Integration Group for the Safety Case (IGSC)

Co-operative projects

Overview

Co-operative projects are highly specialised activities that address issues of interest to a subset of Integration Group for the Safety Case (IGSC) member institutions.

Argillaceous Media (Clay Club)

The Clay Club examines those various argillaceous rocks that are being considered for the deep disposal of radioactive waste, ranging from soft clays to indurated shales. These rocks exhibit a wide spectrum of characteristics that make them useful as barriers to the movement of water and solutes and as repository construction materials. Studies include clay media characterisation and modelling.
Three key initiatives have now been completed:

  1. The FEPCAT report Features, Events, Processes Evaluation: Catalogue for Agillaceous Media (2003).
  2. A Catalogue of Characteristics of Argillaceous Rock (2005). The catalogue consists of a brochure and a CD-ROM containing all data tables in Excel format.
  3. CLAYTRAC project (2009), in which natural tracer data from nine sites was evaluated to assess potential impacts of disposal of radiological waste in geological repositories.
  4. The self-sealing study (2010) that established a state-of-the art document on the self-sealing of fractures in argillaceous media

Features events and processes (FEP) database
The FEP database assembles features, events and processes for geological disposal as an aid to national programmes to identify, classify and screen FEPs in safety assessment. The database consists of two main parts:

  • The International FEP List - a comprehensive and structured list of factors relevant to the assessment of long-term safety of nuclear waste repositories.
  • Project Databases - a collection of FEP lists and databases, with references, compiled during repository safety assessment studies.

An NEA publication on the Features, Events and Processes (FEPs) for the Geologic Disposal of Radioactive Waste was released in 1999. An updated version (2.1) of the FEP database was completed in 2006 and can be downloaded as a zip file (4 Mb).

Sorption project

The NEA Sorption Project was launched in 1997 to study the potential of chemical thermodynamic models for improving representation of sorption phenomena in the long-term safety analysis of radioactive waste repositories. It is currently in its third and final phase.
The first phase of the project ran from 1997 to 1998 and focused on a workshop held in Oxford, U.K. in May 1997. Presentations at the Oxford workshop highlighted the advances that have been made in the field of sorption modelling with many illustrations of the successful interpretation of sorption phenomena in natural samples. A status report on using thermodynamic sorption models for guiding the selection of radioelement distribution coefficient (Kd) was published in 2001.

The second phase of the project was launched in September 2000. It took the form of a benchmarking exercise to interpret well-characterised datasets for the sorption of radionuclides onto complex materials using several different modelling approaches employed by the various organisations participating in the project. A report on the main findings of Phase II of the Sorption Project has been released, along with several publications in the open literature.

The third phase of the project was launched in November 2007 to address the needs identified during Phase II. At the end of the phase, a guidance document in which the critical issues are treated in a way that will facilitate communication with waste management organisations and regulatory authorities will be issued. To this end, a workshop to present and discuss the draft guidance document will be held.

Thermochemical Data Base (TDB)

The Thermochemical Data Base (TDB) project aims to make available a comprehensive, internally consistent, internationally recognised and quality-assured chemical thermodynamic database. A new phase of the project is now under way to develop a guidance document on the application of sorption models in safety assessments for the deep disposal of radioactive waste.

Related links

IGSC core activities
IGSC technical activities
E-mail contact: igsc@oecd.org.

Last reviewed: 10 October 2010