In this research we can demonstrate, that fission technetium-99 can be successfully immobilized as tetravalent cation in solid state refractory oxides such as pyrochlores and perovskites. Pyrochlores show excellent performance in ASTM C1220-10 type corrosion testing and have the ability to structurally bond Tc-99 and therefore avoid the formation of highly-mobile, pertechnetate species under conditions of a generic repository. We have fabricated lanthanide technetium oxides using either dry-chemical ceramic processing, or wet-chemical coprecipitation methods. Tc pyrochlores have shown better Tc retention and corrosion resistance compared with Tc-containing LAWE4-type borosilicate glass, combined with 50-times higher waste loading. However, mechanical properties (fracture toughness, compressive strength) of the pyrochlores are lacking and the microstructure shows high open porosity of about 50 %. To improve these properties we tested a variety of measures such as hot-pressing or the combination of hot pressing and high-temperature synthesis, but the improvement was minor and Tc and the surrogate Ru were partly reduced. The presence of metallic inclusions has strong impact on Tc retention and release rates increased more than tenfold. We have further developed a wet-chemical coprecipitation synthesis route followed by calcination and a 4-days high-temperature sintering cycle for the model composition Sm2(Ru0.5Ti0.5)2O7 where titanium oxide was added as sintering agent. The ceramic surrogate waste forms showed improved theoretical densities of about 73 % combined with sufficient mechanical strength, while maintaining ruthenium in the tetravalent state.

A model of a High Voltage CMOS (HV-CMOS) Monolithic Active Pixel Sensor (MAPS) has been modelled using Technology Computer Aided Design (TCAD). The model has incorporated both the active region and the on-pixel readout circuits which were comprised of a source follower amplifier and an integrated charge amplifier. The simulation has examined the electrical characteristics and response output of a HV-CMOS MAPS sensor using typical dimensions, levels of doping in the structural layers and bias conditions for this sensor. The performance of two alternate designs of amplifier have been examined as a function of the operating parameters. The response of the sensor to the incidence of Minimum Ionizing Particles (MIPs) at different energies has been included in the model.

We have developed Anti- Sievert® concrete, which is a concrete reinforced shielding function as a building material that shields the influence from radioactive materials and its radiation. Cement, water, aggregate, sand material, Anti- Sievert® # 210, Anti- Sievert® # 216 formulation was optimized as those materials constituting Anti- Sievert® concrete. As a result, we realized shielding concrete with high fluidity to realize construction suitability by concrete pump[1]. Anti- Sievert® concrete has a shielding function of about 3 times as compared with ordinary concrete with respect to X ray (100 kV), and shows strength of more than 50 N/mm2. The durability characteristics against nuclear explosion using Anti-Sievert® concrete were simulated and reported in this paper.

Although Pb-based perovskite solar cells already achieve power conversion efficiencies (PCE) beyond 20 %, the use of toxic Pb is causing considerable environmental concern. As a consequence, a variety of alternative cations have been investigated to replace Pb2+ in the perovskite structure. Methylammonium bismuth iodide (MA3Bi2I9, MBI) has shown promising results for environmentally benign and chemically stable devices. While the PCE of MBI-based solar cells are still comparably low, structural improvements have been made by using chemical vapor deposition (CVD). CVD allows for the well-controlled formation of coherent and dense MBI layers in contrast to solution-processing. In this work, CVD as a possible MBI fabrication method for efficient and size-scalable solar cells is discussed. The precursors MA iodide (MAI) and Bi iodide (BiI3) are deposited in an alternating deposition process forming the desired MBI perovskite on the heated substrate. Substrate temperatures as well as deposition times of each precursor are varied with the aim of forming coherent and dense MBI layers. Optimized films are further processed to solar cell prototypes and compared with solution-processed reference devices. The results reveal that CVD possesses great potential to enable the manufacture of MBI photovoltaic (PV) devices processed in a solvent-free environment.

Amorphous TiO2 and SnO2 electron transport layers (ETLs) were deposited by low-temperature atomic layer deposition (ALD). Surface morphology and x-ray photoelectron spectroscopy (XPS) indicate uniform and pinhole free coverage of these ALD hole blocking layers. Both mesoporous and planar perovskite solar cells were fabricated based on these thin films with aperture areas of 1.04 cm2 for TiO2 and 0.09 cm2 and 0.70 cm2 for SnO2. The resulting cell performance of 18.3 % power conversion efficiency (PCE) using planar SnO2 on 0.09 cm2 and 15.3 % PCE using mesoporous TiO2 on 1.04 cm2 active areas are discussed in conjunction with the significance of growth parameters and ETL composition.

Pb-based organometal halide perovskite solar cells have passed the threshold of 20 % power conversion efficiency (PCE). However, the main issues hampering commercialization are toxic Pb contained in these cells and their instability in ambient air. Therefore, great attention is devoted to replace Pb by Sn or Bi, which are less harmful and - in the case of Bi - also expected to yield enhanced stability. In literature, the most efficient hybrid organic-inorganic methylammonium bismuth iodide (MBI) perovskite solar cells reach PCE up to 0.2 %. In this work, we present spin-coated MBI perovskite solar cells and highlight the impact of the concentration of the perovskite solution on the layer morphology and photovoltaic (PV) characteristics. The solar cells exhibit open-circuit voltages of 0.73 V, which is the highest value published for this type of solar cell. The PCE increases from 0.004 % directly after processing to 0.17 % after 48 h of storage in air. 300 h after exposure to air, the cells still yield 56 % of their peak PCE and 84 % of their maximum open-circuit voltage.