Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-22T07:11:44.307Z Has data issue: false hasContentIssue false
  • English
  • Français

An approach to modelling the impact of 14C release from reactor graphite in a geological disposal facility

Published online by Cambridge University Press:  02 January 2018

Charalampos Doulgeris ,
Paul Humphreys  and
Simon Rout
Charalampos Doulgeris*
Affiliation:
Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
Paul Humphreys
Affiliation:
Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
Simon Rout
Affiliation:
Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
*
*E-mail: chdoulgeris@gmail.com
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Carbon-14 (C-14) is a key radionuclide in the assessment of a geological disposal facility (GDF) for radioactive waste. In the UK a significant proportion of the national C-14 inventory is associated with reactor-core graphite generated by the decommissioning of the UK's Magnox and AGR reactors.

There are a number of uncertainties associated with the fate and transport of C-14 in a post-closure disposal environment that need to be considered when calculating the radiological impacts of C-14-containing wastes. Some of these uncertainties are associated with the distribution of C-14-containing gaseous species such as 14CH4 and 14CO2 between the groundwater and gaseous release pathways. As part of the C14-BIG programme, a modelling framework has been developed to investigate these uncertainties. This framework consists of a biogeochemical near-field evolution model, incorporating a graphite carbon-14 release model, which interfaces with a geosphere/biosphere model. The model highlights the potential impact of the microbial reduction of 14CO2 to 14CH4, through the oxidation of H2, on C-14 transport. The modelling results could be used to inform the possible segregation of reactor graphite from other gasgenerating wastes.

Keywords

carbon-14graphitegas generationgeospheredose assessment
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 6 , November 2015 , pp. 1495 - 1503
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2015. This is an open access article, distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Baston, G.M.N., Marshall, T.A., Otlet, R.L., Walker, A.J., Mather, I.D. and Williams, S.J. (2012) Rate and speciation of volatile carbon-14 and tritium releases from irradiated graphite. Mineralogical Magazine, 76, 3293–3302.CrossRefGoogle Scholar
Baston, G., Preston, S., Otlett, R., Walker, J., Clacker, A., Kirkham, M. and Swift, B. (2014) Carbon-14 Release from Oldbury Graphite. AMEC/5352/002 Issue 3, Contractors Report for NDA RWMD, UK.Google Scholar
Bracke, G. and Muller, W (2008) Contribution to a more realistic approach in assessing the release of C-1 4 from low-level radioactive waste repositories. Journal of Contaminant Hydrology, 102, 210–216.CrossRefGoogle Scholar
Gold Sim (2010) User's Guide of GoldSim Contaminant Transport Module (Version 6). GoldSim Technology Group, USA.Google Scholar
Graham, J., Plant R., Small, J. and Smalley, D. (2003) Program User's Guide for the Code GRM, Version 4.1. BNFL Report 00/EN0127/7/1.Google Scholar
Hoch, A.R., Thorne, M.C., Swift, B.T and Bate, F. (2008) Update of the GPA (03) assessment of the consequences of gas. SA/ENV.0948, Contractors Report for NDA RWMD, UK.Google Scholar
Hoch, A.R., Lever, D.A. and Shaw, G. (2014) Uptake of carbon-14 in the biosphere: summary report. AMEC/004041/008 Issue 1, Contractors Report for RWM Ltd, UK.Google Scholar
Humphreys, P., McGarry, R., Hoffmann, A. and Binks, P. (1997) DRINK: a biochemical source term model for low level radioactive waste disposal sites. FEMS Microbiology Reviews, 20, 557–571.CrossRefGoogle Scholar
Humphreys, P.N., West, J.M. and Metcalfe, R. (2010) Microbial Effects on Repository Performance. QRS-1378Q-1, Version 3.0, Contractor's Report for the NDA RWMD, UK.Google Scholar
Jackson, C.P. and Yates, H. (2011) Key Processes and Data for the Migration of 14C Released from a Cementitious Repository. SERCO/TAS/02925/002, Contractor's Report for the NDA RWMD, UK.Google Scholar
Kuitunen, E. (2011) Geological disposal of radioactive waste — effects of repository design and location on post-closure flows and gas migration. Doctoral thesis, University of Manchester, UK.Google Scholar
Limer, L., Smith, G. and Thorne, M. (2010) Disposal of Graphite: A Modelling Exercise to Determine Acceptable Release Rates to the Biosphere. QRS-1454A-1, Contractor's Report for the NDA RWMD, UK.Google Scholar
McNab, W.W. and Narasimham, T.N. (1994) Modelling reactive transport of organic compounds in ground-water using a partial redox disequilibrium approach. Water Resources Research, 30, 2619–2635.CrossRefGoogle Scholar
NDA (2010a) Near-field Evolution Status Report. NDA/ RWMD/033, NDA, UK.Google Scholar
NDA (2010b) Generic Post-closure Safety Assessment. NDA/RWMD/030, NDA, UK.Google Scholar
NDA (2010c) Gas Status Report. NDA Report NDA/ RWMD/037, NDA, UK.Google Scholar
NDA (2011) Higher Active Waste. Reactor Decommissioning Update — Summary of Options for Waste Graphite, NDA, UK.Google Scholar
NDA (2012) Carbon-14 Project-Phase 1 Report. NDA/ RWMD/092, NDA, UK.Google Scholar
NDA (2014) The 2013 UK Radioactive Waste Inventory -Radioactive Waste Composition. NDA/ST/STY(14) 0011, NDA, UK.Google Scholar
Postima, D. and Jacobsen, R. (1996) Redox zonation: equilibrium constraints on the Fe(III)/SO4-reduction interface. Geochimica et Cosmochimica Acta, 60, 3169–3175.CrossRefGoogle Scholar
Rittmann, B.E. and McCarty, P.L. (2001) Environmental Biotechnology: Principles and Applications. McGraw-Hill International editions.Google Scholar
Rodwell, W.A. (2004) Specification for SMOGG Version 4.0: a Simplified Model of Gas Generation from Radioactive Wastes. SERCO/ERRA-0452 Version 5, Serco Assurance, Harwell, UK. Contractor's Report for NDA RWMD, UK.Google Scholar
Rout, S.P., Charles, C.J., Garratt, E.J., Laws, A.P., Gunn, J. and Humphreys, P.N. (2015) Evidence of the generation of isosaccharinic acids and their sub-sequent degradation by local microbial consortia within hyper-alkaline contaminated soils, with relevance to intermediate level radioactive waste disposal. PLoS ONE, DOI: http://dx.doi/org/10.1371/journal.pone.0119164.Google Scholar
Schwartz, M.O. (2012) Modelling groundwater contamination above a nuclear waste repository at Gorleben, Germany. Hydrogeology Journal, 20, 533–546.CrossRefGoogle Scholar
Smith, K., Jackson, D., Smith, G. and Norris, S. (2012) Comparison of modelled uptake to cereal crops of 14C from gaseous or groundwater mediated pathways. Mineralogical Magazine, 76, 3241–3249.CrossRefGoogle Scholar
Suckling, P., Avis, J., Humphreys, P. and King, F. (2011) T2GGM Version 2: Gas Generation and Transport Code. DGR-TR-2011-33, NWMO, Canada.Google Scholar
Suzuki, S., Kuenen, J.G., Schipper, K., van der Velde, S., Ishii, S., Wu, A., Sorokin, D.Y., Tenney, A., Meng, X. Y, Morrill, P.L., Kamagata, Y., Muyzer, G. and Nealson, H. (2014) Physiological and genomic features of highly alkaliphilic hydrogen-utilizing Betaproteobacteria from a continental serpentinizing site. Nature Communications, 5, 3900. http://dx.doi.org/10.1038/ncomms4900.CrossRefGoogle Scholar
Thorne, M.C. (2005) Development of Increased Understanding of Potential Radiological Impacts of Radioactive Gases from a Deep Geological Repository: Review of FSA and Nirex Models and Associated ScopingCalculations.MTA/P0011B/2005-5, Issue 2, Contractor's Report for UK Nirex Ltd, UK.Google Scholar
Towler, G., Penfold, J., Limer, L. and Arter, E. (2012) Geological Disposal of Graphite Wastes. Report on Performance Calculations of UK Graphite in a Deep Repository. CARBOWASTE (Deliverable T-6.4.6).Google Scholar
Virden, B.T. and Kral, T.A. (2010) Methanogen use of insoluble carbonates and the implications for life on Mars. Astrobiology Science Conference 2010, League City, Texas, USA.Google Scholar
Walke, R., Humphreys, P., King, F., Little, R., Metcalfe, R., Penfold, J., Towler, G., Walsh, R. and Wilson, 1 (2011) Post closure Safety Assessment: Data. Report. DGR-TR-2011-32, NWMO, Canada.Google Scholar