Fourth meeting of INAGO, INAGO-4

The fourth meeting of INAGO (The International Advisory Group for Olkiluoto Investigations), INAGO-4, took place in November 2005 at the Hanasaari Cultural Centre, Espoo. The purpose of the meeting was to examine various elements of Posiva’s research and investigation programme in the ONKALO, including the revision of the CEIC procedures and the reorganisation of the ONKALO project; to provide a response to subjects raised by INAGO in their Issue List; to present the proposed programme on the EDZ (a subject raised by STUK); to examine elements of the integration of the ONKALO programme and, jointly with the Safety Committee, to consider a report from Posiva entitled “Control of water inflow and use of cement in the ONKALO after penetration of fracture zone R19”.

The developments in Posiva’s programme since the INAGO-3 meeting were outlined, including Posiva’s new organisational structure, in particular the formation of a new Project Department with responsibility for the construction activities. The status of the ONKALO programme was also presented – this included the revised structure of the various groups within Posiva that are responsible for subjects such as the co-ordination of the investigations and the development of the safety case. The CEIC procedures, that had been presented at the INAGO-3 meeting, have been revised in response to comments from INAGO, and the new procedures were presented.

Presentations were given on four items from INAGO’s issue list: open boreholes, the SAFCA project, the mapping programme in the ONKALO and the integration of the RTD processes within Posiva’s programme. The most interesting of these to INAGO was perhaps the subject of open boreholes, as they have commented on these in previous meetings and because they are important with regard to the impact of the R19 fracture zone. Presentations were also given on Posiva’s proposed programme on the EDZ and on the development of the transport concept, with the use of DFN models.

Considerable discussion took place as a result of the presentation of the R19 report, as the implications regarding grouting, with the effect of a high-pH plume and the potential use of low-pH cementitious grout, together with the potential impact of the upconing of more saline groundwater, are important issues from both a safety and a construction standpoint.

Many of the issues that had been raised by INAGO have been resolved, completely or partially, as a result of the work and the re-organisation that has been carried out, with Posiva having responded constructively to the recommendations from INAGO; and further issues seem likely to be resolved with the publication of the TKS-2006 report next year.

The members of INAGO are: Pekka Särkkä (Helsinki University of Technology, Chair), Cliff Davison (AECL), Paul Degnan (Nirex), Andreas Gautschi (Nagra), Bernard Mouroux (Andra) and Peter Wikberg (SKB); Tim McEwen is the Technical Secretary.

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