The scope of CAST was defined through a process of consultation initiated by a questionnaire circulated to a wide range of organisations. A synthesis of the responses to the questionnaire showed that 14C release from irradiated steels, Zircaloys, graphites and from ion-exchange resins were of widest interest. The responses indicated that there were several on-going (or planned studies) on irradiated graphites and uncertainties on 14C release rates and speciation remain to be resolved. However, there was less on-going work and little information available, for the release of 14C from irradiated steels, Zircaloys and ion-exchange resins.
The objectives of CAST were to:
a) gain a scientific understanding of the 14C release mechanisms and rates from the corrosion of irradiated steels and Zircaloys and from the leaching of ion-exchange resins and irradiated graphites under geological disposal conditions;
b) provide speciation of the 14C release and how this relates to aqueous conditions;
c) evaluate this understanding in the context of national safety assessments; and
d) disseminate this understanding and its relevance to safety assessments to a range of interested stakeholders and provide an opportunity for training of early career researchers.
These objectives address Topic 2 in Key Topic 2 of the Implementing Geological Disposal- Technology Platform (IGD-TP) Strategic Research Agenda, which identifies a need for improved data and understanding of the underpinning scientific mechanisms of the release of radionuclides and chemical species from various long-lived Intermediate Level Wastes. This includes detailed characterisation methods, issues related to adequate inventory determinations, chemical form, speciation on release and transport in the near field and far field.
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| This photo shows a waste package than can contain irradiated zircaloy and steel | This photo shows the remote handling of this packagecontaining these irradiated metals |
