R&D

Sustainable treatment and immobilisation of challenging waste (STREAM)

WP Leader: Federica Pancotti (SOGIN, Italy)

Objectives

Innovative and sustainable design, optimization and upscaling of treatments and conditioning materials for the predisposal of problematic waste

Major highlights (March 2025 - February 2026)

  • Initial State of the Art (SotA) Report
    The Initial SotA Report (Deliverable D6.1) was published in June 2025 
  • Workshops
    • The first online WP6 STREAM Annual Workshop was held on 11 June 2025
    • A joint online workshop with WP5 ICARUS and WP7 L’OPERA took place on 25 June 2025
  • Conference Contributions
    The WP6 STREAM poster was presented at:
    • FISA–EURADWASTE 2025, 11–16 May 2025, Warsaw, Poland
    • NUWCEM 2025, 20–22 May 2025, Avignon, France
  • Scientific Publications
    Two articles were published:
  • Task 3 Milestones (December 2025)
    Two Task 3 milestones were successfully achieved:
    • MS62 — Intermediate report on the selection of the most promising available treatment processes
    • MS63 — Intermediate report on the selection of the most promising conditioning matrices
  • Task 4 Kick-off
    The first online meeting of Task 4 was held on 24 January 2026
  • Students
    A total of 11 PhD, postdoctoral, and MSc students are currently involved in STREAM R&D activities

Forward look

  • Conference Contributions
    An abstract titled “Innovative conditioning matrices for the immobilisation of problematic radioactive waste streams (EURAD‑2 STREAM)” has been submitted to the SNETP Forum 2026, taking place on 25–27 March 2026 in Madrid, Spain

     

  • Training Course
    A joint (WP5-WP6-WP7) training course on “Geopolymers for Radioactive Waste Conditioning” is scheduled to be held at SCK CEN, Mol, Belgium, on 18–20 May 2026

     

  • Workshops
    The WP6 STREAM Annual Workshop 2026 will be held in Brussels on 21–22 May 2026

Description of the WP

Large amounts of waste in Europe need the implementation of management routes prior to disposal. Specifically, management routes for challenging low-level and intermediate-level radioactive waste (solid (reactive metals, spent IERs, incineration ashes) or liquid (aqueous or organic)) still need to be further investigated. 

Processing routes (e.g., thermal treatments) and alternative conditioning methods compared to the traditional cement-based immobilisation (e.g., geopolymers, phosphate binders) have been investigated in previous projects (EURAD, THERAMIN, PREDIS). However, these processes are not yet fully mature and need complementary studies on:

  • The influence of the waste composition on the consolidation process of the conditioning matrix, 

  • The properties of the hardened waste forms,

  • The minimization and management of secondary waste.

The impact of these novel treatment and/or conditioning routes to the safety case has also to be demonstrated to allow their implementation by end users in the future. 

Besides, the evolution of the cement industry to reduce its environmental footprint will lead to progressive disappearance of binders with high clinker content (e.g., CEM I 52.5), currently used for the conditioning of certain types of radioactive waste (e.g., evaporator concentrates). The availability of supplementary cementitious materials, such as fly ash or blast-furnace slag, is also expected to decrease in the near future. Inversely, novel cements (CEM II/C-M, CEM VI, LC3, belite-calcium sulfoaluminate cements…) are under development / standardization and may offer new prospects to design cement-based matrices and backfill materials with reduced environmental impact, following the principles of circular economy. Their performances must be demonstrated to anticipate their implementation at an industrial level.

Finally, LCA and LCC analyses of the most promising processes / materials developed in STREAM WP will be carried out to guide end-users in the selection of the best treatment / conditioning strategy, considering technical, economic and environmental issues.

 

Outcomes

  • Development of new management routes including treatment and conditioning methods as well as new backfills materials, in a safe and sustainable way for waste streams without any previously identified or industrially implemented management routes (to increase TRLs). 

  • Moving technologies from the lab-scale to industrial-scale. Facilitate improved treatment and processing of new and different types of waste streams,  and the optimisation of thermally treated product composition to increase waste loadings and/or improve waste form performance and reduce volumes of secondary waste. Development of more flexible, modular treatment facilities and solutions. Optimised chemical and physical methods of treatment, especially including solutions for decontamination.

  • Increased confidence in simulations by reducing uncertainties in the input data and understanding of key processes. 

  • Identification and sharing of good practices in waste conditioning and packaging approaches for problematic wastes and new / future wastes. 

Deliverables