The distribution and selective decontamination of carbon-14 from nuclear graphite

JOURNAL OF NUCLEAR MATERIALS

卷:556

Article

Worth, Robert N.¹  Theodosiou, Alex¹  Bodel, William¹  Arregui-Mena, Jose David^1,3  Wickham, Anthony J.²  Jones, Abbie N.¹  Mummery, Paul M.¹ 

[1] Univ Manchester, Nucl Graphite Res Grp, Dept Mech Aerosp & Civil Engn, Manchester M13 9PL, Lancs, England

[2] Univ Manchester, Manchester M13 9PL, Lancs, England

[3] Oak Ridge Natl Lab, One Bethel Valley Rd, Oak Ridge, TN 37830 USA

关键词: Nuclear graphite;    Nuclear waste;    Selective decontamination;    Carbon-14;    Thermal oxidation;   

DOI  :  10.1016/j.jnucmat.2021.153167

来源: Elsevier

【 摘 要 】

This work investigates 14 C release behaviour from UK Magnox reactor sourced irradiated graphite under relatively low temperature oxidation conditions: a 1% oxygen in argon atmosphere at temperatures ranging from 600 degrees C to 700 degrees C, and durations from 4 to 120 hours. A method is used for construction of a detailed 14 C release profile with mass loss. The 14 C release profile is predictable between samples, and an empirical release profile is derived to predict releases to higher mass losses than in this work. An accelerated 14 C release rate at small mass losses is observed, indicative of a 14 C-enriched surface region with a depleting concentration gradient into the material, and the source terms and complexities associated with predicting where the 14 C arose from are discussed. Selective decontamination of a fraction of the 14 C is possible, with the limitation of a reducing efficiency with mass loss and time. This work demonstrates a method for determining the distribution of 14 C between near-surface regions and the bulk material in differing sources of irradiated graphite, and provides data in support of making an informed assessment for the adoption of low temperature thermal treatment and isotopic reduction of irradiated graphite wastes. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

【 授权许可】

Free