Features of Planning a Detailed Study of the Hydrodynamic and Hydrochemical Properties of the “Yeniseiskiy” Site of the Nizhnekanskiy Massif

In the coming years, an underground research laboratory will start being constructed at the Yeniseiskiy site within the Nizhnekanskiy rock mass. In this regard, arranging for subsoil monitoring is seen as a priority task to identify the required parameters of undisturbed rock mass. Specific features of hydrogeological setting within the rock mass at the Yeniseiskiy site necessitate interval monitoring in deep wells with open holes using multipacker systems. In-depth studies of sections with a discreteness of 1—2 m are required to identify the monitoring intervals. However, Russia has no hands-on experience in this matter. The article discusses international practice for arranging detailed research at analogue facilities and describes the equipment used. Interpretation of the data obtained is seen as an important part of the research with relevant technique associated with interval injection at constant pressure being discussed in the article

Diffusion in the Matrix of Granitic Rock Field Test in the Stripa Mine

Three similar migration experiments in the matrix of granitic rock are presented. The experiments have been carried out in “undisturbed” rock, that is rock under its natural stress environment. Since the experiments were performed at the 360 m level (in the Stripa Mine), the rock was subjected to nearly the same conditions as the rock surrounding a nuclear waste repository as proposed in the Swedish concept (SKB).A mixture of three non-sorbing (conservative) tracers, Uranine, Cr-EDTA and I−, were injected into the granitic rock matrix for time periods of months up to years. The subsequent overcorings of the injection holes showed that the tracers had in some cases migrated at least ≈ 400 mm (measuring limit) into the rock matrix for the experiment with the longest injection time. It could also be seen that there were large differences in migration distance into the rock matrix for samples taken fairly close to each other. One example where the tracers have diffused through fissure coating (filling) material located in “undisturbed” rock is also presented.The results from all three experiments show that all three tracers have migrated through the disturbed zone close to the injection hole, through the fissure coating material and a distance into the “undisturbed” rock matrix.These results therefore indicate that dissolved compounds may migrate into the rock matrix. This migration into the rock matrix will increase the area available for sorption of radionuclides significantly and may therefore increase the migration times for radionuclides by order(s) of magnitude.Diffusivities and hydraulic conductivities obtained in this in-situ experiment compare well with those obtained in laboratory experiments.

Diffusion in the Matrix of Granitic Rock Field Test in the Stripa Mine Part 2.

ABSTRACTA migration experiment in the rock matrix is presented. The experiment has been carried out in “undisturbed” rock, that is in rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock was subject to nearly the same conditions as the rock surrounding a nuclear waste repository as proposed in the Swedish concept (KBS).The results show that all three tracers (Cr-EDTA, Uranine and 1-) have passed the zone disturbed by the presence of the injection hole and migrated some distance into “undisturbed” rock.These results indicate the existence of a connected micro fissure system in undisturbed rock, in which tracers (and therefore radionuclides) can migrate. Diffusivities obtained in this experiment are comparable to those obtained in laboratory experiments.

Diffusion in the Matrix of Granitic Rock. Field Test in the Stripa Mine

A migration experiment with the objective to investigate the existence of a connected pore system in undisturbed rock has been performed in the Stripa mine at the 360 m-level.