ICEM11 Final Program 9.7.11pm_ICEM07 Final Program ... - Events

Abstracts Session 9
3) GAS TRANSPORT PROPERTIES OF PUMICE TUFF FOR PERFORMANCE
ASSESSMENT OF LLW DISPOSAL FACILITY (wP-59074)
Shuichi Yamamoto, Kenichiro Suzuki, Obayashi Corporation; Mamoru Kumagai, Japan Nuclear Fuel Limited;
Yasuhiro Tawara, Koji Mori, Geosphere Environmental Technology Corporation (Japan)
In Japan, some of the radioactive waste with a relatively higher radioactivity concentration from nuclear facilities is to be packaged
in rectangle steel containers and disposed of in sub-surface disposal facilities, where normal human intrusion is unlikely to
occur. If dissolved oxygen in pore water is consumed by steel corrosion after the closure of the facility, hydrogen gas will be generated
from the metallic waste, steel containers and concrete reinforcing bars largely by anaerobic corrosion. If the generated gas
accumulates and the gas pressure increases excessively in the facility, the facilitys barrier performance might be degraded by
mechanical influences such as fracturing of surrounding rock and cementitious materials or plastic deformation of the bentonite
buffer.
In this study laboratory experiments for gas and water transport properties of the rock were performed to evaluate gas flow
through the rock mass (pumice tuff) around a facility for low level waste disposal. Based on the experimental results two-phase
flow properties were evaluated by means of an inverse analysis method.
The pumice tuff was subjected to hydraulic conductivity tests, water retention (moisture characteristic) tests, and gas injection
tests. Non-linear properties such as relative permeability and water retention curve and hydraulic conductivity as a function…
4) EXTRACTION AND CONFINEMENT OF CAESIUM USING FUNCTIONALIZED
POROUS MATERIALS (w/oP-59106)
Carole Delchet, Guillaume Toquer, Agnès Grandjean, Institut de Chimie Séparative de Marcoule;
Joulia Larionova, Yannick GUARI (France)
An original approach to immobilize caesium species that uses hybrid functionalized porous media is presented. This study is
part of radioactive waste water treatment Indeed, one of the most abundant fission product to be extracted from radioactive effluents
are the caesium isotopes : 137Cs (T1/2 ~30y) and 135Cs (T1/2~2.106y). Transition metal hexacyanoferrates HFC (II) or (III)
exhibit better sorption properties compared to organic resins or zeolites. There are then widely studied for this application over a
wide pH range and wide range of ionic strength. Moreover, they show a good resistance to ionising radiation. First we present kinetic
and thermodynamic data of Cs sorption properties in batch experiment for pure K2Ni(FeCN) 6 , Co3 (Fe(CN) 6 ) 2 and
Ni3 (Fe(CN) 6 ) 2 . A comparison of the kinetics parameters and adsorption capacity between these HFC is then done. Furthermore,
first tests of grafting Ni3 (Fe(CN) 6 ) 2 on porous glass and ordered porous silica have allowed the extraction of Cs from an aqueous
solution. Then we show that an ammoniac atmosphere during two days at ambient temperature allows closing the porosity of
ordered porous silica. So this soft treatment will be tested with silica solids containing HFC and extracted caesium in order to immobilized
caesium species without high temperature steps, avoiding then any volatilisation.
5) PHOTOCATALYTIC AND PHOTOCHEMISTRY DEGRADATION OF LIQUID
WASTE CONTAINING EDTA (wP-59144)
Célia Lepeytre, Cyril Lavaud, Guillaume Serve, CEA Marcoule (France)
The decontamination factor of liquid waste containing 60Co is generally weak. This is due to the presence of complexant molecules.
For instance, complexation of EDTA with 60Co decreases efficiency of radioactive waste treatment. The aim of this study
was to degrade EDTA in H2O and CO2 and to concentrate free 60Co in order to increase decontamination factor. A first test of
radioactive waste treatment by photocatalysis was allowed to increase decontamination factor ( 60Co) from 16 to 196 with a device
requiring to be improved. The present work concerns the first step of the degradation process development with a more powerful
device. These first experiments were leaded to follow the only EDTA oxidation. EDTA degradation was carried out by the following
Advanced Oxidation Processes (AOP): UV/H2O2 (photochemistry); UV/TiO2 (photocatalysis); UV/TiO2 /H2O2 . A specific reactor
was achieved for this study. The wavelength used was 254 nm (UV-C). The photocatalytic degradation of EDTA was carried
out with Degussa P-25 titanium dioxide (TiO2 ), which is a semiconductor photocatalyst. The degradation degree of EDTA and the
intermediate products were monitored by TOC and ionic chromatography methods. The effects of various parameters such as pH
and the quantity of H2O2 were studied. This allows us to conclude…
6) HISTORICAL WASTE – BIOLOGICAL SHIELD & DOCUMENTATION DURING
DECOMMISSIONING (w/oP-59056)
Thomas Nellemann, Anne Sørensen, Danish Decommissioning (Denmark)
Inventory records of isotopes in radioactive waste are important as documentation with respect to governmental control, final
disposal and public transparency. We present a simple, practical and cost-effective method for characterization of a part of the
radioactive waste from decommissioning of a research reactor: The biological shielding. The method uses documentation from the
decommissioning and from the construction drawings and blueprints of the reactor as well as measurements based on samples from
the facility.
The data presented is from a 5MW experimental light water nuclear reactor (DR-2) shutdown in 1975 and decommissioned in
2008. The method incorporates an activity distribution in the biological shield. The distribution is based on measurements of samples
from across the shielding and coupled with the distance to the center of the reactor core. The exact origin of each waste item
is determined from pictures from the decommissioning and from old blueprints and construction drawings of the reactor.
The uncertainty and usefulness of the method is related directly to different factors such as: The amount of samples obtained
and the position of these with respect to the origin of the waste, the accuracy of the documentation of the decommissioning, the
size of the waste items in…
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