Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-23T17:09:14.166Z Has data issue: false hasContentIssue false

Intercomparison of Models of 14C in the Biosphere for Solid Radioactive Waste Disposal

Published online by Cambridge University Press:  09 February 2016

Shelly Mobbs*
Affiliation:
Eden Nuclear and Environment, Eden Conference Barn, Low Moor, Penrith CA10 1XQ, United Kingdom
George Shaw
Affiliation:
University of Nottingham, United Kingdom
Simon Norris
Affiliation:
Nuclear Decommissioning Authority (NDA), United Kingdom
Laura Marang
Affiliation:
Electricité de France (EDF), France
Trevor Sumerling
Affiliation:
Low Level Waste Repository Ltd (LLWR), United Kingdom
Achim Albrecht
Affiliation:
L'Agence Nationale pour la gestion des Déchets Radioactifs (ANDRA), France
Shulan Xu
Affiliation:
Strålsäkerhetsmyndigheten (SSM), Sweden
Mike Thorne
Affiliation:
Mike Thorne and Associates Ltd, United Kingdom
Laura Limer
Affiliation:
Limer Scientific Consulting Ltd, China
Karen Smith
Affiliation:
Eden Nuclear and Environment, Eden Conference Barn, Low Moor, Penrith CA10 1XQ, United Kingdom
Graham Smith
Affiliation:
GMS Abingdon Ltd, United Kingdom
*
2Corresponding author. Email: sfm@eden-ne.co.uk.

Abstract

Radiocarbon is present in solid radioactive wastes arising from the nuclear power industry, in reactor operating wastes, and in graphite and activated metals that will arise from reactor decommissioning. Its half-life of 5730 yr, among other factors, means that 14C may be released to the biosphere from radioactive waste repositories. These releases may occur as 14C-bearing gases, especially methane, or as aqueous species, and enter the biosphere from below via natural processes or via groundwater pumped from wells. Assessment of radiation doses to humans due to such releases must take account of the major role of carbon in biological processes, requiring specific 14C assessment models to be developed. Therefore, an intercomparison of 5 14C assessment models was organized by the international collaborative forum, BIOPROTA. The intercomparison identified significantly different results for the activity concentrations in the soil, atmosphere, and plant compartments, based upon the different modeling approaches. The major source of uncertainty was related to the identification of conditions under which mixing occurs and isotopic equilibrium is established. Furthermore, while the assumed release area plays a role in determining the calculated atmospheric 14C concentrations, the openness of the plant canopy and the wind profile in and above the canopy are the key drivers. The intercomparison has aided understanding of the processes involved and helped to identify areas where further research is required to address some of the uncertainties.

Type
Articles
Copyright
Copyright © 2013 by the Arizona Board of Regents on behalf of the University of Arizona 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agüero, A, Pérez-Sánchez, D, Trueba, C, Moraleda, M. 2006. Characteristics and behaviour of C-14, Cl-36, Pu-239 and Tc-99 in the biosphere in the context of performance assessments of geological repositories for high-level radioactive wastes. Madrid: CIEMAT.Google Scholar
Albrecht, A. 2010. Les équations du modèle de transfert du carbone-14 (14C) dans la biosphère (AquaC_14) et leur intégration dans le code “Modèle Management, MoM”; Note technique. Report number: C.NT.AS-TR.10.0052.A, ANDRA, Châtenay-Malabry.Google Scholar
Amiro, BD, Zhuang, Y, Sheppard, SC. 1991. Relative importance of atmospheric and root uptake pathways for 14CO2 transfer from contaminated soil to plants. Health Physics 61(6):825–9.CrossRefGoogle ScholarPubMed
Avila, R, Pröhl, G. 2008. Models used in the SFR 1 SAR-08 and KBS-3H safety assessments for calculation of C-14 doses, SKB Rapport R-08–16.Google Scholar
Bush, RP, White, IF, Smith, GM. 1984. Carbon-14 waste management. CEC, Euratom Report EUR-8749.Google Scholar
Ciffroy, P, Siclet, F, Damois, C, Luck, M, Duboudin, C. 2005. A dynamic model for assessing radiological consequences of routine releases in the Loire River: parameterisation and uncertainty/sensitivity analysis. Journal of Environmental Radioactivity 83(1):948.Google Scholar
Ekdahl, CA, Bacastow, R, Keeling, DC. 1972. Atmospheric carbon dioxide and radiocarbon in the natural carbon cycle. In: Brookhaven Symposium on Carbon in the Biosphere. CONF-720510.Google Scholar
Hou, X. 2005. Rapid analysis of 14C and 3H in graphite and concrete for decommissioning of nuclear reactor. Applied Radiation and Isotopes 62(6):871–82.Google Scholar
Hou, X. 2007. Radiochemical analysis of radionuclides difficult to measure for waste characterization in decommissioning of nuclear facilities. Journal of Radioanalytical and Nuclear Chemistry 273(1):43–8.Google Scholar
International Atomic Energy Agency (IAEA). 2003. “Reference Biospheres” for Solid Radioactive Waste Disposal Report of BIOMASS Theme 1 of the BIO-sphere Modelling and ASSessment (BIOMASS) Programme, IAEA-BIOMASS-6. Vienna: IAEA.Google Scholar
International Union of Radioecology (IUR). 2006. Recommendations for improving predictions of the long-term environmental behaviour of 14C, 36Cl, 99Tc, 237Np and 238U, Findings of the IUR “Radioecology and Waste” Task Force. IUR Report 6.Google Scholar
Killough, GG. 1980. A dynamic model for estimating radiation dose to the world population from releases of 14C to the atmosphere. Health Physics 38(3):269–300.CrossRefGoogle Scholar
Limer, L, Albrecht, A, Marang, L, Miquel, S, Tamponnet, C, Nakai, K, Gierszewski, P, Thorne, M, Smith, G. 2008. Investigation of Cl-36 behaviour in soils and uptake into crops. A report prepared within the BIOPROTA international cooperation programme and published by ANDRA: C.RO.ASTR.08.0048.Google Scholar
Limer, L, Smith, G, Thorne, M. 2010. Disposal of graphite: a modelling exercise to determine acceptable release rates to the biosphere. A study for the Nuclear Decommissioning Authority, Radioactive Waste Management Division, QRS-1454A-1, Version 2.2.Google Scholar
Limer, LMC, Thorne, MC, Towler, GH. 2011. Assessment calculations for C-14 labelled gas for the LLWR 2011 ESC. Quintessa Limited report to LLWR Limited QRS-1443Z-1, Version 4.0, April 2011.Google Scholar
Limer, LMC, Smith, K, Albrecht, A, Marang, L, Norris, S, Smith, GM, Thorne, MC, Xu, S. 2012. C-14 long-term dose assessment: data review, scenario development, and model comparison. SSM 2012:47. Available from http://www.stralsakerhetsmyndigheten.se.Google Scholar
Magnusson, Å, Strenström, K, Aronsson, P-O. 2008. 14C in spent ion-exchange resins and process water from nuclear reactors: a method for quantitative determination of organic and inorganic fractions. Journal of Radioanalytical and Nuclear Chemistry 275(2):261–73.Google Scholar
Penfold, JP, Watkins, B. 1998. Transfer of C-14 in the biosphere bibliography and modelling. Rapport QuantiSci n° C NT OQUA 98-001.Google Scholar
Sheppard, SC, Ciffroy, P, Siclet, F, Damois, C, Sheppard, MI, 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(1):3251.CrossRefGoogle Scholar
Thomson, G, Miller, A, Smith, G, Jackson, D. 2008. Radionuclide release calculations for SAR-08. Swedish Nuclear Fuel and Waste Management Company, SKB Report R-08-14. Stockholm.Google Scholar
Thorne, MC. 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 scoping calculations. Mike Thorne and Associates Limited report to UK Nirex Limited MTA/P0011b/2005-5: Issue 2, November 2005.Google Scholar
Thorne, MC. 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 to Nirex, Report No. MTA/P0011b/2005-10: Issue 2.Google Scholar
van Hecke, W. 2001. Intégration du modèle 14C développé par Quantisci au code de calcul Aquabios et comparaison avec le modèle utilisé précédemment. Report ANDRA N° C NT ABSE 00-032/A, Châtenay-Malabry.Google Scholar