The 12th International Conference on Environmental ... - Events

Session 50-51 Abstracts
In 2004, a novel Non-Destructive Assay (NDA) method was used to validate the applied waste storage strategies in terms of
spatial dose rate distribution. With this method measurements were performed in one of the interim storage modules for LILW. <strong>The</strong>
dose rate at a height of 6m, mainly responsible for the sky-shine at the site boundary, was somewhat higher then expected.
Based on the experience and feedback, the NDA method was developed further, into the present INDSS-R (acronym for
INDoor Survey System Radiation) method.
3) SORPTION DATABASES FOR INCREASING CONFIDENCE IN PERFORMANCE ASSESSMENT - 16053
Anke Richter, Vinzenz Brendler, Cordula Nebelung,Forschungszentrum Dresden-Rossendorf e.V. (Germany);
Timothy E. Payne, Australian Nuclear Science and Technology Organization (Australia);
Thomas Brasser, GRS Braunschweig (Germany)
World-wide activities focus on the remediation of radioactively contaminated sites. One common aim is to deliver a more profound
chemical base for risk assessment, namely all those physico-chemical phenomena governing the contamination plume development
in time and space. Coupled transport codes able to tackle this challenge have to simplify the resulting very complex reaction
pattern. To do so in an adequate way requires extending the knowledge about retardation and mobilisation phenomena and the
underlying basic processes and interactions (e.g. physisorption, chemisorption, surface precipitation).
Interactions at the solid-liquid interface can be described by complementary approaches, the empirical Kd concept and the
mechanistic Surface Complexation Models (SCM).
Kds are used by most reactive transport and risk assessment codes due to the straightforward numerics involved. In addition,
the Kd concept is often the only feasible option for complex solid phases. However, the Kd concept is a rather simplistic approach.
Many very different basic physicochemical phenomena are subsumed in just one conditional parameter. <strong>The</strong>refore, extrapolating
Kd values may yield very large uncertainties.
4) DECOMMISSIONING AND WASTE TREATMENT HAZARD EVALUATION AND MODELING - 16409
Martin Plys, Michael Epstein, Fauske & Associates, LLC (USA)
Hazards encountered during decommissioning and waste treatment involve different issues, emphasis, and scenarios than
encountered during normal facility operations. This paper provides examples from experience in analysis and modeling of diverse
facilities, framed in terms of custom phenomena models and their incorporation into integral facility analysis modeling. Models for
entrainment of contamination and aerosol behavior are described and applied. <strong>The</strong> FATETM (Facility Flow, Aerosol, <strong>The</strong>rmal, and
Explosion) computer program is described, and example calculations are given for contamination release due to a dust explosion
in order to demonstrate the sensitivity to boundary conditions and the use of engineered safeguards.
SESSION 51 - VITRIFICATION AND BOROSILICATE GLASS ALTERNATIVES FOR IMMOBILIZATION
1) THE RESULTS OF TESTING TO EVALUATE CRYSTAL FORMATION AND
SETTLING IN THE COLD CRUCIBLE INDUCTION MELTER - 16282
James Marra, SRNL (USA); Sergey Stefanovsky, Dmitriy Suntsov,Vladimir Lebedev, SIA Radon (Russia)
<strong>The</strong> Cold Crucible Induction Melter (CCIM) technology offers the potential to increase waste loading for High Level Waste
(HLW) glasses leading to significant improvements in waste throughput rates compared to the reference Joule Heated Melter
(JHM). Prior to implementation of a CCIM in a production facility it is necessary to better understand processing constraints associated
with the CCIM. <strong>The</strong> glass liquidus temperature requirement and tolerance to crystal formation for processing in the CCIM
is an open issue. Testing was conducted to evaluate crystal formation and crystal settling during processing in the CCIM to gain
insight into the effects on processing. A high aluminum/high iron content glass composition with known crystal formation tendencies
was selected for testing. A continuous melter test was conducted for approximately 51 hours. To evaluate crystal formation,
glass samples were obtained from pours and from glass receipt canisters where the glass melt had varying residence time in the
melter. Additionally, upon conclusion of the testing, glass samples from the bottom of the melter were obtained to assess the degree
of crystal settling. Glass samples were characterized in an attempt to determine quantitative fractions of crystals in the glass matrix.
Crystal identity and relative composition were determined using a combination of x-ray diffraction (XRD) and scanning electron
microscopy coupled with energy dispersive spectroscopy (SEM/EDS). Select samples were also analyzed by digesting the glass
and determining the composition using inductively coupled atomic emission spectroscopy (ICP-AES). <strong>The</strong>re was evidence of crystal
formation (primarily spinels) in the melt and during cooling of the collected glass. <strong>The</strong>re was evidence of crystal settling in the
melt over the duration of the melter campaign.
2) COLD CRUCIBLE VITRIFICATION OF SRS SB4 WASTE AT HIGH WASTE LOADINGS - 16197
Sergey Stefanovsky, Alexander Kobelev, Vladimir Lebedev,Michael Polkanov, Oleg Knyazev, SIA Radon (Russia);
James Marra, SRNL (USA)
<strong>The</strong> test on determination of maximized waste loading was performed at the Radon bench-scale facility equipped with a 236
mm inner diameter cold crucible. Waste surrogate was vitrified using a commercially available Frit 503-R4 (in wt.%: 8 Li2O, 16
B2O3 , 76 SiO2 ). Waste loading ranged between ~45 and 70 wt.%. Viscosity of the melt with 50 wt.% waste loading remains lower
100 Poises (maximum value for glass melting) even at temperatures below 1300 oC. Electric resistivity value for this glass allows
electric melting at temperatures of 1100-1150 oC and higher. Melt viscosity increases with the increase of waste loading and glass
with 60 wt.% waste loading has appropriate viscosity for melting at temperatures over 1350 oC. This glass is much shorter than the
glass with 50 wt.% waste loading. Its electric resistivity at the same temperature is higher than that of glass with 50 wt.% waste
loading and allows to produce this glass at temperatures 1250 oC and lower, but high viscosity is a restricting factor and this glass
requires for its production temperatures ~ 1400 oC and over. <strong>The</strong> melt with 70 wt.% waste loading is too inhomogeneous and viscous
and its viscosity and electric resistivity cannot be measured precisely. As a result the glasses with 70 and 60 wt.% waste load-
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