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Comparison of modelled uptake to cereal crops of 14C from gaseous or groundwater mediated pathways

Published online by Cambridge University Press:  05 July 2018

K. Smith ,
D. Jackson ,
G. Smith  and
S. Norris
K. Smith*
Affiliation:
Eden Nuclear & Environment Ltd, Eden Conference Barn, Temple Sowerby, Penrith, Cumbria CA10 1XQ, UK
D. Jackson
Affiliation:
Eden Nuclear & Environment Ltd, Eden Conference Barn, Temple Sowerby, Penrith, Cumbria CA10 1XQ, UK
G. Smith
Affiliation:
GMS Abingdon Ltd, Tamarisk, Radley Road, Abingdon, Oxfordshire OX14 3PP, UK
S. Norris
Affiliation:
Radioactive Waste Management Directorate, Nuclear Decommissioning Authority, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0RH, UK
*
*E-mail: ks@eden-ne.co.uk
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Abstract

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Carbon-14 has been identified as one of the more significant radionuclides in solid radioactive wastes in a repository, due to the potential radiological impact arising if 14C were to be released and enter the biosphere. However, the assessment of radiation doses is complicated by the major role of carbon in biological processes, and this has tended to lead to the adoption of a cautious assessment approach.

An international comparison of five models used to predict uptake of 14C to agricultural crops has been undertaken, within the BIOPROTA framework. Processes investigated include conversion of 14C-labelled CH4 into CO2 in soils, carbon accumulation in and release from soil carbon pools, gaseous emanation to, and dispersion from, the plant canopy atmosphere and, incorporation into plants by photosynthesis.

For a unit rate of entry of 14C to soil, modelled activity concentrations in cereal crops differ by three to five orders of magnitude. This reflects, in part, differing assumptions for mixing and dispersion of air above the soil surface and within the crop canopy layer. For a unit activity concentration of 14C in air, the modelled uptake to cereal crops converges significantly. Following an assumed irrigation of crops with groundwater containing unit activity of 14C, the predicted uptake to crops varied by two to four orders of magnitude, again largely dominated by assumptions regarding the canopy atmosphere. In all cases, there is some convergence in model predictions as field size increases.

A continuing programme of field research is being undertaken in parallel with the assessment work.

Keywords

disposalbiospheredose assessment
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 3241 - 3249
Creative Commons
Creative Common License - CCCreative Common License - BY
© [2012] The Mineralogical Society of Great Britain and Ireland. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence (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 2012

References

Albrecht, A. and Miquel, S. (2010) Extension of sensitivity and uncertainty analysis for long term dose assessment of high level nuclear waste disposal sites to uncertainties in the human behaviour. Journal of Environmental Radioactivity, 101, 55–67.CrossRefGoogle ScholarPubMed
Amiro, B.D., Zhuang, Y. and Sheppard, S.C. (1991) Relative importance of atmospheric and root uptake pathways for 14CO2 transfer from contaminated soil to plants. Health Physics 61, 825–829.Google ScholarPubMed
Avila, R. and Pröhl, G. (2008) Models used in the SFR 1 SAR-08 and KBS-3H safety assessments for calculation of C-14 doses. SKB Report R-08–16. Swedish Nuclear Fuel and Waste Management Company, Stockholm.Google Scholar
Atkinson, B.S., Meredith, W., Snape, C., Steven, M., Hoch, A., Lever, D. and Shaw, G. (2012) Migration and fate of 14CH4 in subsoil - tracer experiments to inform model development. Mineralogical Magazine, 76, 3345–3354.Google Scholar
BIOPROTA (2005) Model Review and Comparison for C-14 Dose Assessment. Theme 2 Task 3 Report. UK Nirex Ltd, UK. Bush, R.P., White, I.F. and Smith, G.M. (1983) Carbon- 14 Waste Management. UK Atomic Energy Authority Report No. AERE-R10543.Google Scholar
Bytwerk, B., Limer, L., Albrecht, A., Marang, L., Smith, G. and Thorne, M. (2011) Sources and significance of variation in the dose estimates of 36Cl biosphere transfer models: a model intercomparison study. Journal of Radiological Protection, 31, 63–82.CrossRefGoogle ScholarPubMed
Harris, A.W., Boult, K.A., Manning M.C. and Tearle, W.M. (2003) Experimental study of Carbon Dioxide Uptake by NRVB and 3:1 BFS/OPC. Serco Report Serco/ERRA-0453. Serco Assurance, UK Google Scholar
Limer, L., Albrecht, A., Marang, L., Miquel, S., Tamponnet, C., Nakai, K., Gierszewski, P., Thorne, M. and Smith, G. (2008) Investigation of Cl-36 Behaviour in Soils and Uptake into Crops. Andra report C.RO.ASTR.08.0048. Andra, Ch âtenay- Malabry, France.Google Scholar
Limer, L., Smith, G. and Thorne, M. (2010) Disposal of Graphite: A Modelling Exercise to Determine Acceptable Release Rates to the Biosphere. Quintessa report for the Nuclear Decommissioning Authority, Radioactive Waste Management Division, QRS-1454A-1, Version 2.2.Google Scholar
Limer, L.M.C., Smith, K., Albrecht, A., Marang, L., Norris, S. Smith, G.M., Thorne, M.C. and Xu, S. (2011a) C-14 Long-Term Dose Assessment in a Terrestrial Agricultural Ecosystem: FEP Analysis, Scenario Development, and Model Comparison. BIOPROTA Report, Version 3.0, 14 November 2011.Google Scholar
Limer, L.M.C., Thorne, M.C. and Towler, G.H. (2011b) Assessment Calculations for C-14 Labelled Gas for the LLWR 2011 ESC. Quintessa Report No. QRS- 1443Z-1, Version 4.0, April 2011.Google Scholar
Penfold, J.P. and Watkins, B. (1998). Transfer of C-14 in the Biosphere Bibliography and Modelling. QuantiSci Report No. C NT OQUA 98–001.Google Scholar
Sheppard, S.C., Ciffroy, P., Siclet, F., Damois, C., Sheppard, M.I. and Stephenson, M. (2006) Conceptual approaches for the development of dynamic specific activity models of 14C transfer from surface water to humans. Journal of Environmental Radioactivity, 87, 32–51.CrossRefGoogle Scholar
Thorne, M.C. (2006) Development of Increased Understanding of Potential Radiological Impacts of Radioactive Gases from a Deep Geological Repository: Sensitivity Studies with the Enhanced RIMERS Model. Mike Thorne and Associates Limited Report No. MTA/P0011b/2005–10. Issue 2.Google Scholar
Thomson, G., Miller, A., Smith, G. and Jackson, D. (2008). Radionuclide Release Calculations for SAR- 08. SKB Report R-08–14. Swedish Nuclear Fuel and Waste Management Company, Stockholm.Google Scholar
van Hecke, W. (2001) Intégration du modéle C14 développé par Quantisci au code de calcul Aquabios et comparaison avec le modéle utilisé précédemment. Andra Report C NT ABSE 00–032.A. Andra, Ch âtenay-Malabry, France.Google Scholar