R&D

Cement-Organic-Radionuclide interactions (CORI)

Improved understanding of the role off organics (either naturally occurring or as introduced in the wastes and their influence on radionuclide migration in cement based environments)

Major highlights (June 2022 - May 2023) and forward look 

CORI has continued the experimental programme within Year 4 of EURAD, and will further continue until EURAD PM 60. No impact from Covid-19 was experienced and the global challenges in connection to the war in Ukraine, with the related impacts on overall energy costs and planning, did not raise significant problems for the work performed in CORI.
The technical progress in CORI focused on continuing the studies performed within the three R&D tasks. New data and results were reported regarding organics degradation and retention processes in the binary organics-cement and ternary radionuclide-organics-cement systems. Ten peer-reviewed publication were published in Year 4, for instance focusing on (i) nickel retention by calcium silicate hydrate phases and the evaluation of the role of the Ca/Si ratio on adsorption and precipitation processes, (ii) radium behavior in contact with Calcium-Silicate-Hydrates, or (iii) solubility of Ca(II), Ni(II), Nd(III) and Pu(IV) in the presence of proxy ligands for the degradation of polyacrylonitrile in cementitious systems. The joint publication of CORI with FUTURE, CONCORD and MODATS (Long-term radionuclide retention in the near field: collaborative R&D studies within EURAD focusing on container optimisation, mobility, mechanisms and monitoring) related to the joint EURADWASTE presentation has likewise been issued.
Regarding the 6 KPIs defined for Year 4 in EURAD, 5 KPIs have been positively completed. The contributions to the Proceedings document from the last Annual CORI Workshop will only be completed in the summer of 2023. 
A highlight was the contributions from CORI at the EURAD Annual Event in Cyprus. Together with FUTURE a specific session presenting and discussing studies performed on migration was successfully organised. 
Within the trilateral exchange between CORI, UMAN and ICS, several meetings were held and the path forward discussed and defined. 
With a look forward into the last Year 5 in EURAD, CORI will finalize the experimental programme, continue the dissemination or results and work to achieve a continued positive publication output. The interaction with other EURAD partners will likewise be continued, especially regarding the interactions between CORI, UMAN and the ICS group, or within exchanges at the Annual EURAD event. A special focus will be given to the preparation of Deliveralbes and final reporting in EURAD as well as performing a systematic assessment of the CORI impact. 
Seen it total, the CORI project was progressing well during the 4th project year. The technical programme is developing and the additional tools made available in EURAD are established and being used. 
The WP leader wants to thank all partners involved in CORI for the good and motivated work performed over the project duration, especially regarding the mitigation of the impact of the past Covid crisis on the experimental program.

‘What’


This WP aims to develop an in-depth understanding of the interaction of cementitious materials with omnipresent organic matter and with radionuclides. Organic materials are present in some nuclear waste and as admixtures in cement-based materials and can potentially influence the performance of a geological disposal system, especially in the context of low and intermediate level waste disposal. The potential accelerating effect of organic molecules on radionuclide migration is related to the formation of complexes in solution with some radionuclides of interest (actinides and lanthanides) which can (i) increase the radionuclide solubility and (ii) decrease the radionuclide sorption. The WP’s raison d’être is to quantify the organic release issues which can accelerate the radionuclide migration in the context of the post closure phase of geological repositories for ILW and LLW/VLLW, including surface/shallow disposal.

‘Why’


The thematic represented by the WP Cori has been selected for the first phase of the EJP as “improved understanding of the role of organics (either naturally occurring or introduced by the wastes) and their influence on radionuclide migration” was identified as an important subject in theme 4 (Geoscience to understand rock properties, radionuclide transport and long-term geological evolution) phase 1 and 2 of the roadmap. Due to the potential degradation of organic matter, this subject is particularly challenging in cementitious environments. Due to the importance of this subject in national programs, various mandated actors are working already since long time on the issues addressed by this WP (see for instance the meetings of the former TSWG in May 2013, Ghent, Belgium, leading to CEBAMA, or the latter extended discussion on CORI at the IGD-TP EF 6 (2015) in London, UK). Over this entire period, partners were eager to join forces for a strong improvement in scientific understanding allowing assessing long term radionuclide mobility in organic rich cementitious waste disposal environments.