Skip to main content

PORE SPACE INVESTIGATION IN NATURAL AND ARTIFICIAL MATERIALS

Final Report Summary - POSINAM (PORE SPACE INVESTIGATION IN NATURAL AND ARTIFICIAL MATERIALS)

POSINAM (POre Space Investigation in Natural and Artificial Materials) is an EU project. It is one of PEOPLE MARIE CURIE ACTIONS; Industry-Academia Partnerships and Pathways (IAPP); we answered successfully to the Call: FP7-PEOPLE-IAPP 2008. POSINAM started the 15.10.2009 and ended 14.10.2013. This type of project is made possible by the collaboration of one public laboratory and a private company located in two different countries. Radiochemistry laboratory of University of Helsinki was the public partner located in Finland and ERM Company was the private partner. University of Poitiers, historical partner of both entities was associated to the project. The PMMA methodology was mainly developed by Marja Siitari-Kauppi.She was responsible for the project in the Radiochemistry laboratory of University of Helsinki.

The objective of the research program of Posinam was to produce realistic 3D models of natural and artificial materials including porosity distribution. This needs to integrate techniques that characterize 3D pore network in natural and artificial materials likegranite and clay rocks,soils, cements and graphite. The aim is to understand how porosity distribution is related to minerals and how pore structure is related to solute diffusion and transport processes.

The aim of the program is to link the know how of the following partners:
- To improve knowledge of petrography on granite and clay rocks, cements and soils, related to porosity organisation (expertise of IC2MP/HYDRASA in Poitiers, France).
- To characterize heterogeneous spatial porosities of these materials using an impregnation technique with 14C- or 3H PolyMethylMethAcrylate (PMMA) resin (expertise of HYRL in Helsinki, Finland).
- To provide service for industries which need 3D models of their materials (SME ERM, Poitiers, France).

Radioactive resin saturation combined with autoradiograph acquisition and image processing isa unique manner to produce a heterogeneous quantitative porosity map which integrates all the connected pores whatever their size.

The main developments during Posinam project are described below:

- A tangible achievement of Posinam is the PMMA laboratory built in Poitiers
(http://uptv.univ-poitiers.fr/program/posinam-workshop/video/3919/pmma-laboratory-virtual-visit-poitiers-university/index.html.)
Risk assessment and radioprotection in this PMMA laboratory are taken into account.

- Optimization of thermal polymerization using chemical initiators. Within the PMMA methodology it has been used two techniques to polymerize MMA: polymerization by irradiation and by thermal polymerization. Polymerization by irradiation is rarely possible to implement; so thermal polymerization is the solution that will be used in Poitiers laboratory. In addition to the earlier results clay samples (non swelling) were impregnated and polymerized by thermal method. The results provided by irradiation polymerization versus thermal polymerization were checked. Using thermal polymerization method, the PMMA porosities for bricks (about 30%) were in good agreement with porosities measured by the irradiation polymerization. The PMMA porosities for Grimsel granodiorite are similar too. The initial results for the clay samples show fairly good agreement between the porosities done by different polymerization techniques.

Interaction between swelling clay and different solvents. The first step of impregnation of material containing swelling clay minerals is often performed via the solvent exchange process. The work consists an investigation of polymer/clay systems using pure montmorillonite (effect of structure, size, charge), functional groups of monomers and monomer/water combinations on the clay structure e.g. interlamellar spacing (using XRDF, IR techniques) and polymerization of various monomers in the clay pore space.
- Quantitative image analyses tools on autoradiographs. Image is an end product of the 14CPMMA technique. Relationship between cracks’ density and age are studied on a sequence of altered granodiorite from Bishop Creek (USA) (age of alteration known by 36Cl, from present time to 130 ky). The PMMA autoradiographic method is linked and compared with and XRCT microtomography. In addition the PMMA autoradiographs and images from optical microscopy and SEM are compared. Petrographic observations and XRD analysis of mineralogy are conducted, and the results are combined with the porosity results. Digital autoradiography (Fuji FLA scanner using phosphor plate technique) was calibrated for 14C-PMMA method, and was used comparatively to conventional film autoradiography.
-
- Interfaces of porosity calculation program Mankeli (MatlabR), a software developed since 2000 in Helsinki, was improved during this project.

Posinam workshop held in Poitiers (September, 2013, 25-26) gave an overview of the project and the potential applications of PMMA impregnation technique (uptv.univ-poitiers.fr/program/posinam-workshop/index.html):

- nuclear waste management: relationships between autoradiographs, SEM and X-ray tomography images applied on clay samples coming from Underground Laboratory of ANDRA (France) ; study of clay/cement interface ; description of porous structures adjacent to water conducting fractures in Olkiluoto site (Finland); in-situ impregnation at Grimsel Test Site (Switzerland).
- CO2 sequestration with the study of a chemo-mechanical stress for a porous cement mortar subjected to CO2 attack.
- applications of PMMA method on mining or on oil exploration either for the study of mineral alteration processes or on environmental impact of extraction processes.


The potential impact of POSINAM project is the creation of a group able to provide scientific results and services. This group is able to answer to demands originating from industrial companies or public bodies for characterizing porosity of clay, rocks and artificial geo materials. The Finnish governmental authority for the nuclear industry (STUK) and The French Institute for Radiological Protection and Nuclear Safety (IRSN) expressed their interest for POSINAM project.

www.posinam.eu