Groundwater flow transports possibly released radionuclides from underground repositories to the biosphere. It can also make construction difficult as is obvious from examining technical solutions for disposal of high-level radioactive waste (HLW) in long subhorizontally bored holes (KBS-3H) and in very deep boreholes (VDH). The presence of intersected, water-bearing fracture zones requires concrete for sealing these parts of the holes while the rest contains canisters surrounded and separated by dense, expandable clay. Casting of the concrete should be preceded by grouting of the fractured rock using cementitious materials composed so that mutual physical and chemical interaction do not degrade either of them. For the sake of rock stability the horizontal holes have to be located at very moderate depth, 400-500 m, where the rock has a high average hydraulic conductivity, while the slimmer, steep holes reaching down to 4 km are kept stable by using clay mud in the construction phase and dense clay for long term performance. The rock at this depth is much less permeable than higher up and the groundwater sufficiently salt to be maintained there, causing only local thermally induced circulation of possibly contaminated water. The KBS-3H concept involves practical difficulties and risks in the installation of the clay seals and waste canisters, for which the risk of shearing by slip of frequently intersected steep fractures is a major threat after closure of the repository. The VDH concept relies on effective sealing of the upper part of the deep holes and puts less demand on the seals in the lower, waste-bearing part, for which the buoyancy conditions of the groundwater make it a major barrier to upward migration of possibly released radionuclides.

Retaining walls are used to retain earth or other materials which have the tendency to slide and repose at a particular inclination. They provide lateral support to the embankment or other materials in order to hold them in a vertical position. As against equal forces shells are less thick in comparison with flat slabs, their application is economical regarding consumptive materials, so in this research in order to reduce consumptive materials, multi cylindrical shells are adapted with retaining walls and calculation and analysis of one kind of new lightened retaining wall is proposed. To analyze shell structures, there are different theories. The application of these theories depends on geometrical shape, shell quality, shell usage, boundary condition and enforced loads. To analyze and calculate lightened shell retaining wall, equations are required which should both present the mechanical behavior of the shell with required exactness and also be solvable mathematically. To attain this goal, the method proposed in this research can be applied. In solving the problem formed of multi cylindrical shell with slabs, engineering mechanics combined principles are used and the equations of bending theory of cylindrical shell are adapted with retaining walls. Generally, in this paper the analysis method of lightened retaining walls consisted of multi cylindrical shells are presented.

Effect of water extracts of red algae Grateloupia divaricata, Chondrus pinnulatus, Ahnteltiopsis flabelliformis, Neorhodomela larix, Tichocarpus crinitus, of brown algae Stephanocystis crassipes, Coccophora langsdorfii, Sphaerotrichia divaricata, Saccharina japonica, Sargassum pallidum, Chorda filum, and green algae Ulva fenestrata and Codium fragile on the growth of seedling roots of buckwheat (Fagopyrum esculentum varieties Izumrud) was screened. It was showed that low and ultra-low (from 10^-3 to 10^{-14 g of dried seaweeds per mL of distillated water) concentration of aqueous seaweed extracts may stimulate roots elongation of the buckwheat seedlings. The most perspective for use as biostimulants are red algae Ahnfeltiopsis flabelliformis, Neorhodomela larix, and brown alga Stephanocystis crassipes. Extracts of these algae in a studied range of concentrations increased  growth of the seedling roots in maximum by 16, 20 and 15 % over control, respectively. The extracts of the other examined algae showed a weak or no stimulatory effect} on the growth of seedling roots. The dose-effect curves of the majority of tested seaweed extracts were bi- or polymodal.