dashboard Cite

SUMMARYThe U.S. Department of Energy is currently investigating alternative sorbents for the removal and immobilization of radioiodine from the gas streams in a nuclear fuel reprocessing plant. One of these new sorbents, Ag 0 -functionalized silica aerogels, shows promise as a potential replacement for Ag-bearing mordenites because of its high selectivity and sorption capacity for iodine. Moreover, a feasible consolidation of iodine-loaded Ag 0 -functionalized silica aerogels to a durable SiO 2 -based waste form makes this aerogel an attractive choice for sequestering radioiodine.This report provides a preliminary assessment of the methods that can be used to consolidate iodineloaded Ag 0 -functionalized silica aerogels into a final waste form. In particular, it focuses on experimental investigation of densification of as-prepared Ag 0 -functionalized silica aerogel powders, with or without an organic moiety and with or without a sintering additive (colloidal silica), with three commercially available techniques: 1) hot uniaxial pressing (HUP), 2) hot isostatic pressing (HIP), and 3) spark plasma sintering (SPS). Since there are no studies reported in literature on the sintering of aerogels with HIP and SPS, the preliminary experiments were performed without iodine-loaded aerogels and were focused on investigating feasibility of these methods to produce a fully dense product. Iodine was excluded from these initial studies to avoid potential damage to vendor equipment due to the potential release of iodine during consolidation. The densified products were evaluated with a helium gas pycnometer for apparent density, with the Archimedes method for apparent density and open porosity, and with high-resolution scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) for the extent of densification and distribution of individual elements.The preliminary investigation of HUP, HIP, and SPS showed that these sintering methods can be used to effectively consolidate powders of Ag 0 -functionalized silica aerogel into products of near-theoretical density. Also, removal of the organic moiety and adding 5.6 mass% of colloidal silica to Ag 0 -functionalized silica aerogel powders before processing resulted in denser products. Furthermore, the ram travel data for SPS indicated that rapid consolidation of powders with SPS can be performed at temperatures below 950 °C.

show abstract

Summary Report on the Volatile Radionuclide and Immobilization Research for FY2011 at PNNL

Cited by 16 publications

References 64 publications

Initial Assessment of Alternate Metals in Chalcogels

Initial Assessment of Alternate Metals in Chalcogels

Novel synthesis of bismuth-based adsorbents for the removal of 129I in off-gas

Assessment of Methods to Consolidate Iodine-Loaded Silver-Functionalized Silica Aerogel

Contact Info

Product

Resources

About