Vitrification of high molybdenum feeds in the presence of reprocessing waste liquor

2013 ◽  
Vol 1518 ◽  
pp. 21-39
Author(s):  
Rick Short ◽  
Barbara Dunnett ◽  
Nick Gribble ◽  
Hannah Steel ◽  
Carl James Steele
Keyword(s):  
Borosilicate Glass ◽  
Solubility Limit ◽  
Test Rig ◽  
Waste Liquor ◽  
Highly Active ◽  
Waste Storage ◽  
Waste Vitrification ◽  
Processing Line ◽  
Active Waste ◽  
Glass Formulation

ABSTRACTAt Sellafield, the Post Operational Clean Out (POCO) of solids from the base of the highly active waste storage tanks, in preparation for decommissioning, will result in a high molybdenum stream which will be vitrified using the current Waste Vitrification Plant (WVP). In order to minimise the number of containers required for POCO, the high molybdenum feed could be co-vitrified by addition to reprocessing waste, using the borosilicate glass formulation currently utilised on WVP. Co-vitrification of high molybdenum feeds has been carried out using non-active simulants, both in the laboratory and on the Vitrification Test Rig (VTR) which is a full scale working replica of a WVP processing line.In addition, a new borosilicate glass formulation containing calcium has been developed by NNL which allows a higher incorporation of molybdenum through the formation of a durable CaMoO4 phase, after the solubility limit of molybdenum in the glass has been reached. Vitrification of the high molybdenum feed in the presence of varying quantities of reprocessing waste liquor using the new glass formulation has been carried out in the laboratory. Up to ∼10 wt% MoO3 could be incorporated without any detrimental phase separation in the product glass, but increasing the fraction of reprocessing waste was found to decrease the MoO3 incorporation. Soxhlet and static powder leach tests have been performed to assess the durability of the glass products. This paper discusses the results of the vitrification of high molybdenum feeds in the presence of reprocessing liquor in both the borosilicate glass formulation currently utilised on WVP and the modified formulation which contain calcium.

Initial Investigation Into the Vitrification of High Molybdenum Solids in Borosilicate Glass

2009 ◽  
Vol 1193 ◽  
Author(s):  
Barbara F. Dunnett ◽  
Nick R. Gribble ◽  
Andrew D. Riley ◽  
Carl J. Steele
Keyword(s):  
Phase Separation ◽  
Borosilicate Glass ◽  
Spent Nuclear Fuel ◽  
Storage Tanks ◽  
Waste Storage ◽  
Waste Vitrification ◽  
Durability Testing ◽  
Glass Formulation ◽  
Selection Of ◽  
Scanning Electron

AbstractSellafield Ltd operates a Waste Vitrification Plant (WVP) to immobilise the arisings from the reprocessing of spent nuclear fuel. Washout of solids from the base of waste storage tanks in preparation for decommissioning is likely to produce feeds enriched in molybdenum to the WVP. Vitrification of such feeds in the borosilicate glass formulation currently used by the WVP for vitrification of reprocessing waste has been investigated to determine the maximum achievable loading of MoO3.The vitrification of molybdenum in the absence and presence of reprocessing waste was studied. A number of glasses were manufactured in the laboratory containing various waste loadings. The resultant glasses were examined both visually and under the scanning electron microscope for the presence of any phase separation. Additional aluminium was added to the glasses manufactured in the absence of reprocessing waste to improve the durability of the glass. In borosilicate glass containing 3.5 wt% Al2O3 the onset of a molybdenum phase separation was observed in glasses containing 2.6 wt% MoO3. In the presence of Magnox reprocessing waste, phase separation was observed when the product contained >3.8 wt% MoO3. Soxhlet durability testing of a selection of the glasses manufactured was carried out. The Soxhlet durability of glasses in the absence of phase separation was good.

Composition Changes and Future Challenges for the Sellafield Waste Vitrification Plant

2009 ◽  
Vol 1193 ◽  
Author(s):  
A. Riley ◽  
S. Walker ◽  
Nick R. Gribble
Keyword(s):  
Spent Nuclear Fuel ◽  
Fission Products ◽  
Feed Composition ◽  
Power Stations ◽  
Highly Active ◽  
Long Term Storage ◽  
Waste Storage ◽  
Waste Vitrification ◽  
Future Challenges ◽  
Future Work

AbstractThe Sellafield Waste Vitrification Plant (WVP) immobilises highly active liquors produced during reprocessing of spent nuclear fuel by bonding the fission products as metal oxides into a borosilicate glass matrix. This provides a stable and durable waste form suitable for safe long term storage and ultimate disposal.WVP was commissioned with feed from reprocessing of Magnox reactor fuel. This material is relatively low in fission product content per tonne of fuel, but contains significant Al and Mg from fuel cladding. WVP also routinely treats a blended feed made from a mixture of Magnox and Oxide reprocessing products. The Oxide fuel from Light Water Reactor (LWR) and Advanced Gas Cooled (AGR) power stations is of higher burnup and contains more fission products per tonne of fuel, also Gd and other process additives. Blending allows 25% incorporation of waste oxides by weight in glass to be achieved routinely.Recent programmes of development work in WVP have been aimed at increasing incorporation rates for these feeds, to reduce the number of waste containers produced for disposal. Work has also focussed on increasing the throughput of WVP, to more rapidly treat current stocks of liquid reprocessing waste, both by increasing the feed rate and by improving the lifetime of key components to improve plant availability.Future challenges for WVP include flowsheet changes to treat historic stocks of reprocessing wastes containing high U, Fe and Cr. Washout of solids from the base of waste storage tanks in preparation for decommissioning is also likely to give high Mo feeds. Development of flowsheet and glass formulation to accept these changes in feed composition will be a key objective of future work.

Using the Vitrification Test Rig for Process Improvements on the Waste Vitrification Plants

2010 ◽  
Vol 73 ◽  
pp. 176-182 ◽  
Author(s):  
Rick Short ◽  
Nick Gribble ◽  
Edward Turner ◽  
Andrew D. Riley
Keyword(s):  
Glass Frit ◽  
High Level Waste ◽  
Process Conditions ◽  
Test Rig ◽  
Processing Efficiency ◽  
Process Improvements ◽  
Highly Active ◽  
Waste Vitrification ◽  
The Uk ◽  
High Level

The Vitrification Test Rig (VTR) is a full scale non-active waste vitrification plant (WVP), that replicates the lines used for immobilising highly active reprocessing waste at Sellafield in the UK. In the high level waste (HLW) vitrification process, liquid HLW is dried in a rotating tube furnace then mixed with an alkali borosilicate glass frit. This mixture is heated to form a homogeneous product glass that is poured, cooled and stored in steel canisters. The primary function of the VTR is to trial and develop methods to increase the efficiency of high level waste processing at the active WVP. Efficiency gains are mainly achieved by increasing the rate at which the immobilised product is created and by increasing the ratio of HLW to glass frit in the product. The VTR has also been used to investigate the chemistry of various process additions and conditions, the effects of potential fault scenarios, and the processing of dilute waste streams that will be received by WVP in the future. All of these areas have the potential to improve processing efficiency through the optimisation of process conditions and the minimisation of unplanned plant outages. This paper discusses several VTR campaigns that have led to overall improvements of WVP operation.

scholarly journals β-Irradiation Effects on the Formation and Stability of CaMoO4 in a Soda Lime Borosilicate Glass Ceramic for Nuclear Waste Storage

2017 ◽  
Vol 56 (3) ◽  
pp. 1558-1573 ◽  
Author(s):  
Karishma B. Patel ◽  
Bruno Boizot ◽  
Sébastien P. Facq ◽  
Giulio I. Lampronti ◽  
Sylvain Peuget ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Glass Ceramic ◽  
Soda Lime ◽  
Irradiation Effects ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Β Irradiation

scholarly journals Effective polymer concrete on waste concrete production

2019 ◽  
Vol 97 ◽  
pp. 02032
Author(s):  
Evgeny Pyataev ◽  
Alexey Zhukov ◽  
Kirill Vako ◽  
Marina Burtseva ◽  
Elizaveta Mednikova ◽  
...  
Keyword(s):  
Average Density ◽  
Polymer Concrete ◽  
Polymer Additive ◽  
Highly Active ◽  
Active Experiment ◽  
High Durability ◽  
Concrete Production ◽  
Building Systems ◽  
Active Waste ◽  
Selection Of

Finish materials in facade systems are experiencing significant stress associated with atmospheric and mechanical influences. The use of tiles with high durability and the ability to relax deformations will allow to obtain efficient cladding for building systems. The article presents the results of the selection of compositions and technologies of a composite material based on finely ground highly active waste produced by portland cement, mineral binder, additives based on polycarboxylic ether MC-6955, and polymer additive MC-Adhesive. MC-Adhesive is a polymer additive used for: a significant increase in flexural strength; reduce the elastic modulus; increase water resistance; increase the concrete mix cohesion; making coatings with high requirements for abrasion, low dusting and high resistance to aggressive substances.The article presents the results of research methods of selection of compositions of composite polymer concrete. The strength characteristics of polymer concrete with an average density of 2370-2450 kg/m3 are most dependent on the consumption of fine waste and polymer additives. The nomogram obtained as a result of an active experiment makes it possible to evaluate the dependence of the strength on these factors and select their optimal ratio.

Nanoscopic structure of borosilicate glass with additives for nuclear waste vitrification

2022 ◽  
Vol 578 ◽  
pp. 121352
Author(s):  
Ryuhei Motokawa ◽  
Koji Kaneko ◽  
Yojiro Oba ◽  
Takayuki Nagai ◽  
Yoshihiro Okamoto ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Waste Vitrification ◽  
Nanoscopic Structure

Gadolinium Solubility Limits in Sodium-Aluminoborosilicate Glasses

1999 ◽  
Vol 556 ◽  
Author(s):  
L. Li ◽  
D. M. Strachan ◽  
L. L. Davis ◽  
H. Li ◽  
M. Qian
Keyword(s):  
Melting Temperature ◽  
Borosilicate Glass ◽  
Solubility Limit ◽  
Enthalpy Change ◽  
Glass System ◽  
Mole Percent ◽  
Molar Composition

AbstractGadolinium and lanthanum solubility limits in a sodium-alumino-borosilicate glass system were studied. As melting temperature increased from 1400°C to 1450°C, 1500°C and 1550°C, the solubility of gadolinium in the baseline glass 15B2O3-5A12O3-20Na2O-60SiO2 (in molar composition) increased from 10.1 to 11.3, 12.2 and 13.1 (in mole percent of Gd2O3). The enthalpy change of Gd2O3 dissolution in this baseline glass is about 43.6 kJ/mol. Boron effect on lanthanum solubility was studied using the following baseline glasses: xB2O3-20Na2O- 5Al2O3-60SiO2, where x equals to 5, 10, 15, and 20, respectively. It was found that lanthanum solubility limit increased from 8.4 to 10.3, 12.5 and 14.9 (in mole percent of La2O3) as B2O3 increased from 5.1 to 9.5, 13.1 and 16.2 mol%. Gd2O. and La2O3 have similar solubility limits. Solubility limits of mixtures containing different ratios of Gd2O3 to La2O3 in the baseline glass 15B2O3-20Na2O-5A12O3-60SiO2 were found insensitive to the ratio of La/Gd. As far as gadolinium is concerned, its solubility limit will decrease when other lanthanides are introduced.

scholarly journals Direct Conversion of Halogen-Containing Wastes to Borosilicate Glass

1996 ◽  
Vol 465 ◽  
Author(s):  
C. W. Forsberg ◽  
E. C. Beahm ◽  
J. C. Rudolph
Keyword(s):  
Borosilicate Glass ◽  
Direct Conversion ◽  
Poor Quality ◽  
Radioactive Wastes ◽  
Waste Form ◽  
Glass Material ◽  
Waste Vitrification ◽  
Second Phases

ABSTRACTGlass has become a preferred waste form worldwide for radioactive wastes; however, there are limitations. Halogen-containing wastes can not be converted to glass because halogens (chlorides, fluorides, etc.) form poor-quality waste glasses. Furthermore, halides in glass melters often form second phases that create operating problems. A new waste vitrification process, the Glass Material Oxidation and Dissolution System (GMODS), removes these limitations by converting halogen-containing wastes into borosilicate glass and a secondary, clean, sodium-halide stream.

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