Grimsel Test Site (Switzerland)

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Colloid Formation and Migration Introduction

Current CFM Project Partners

German Flag BMWi / KIT (Federal Ministry of Economics & Labour / Karlsruhe Institute of Technology), Germany
japanese flag Japan Atomic Energy Agency (JAEA), Japan
Swedish Flag Swedish Nuclear Fuel and Wast Management Co. (SKB), Sweden
Japanese Flag Central Research Institute of Electric Power Industry (CRIEPI), Japan
South Korean Flag Korea Atomic Energy Research Institute (KAERI), Korea
Finnish Flag POSIVA, Finland
US Flag Department of Energy (DOE), USA
alt Nuclear Decommissioning Authority (NDA), UK
Japanese Flag Nuclear Waste Management Organization (NUMO), Japan
Swiss Flag Nagra, Switzerland


Centro de Investigaciones Energéticas Medioambientales y Tecnológicas, (CIEMAT), Spain
Paul Scherrer Institute (PSI), Switzerland
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS), Germany
KTH Royal Institute of Technology, Not Sweden
Los Alamos National Laboratory / Earth Systems Observations (LANL), USA
University of Helsinki / Departement of Chemistry (HYRL), Finland

cfm partners 002
CFM partner meeting in Karlsruhe (Hosted by KIT/INE) 29 to 30 June 2016

The Colloid Formation and Migration project is dedicated to study :

  • Colloid formation/bentonite erosion
  • Groundwater/porewater mixing zone
  • Colloid migration (filtration)
  • Colloid associated RN transport
Laboratory studies
Colloid-Rn interaction
Colloid Generation
Field test analysis
Field experiments
In situ test: formation &
Migration tests with colloids,
homologues, Rn tracers
Modelling studies
Solute, colloid and associated Rn transport
Colloid generation

The expected outputs by the end of the 10-year CFM project include:

  • Significantly enhanced understanding of the processes related to colloid formation at the bentonite/host rock interface
  • Performance-assessment relevant information concerning the influence of colloids on radionuclide migration and retardation
  • Added experience in the long-term monitoring for repository surveillance purposes

The CFM project is the most recent in a series of experiments conducted within the Radionuclide Retardation Programme at the GTS which started in 1984. Of interest is the colloid-facilitated transport of radionuclides in a repository host rock. Such transport could influence the long-term performance of a deep geological repository for radioactive waste. The colloid ladder illustrates the five requirements that must be fulfilled for colloid-facilitated radionuclide transport to be significant.

Colloid ladder with the requirements for significant colloid-facilitated radionuclide transport in a deep geological repository

Recent investigations of colloid-facilitated radionuclide transport tend to address mainly two aspects of the colloid ladder:

  1. The reversibility of the uptake of radionuclides onto colloids – For example does it vary with the colloid type?
  2. The evolution of the associated processes in a repository-relevant system – Although much of the in-situ work conducted around the world has been on longer temporal and spatial scales than is normally possible in laboratory experiments, for reasons of practicality the groundwater velocities are typically more than 100 times greater than would be expected in a suitable repository host rock. We believe that process understanding has progressed to the stage where more realistic experiment set-ups are necessary in order to gain new insights. The aim should be to work with significantly longer time scales and to focus on, for example, semi-stagnant groundwater systems that better match the conditions in and around a waste repository.

For more information please contact : Ingo Blechschmidt, This email address is being protected from spambots. You need JavaScript enabled to view it.

Colloid Formation and Migration Experiment

The GTS underground facilities are also available to interested 3rd parties for underground testing and research. The GTS offers cost-effective access to a fully developed, well characterised underground research facility with round the year logistical support - please contact Dr. Ingo Blechschmidt, Head of the Grimsel Test Site, for further details.