This review paper addresses the escalating operation and maintenance costs of nuclear power plants, primarily attributed to rising labor costs and intensified competition from renewable energy sources. The paper proposes a paradigm shift towards a technology-centric approach, leveraging mobile and automated robots for physical security, aiming to replace labor-intensive methods. Focusing on the human–robot interaction principle, the review conducts a state-of-the-art analysis of dog robots’ potential in infrastructure security and remote inspection within human–robot shared environments. Additionally, this paper surveys research on the capabilities of mobile robots, exploring their applications in various industries, including disaster response, exploration, surveillance, and environmental conservation. This study emphasizes the crucial role of autonomous mobility and manipulation in robots for diverse tasks, and discusses the formalization of problems, performance assessment criteria, and operational capabilities. It provides a comprehensive comparison of three prominent robotic platforms (SPOT, Ghost Robotics, and ANYmal Robotics) across various parameters, shedding light on their suitability for different applications. This review culminates in a research roadmap, delineating experiments and parameters for assessing dog robots’ performance in safeguarding nuclear power plants, offering a structured approach for future research endeavors.

The purpose of this study is to utilize waste products—precipitated calcium carbonate (PCC) and upcycled recycled concrete aggregate (upcycled RCA or UCA)—in civil works projects. To do so, tests must be performed to determine the engineering properties of the materials in which PCC and UCA are sequestered. PCC is a fine to coarse grain waste product generated during the production of sugar from sugar beets. UCA is produced from demolished and returned concrete by the extraction of primarily calcium and alkalinity. The study also includes the use of both PCC and UCA in the same concrete mix design. The test results on PCC alone show that the optimum content to achieve a minimum 28 MPa (4000 psi) compressive strength is 25% and 30%. The corresponding compressive strength of mixes in which conventional aggregate was replaced by UCA is about 48 MPa (7000 psi) to 55 MPa (8000 psi) at the same water: cement ratio (0.44) by weight. The compressive strength of concrete with 25% to 30% cement replaced by PCC and varying aggregates replaced with UCA ranges from 19.3 to 40 MPa (2800 to 5800 psi). Other tests on PCC and UCA include tensile strength of 2 to 3 MPa (293 to 423 psi) and flexural strength of 1.3 to 1.9 MPa (183 to 279 psi). Analytical techniques such as X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), and scanning electron microscopy (SEM) were used to identify the constituent elements and chemical compounds present in PCC, including calcium carbonate and silica. Based on the test results, the composition of PCC by weight indicates 45.9% calcium, 39.4% oxygen, and 9.2% carbon. Based on the results of this study, we can expect to reduce carbon emissions in the production of cement and aggregates, as well as utilize waste products in the civil engineering field.

The objective of this research is to examine the use of precipitated calcium carbonate (PCC), obtained during the production of sugar from sugar beets, and to stabilize subgrades beneath highway pavements or to stabilize foundations built on loess (windblown silt). The research also aims to permanently capture the carbon from PCC in soil. The experimental process involved the collection of representative loess samples, the addition of variable percentages of PCC, and conducting laboratory experiments on compacted PCC soil mixes to evaluate the effect of PCC on subgrades beneath pavement and foundations beneath buildings. Samples of PCC were obtained from the Amalgamated Sugar Corporation, located 187 km away from Pocatello. In addition, soil was collected from local sources in which saturation collapse and damage have occurred in the past. Unconfined compressive strength tests, which index subgrade bearing failures, were performed on both untreated and PCC-treated soils to evaluate the effect of PCC in stabilizing pavement subgrades and foundations as well as sequestering carbon. The experimental test results revealed a significant average increase of 10% to 28% in the strength of loess samples stabilized with 5% PCC compared to the native soil. The chemical composition and microstructure of PCC were further analyzed through energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) tests. EDX analysis unveiled a carbon content of 9% by weight in PCC, which could contribute to the carbon footprint when it breaks down. Additionally, SEM images displayed an unsymmetrical and sub-rounded microstructure of PCC particles. Based on these findings, the study suggests that utilizing PCC could improve the resistance of loess to saturation collapse and potentially reduce carbon emissions associated with cement or lime production while offering an opportunity to use PCC in soil application.

Geothermal energy production requires durable well-cementing materials capable of withstanding extreme thermal fluctuations, yet the high carbon footprint and cost of Ordinary Portland Cement (OPC) necessitate sustainable alternatives such as fillers and supplementary cementitious materials. This study investigates whether waste-based Precipitated Calcium Carbonate (PCC), a sugar beet industry by-product, is feasible for use as a sustainable partial replacement/filler material in OPC-based concrete mixtures considered for geothermal-related cementitious applications. The experimental program was conducted in two distinct phases. Initially, PCC replaced OPC at 5%, 10%, 15%, 20%, and 25% by weight to evaluate mechanical performance. In the second phase, optimized mixes with 0%, 5%, and 10% PCC were subjected to thermal cycling between 10 °C and 250 °C for up to 30 cycles to simulate harsh geothermal conditions. Results showed that 5% PCC increased compressive strength by 9.47% (34.3 MPa) and tensile strength by 2.93% (3.0 MPa) relative to the control mixture. During thermal cycling, the 5% PCC mix demonstrated superior stability, maintaining 32.1 MPa after 10 cycles, while higher PCC contents led to significant degradation. Within the limits of the laboratory tests conducted, the study concludes that a low PCC replacement level, particularly 5%, is an optimal threshold, offering improved thermal resilience and mechanical strength while reducing OPC consumption and carbon emissions. Further slurry-level, chemical durability, and field-representative testing are required before broader geothermal well cementing validation.

This study aims to investigate utilizing Precipitated Calcium Carbonate (PCC), a by-product of sugar beet, as a soil stabilizer for addressing settlement issues beneath pavements. Various tests were conducted to assess the engineering properties of PCC-stabilized subgrades using PCC obtained from Amalgamated Sugar Cooperation in Twin Falls, Idaho. Local loess samples, like those found beneath pavements, were collected for testing purposes. Initial tests involved evaluating the unconfined compressive strength of compacted loess samples, followed by tests on samples mixed with different weight percentages of PCC. The results revealed a significant average increase of 10% to 28% in the strength of loess samples stabilized with 5% PCC compared to the strength of the native soil. The chemical composition and microstructure of PCC were further analyzed through X-ray Diffraction (XRD), Energy Dispersive X-ray Spectrometer (EDX), and Scanning Electron Microscopy (SEM) Tests conducted at the Idaho National Laboratory (INL). XRD analysis indicates the presence of calcium carbonate and silica. EDX analysis unveiled a carbon content of 9% by weight in PCC, which could contribute to the carbon footprint when it breaks down. Additionally, SEM images displayed an irregular microstructure and particle shape of PCC. Furthermore, the inclusion of PCC improved the resistance of loess to saturation collapse.