Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges
Abstract
One of the most challenging components of the UK nuclear legacy is Magnox sludge, arising from the corrosion of Mg alloy-clad irradiated metallic U fuel that has been stored in high pH ponds. The sludges mainly comprise Mg hydroxide and carbonate phases, contaminated with fission products and actinides, including Pu. Cementation and deep geological disposal is one option for the long-term management of this material, but there is a need to understand how Pu may be leached from the waste, if it is exposed to groundwater. Here, we show that cemented Mg(OH)2 powder prepared with Pu(IV)aq is altered on contact with water to produce a visibly altered ‘leached zone’, which penetrates several hundred microns into the sample. In turn, this zone shows slow leaching of Pu, with long-term leaching rates between 1.8–4.4 × 10-5% of total Pu per day. Synchrotron micro-focus X-ray fluorescence mapping identified decreased Pu concentration within the ‘leached zone’. A comparison of micro-focus X-ray absorption spectroscopy (µ-XAS) spectra collected across both leached and unleached samples showed little variation, and indicated that Pu was present in a similar oxidation state and coordination environment. Fitting of the XANES spectra between single oxidation state standards and EXAFS modeling showed thatmore »
- Authors:
-
[1];
- Univ. of Manchester (United Kingdom)
- Univ. of Manchester (United Kingdom); National Nuclear Laboratory, Warrington (United Kingdom)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- National Nuclear Laboratory, Warrington (United Kingdom)
- University of Helsinki (Finland)
- Univ. of Manchester (United Kingdom); University of Helsinki (Finland)
- Publication Date:
- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- OSTI Identifier:
- 1491807
- Grant/Contract Number:
- AC02-06CH11357
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Geosciences
- Additional Journal Information:
- Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 2076-3263
- Publisher:
- MDPI
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; plutonium; radioactive waste; speciation; cement; leaching
Citation Formats
Law, Kathleen A., Parry, Stephen, Bryan, Nicholas D., Heath, Sarah L., Heald, Steven M., Knight, Darrell, O’Brien, Luke, Fuller, Adam, Bower, William, Law, Gareth, and Livens, Francis. Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges. United States: N. p., 2019.
Web. doi:10.3390/geosciences9010031.
Law, Kathleen A., Parry, Stephen, Bryan, Nicholas D., Heath, Sarah L., Heald, Steven M., Knight, Darrell, O’Brien, Luke, Fuller, Adam, Bower, William, Law, Gareth, & Livens, Francis. Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges. United States. https://doi.org/10.3390/geosciences9010031
Law, Kathleen A., Parry, Stephen, Bryan, Nicholas D., Heath, Sarah L., Heald, Steven M., Knight, Darrell, O’Brien, Luke, Fuller, Adam, Bower, William, Law, Gareth, and Livens, Francis. Tue .
"Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges". United States. https://doi.org/10.3390/geosciences9010031. https://www.osti.gov/servlets/purl/1491807.
@article{osti_1491807,
title = {Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges},
author = {Law, Kathleen A. and Parry, Stephen and Bryan, Nicholas D. and Heath, Sarah L. and Heald, Steven M. and Knight, Darrell and O’Brien, Luke and Fuller, Adam and Bower, William and Law, Gareth and Livens, Francis},
abstractNote = {One of the most challenging components of the UK nuclear legacy is Magnox sludge, arising from the corrosion of Mg alloy-clad irradiated metallic U fuel that has been stored in high pH ponds. The sludges mainly comprise Mg hydroxide and carbonate phases, contaminated with fission products and actinides, including Pu. Cementation and deep geological disposal is one option for the long-term management of this material, but there is a need to understand how Pu may be leached from the waste, if it is exposed to groundwater. Here, we show that cemented Mg(OH)2 powder prepared with Pu(IV)aq is altered on contact with water to produce a visibly altered ‘leached zone’, which penetrates several hundred microns into the sample. In turn, this zone shows slow leaching of Pu, with long-term leaching rates between 1.8–4.4 × 10-5% of total Pu per day. Synchrotron micro-focus X-ray fluorescence mapping identified decreased Pu concentration within the ‘leached zone’. A comparison of micro-focus X-ray absorption spectroscopy (µ-XAS) spectra collected across both leached and unleached samples showed little variation, and indicated that Pu was present in a similar oxidation state and coordination environment. Fitting of the XANES spectra between single oxidation state standards and EXAFS modeling showed that Pu was present as a mixture of Pu(IV) and Pu(V). The change in Pu oxidation from the stock solution suggests that partial Pu oxidation occurred during sample ageing. Similarity in the XAS spectra from all samples, with different local chemistries, indicated that the Pu oxidation state was not perturbed by macro-scale variations in cement chemistry, surface oxidation, sample aging, or the leaching treatment. These experiments have demonstrated the potential for leaching of Pu from cementitious waste forms, and its underlying significance requires further investigation.},
doi = {10.3390/geosciences9010031},
journal = {Geosciences},
number = 1,
volume = 9,
place = {United States},
year = {Tue Jan 08 00:00:00 EST 2019},
month = {Tue Jan 08 00:00:00 EST 2019}
}
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Table 1.: Summary of Pu-containing sample preparation and pre-treatment. Samples containing 239Pu were used for leaching experiments, while those containing 242Pu were used for spectroscopic studies. Leached and unleached examples of the 242Pu-containing samples were prepared.
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Works referenced in this record:
ATHENA , ARTEMIS , HEPHAESTUS : data analysis for X-ray absorption spectroscopy using IFEFFIT
journal, June 2005
- Ravel, B.; Newville, M.
- Journal of Synchrotron Radiation, Vol. 12, Issue 4
Probing the microstructure and water phases in composite cement blends
journal, March 2007
- Gorce, Jean-Philippe; Milestone, Neil B.
- Cement and Concrete Research, Vol. 37, Issue 3
Characterisation of plutonium species in alkaline liquors sampled from a UK legacy nuclear fuel storage pond
journal, January 2011
- Gregson, Colin R.; Hastings, Jeremy J.; Sims, Howard E.
- Analytical Methods, Vol. 3, Issue 9
Solubility and hydrolysis of tetravalent actinides
journal, January 2001
- Neck, Volker; Kim, J. I.
- Radiochimica Acta, Vol. 89, Issue 1
Calcium carbonate efflorescence on Portland cement and building materials
journal, January 2003
- Dow, C.; Glasser, F. P.
- Cement and Concrete Research, Vol. 33, Issue 1
Analysis of calcium leaching behavior of plain and modified cement pastes in pure water
journal, March 2009
- Jain, Jitendra; Neithalath, Narayanan
- Cement and Concrete Composites, Vol. 31, Issue 3
Properties of cement systems containing intermediate level wastes
journal, March 1992
- Palmer, J. D.; Fairhall, G. A.
- Cement and Concrete Research, Vol. 22, Issue 2-3
The PNC/XOR X-ray microprobe station at APS sector 20
journal, November 2007
- Heald, S. M.; Cross, J. O.; Brewe, D. L.
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 582, Issue 1
Discharges to the environment from the Sellafield site, 1951-1992
journal, June 1995
- Gray, J.; Jones, S. R.; Smith, A. D.
- Journal of Radiological Protection, Vol. 15, Issue 2
Protective or damage promoting effect of calcium carbonate layers on the surface of cement based materials in aqueous environments
journal, September 2010
- Schwotzer, M.; Scherer, T.; Gerdes, A.
- Cement and Concrete Research, Vol. 40, Issue 9
Real-space multiple-scattering calculation and interpretation of x-ray-absorption near-edge structure
journal, September 1998
- Ankudinov, A. L.; Ravel, B.; Rehr, J. J.
- Physical Review B, Vol. 58, Issue 12
Plutonium(III,IV,VI) speciation in Gorleben groundwater using XAFS
journal, January 2009
- Dardenne, Kathy; Seibert, Alice; Denecke, Melissa A.
- Radiochimica Acta, Vol. 97, Issue 2
Combined electron microscopy and vibrational spectroscopy study of corroded Magnox sludge from a legacy spent nuclear fuel storage pond
journal, May 2011
- Gregson, Colin R.; Goddard, David T.; Sarsfield, Mark J.
- Journal of Nuclear Materials, Vol. 412, Issue 1
The encapsulation of Mg(OH)2 sludge in composite cement
journal, March 2010
- Collier, N. C.; Milestone, N. B.
- Cement and Concrete Research, Vol. 40, Issue 3
XANES identification of plutonium speciation in RFETS samples
journal, October 2007
- LoPresti, V.; Conradson, S. D.; Clark, D. L.
- Journal of Alloys and Compounds, Vol. 444-445
Structure of early actinides(V) in acidic solutions
journal, January 2009
- Di Giandomenico, M. V.; Naour, C. Le; Simoni, E.
- Radiochimica Acta, Vol. 97, Issue 7
Solubility and hydrolysis of tetravalent actinides
text, January 1999
- Neck, V.; Kim, J. I.
- Karlsruhe
Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.