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Deep geological repositories are the sole option for safeguarding the atmosphere from hazardous radiation from high-level radioactive waste. Hyperalkaline pore fluids are produced when fluids from host rocks penetrate through the concrete/cement layers of such repositories, the layers created as bulkheads in vaults or to facilitate gallery access between buffers and the host rock. Such fluids also disperse through the compacted bentonite layers placed around the steel canisters that contain the waste in the repositories. The corrosion of steel canisters inside such repositories can be observed over a certain time. Chemical corrosion can lead to harmful leachates that can seep through the compacted bentonite layers that surround the steel canisters, altering the bentonite properties. In addition, these compacted bentonite layers are subjected to thermal histories due to the canisters emitting continuous heat (150°C to 200°C). These compacted bentonite layers have to hold up under these three conditions in repositories, all of which can affect the swelling properties of the bentonite. Two bentonite samples (B1 and B2) from Rajasthan's Barmer area were mixed with corrosion products and compacted to dry densities of 1.5, 1.75, and 2.0 Mg/m3 for this investigation. Thermal histories were induced at 110°C and 200°C for 3 h to prepare samples that were then saturated with hyperalkaline cement water. The presence of corrosion products resulted in a decrease in swelling pressure values when compared with samples without adding corrosion products. This decrease was more significant with an increase in the temperature of the induced thermal history. [ABSTRACT FROM AUTHOR]

Cotton leaf curl disease (CLCuD), caused by whitefly (Bemisiatabaci) transmitted single-stranded DNA viruses belonging to the Genus, Begomovirus (family, Geminiviridae) in association with satellite molecules; is responsible for major economic losses in cotton in three northwest (NW) Indian states Haryana, Punjab, and Rajasthan. Annual CLCuD incidences during 2012 to 2014 were estimated to be 37.5%, 63.6%, and 38.8% respectively. Cotton leaves were collected from symptomatic plants annually for three years and subjected to DNA isolation, followed by rolling circle amplification (RCA), cloning, and DNA sequencing of apparently full-length begomoviral genomes and associated betasatellites and alphasatellites. Among the thirteen CLCuD-begomoviral genomes recovered, eight were identified as Cotton leaf curl Multan virus-Rajasthan (CLCuMuV-Ra), one as -Pakistan (PK) and another as -Faisalabad (Fai), whereas, three were as Cotton leaf curl Kokhran virus-Burewala (CLCuKoV-Bu), indicating that CLCuMuV-Ra was the most prevalent begomovirus species. Five of the eight CLCuMuV-Ra sequences were found to be recombinants. The CLCuMuV-Ra- associated satellites consisted of Cotton leaf curl Multan betasatellite (CLCuMB), and Gossypium darwinii symptomless alphasatellite (GDarSLA), and Croton yellow vein mosaic alphasatellite (CrYVMoA). The second most abundant helper virus species, CLCuKoV-Bu, was associated with CLCuMB and GDarSLA. [ABSTRACT FROM AUTHOR]

The bentonite is compacted around the steel canister containing high-level waste to ensure the sealing of the canister by blocking the entry of harmful radiations emitted due to the reactions of active radionuclides. However, the canister continuously exhibits a high temperature (150 °C–200 °C) due to radioactive waste decay over a long time, which creates a thermal history on the surrounded compacted bentonite. Corrosion can generate changes in the bentonite buffer, which comes in direct contact with the canister and may lead to a change in its swelling ability. This study investigates the influence of corrosion products on the swell pressure of compacted bentonite specimens subjected to thermal history. Two Bentonite samples (B 1 and B 2) from the Barmer district of Rajasthan, India, were mixed with corrosion products and compacted at dry densities 1.5 Mg/m3, 1.75 Mg/m3 and 2.0 Mg/m3. These specimens were subjected to thermal histories at 110 °C and 200 °C and saturated with distilled water. The decrease in the swell pressure values was observed with the corrosion product and the increase in temperature of induced thermal history—comparatively, more time required for saturation in the presence of corrosion products than in its absence. The alteration in montmorillonite minerals might have occurred under the induced thermal history and corrosion reaction. [ABSTRACT FROM AUTHOR]

• Thermo-mechanical characteristics of two bentonites from India are presented. • Variation of swell pressures of bentonite with variation in thermal loading and densities is presented. • The development of time swelling curves for various thermal histories is presented. • The swell pressures of both the bentonite decreased with an increase in the thermal loading. The deep geological disposal system is an internationally adopted option for the disposal of high-level nuclear waste (HLW). It consists of a highly expansive bentonite, which is used as a buffer material and as a part of an engineered barrier system. Bentonite provides sufficient swelling pressure and low hydraulic conductivity to the barrier system giving long-term stability. The high-temperature waste canister in DGR and the variation in temperature due to thermal gradient impose a thermal loading on the compacted bentonite buffer and may alter the swelling pressures of the compacted bentonite. Hence it is necessary to investigate the influence of thermal loading on the swelling pressure of compacted bentonite. The paper discusses an assessments of swell pressures of two compacted bentonites (Barmer 1 (B 1) and Barmer 2 (B 2)) from Barmer district of Rajasthan, India with initial dry densities of 1.5 Mg/m3, 1.75 Mg/m3, and 2 Mg/m3 and subjected to 110 °C and 200 °C, hydrated with distilled water. The swelling load is recorded and compared with non-heated samples of same densities. Experimental and theoretical evidences indicated that the swelling pressure of heated compacted bentonite decreased with an increase in the temperature. Statistical analysis is also presented with the help of analysis of variance (ANOVA). [ABSTRACT FROM AUTHOR]