Supercritical Plant Research Articles

Environmental, technological, and economic analysis of supercritical coal-fired power system.

Developing countries primarily rely on fossil-based energy sources to meet their energy demands. The use of fossil fuels has several adverse environmental repercussions that damage the biosphere both directly and indirectly. Among fossil fuels, coal brings about the heaviest environmental externalities, yet its abundance makes its use widespread, particular in countries having significant power generation deficits, such as Pakistan. This study presents an environmental, technological, and economic analysis of a supercritical coal-based power unit located in Pakistan and used for electricity generation. For environmental assessment, the CML-1A baseline method in OpenLCA software was used, and eight midpoint impact indicators were selected. The functional unit chosen was 1 MWh of generated electricity. The results indicated that the category of ozone layer depletion has the least impact, whereas global warming potential has the highest impact score. Except for photochemical oxidation and human toxicity, the plant operational stage dominated most of the selected impact categories. The current paper also reveals that the removal efficiency of CO2 and other pollutants is higher in supercritical compared to subcritical plants. Moreover, the economic feasibility of supercritical plant is compared with chemical looping combustion (CLC)-based supercritical coal-fired power plant, and results shows that CLC-based coal-fired power plant is a more competitive and environmentally friendly option. The utilization of a scientific cleaner energy-management system in real-time, as exemplified in this study, may facilitate the development of a optimalpolicy framework that encouragesfor the adoption of cleaner coal power generation in developing countries, ultimately resulting in improved energy sustainability. Furthermore, this paper also presents some policy implications which could be helpful for policymakers, researchers, and industrialists to improve the sustainability of energy in emerging economies.

Thermodynamic and economic analyses of the retrofit of existing electric power plants with fusion reactors

Electricity generation will need to reach net zero emissions globally in 2050. This will require an increase in share of renewable energy and the implementation of a controllable carbon-free base-load source. Nuclear fusion is a promising option to decarbonize base-load electricity production but its capital cost still doubles the one of technologically more mature alternatives such as large photovoltaic fields or off-shore wind installations. Within this framework, the retrofit of a dismissed power-plant could allow significant cost savings, thus facilitating the realization of a fusion electricity demonstrator. Among fusion reactors, stellarators are a valid alternative to tokamaks thanks to the higher blanket temperature and inherent continuous operation. In this scenario, we posit the challenge to use a nuclear fusion stellarator-based reactor to retrofit conventional power plants (PPs). Specifically, we select a nuclear fission plant in France and a supercritical coal fired site in Italy, by constructing 4 different retrofit scenarios as a function of the re-used components. We compare each option with a greenfield and optimized plant with the same reactor thermal power. through a thermodynamic, economic, and investment analysis.The results proves significant savings by retrofitting an existing plant, with a CapEx reduction up to 50% compared to the greenfield plants. Specifically, the most convenient retrofit strategy is to select a site that already implements cutting edge thermodynamic parameters while reusing the most existing systems (i.e. buildings, steam cycle, electricity generation, and heat rejection). This is the case of the 2 x 660 MWe supercritical coal-fired plant in Italy. Therein, the LCOEs are 39 $/MWh and 51 $/MWh, calculated with an interest rate of 2.7% and 6%, respectively, and compare with the conventional energy technologies. Moreover, such costs are competitive in the current European energy markets and yield significant net present values at the plant end of life.

Optimization of reheat-pressure ratios in Supercritical, Ultra Supercritical and advanced ultra-supercritical Thermal Power Plants with Single Reheating

This research paper presents the thermodynamic analysis of a modern supercritical (SC), ultra supercritical (USC) and advanced ultra supercritical (AUSC) steam power plants with a power generating capacity of 1200 MW, employing with single re-heat configuration. A MATLAB software code has been developed to accurately estimate the steam properties under varying conditions. The study focuses on the temperature and pressure at the turbine's inlet and outlet. The cycle's energy efficiency and exergy efficiency have been thoroughly examined, along with the impact of single reheat pressure on the cycle's performance. It has been observed that both efficiencies exhibit a more pronounced increase with rising temperatures compared to increasing pressures. The exergy losses incurred in each of the cycle's components have been meticulously studied and analyzed by systematically varying the pressure ratios of SC, USC and AUSC power plants.

A life cycle assessment of coal-fired thermal power plants with post-combustion control techniques: an India scenario.

In recent years, there has been a focus on clean power generation, and it is critical to assess the environmental impact of novel technologies used in pollution control in power generation. The study uses life cycle assessment (LCA) to assess the environmental impacts of coal-fired thermal power plants with different emission control techniques in an Indian scenario. As there are no such studies available in the Indian context, this work might provide a holistic view of the impacts of energy generation. A supercritical coal-fired plant with a capacity of 660 MW is considered in this study. The system boundary included coal extraction, transportation, power plant operation, and transmission losses of electricity with a functional unit of 1 kWh. It was observed that there was an energy penalty due to the power consumed in emission control devices, but the maximum energy penalty was due to the power used in the carbon capture system. The LCA is done from "cradle to gate", with impact indicators at the mid-point evaluated using the RECIPE (H) 2016 LCIA method. LCA results showed that power plant operation is the most significant contributor to environmental impact. Initially, in cases 1 and 2, climate change (CC) potential was a major impact category, but CC potential was reduced with carbon capture and storage, 0.27 kg CO2 eq. in case 3 with ESP, FGD, SCR, and carbon capture and storage (CCS) and 0.263 kg CO2 eq. in case 4 with ESP and CCS. But there was a considerable increase in the majority of the impact categories in case 4. Freshwater consumption potential increased from 3.98 E-03 m3 in base case 1 to 4.98 E-03 m3 in case 3 due to the amount of water used in chemical production during CCS, as CC potential is a major concern in power generation, However, compared to case 1, the potential for climate change increased in case 2, whilst in case 4, the potential for climate change is lower but has resulted in an increase in the majority of impact categories. Case 3 shows an optimal approach to reducing CO2 emissions compared to other cases. The combination of ESP, FGD, SCR, and CCS is favourable for cleaner energy generation.

Thermal aging of Gr. 91 steel in supercritical thermal plant and its effect on structural integrity at elevated temperature

In this study, the influence of thermal aging on structural integrity is investigated for Gr. 91 steel. A commercial grade Gr. 91 steel is used for the virgin material, and service-exposed Gr. 91 steel is sampled from a steam pipe of a super critical plant. Time versus creep strain curves are obtained through creep tests with various stress levels at 600 °C for the virgin and service-exposed Gr. 91 steels, respectively. Based on the creep test results, the improved Omega model is characterized for describing the total creep strain curve for both Gr. 91 steels. The proposed parameters for creep deformation model are used for predicting the steady-state creep strain rate, creep rupture curve, and stress relaxation. Creep-fatigue damage is evaluated for the intermediate heat exchanger (IHX) in a large-scale sodium test facility of STELLA-2 by using creep deformation model with proposed creep parameters and creep rupture curve for both Gr. 91 steels. Based on the comparison results of creep fatigue damage for the virgin and service-exposed Gr. 91 steels, the thermal aging effect has been shown to be significant.

Different susceptibility of two Botrytis cinerea strains to supercritical CO2 plant extracts

Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle. As a generalist, B. cinerea has no host specificity and infects over 500 plant species. There are many studies about phenotypic and genotypic diversity of B. cinerea strains from different regions of the world. Two different morphological strains of B. cinerea were previously isolated also in Slovenia from buckwheat. The morphological diversity of B. cinerea is also reflected in different susceptibility to plant extracts. We tested the susceptibility of two B. cinerea strains derived from buckwheat grain to eleven extracts of plant species Humulus lupulus, Nepeta cataria, Taraxacum officinale, Achillea millefolium, Calendula officinalis, Chamomilla recutita, Helichrysum arenarium, Hypericum perforatum, Juniperus communis, Sambucus nigra and Crataegus sp. obtained by supercritical fluid extraction using CO2 (SFE-CO2). The resistance profiles showed that strain II of B. cinerea was generally susceptible to the action of these SFE-CO2 extracts, whereas strain I was more resistant. The concentration-dependent antifungal activity of the extract of chamomile and sandy everlasting indicates their possible use as a fungicide for both strains of B. cinerea.

Study of combined heat and power plant integration with thermal energy storage for operational flexibility

Increasing the share of renewable energy in the future electricity market requires measures to maintain the stability of the grid, owing to the volatility and intermittency of renewable energy. For a combined heat and power (CHP) plant, molten salt thermal energy storage (TES) can be added to improve the flexibility to meet the needs of peak shaving. This paper proposed a novel cascade reheat steam extraction system to adjust the electrical load by using EBSILON software applied to thermal simulation and thermal analysis. A 350 MW supercritical CHP plant was used as an example to analyze the thermal and peak shaving performance under variable operating conditions. Meanwhile, through the static simulation, the change in the load and the efficiency of TES can be calculated during the charging and discharging cycle. The results show that the efficiency of TES is 40–51 %. With an increase in the load, the efficiency of TES is reduced, and the exergy loss range is from 4 MW to 12.4 MW mainly due to the throttling process and the molten salt heat transfer process. Moreover, the thermal efficiency and exergy efficiency of the novel system are higher than those of the traditional CHP plant below 60 % turbine heat acceptance, so it is relatively economical to run for peak shaving under low loads. Finally, depending on the corresponding operating strategy, a reduction of the minimum load by up to 1 % of the rated output electrical load during charging and an increase of the maximum load by up to 2 % of the rated output electrical load during discharging are possible. Overall, the proposed system provides a feasible method for the flexibilization of CHP plants alongside new renewable systems.

Mitigation of cellular collapse during drying of Eucalyptus nitens wood using supercritical CO2 dewatering

Summary Removal of lumen water by dewatering using supercritical CO2 offers an alternative method to mitigate cellular collapse in susceptible hardwoods compared to conventional timber drying methods. The anatomy of Eucalyptus nitens was quantitatively measured by light microscopy, SEM and micro-CT to provide an understanding of the mechanism of collapse during drying. These measurements were then used to recalibrate a previously developed fluid-dynamics model to predict E. nitens vessel dewatering and develop a dewatering treatment strategy for collapse mitigation. The lumens of E. nitens were from fibres (58.5% cross-section) and vessels (10.0% cross-section) with mean diameters of 8 and 142 μm, respectively. Micro-CT measurements revealed that the vessels were empty after treatment with a supercritical CO2 dewatering schedule optimised for softwood. However, the fibres remained full and this led to significant collapse during subsequent oven drying. Based on this information, a two-phase dewatering schedule was developed to include removal of fibre lumen water. Results showed that 90% of collapse could be mitigated to a change in external volume of only 3.9% provided the green moisture content was lowered to 70% before oven drying. The predicted effective diffusion coefficient of CO2 in E. nitens was comparable to Pinus radiata and they showed similar anatomical tortuosity and porosity resistance in their hydrofluidic networks. Collapse mitigation using supercritical CO2 could be combined with extraction of desirable sap components, post-dewatering drying, preservative treatment, and mechanical forming. These processes may be achieved in a single supercritical plant and apply to most anatomically similar hardwoods.

Issues and solutions for integrity of pressure vessels and piping subjected to long-term creep exposure in supercritical thermal plants

ABSTRACT ASME BPVC Section VIII Division 2 (‘ASME VIII(2)’) and ASME B31.1 are being used not only for low-temperature design but also for high-temperature design in the creep range in supercritical thermal power plants. However, creep effects in ASME VIII(2) and B31.1 are taken into account implicitly, and there could be significant technical issues in terms of conservatism in the case of long-term operation in the creep range because their design evaluation results do not change across plant operation time. The conservatisms of ASME VIII(2) and B31.1 have been quantified based on comparisons with nuclear-grade design rules of ASME BPVC Section III Division 5 and RCC-MRx which take creep hold time into account explicitly. It was shown that ASME VIII(2) and B31.1 results could be non-conservative if operation time exceeds a certain time limit, which raises concerns around non-conservatism in the case of long-term operation within the creep range.

Supercritical CO2 Plant Extracts Show Antifungal Activities against Crop-Borne Fungi.

Fungal infections of cultivated food crops result in extensive losses of crops at the global level, while resistance to antifungal agents continues to grow. Supercritical fluid extraction using CO2 (SFE-CO2) has gained attention as an environmentally well-accepted extraction method, as CO2 is a non-toxic, inert and available solvent, and the extracts obtained are, chemically, of greater or different complexities compared to those of conventional extracts. The SFE-CO2 extracts of Achillea millefolium, Calendula officinalis, Chamomilla recutita, Helichrysum arenarium, Humulus lupulus, Taraxacum officinale, Juniperus communis, Hypericum perforatum, Nepeta cataria, Crataegus sp. and Sambucus nigra were studied in terms of their compositions and antifungal activities against the wheat- and buckwheat-borne fungi Alternaria alternata, Epicoccum nigrum, Botrytis cinerea, Fusarium oxysporum and Fusarium poae. The C. recutita and H. arenarium extracts were the most efficacious, and these inhibited the growth of most of the fungi by 80% to 100%. Among the fungal species, B. cinerea was the most susceptible to the treatments with the SFE-CO2 extracts, while Fusarium spp. were the least. This study shows that some of these SFE-CO2 extracts have promising potential for use as antifungal agents for selected crop-borne fungi.

Securing integrity of high-temperature pressure boundary components in supercritical thermal plants with application of alternative design rules

Technical issues of ASME BPVC Section VIII Division 2 (hereafter, ‘ASME VIII(2)’) were investigated when it was applied to design of high-temperature pressure vessels in supercritical thermal power plants subjected to long-term operation in the creep regime. The design rules of ASME VIII(2) are generally used for the design of pressure vessels operating not only at low temperature but also at high temperature in the creep range. The potential connections of ASME VIII(2) with a number of defects in pressure vessels due to technical issues on the implicit consideration of the creep effects were investigated. For the superheater component subjected to long-term operation in the creep regime, design evaluations were conducted according to ASME VIII(2) and three alternative design rules of ASME BPVC Section III Division 5 Subsection HB, French RCC-MRx and ASME Section VIII Division 2 Code Case 2843–2 that consider creep effects explicitly. Code comparisons were made in terms of conservatism. It was shown that there does exist concern about the non-conservatism of ASME VIII(2) associated with designs subjected to long-term operation in the creep range; the issues can be addressed with application of three alternative design rules to enhance integrity of pressure vessel.

Thermodynamic analysis of a novel integrated system operating with gas turbine, s-CO2 and t-CO2 power systems for hydrogen production and storage

In this paper, a proposal for a novel integrated Brayton cycle, supercritical plant, trans critical plant and organic Rankine cycle-based power systems for multi-generation applications are presented and analyzed thermodynamically. The plant can generate power, heating-cooling for residential applications, and hydrogen simultaneously from a single energy source. Both energetic and exergetic analyses are conducted on this multi-generation plant and its subsystems in order to evaluate and compare them thermodynamically, in terms of their useful product capabilities. The energetic and exergetic effectiveness of the multi-generation system are computed as 44.69% and 42.03%, respectively. After that, a parametric study on each of the subsystems of the proposed combined system is given in order to provide a deeper understanding of the working of these subsystems under different states. Lastly, environmental impact assessments are provided to raise environmental concerns for several operating conditions. For the base working condition, the results illustrate that the proposed plant has 0.5961, 0.0442, 0.6265 and 1.678 of exergo-environmental impact factor, exergy sustainability index, exergy stability factor and sustainability index, respectively.

Effects of coal compositions on the environment and economic feasibility of coal generation technologies

Coal has strategic importance for the global generation of electricity. However, the environmental impacts of its intense use are a concern, especially about greenhouse gases emissions. High Efficiency and Low Emissions coal-fired power plants are part of the approach known as Clean Coal Technologies, including supercritical (SC) and ultra-supercritical (USC) plants, since they allow cleaner and more efficient coal usage. This study analyzes how the usage of different coal compositions impacts the economic and environmental feasibility of operating units with higher efficiency when compared to conventional subcritical power plants. The analysis identified that the application of supercritical and ultra-supercritical technologies provided significant savings in fuel consumption, and consequently in CO2 emissions. The economic feasibility analysis identified that the annual savings change significantly among the analyzed coal compositions, in such manner that it determines whether the supercritical and ultra-supercritical technological alternatives can be economically viable in the long term or not. In general, these technologies are viable both as an alternative to mitigate CO2 emissions and to obtain better profitability through energy generation.

Techno-economic assessment of calcium and magnesium-based sorbents for post-combustion CO2 capture applied in fossil-fueled power plants

This work evaluates the most relevant techno-economic performances of calcium and magnesium-based sorbents used in high temperature solid looping cycles for post-combustion CO2 capture applied in fossil power generation. The evaluated power plants generate 1000 MW net electricity with 90% CO2 capture rate. As fuels, natural gas was assessed for combined cycle power plants since coal and lignite were assessed for super-critical power plants. As comparison benchmark systems, the correspondent plants with non-capture feature and with carbon capture using reactive gas–liquid absorption were also assessed. As the results show, both calcium and magnesium carbonate looping concepts applied in solid fossil fuel super-critical plants induce lower carbon capture energy penalty compared to the reactive gas–liquid absorption by about 1–2.2 net efficiency percentage points. The Calcium Looping (CaL) cycle shows higher net power efficiency than the Magnesium Looping (MgL) cycle by about 1–1.4 net percentage points. In case of natural gas combined cycle plants, the chemical absorption system has higher net power efficiency than CaL and MgL systems by about 4–6 percentage points. The key economic indicators (e.g., electricity production cost, CO2 capture costs etc.) show that both evaluated carbonate looping systems perform better than amine-based chemical scrubbing.

Performance evaluation of a supercritical circulating fluidized bed boiler for power generation under flexible operation

It is well known that the Łagisza power plant in Poland is the world’s first supercritical circulating fluidized bed (CFB) boiler, whose commercial operation started on June 2009. It has attracted a great deal of interest and operational data are publicly available, therefore it has been chosen as the object of the present study aimed at assessing load and fuel flexibility of supercritical CFB plants. First, the thermal cycle was modelled, by means of the commercial code Thermoflex®, at nominal and part load conditions for validation purposes. After having verified the validity of the applied modelling and simulation tool, the advantage of having supercritical steam combined with CFB boiler over subcritical steam and pulverized coal (PC) boiler, respectively, was quantified in terms of electric efficiency. As a next step, the designed fuel, i.e. locally mined hard coal, was replaced with biomass: 100% biomass firing was taken into account in the case of subcritical CFB boiler whereas the maximum share of biomass with coal was set at 50% with supercritical CFB boiler, consistently with the guidelines provided by the world leading manufacturers of CFB units. A broad range of biomass types was tested to conceive mixtures of fuel capable of preserving quite high performance, despite the energy consumption in pretreatment. However, the overall efficiency penalty, due to biomass co-firing, was found to potentially undermine the benefit of supercritical steam conditions compared to conventional subcritical power cycles. Indeed, the use of low-quality biomass in thermal power generation based on steam Rankine cycle may frustrate efforts to push the steam cycle boundaries.

Dissimilar Metal Welds used in AUSC Power Plant, Fabrication and Structural Integrity Issues

ABSTRACTIn the current era, the Advanced Ultra Super-Critical (AUSC) plants have been used to substantially increased efficiency with environmental protection. AUSC components boiler header, re-heater and super-heater tube etc. are fabricated by using advanced materials to join by the welding process. Any failure of the power plant can lead to grave consequences, not only of substantial financial losses but additionally immensely treasured and irreparable human life loss. In this review, the dissimilar metal welds (DMWs) have many issues such as metallurgical issue, cracking, carbon migration, welding electrode selection, creep properties, suitable welding process and structure integrity issues which enhanced the failure of weldments. The results of our review showed that DMWs of AUSC power plant are joined by activated flux Tungsten Inert Gas (A-TIG) and Pulse A-TIG process to increase the productivity and cut the significant fraction of cost. However, A-TIG process with Post Weld Heat Treatment (PWHT) improved the mechanical properties and high-temperature creep resistance properties of DMWs. This state of the art is encouraged the researchers about the enormous future scope.

Optimization of a 660 MWe Supercritical Power Plant Performance—A Case of Industry 4.0 in the Data-Driven Operational Management Part 1. Thermal Efficiency

This paper presents a comprehensive step-wise methodology for implementing industry 4.0 in a functional coal power plant. The overall efficiency of a 660 MWe supercritical coal-fired plant using real operational data is considered in the study. Conventional and advanced AI-based techniques are used to present comprehensive data visualization. Monte-Carlo experimentation on artificial neural network (ANN) and least square support vector machine (LSSVM) process models and interval adjoint significance analysis (IASA) are performed to eliminate insignificant control variables. Effective and validated ANN and LSSVM process models are developed and comprehensively compared. The ANN process model proved to be significantly more effective; especially, in terms of the capacity to be deployed as a robust and reliable AI model for industrial data analysis and decision making. A detailed investigation of efficient power generation is presented under 50%, 75%, and 100% power plant unit load. Up to 7.20%, 6.85%, and 8.60% savings in heat input values are identified at 50%, 75%, and 100% unit load, respectively, without compromising the power plant’s overall thermal efficiency.

Enhancing the thermal and economic performance of supercritical CO2 plant by waste heat recovery using an ejector refrigeration cycle

Supercritical CO2 cycle has an optimal performance when the cycle minimum temperature is around the critical temperature (31 °C), which is impossible at hot climatic conditions. To solve this problem, this work hybridizes a supercritical CO2 cycle with an ejector refrigeration cycle (ERC) to cool the minimum temperature of the cycle to be about 31 °C and hence achieving the highest possible performance. Comprehensive energy, exergy, and economic analyses are carried out to explore the mechanisms of performance improvement of the novel combined plant. Sensitivity analysis is performed to recognize the most influencing parameters on the performance of the combined plant. Based on the sensitivity analysis, the effect of different operating and design parameters on the system performance is investigated. Furthermore, a multi-objective optimization study is performed to find the trade-off between exergy efficiency and cost-saving. Among the different the five refrigerants used for ERC, the results illustrate that R717 is the most efficient one for the present hybridization. The exergy destruction in the precooler reduces from 15.5% to 0.7% when ERC is combined with the sCO2 cycle. Thus, the energy efficiency (ηth) and exergy efficiency (ηex) increase by 9.5%, while the levelized cost of energy (LCOE) declines by 10.7%. Compared with the standalone sCO2 cycle, the produced power, ηth, ηex, and LCOE of the optimized plant improve by 94.3%, 36.2%, 28.6%, and 18.3%, respectively.

Abstract 4118: Reducing the effects of glucocorticoids on breast cancer outcome in-vitro and in-vivo

Abstract Background: Research indicates that natural and synthetic glucocorticoids (GCs) may play a role in cancer progression and patient survival. The main natural GC is cortisol which is released during psychological stress. Whereas, synthetic GCs, such as dexamethasone, are widely used in conjugation with cancer therapy due to their ability to induce apoptosis. Surprisingly, recent evidence suggests that GCs can induce therapy-resistance in solid tumors, although the precise mechanisms are not well defined. The goal of this study was to assess the role of natural and synthetic GCs on resistance to cytotoxic therapy in breast cancer and to examine the usage of a novel supercritical plant extract derived from the neem tree (SCNE) in reversing the antagonizing effects of GCs. Methods: We co-treated human breast cancer cells (MDA-MB-231) with physiological and therapeutic doses of cortisol and dexamethasone (0.1-10 µM) alone or in combination with chemotherapy drug Fluorouracil (5FU) and SCNE for 72 hours. We performed cell viability, proliferation, cell cycle, flow cytometry, and apoptosis assays. Thus, we used the glucocorticoid receptor (GR) antagonist (RU-486) to investigate the role of GC receptor signaling. The expression of GR was confirmed by western blots and q-PCR. Finally, we exposed breast cancer tumors bearing mice to a novel type of unpredictable social stress which well aligns with the psychological stressors experienced by breast cancer patients. Results: Our results indicate that GCs alone or in combination with 5FU enhanced cell proliferation (p<0.001) and reduced apoptosis, whereas RU-486, which antagonizes the action of GR, restored the apoptosis sensitivity of the GCs treated cells. SCNE minimized the effects of CGs. Currently, we are investigating the impact of unpredictable social environment as a chronic stressor on the growth of xenografted breast cancers in nude mice. Conclusions: Our study suggests that co-treatment of GCs protected breast cancer cells from 5FU-induced apoptosis, however utilizing SCNE may lessen the antagonizing effects of GCs. We cannot rule out the possibility that GCs may enhance resistance to chemotherapeutic drugs by modifying inflammation, angiogenesis or cell migration. Therefore, our current studies are aimed at investigating the possible pathways mediating GCs induced resistance to therapy in vitro and in vivo. Our ultimate goal is to elucidate the molecular mechanisms of GCs mediated inhibition of chemotherapy-induced cell death thereby proposing the ways of reversing this process. The literature suggests that around 35-45 % of cancer patients experience a significant level of stress which manifests in elevated production of natural GC cortisol. Furthermore, given that GCs are widely accepted as an adjuvant treatment during chemotherapy or radiotherapy for reducing side effects, it is critical to investigate the conditions upon which they exert either pro-apoptotic or anti-apoptotic action in different cancer types. Although more data is needed, our findings imply careful consideration for the profligate use of GCs combination therapy in the treatment of cancer patients. Citation Format: Kristina Andrijauskaite. Reducing the effects of glucocorticoids on breast cancer outcome in-vitro and in-vivo [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4118.

Evaluation of tension and creep rupture behaviors of long-term exposed P91 steel in a supercritical plant

Tension and creep rupture behaviors of long-term exposed P91 steel, sampled from of a T-fitting part of reheat steam piping serviced for 73,716 h at 569 °C and 46.7 bars in a supercritical plant, were evaluated in comparison with those of virgin Gr. 91 steel. Tensile strength reduction factors were proposed for the exposed P91, and creep rupture behaviors were analyzed using various creep laws: Norton’s power law, the Monkman-Grant relations, and a damage tolerance factor (λ). The exposed P91 revealed a significant reduction in tensile strengths, but an increase in elongation. It was found to have a lower creep strength, faster creep strain rate, and higher rupture ductility than the virgin steel. The reduction of mechanical strengths in the exposed P91 was due to the coarsening of precipitates, dissolution of useful fine MX precipitates, and recovery of dislocation substructure during the long-term thermal exposure.