Lifetime Extension Research Articles

Radio-Oxidation Ageing of XLPE Containing Different Additives and Filler: Principal Component Analyses of Gases Emission and Consumption.

In the context of lifetime extension of Nuclear Power Plants (NPPs), electric cable ageing has to be checked to evaluate their performance during normal operation. These electric cables are complex materials, with a conductor and insulating shield in the metal and insulating layer and sheath in the polymer; the most sensitive layer is commonly considered to be the insulating layer. The ageing mechanism upon irradiation under oxidative conditions has been evaluated using gas mass spectrometry and the first conclusions have been drawn. Nonetheless, the data obtained are very numerous and complex; thus, the objective of this new article regards these experimental results using mathematical tools. It allowed confirmation of all the results obtained on these materials, but using chemometrics, i.e., statistical/mathematical analyses, of the results. Using these powerful mathematical tools gives strength to the analyses realised and to the conclusions obtained.

Circular economy priorities for photovoltaics in the energy transition.

Among the many ambitious decarbonization goals globally, the US intends grid decarbonization by 2035, requiring 1 TW of installed photovoltaics (PV), up from ~110 GW in 2021. This unprecedented global scale-up will stress existing PV supply chains with increased material and energy demands. By 2050, 1.75 TW of PV in the US cumulatively demands 97 million metric tonnes of virgin material and creates 8 million metric tonnes of life cycle waste. This analysis leverages the PV in Circular Economy tool (PV ICE) to evaluate two circular economy approaches, lifetime extension and closed-loop recycling, on their ability to reduce virgin material demands and life cycle wastes while meeting capacity goals. Modules with 50-year lifetimes can reduce virgin material demand by 3% through reduced deployment. Modules with 15-year lifetimes require an additional 1.2 TW of replacement modules to maintain capacity, increasing virgin material demand and waste unless >90% of module mass is closed-loop recycled. Currently, no PV technology is more than 90% closed-loop recycled. Glass, the majority of mass in all PV technologies and an energy intensive component with a problematic supply chain, should be targeted for a circular redesign. Our work contributes data-backed insights prioritizing circular PV strategies for a sustainable energy transition.

Waste LEDs in China: Generation estimation and potential recycling benefits

With light emitting diode (LED) devices popularizing, waste LEDs are expected to increase rapidly. Nevertheless, recycling policies and chains lag, largely due to scattered knowledge of waste generation and recycling benefits. Herein, Holt's method is used to estimate the sales of LED devices in China from 2012-2025. Then, we employ the market supply A model with Weibull lifetime distribution embedded to quantify the waste generation and in-use stock of LEDs. On this basis, the potential economic and environmental benefits of recycling are explored. Results show that: (1) From 2012 to 2025, the in-use stock of LEDs will increase from 0.13 to 66.17 billion pieces, while waste generation will increase from 1.57 million to 4.79 billion pieces; (2) In 2025, the potential economic benefits of recycling will reach $11.99 billion, mainly from precious metals; (3) In 2025, the carbon emission reductions of recycling will reach 7.54 billion tons (CO2-eq.), derived from the substitution of recycling for other waste disposal options. To keep technologies, capacities, and collection systems relatively in sync with the growing waste LEDs, priority should be given to lifetime extension and then sustainable designs. Nowadays, incentives for lifetime extension and the utilization of recycling systems for other e-waste are beneficial. In the medium-term, designs of modularity, standardization, and generalization, as well as the integration of disassembly, pre-treatment, and resource extraction, would be the focus. In the long run, the authority and stakeholders should spend efforts on clarifying recycling responsibilities, developing tailed business models, and promoting cost-effective recycling technologies.

Dimension learning based chimp optimizer for energy efficient wireless sensor networks

Wireless sensors are the basic requisite of today’s smart infrastructure based on internet of things (IoTs), 5G and wireless sensor networks (WSNs). WSNs are widely used in industrial applications, precision agriculture and animal tracking systems, environment monitoring, smart grids, energy control systems, smart buildings and entertainment industry etc. The distributed and dynamic scheme of WSNs establishes very unique demands in developing clustering and routing protocols. In order to meet the demand of efficient WSNs, most important requirement is energy management and extension of network lifetime. So energy constraints issue is one of the most emerging area for research to reduce the complexity of network functioning. Due to the complexity of this task we need more robustness optimizer algorithms which can tackle these types of tasks. In this article we are trying to develop one improved version of chimp optimizer for energy constraint issues. In this modification have been integrated the chimp optimizer with dimension learning based hunting (DLH) search technique, known as Improved Chimp Optimizer Algorithm (IChoA). Here the DLH search strategy helps in maintaining diversity and improves the balance between exploitation and exploration. To compute the robustness in solving the optimizer issues, IChoA has been tested on 29-CEC-2017 test suites and energy constraint issues. Experimental solutions obtained by proposed methods are verified with recent methods. All simulation shows that the IChoA method can be most effective in solving the standard complex suites and energy constraint issues.

Lifetime extension of gears and main bearings in wind turbines, scientific calculations and practical implementation

REWITEC, as a part of Cargill Bioindustrial, is a developer and manufacturer of an innovative particle-based surface treatment phyllosilicate-technology for increasing the reliability and the lifetime of wind turbine gears and bearings. The active particles are compatible to all common oils and greases and use lubricants as a carrier to build through their adsorption a protective and repairing phyllosilicate-based coating on the surface. The modified surface has a significantly lower surface roughness, which ensures a better load distribution, lower local pressure and lower tribological stress. Additionally, due to the special layered material structure the particles can be sheared in the tribological contact, which leads to a reduction in friction. All in all, when applying the products systems can run better with reduced friction, wear, surface roughness and temperature. These effects lead to higher reliability and a longer lifetime and thus to cost savings for operators. We would like to show our new scientific study about the lifetime calculation of a grease-lubricated wind turbine main bearing (1.5 MW) with and without the use of technology. The project is a cooperation between REWITEC and Sentient Science who performs lifetime calculations using digital clone method based on real friction coefficient and surface roughness data. The project includes data generation using MTM test bench, in a wind turbine bearing and subsequent simulation based on this data and bearing geometry. The simulation shows that with REWITEC the probability for a bearing failure significantly decreases which leads to a lifetime extension of up to 17.3 years.

A Novel Routing Protocol for Low-Energy Wireless Sensor Networks

The battery power limits the energy consumption of wireless sensor networks (WSN). As a result, its network performance suffered significantly. Therefore, this paper proposes an opportunistic energy-efficient routing protocol (OEERP) algorithm for reducing network energy consumption. It provides accurate target location detection, energy efficiency, and network lifespan extension. It is intended to schedule idle nodes into a sleep state, thereby optimising network energy consumption. Sleep is dynamically adjusted based on the network’s residual energy (RE) and flow rate (FR). It saves energy for a longer period. The sleep nodes are triggered to wake up after a certain time interval. The simulation results show that the proposed OEERP algorithm outperforms existing state-of-the-art algorithms in terms of accuracy, energy efficiency, and network lifetime extension.

Multiphase Eulerian-Eulerian CFD supporting the nuclear safety demonstration

Nuclear safety demonstration is a key issue where thermal hydraulics plays a central role, whether at the design stage or for nuclear power plants lifetime extension. Combined with huge efforts dedicated to simulation software developments during the past decades, this context naturally leads to a progressive introduction of CFD (Computational Fluid Dynamics) tools to support the nuclear safety demonstration. However, this progressively increasing use of CFD also implies strong requirements related to nuclear safety issues. A declination of this methodology will show what is the current place of multiphase CFD in nuclear safety, and what are the necessary prerequisites to use it in this context. Including the development and validation of dedicated models, allowing for example, all-flow regimes transitions. An illustration of application on one of the most challenging case, involving all these flow phenomena with heat and mass transfer will be described to show where we are in terms of limit of usage for the safety demonstration purpose.

Effects of electrolyte variation on ammonia sensing temperature for BiVO4 sensing electrode in mixed potential gas sensor

The aim of the present study is to investigate BiVO4 sensing electrode (SE) based electrochemical gas sensor for ammonia (NH3) sensing. Additionally, this study is also focused to reduce the operating temperature of sensor by applying different electrolytes i.e., yttria stabilized zirconia (YSZ) and gadolinia doped ceria (GDC). The maximum sensor response obtained for YSZ and GDC based cells towards 80 ppm NH3 were − 103.03 and − 78.81 mV at 600 ℃ and 550 ℃, respectively. Corresponding sensitivity of YSZ and GDC based cells for NH3 sensing were − 99.24 and − 42.66 mV/decade, respectively. Both the sensors demonstrate excellent selectivity as well as stability against 80 ppm NH3 (10 cycles) and humidity variation (pH2O = 0–0.12 atm.). Electrochemical impedance spectra (EIS) and dc polarization (I-V) curves confirms the mixed-potential sensing mechanism of the sensors. The systematic dependency of electrode’s resistance at a given frequency on the gas concentration reveals a novel pathway for prediction of sensors’ behavior. Additionally, the presence of GDC electrolyte decreases the response/recovery time (16/125 s) compared to YSZ-based cells (21/159 s) against 320 ppm NH3 at 550 ℃ which demonstrate its low temperature sensing capability. This 50 ℃ reduction in the operating temperature can be useful for extension of lifetime of sensor.

Insights into the dual Z-scheme and piezoelectricity co-driven photocatalyst for ultra-speed degradation of nitenpyram

A highly active catalyst AgI/Ag3PO4/BaTiO3 with the synergistic effect of photocatalysis and piezoelectricity was prepared, which can remove 100 % of Nitenpyram (NTP) in a wide pH range within 10 min. This piezo-photocatalyst AgI/Ag3PO4/BaTiO3 with dual Z-scheme shows a higher NTP degradation rate than their mono-material and binary composites. The apparent rate constant of AgI/Ag3PO4/BaTiO3 in NTP removal is 2.12 times higher than the second-performing catalyst. In the quenching experiment, h+ and ·O2– were observed to be the main active substance in NTP degradation and the former contributes the most. The dual Z-scheme mechanism and the built-in electric field are both beneficial for the separation of electron-hole pairs, as well as the extension of the photo-generated carrier lifetime. At last, the effect factor experiments proved that the prepared AgI/Ag3PO4/BaTiO3 catalyst owns stable and efficient activity. This work provides novel guidance for the construction of highly efficient and stable piezo-photocatalytic heterojunction catalysts.

Lifetime Maximization in Underwater Wireless Communication Networks

The rise in demand for underwater wireless communication networks (UWCN) has been driven by the emergence of new applications including unmanned underwater vehicles, deep-sea exploration, maritime and underwater archaeology research, and diver communications. For various applications, underwater network lifetime must be long, since unlike terrestrial sensor networks, it is a major job to change/recharge node batteries in underwater environments. In this paper, we introduce a solution where critical nodes in a UWCN are periodically recharged by small renewable energy sources. Further, a caching mechanism is introduced to relieve critical nodes of heavy workload when their residual energies run low. By leveraging these two techniques of energy replenishment and content-caching, the network lifetime extension challenge is formulated as an optimization problem. The results indicate that our proposed solution offers up to 45% longer UWCN lifetime compared to existing solutions.

THE EFFECT OF SOME ATTRACTIVE MEDIA ON THE NUMBER OF MARRIAGE PARTNERS, EGGS WEIGHT AND LIFETIME OF BLACK SOLDIER FLY (Hermetia illucens L.)

The black soldier fly (BSF) Hermetia illucens L.(Diptera:Stratiomyidae) is widely used in biorecycling organic waste has gained huge populatarity in different industrial. And commercial sector becouse of its excellent potential to treat organic waste and high biomass production. The obstacle experienced during the rearing process was that a small number of eggs were obtained, therefore efforts were made to increase the black soldier fly population by providing bait in the form of attractants. Media bait technique in the form of several media with a specific and pungent aroma, so that it will lure BSF females to mate, lay eggs, extend life time. The present study deal to investigation of different number of mating pairs, eggs weight dan lifetime as function respon of different lure media.This study used a completely randomized design (CRD) with (1) cassava tape, (2) Fermented bran (3) rotten pineapple (4) rotten banana media with each treatment repeated 6 times with the variables observed were the number of mating pairs of fly (per day), egg weight, and life span of imago. each attractant medium had an effect on the number of mating females, the weight of the eggs laid and the length of life of BSF. The best medium was rotten pineapple media (number of mating pairs 55 pairs of BSF, and egg weight laid 0.007 per day) while the worst medium was fermented bran media with a long life (10.9 days)

Environmental Impacts of Global Offshore Wind Energy Development until 2040.

Continuous reduction in the levelized cost of energy is driving the rapid development of offshore wind energy (OWE). It is thus important to evaluate, from an environmental perspective, the implications of expanding OWE capacity on a global scale. Nevertheless, this assessment must take into account various scenarios for the growth of different OWE technologies in the near future. To evaluate the environmental impacts of future OWE development, this paper conducts a prospective life cycle assessment (LCA) including parameterized supply chains with high technology resolution. Results show that OWE-related environmental impacts, including climate change, marine ecotoxicity, marine eutrophication, and metal depletion, are reduced by ∼20% per MWh from 2020 to 2040 due to various developments including size expansion, lifetime extension, and technology innovation. At the global scale, 2.6–3.6 Gt CO2 equiv of greenhouse gas emissions are emitted cumulatively due to OWE deployment from 2020 to 2040. The manufacturing of primary raw materials, such as steel and fibers, is the dominant contributor to impacts. Overall, 6–9% of the cumulative OWE-related environmental impacts could be reduced by end-of-life (EoL) recycling and the substitution of raw materials.

A Detailed Analysis of the H.B. Robinson-2 Reactor Pressure Vessel Dosimetry Benchmark

The operation of many nuclear pressurized water reactors is being extended beyond their design lifetime limit. From the perspective of possible further lifetime extension, safety requirements are a priority. Therefore, the quantification of the neutron irradiation embrittlement of the reactor pressure vessel (RPV) is an important issue, as this is a guiding parameter that influences the reactor lifetime. In this context, the Institut de Radioprotection et de Sûreté Nucléaire developed a calculation scheme for the analysis of RPV aging under neutron irradiation, named VACS (vessel aging calculation scheme). VACS couples a deterministic approach (CASMO5 and SIMULATE5) to evaluate the full-core fission neutron source term and a Monte Carlo modeling (MCNP6) approach to model the neutron attenuation from the core to sites of interest (RPV, surveillance capsules, etc.). To ensure the reliability of aging predictions, this paper describes a detailed analysis of the neutron H.B. Robinson-2 reactor pressure vessel dosimetry benchmark. The results indicate that VACS shows satisfactory accuracy when the ENDF-B/VII.1 or JEFF-3.3 nuclear data libraries are used in the attenuation calculation. However, the use of ENDF-B/VIII.0 leads to significantly worse results.

Electricity Market and Energy Policies Uncertainties for Investment in Life Time Operation of Nuclear Power Plants

In the electricity sector, market participants must make decisions about capacity choice in a situation of radical uncertainty about future market conditions. Electricity sector is characterized by non-storability and periodic and stochastic demand fluctuations. Capacity determination is a decision for the long term, whereas production is adjusted in the short run. Today decisions pertaining to investment in new capacity or life time extension are surrounded by considerable uncertainties about the future economics of the projects. One reason is that in a deregulated market private investors typically have to bear a greater portion of the investment risk compared to a monopoly utility in a regulated market. This favours flexible investment alternatives with short-lead times and low capital requirements. Moreover, energy and climate policy – with feed-in tariffs for RES or green certificate system and the EU CO2 ETS may add to investment uncertainties. From the economic point of view, the costs of LTO are usually lower than the construction of any other source of electricity. But in the aftermath of the Fukushima accident, policies towards nuclear energy in some countries were changed. Because of that economic life decisions are plant specific. In evaluating the future economic prospects of existing plant, the owners/utility focus on the unique circumstances of that plant and its cost and performance, and the future demand for electricity, and value of electricity. Nevertheless, quantification of the LTO costs is not an easy task. It is recognized that LTO costs are highly dependent on specific conditions related to each NPP, such as: design of the plant; NPP operating history including ageing conditions; regulatory requirements; full or partial replacement of components; refurbishment for LTO; accounting methodologies; etc. The risks that may have an impact on the economic case for the long term operation of NPP should be identified with pre mitigation impact and probability assessment.

Carbon Dioxide Triggers Carbon Nanotube Nucleation: Isotope Labeling Study on the Growth Process of Individual Nanotubes

Growing long and high-density arrays of semiconducting single-walled carbon nanotubes is the key to building high-performance electronics. From the growth process perspective, the density and length of carbon nanotubes are determined by their nucleation probability from individual catalysts, subsequent growth rates, and growth lifetime. Here, we study the effects of additive oxygen-containing species on the growth process at the individual nanotube level during alcohol chemical vapor deposition. When tracing the growth process by isotope labeling techniques, the growth rates are slowed down upon the addition of CO2 due to carbon removal from catalysts. This simultaneously leads to a noticeable extension of the growth lifetime, which has the overall effect of lengthening the nanotube arrays. According to the relationship between the timing of CO2 supply and the growth initiation time of each nanotube, we surprisingly find that the oxidants also trigger the growth initiation, leading to the improvement of nanotube density. As all these effects of the additive oxidants can be explained by the tuning of the supersaturation level of carbon on catalysts, our results suggest the importance of choosing the appropriate balance of carbon sources and oxidants for the simultaneous control of density and length of carbon nanotube arrays.

Quantifying the Impact of Lagged Hydrological Responses on the Effectiveness of Groundwater Conservation

AbstractMany irrigated agricultural areas seek to prolong the lifetime of their groundwater resources by reducing pumping. However, it is unclear how lagged responses, such as reduced groundwater recharge caused by more efficient irrigation, may impact the long‐term effectiveness of conservation initiatives. Here, we use a variably saturated, simplified surrogate groundwater model to: (a) analyze aquifer responses to pumping reductions, (b) quantify time lags between reductions and groundwater level responses, and (c) identify the physical controls on lagged responses. We explore a range of plausible model parameters for an area of the High Plains aquifer (USA) where stakeholder‐driven conservation has slowed groundwater depletion. We identify two types of lagged responses that reduce the long‐term effectiveness of groundwater conservation, recharge‐dominated and lateral‐flow‐dominated, with vertical hydraulic conductivity (KZ) the major controlling variable. When high KZ allows percolation to reach the aquifer, more efficient irrigation reduces groundwater recharge. By contrast, when low KZ impedes vertical flow, short term changes in recharge are negligible, but pumping reductions alter the lateral flow between the groundwater conservation area and the surrounding regions (lateral‐flow‐dominated response). For the modeled area, we found that a pumping reduction of 30% resulted in median usable lifetime extensions of 20 or 25 years, depending on the dominant lagged response mechanism (recharge‐ vs. lateral‐flow‐dominated). These estimates are far shorter than estimates that do not account for lagged responses. Results indicate that conservation‐based pumping reductions can extend aquifer lifetimes, but lagged responses can create a sizable difference between the initially perceived and actual long‐term effectiveness.

Keys Unlocking Redispersion of Reactive PdOx Nanoclusters on Ce-Functionalized Perovskite Oxides for Methane Activation.

Nowadays, trace CH4 emitted from vehicle exhausts severely threaten the balance of the ecology system of our earth. Thereby, the development of active and stable catalysts capable of methane conversion under mild conditions is critical. Here, we present a convenient method to redisperse catalytically inert PdO nanoparticles (NPs) (>10 nm) into reactive PdOx nanoclusters (∼2 nm) anchored on a Ce-doped LaFeO3 parent. Isothermally activated in an N2 flow, the redispersed catalyst achieved a CH4 conversion of 90% at 400 °C, which is significantly higher than the fresh and H2- and O2-treated counterparts (625, 616, and 641 °C, respectively), indicating the importance of the gas atmosphere in the redispersion of PdO NPs. In addition, the comprehensive catalyst characterizations demonstrated that the isolated Ce ions in the perovskite lattice play an irreplaceable role in the redispersion of reactive sites and the reduction of the energy barrier for C-H scission. More importantly, the Ce additive helps to stabilize the PdOx species by reducing overoxidation, resulting in significant lifetime extension. Through a thorough understanding of structural manipulation, this study sheds light on the design of highly performing supported catalysts for methane oxidation.

Evaluation of Bookkeeper mass deacidification based on historical book papers

Bookkeeper, the most widely used deacidification process based on MgO particles, was systematically evaluated on two sets of nonvaluable historical paper samples. Established analytical methods, such as pH and alkaline reserve determination, were used, as well as SEM EDS analyses to evaluate the distribution of Mg-rich particles on the paper surface and in the cross-section of the paper. The degradation rate constants of untreated and deacidified paper samples after accelerated thermal degradation were calculated based on weight average molecular mass determination to evaluate the lifetime extension of paper. The efficiency factors determined after accelerated thermal degradation of untreated and treated paper showed that paper lifetime prolongation after Bookkeeper deacidification treatment is highly limited for most of the investigated paper samples. No correlation was found between the alkaline reserve content or the pH and the degradation rate constants of the deacidified paper samples, but the paper degradation rate correlated with the paper samples pH before deacidification treatment. SEM EDS analysis showed that Mg-rich particles remained on the paper surface, which explains the limited effectiveness of the treatment.Graphical abstract

Medium and Low Voltage Cable Measurements - TD, PD, LIRA

Elmont d.o.o. Krško – We have spread our main scope of the services from electrical maintenance, modifications implementations and quality control to cable testing area. The main reason for expanding our scope was to support Nuclear Power Plant Krško Cable Aging Management program and the world trend of LTE (Life Time Extension) in power plants. Scope of work – We are identifying potential downgraded conditions for safety and operational important cables in special areas (heat, water, radiation). Our main scope is visual control, and testing with analysis. For low voltage cables the main testing method is Line Resonance Analysis (LIRA). LIRA technology is based on the transmission line theory, through the estimation and analysis of the complex line impedance as a function of the applied signal frequency. We can monitor the global, progressive degradation of the cable insulation due to harsh environment conditions (high temperature, humidity, radiation) and detect local degradation of the insulation material due to mechanical impacts or local abnormal environmental conditions. For medium voltage cables we are using new methods with a power generator that uses Very Low Frequency – 0,1Hz (VLF). The main reason for this is that the measurement unit needs 500 times less energy than the unit which uses 50Hz frequency (50/0,1=500). With this power source we are performing dielectric loss measurements – Tan delta (TD) and Partial discharge measurements (PD). TD measurements show the severity of Water treeing in the measured cable. Water trees mainly come from moisture and are therefore present in cables that lie in manholes filled with water or they submerged in any other way. PD measurements show the severity of voids or other types of defects in cable insulation. These defects can arise during the manufacturing of the cable or they can arise during the installation of the cable or from an accident with the cable during the operational time.

Arbitrary extension of the antibubble lifetime

The lifetime of antibubbles - droplets separated from a liquid bath by a thin layer of air - has typically been too short for further study or application. We experimentally demonstrate a mechanical method for extending the antibubble lifetime from minutes to hours. The recorded longest lifetime is up to 13 hours. In our method, vertical vibrations stabilize the air film as successive shocks on the antibubble top compensate the upward air drainage. To suppress Faraday waves, the liquid surface is covered with bubbles. A theoretical model is built to obtain the threshold for a long-lived antibubble. In the figure, the black scale bar is 20mm and the blue one 2mm.