The shift toward a dual-carbon strategy is expected to instigate extensive and profound changes across virtually all economic sectors and aspects of national life in China.The transformation and upgrading of energy sy...The shift toward a dual-carbon strategy is expected to instigate extensive and profound changes across virtually all economic sectors and aspects of national life in China.The transformation and upgrading of energy systems and related infrastructure are particularly noteworthy.The future of energy supply will likely be dominated by renewable generation.One of the most significant challenges in this future landscape is the fluctuation and variability of wind and solar power,which often lead to a substantial amount of curtailed wind,solar,and hydropower.Such curtailment has shown an increasing trend,becoming a major obstacle to the swift deployment of renewable power generation.This challenge must be addressed to ensure the successful implementation of the dual-carbon strategy and the dominance of renewable energy in the future.展开更多
Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten...Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten salt technology for thermal energy storage(TES) has further contributed to the growth of CSP plants;however, the corrosive nature of molten salts poses challenges to the durability of container materials, necessitating innovative corrosion mitigation strategies.This review summarizes scientific advancements in high-temperature anticorrosion coatings for molten nitrate salts, highlighting the key challenges and future trends.It also explores various coating types, including metallic, ceramic, and carbon-based coatings, and compares different coating deposition methods.This review emphasizes the need for durable coatings that meet long-term performance requirements and regulatory limitations, with an emphasis on carbon-based coatings and emerging nanomaterials.A combination of multiple coatings is required to achieve desirable anticorrosion properties while addressing material compatibility and cost considerations.The overall goal is to advance the manufacturing, assembly, and performance of CSP systems for increased efficiency, reliability, and durability in various applications.展开更多
Liquefied natural gas(LNG)is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years.The liquefaction process of natural gas is energy-intensive,while the regasificatio...Liquefied natural gas(LNG)is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years.The liquefaction process of natural gas is energy-intensive,while the regasification of LNG gives out a huge amount of waste energy since plenty of high grade cold energy(-160℃)from LNG is released to sea water directly in most cases,and also sometimes LNG is burned for regasification.On the other hand,liquid air energy storage(LAES)is an emerging energy storage technology for applications such as peak load shifting of power grids,which generates 30%-40%of compression heat(-200℃).Such heat could lead to energy waste if not recovered and used.The recovery of the compression heat is technically feasible but requires additional capital investment,which may not always be economically attractive.Therefore,we propose a power plant for recovering the waste cryogenic energy from LNG regasification and compression heat from the LAES.The challenge for such a power plant is the wide working temperature range between the low-temperature exergy source(-160℃)and heat source(-200℃).Nitrogen and argon are proposed as the working fluids to address the challenge.Thermodynamic analyses are carried out and the results show that the power plant could achieve a thermal efficiency of 27%and 19%and an exergy efficiency of 40%and 28%for nitrogen and argon,respectively.Here,with the nitrogen as working fluid undergoes a complete Brayton Cycle,while the argon based power plant goes through a combined Brayton and Rankine Cycle.Besides,the economic analysis shows that the payback period of this proposed system is only 2.2 years,utilizing the excess heat from a 5 MW/40 MWh LAES system.The findings suggest that the waste energy based power plant could be co-located with the LNG terminal and LAES plant,providing additional power output and reducing energy waste.展开更多
With the increasing deployment of renewable energy-based power generation plants,the power system is becoming increasingly vulnerable due to the intermittent nature of renewable energy,and a blackout can be the worst ...With the increasing deployment of renewable energy-based power generation plants,the power system is becoming increasingly vulnerable due to the intermittent nature of renewable energy,and a blackout can be the worst scenario.The current auxiliary generators must be upgraded to energy sources with substantially high power and storage capacity,a short response time,good profitability,and minimal environmental concern.Difficulties in the power restoration of renewable energy generators should also be addressed.The different energy storage methods can store and release electrical/thermal/mechanical energy and provide flexibility and stability to the power system.Herein,a review of the use of energy storage methods for black start services is provided,for which little has been discussed in the literature.First,the challenges that impede a stable,environmentally friendly,and cost-effective energy storage-based black start are identified.The energy storagebased black start service may lack supply resilience.Second,the typical energy storage-based black start service,including explanations on its steps and configurations,is introduced.Black start services with different energy storage technologies,including electrochemical,thermal,and electromechanical resources,are compared.Results suggest that hybridization of energy storage technologies should be developed,which mitigates the disadvantages of individual energy storage methods,considering the deployment of energy storage-based black start services.展开更多
Decarbonization of the electric power sector is essential for sustainable development.Low-carbon generation technologies,such as solar and wind energy,can replace the CO_(2)-emitting energy sources(coal and natural ga...Decarbonization of the electric power sector is essential for sustainable development.Low-carbon generation technologies,such as solar and wind energy,can replace the CO_(2)-emitting energy sources(coal and natural gas plants).As a sustainable engineering practice,long-duration energy storage technologies must be employed to manage imbalances in the variable renewable energy supply and electricity demand.Compressed air energy storage(CAES)is an effective solution for balancing this mismatch and therefore is suitable for use in future electrical systems to achieve a high penetration of renewable energy generation.This study introduces recent progress in CAES,mainly advanced CAES,which is a clean energy technology that eliminates the use of fossil fuels,compared with two commercial CAES plants at Huntorf and McIntosh which are conventional ones utilizing fossil fuels.Advanced CAES include adiabatic CAES,isothermal CAES,liquid air energy storage,supercritical CAES,underwater CAES,and CAES coupled with other technologies.The principles and configurations of these advanced CAES technologies are briefly discussed and a comprehensive review of the state-of-the-art technologies is presented,including theoretical studies,experiments,demonstrations,and applications.The comparison and discussion of these CAES technologies are summarized with a focus on technical maturity,power sizing,storage capacity,operation pressure,round-trip efficiency,efficiency of the components,operation duration,and investment cost.Potential application trends were compiled.This paper presents a comprehensive reference for developing novel CAES systems and makes recommendations for future research and development to facilitate their application in several areas,ranging from fundamentals to applications.展开更多
Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system pro...Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces.In the present article,mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone i.e.Jaipur.The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months(May to July).L25 Orthogonal array of design parameters(air cavity thickness,air velocity,and PV panel’s transparency)and their respective levels have been developed using Taguchi design to perform experiments.Based on experimental results,multiple linear regression has been used to forecast solar heat gain coefficient,PVs electrical power and daylighting illuminance indoors as function of design factors.The statistical significance of mathematical relationships is sorted by variance analysis,which is found to be in good accord with field measurements(R2>0.90).The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions.The Photovoltaic-DSF system with 30%transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers.展开更多
Cellulose-based film has gained popularity as an alternative to synthetic polymers due to its outstanding properties.Among all types of cellulose materials available,cellulose nanofiber(CNF)has great potential to be u...Cellulose-based film has gained popularity as an alternative to synthetic polymers due to its outstanding properties.Among all types of cellulose materials available,cellulose nanofiber(CNF)has great potential to be utilized in a diverse range of applications,including as a film material.In this study,CNF biocomposite film was prepared by using polyvinyl alcohol(PVA)as a matrix and Uncaria gambir extract as a filler.This study aims to investigate the effect of Uncaria gambir extract on the optical properties and thermal stability of the produced film.The formation of the CNF biocomposite films was confirmed using Fourier Transform Infrared Spectroscopy,their transmittance characteristics were measured using UV-Vis spectroscopy and a transmittance meter,while their reflectance was determined using a reflectance meter.The results revealed that the addition of Uncaria gambir extract to the CNF biocomposite film improved its UV-shielding properties,as indicated by the lower percentage of transmittance in the visible region,10%–70%.In addition,its reflectance increased to 10.6%compared to the CNF film without the addition of Uncaria gambir extract.Furthermore,the thermal stability of the CNF biocomposite film with the addition of Uncaria gambir extract improved to around 400℃–500℃.In conclusion,the results showed that CNF biocomposite film prepared by adding Uncaria gambir extract can be a promising candidate for optical and thermal management materials.展开更多
Au-based catalysts have been reported to be active in the cyclohexane oxidation to K-A oil, but they showed some limitiations in terms of productivity, selectivity and required reaction conditions. The possibility to ...Au-based catalysts have been reported to be active in the cyclohexane oxidation to K-A oil, but they showed some limitiations in terms of productivity, selectivity and required reaction conditions. The possibility to overcome some of these limits has been explored coupling Au with Cu, which can be suitable for undergoing the electron-switch in the initial step of the cyclohexane oxidation. Hence, a bimetallic 2 wt% Au Cu/Al_(2)O_(3) catalyst was tested in the oxidation of cyclohexane, working at mild conditions of 120 ℃ and 4 bar of O_(2). The combination of the catalyst with a very small amount of benzaldehyde used as cheaper and non-toxic radical initiator allowed to obtain a very high productivity of cyclohexanol and cyclohexanone(45 mmol*m L/mgmet*h) with a selectivity of 94%. Moreover, comparing the catalysed reaction with the non-catalysed one, the role of the catalyst has been disclosed.展开更多
Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/AI ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene sele...Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/AI ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene selectivity (45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM- 5-F showed much longer lifetime (305 h) compared with ZSM-5-OH (157 h) in spite of similar crystal size and aluminum content. Characterization by NH3-TPD. Py-IR, OH-IR, SEM, TG-DTA, XRD and 1H MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-S-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests.展开更多
Lithium-sulfur batteries attract lots of attention due to their high specific capacity,low cost,and environmental friendliness.However,the low sulfur utilization and short cycle life extremely hinder their application...Lithium-sulfur batteries attract lots of attention due to their high specific capacity,low cost,and environmental friendliness.However,the low sulfur utilization and short cycle life extremely hinder their application.Herein,we design and fabricate a three-dimensional electrode by a simple filtration method to achieve a high-sulfur loading.Biomass porous carbon is employed as a current collector,which not only enhances the electronic transport but also effectively limits the volume expansion of the active material.Meanwhile,an optimized carboxymethyl cellulose binder is chosen.The chemical bonding restricts the shuttle effect,leading to improved electrochemical performance.Under the ultrahigh sulfur load of 28mg/cm2,the high capacity of 18mAh/cm2 is still maintained,and stable cycling performance is obtained.This study demonstrates a viable strategy to develop promising lithium-sulfur batteries with a three-dimensional electrode,which promotes sulfur loading and electrochemical performance.展开更多
Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milde...Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions.CO2 being an inert gas becomes the most challenging to be utilized during the gasification process.The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900°C.The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs.The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied.Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction.展开更多
Many oases(wet interdunes)are sedimentary systems characterized by high-frequency water-level oscillations,marked changes in salinity and intense biological activity at their margins.They are considered to be one of t...Many oases(wet interdunes)are sedimentary systems characterized by high-frequency water-level oscillations,marked changes in salinity and intense biological activity at their margins.They are considered to be one of the most challenging environments on Earth for ecosystem development.These dynamic,depositional settings are usually unfavourable for fossilization and subsequent preservation of vegetal remains.This paper describes bryophyte(liverwort)assemblages occurring in three successive horizons interpreted to represent(i)recurrent early successional phases of biological soil crust colonization of wet interdune margins or(ii)exceptional preservation of floating or riparian liverworts in oasis pond waters associated with a progressive fall of the interdune water level.The record of in situ colonization surfaces characterized by delicate(e.g.lignin-free)three-dimensional structures represents an exceptional type of preservation herein associated with a rapid variation in phreatic interdune water level and the subsequent establishment of anoxic and reducing conditions.The occurrence of exceptionally preserved liverwort colonies coincides with the sedimentary record of,at least,three seismite levels in the oasis.Data gathered from the site suggests that the water table of the oasis was controlled by a combination of(i)a positive creation of accommodation space due to subsidence associated with movement on syn-sedimentary extensional faults,and(ii)the rise and fall of the oasis water table controlled by the oscillations of the groundwater system due to orbital changes which appear to drive the variability of the climate system.Rising groundwater levels flooded the oasis soil crusts and lead to the exceptional recurrent preservation of liverwort colonies at the oasis margins.Alternatively,considering the hypothesis of floating or riparian liverworts in the oasis pond waters,the fall in the level of the oasis water table placed the floating liverworts in contact with the oasis bottom sediments.This fall in the level of the oasis water table could indicate a cessation of accommodation space by syn-sedimentary extensional faults and/or a regional lowering of the groundwater system level associated with drought periods.Preliminary results indicate that oasis lamination between liverwort colonies records decadal and sub-decadal cyclicity,related with 11-year Schwabe sunspot and sub-decadal NAO cyclicities,conferring for every sedimentary cycle between liverwort colonies a duration of approximately 200 years,that otherwise matches the expected recurrence period for the De Vries cycle of solar activity.展开更多
Narrow spectral response,low charge separation efficiency and slow water oxidation kinetics of TiO_(2)limit its application in photoelectrochemical and photocatalytic water splitting.Herein,a promising organic/inorgan...Narrow spectral response,low charge separation efficiency and slow water oxidation kinetics of TiO_(2)limit its application in photoelectrochemical and photocatalytic water splitting.Herein,a promising organic/inorganic composite catalyst Ag/PANI/3DOMM‐TiO_(2–x)with a three‐dimensional ordered macro‐and meso‐porous(3DO MM)structure,oxygen vacancy and Ti^(3+)defects,heterojunction formation and noble metal Ag was designed based on the Z‐scheme mechanism and successfully prepared.The Ag/PANI/3DOMM‐TiO_(2–x)ternary catalyst exhibited enhanced hydrogen production activity in both photocatalytic and photoelectrochemical water splitting.The photocatalytic hydrogen production rate is 420.90μmol g^(–1)h^(–1),which are 19.80 times and 2.06 times higher than the commercial P25 and 3DOMM‐TiO_(2),respectively.In the photoelectrochemical tests,the Ag/PANI/3DOMM‐TiO_(2–x)photoelectrode shows enhanced separation and transfer of carriers with a high current density of 1.55 mA cm^(–2)at equilibrium potential of 1.23 V under simulated AM 1.5 G illumination,which is approximately 5 times greater than the 3DOMM‐TiO_(2).The present work has demonstrated the promising potential of organic/inorganic Z‐scheme photocatalyst in driving water splitting for hydrogen production.展开更多
In this work, a radiological technique which simultaneously measures soil bulk density and water contents accurately and quickly in a non-destructive manner at different depths of the soil profile of the major soil se...In this work, a radiological technique which simultaneously measures soil bulk density and water contents accurately and quickly in a non-destructive manner at different depths of the soil profile of the major soil series of Central Southwestern Nigeria is developed. Undisturbed samples from Iwo, Ondo, Egbeda, Itagunmodi, Okemessi, Mamu, Origo and Jago soil series of Southwestern Nigeria were collected on monthly intervals from June 2006 to May 2007. Using gamma-ray energy pairs of 122 and 1112 keV;and 344 and 1408 keV obtained from europium-152 (152Eu) radionuclide, the attenuation coefficients for soil and water, μs, μw and consequently ρs and θv at varying soil depths of these series were calculated. Comparative gravimetric measurements of these soil parameters were carried out. Using the XCOM computer algorithm with the soil elemental concentrations obtained using the Energy Dispersive X-Ray Fluorescence analysis (EDXRF) technique, theoretical estimates of μs for the various soil series were obtained and compared with the experimental values. The result of the developed dual energy gamma-ray transmission technique was compared with the gravimetric measurement method and Pearson correlation coefficient (0.987, p s and (0.996, p θv. The results of the measurements showed that θv minima with values 0.1931, 0.1987, 0.2377, 0.2111, 0.1738, 0.1701, 0.2334, 0.2341 and minima ρs values of 1.21 g/cm3, 1.20 g/cm3, 1.02 g/cm3, 1.38 g/cm3, 1.12 g/cm3, 1.14 g/cm3, 0.64 g/cm3, 1.33 g/cm3 were obtained respectively for the soil series stated above in January. The maxima θv with values 0.3621, 0.4212, 0.3962, 0.3794, 0.3049, 0.2811, 0.4415, 0.4416 and maxima ρs values of 1.52 g/cm3, 1.67 g/cm3, 1.74 g/cm3, 1.69 g/cm3, 1.70 g/cm3, 1.68 g/cm3, 1.08 g/cm3, 1.54 g/cm3 occurred for these soil series respectively in July except for Mamu soil series which occurred in May. These correlated very well with the occurrence of the Dry and Rainy seasons in the study area. The results of the EDXRF analysis showed that maxima Iron, Fe concentrations of 5.0890 ppm at the depth of 90 - 120 cm into the soil profile, was obtained for Iwo series, 4.4691 ppm at 50 - 70 cm for Ondo, 6.3438 ppm at 15 - 30 cm for Egbeda, 6.6845 ppm at 30 - 50 cm for Itagunmodi, 5.0252 ppm at 90 - 120 cm for Okemessi, 3.4996 ppm at 30 - 50 cm for Mamu, 5.1191 ppm at 50 - 70 cm for Jago and 4.7193 ppm at 90 - 120 cm for Origo. Maxima Potassium, K concentrations of 2.9613 ppm at the depth of 50 - 70 cm, was obtained for Iwo soil series, 2.3315 ppm at 0 - 15 cm for Egbeda, 2.2763 ppm at 70 - 90 cm for Okemessi and 3.3636 ppm at 50 - 70 cm for Mamu. Maxima Ti concentrations of 1.4822 ppm at 0 - 15 cm was obtained for Ondo soil series, 2.5159 ppm at 15 - 30 cm for Egbeda, 1.8690 ppm at 90 - 120 cm for Itagunmodi, 2.2975 ppm at 15-30 cm for Okemessi, 1.6453 ppm at 0 - 15 cm for Jago and 1.0513 ppm at 30 - 50 cm for Origo.展开更多
With increasing global shortage of fresh water resources,many countries are prioritizing desalination as a means of utilizing abundantly available seawater resources.Integrated energy efficiency evaluation is a scient...With increasing global shortage of fresh water resources,many countries are prioritizing desalination as a means of utilizing abundantly available seawater resources.Integrated energy efficiency evaluation is a scientific method for the quantitative analysis of energy efficiency based on multiple indicators and is very useful for investment,construction,and scientific decision-making for desalination projects.In this paper,the energy efficiency evaluation of the micro energy network (MEN) of desalination for multi-source and multi-load is studied,and the basic idea of comprehensive energy efficiency evaluation is analyzed.The process includes the use of a MEN model to establish an integrated energy efficiency evaluation index system,taking into consideration energy,equipment,economic,environmental,and social factors.A combined evaluation method considering subjective and objective comprehensive weights for multi-source multi-load desalination MENs is proposed to evaluate the energy efficiency of desalination and from multiple perspectives.展开更多
The epithermal neutron shape factor (α) was determined in the permanent cadmium lined irradiation channel installed in the large outer irradiation site of the Nigeria Research Reactor-1 (NIRR- 1) by the cadmium cover...The epithermal neutron shape factor (α) was determined in the permanent cadmium lined irradiation channel installed in the large outer irradiation site of the Nigeria Research Reactor-1 (NIRR- 1) by the cadmium covered multimonitor method using the monitors Al-0.1% Au, Zr and Zn thin foils and Mo thin wire and was found to be -0.137 ± 0.018. The high negative value of α indicates a hardened epithermal neutron spectrum in the cadmium lined irradiation channel. The α value obtained was used in the single comparator method of ENAA (ko-ENAA) for the determination of the concentrations of elements in the standard reference material NIST 1515 Apple leaves using Al-0.1% Au thin foil as the single comparator. The concentrations of the elements Sm and Br were determined in the NIST 1515 Apple leaves because of their high Qo values and are in good agreement with the certified values.展开更多
This paper assesses the evolution of generation technology-mix in Australia,with specific emphasis on understanding how such evolution has been shaped by wider political and socioeconomic influences.This assessment is...This paper assesses the evolution of generation technology-mix in Australia,with specific emphasis on understanding how such evolution has been shaped by wider political and socioeconomic influences.This assessment is predicated on the argument that the contemporary,quintessentially techno-economic,policy discourse on renewable energy is deficient,as it ignores climacteric political and socio-economic influences on generation technology-mix.The methodological framework employed in this paper is informed by the core tenets of technological change theory.The assessment suggests that generation technology-mix in Australia has historically been overwhelmingly influenced by the underlying technological paradigm of the electricity industry;and that this technological paradigm essentially draws its imprimatur from the wider political and socio-economic contexts.By implication,it suggests that a rapid uptake of renewables will have widespread ramifications,extending into political,socio-economic and cultural realms of a society.Clearly,existing policy discourse-that tends to focus on technical potentials,cost competitiveness,externalities and risks of various renewable technologies-is deficient.A much broader discourse is needed.This paper also made an attempt to develop a basis for such a discourse by reviewing broader aspects of the Australian society that would be affected by a rapid uptake of renewables.展开更多
This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating syste...This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating system consists of an air source heat pump (ASHP) incorporated with a hot water tank as active Thermal Energy Storage (TES), where two optimization problems are integrated together to optimize both the ASHP electricity consumption and the building heating consumption utilizing a heat dynamic model of the building. The results show that the proposed EMPC can save the energy cost by load shifting compared with some reference cases.展开更多
The Nigeria Research Reactor-1 (NIRR-1) is one of the Commercial Miniature Neutron Source Reactors (MNSRs) sited outside China and scheduled for conversion under the auspices of Reduced Enrichment for Research and Tes...The Nigeria Research Reactor-1 (NIRR-1) is one of the Commercial Miniature Neutron Source Reactors (MNSRs) sited outside China and scheduled for conversion under the auspices of Reduced Enrichment for Research and Test Reactors (RERTR) program. Since 2006, the reduction in the fuel enrichment of MSNR facilities from greater than 90% HEU cores to less than 20% LEU cores has been embarked upon. Consequently in this work, the physics parameters of three dispersion LEU fuels, which include U3Si, U3Si2, and U9Mo enriched to 19.75% were determined by the MCNP code to investigate their suitability for the conversion of NIRR-1 to LEU. The following reactor core physics parameters were computed for the LEU fuel options: clean cold core excess reactivity (ρex), control rod (CR) worth, shut down margin (SDM), neutron flux distributions in the irradiation channels and kinetics data (i.e. effective delayed neutron fraction, βeff?and prompt neutron lifetime, lf). Results are compared with experimental and calculated data of the current HEU core and indicate that it would be feasible to use any of the LEU options for the conversion of commercial MNSR in general and NIRR-1 in particular from HEU to LEU.展开更多
Prior to the installation of the Cd-liner in one of the large outer irradiation channels of NIRR-1, a Monte Carlo simulation was performed using MCNP5 version 1.4 code. This was done to investigate the effect of insta...Prior to the installation of the Cd-liner in one of the large outer irradiation channels of NIRR-1, a Monte Carlo simulation was performed using MCNP5 version 1.4 code. This was done to investigate the effect of installation of Cd-liner in either an inner or outer irradiation channel on reactor physics parameters. Data obtained indicate that the core excess reactivity in both inner and outer irradiations channels is reduced by 3.60 ± 0.07 mk and 0.64 ± 0.06 mk, respectively. Considering the fact that NIRR-1 has a cold core excess reactivity of 3.77 mk, results obtained show that installation of the 1 mm thick Cd-sheet in one of the large outer irradiation channels would have no significant impact on the core physics data. After installation of a 1 mm Cd sheath in a large outer irradiation channel, the neutron flux distribution and the stability in the irradiation channels were monitored by foil activation method. Results indicate that the uniformity of neutron flux distribution in the irradiation channel is preserved and the neutron flux data were found to be comparable with the data obtained before the installation.展开更多
文摘The shift toward a dual-carbon strategy is expected to instigate extensive and profound changes across virtually all economic sectors and aspects of national life in China.The transformation and upgrading of energy systems and related infrastructure are particularly noteworthy.The future of energy supply will likely be dominated by renewable generation.One of the most significant challenges in this future landscape is the fluctuation and variability of wind and solar power,which often lead to a substantial amount of curtailed wind,solar,and hydropower.Such curtailment has shown an increasing trend,becoming a major obstacle to the swift deployment of renewable power generation.This challenge must be addressed to ensure the successful implementation of the dual-carbon strategy and the dominance of renewable energy in the future.
文摘Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten salt technology for thermal energy storage(TES) has further contributed to the growth of CSP plants;however, the corrosive nature of molten salts poses challenges to the durability of container materials, necessitating innovative corrosion mitigation strategies.This review summarizes scientific advancements in high-temperature anticorrosion coatings for molten nitrate salts, highlighting the key challenges and future trends.It also explores various coating types, including metallic, ceramic, and carbon-based coatings, and compares different coating deposition methods.This review emphasizes the need for durable coatings that meet long-term performance requirements and regulatory limitations, with an emphasis on carbon-based coatings and emerging nanomaterials.A combination of multiple coatings is required to achieve desirable anticorrosion properties while addressing material compatibility and cost considerations.The overall goal is to advance the manufacturing, assembly, and performance of CSP systems for increased efficiency, reliability, and durability in various applications.
基金partial support of UK EPSRC under grants EP/V012053/1,EP/S032622/1,EP/P004709/1,EP/P003605/1 and EP/N032888/1the British Council under 2020-RLWK12-10478 and 2019-RLWK11-10724。
文摘Liquefied natural gas(LNG)is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years.The liquefaction process of natural gas is energy-intensive,while the regasification of LNG gives out a huge amount of waste energy since plenty of high grade cold energy(-160℃)from LNG is released to sea water directly in most cases,and also sometimes LNG is burned for regasification.On the other hand,liquid air energy storage(LAES)is an emerging energy storage technology for applications such as peak load shifting of power grids,which generates 30%-40%of compression heat(-200℃).Such heat could lead to energy waste if not recovered and used.The recovery of the compression heat is technically feasible but requires additional capital investment,which may not always be economically attractive.Therefore,we propose a power plant for recovering the waste cryogenic energy from LNG regasification and compression heat from the LAES.The challenge for such a power plant is the wide working temperature range between the low-temperature exergy source(-160℃)and heat source(-200℃).Nitrogen and argon are proposed as the working fluids to address the challenge.Thermodynamic analyses are carried out and the results show that the power plant could achieve a thermal efficiency of 27%and 19%and an exergy efficiency of 40%and 28%for nitrogen and argon,respectively.Here,with the nitrogen as working fluid undergoes a complete Brayton Cycle,while the argon based power plant goes through a combined Brayton and Rankine Cycle.Besides,the economic analysis shows that the payback period of this proposed system is only 2.2 years,utilizing the excess heat from a 5 MW/40 MWh LAES system.The findings suggest that the waste energy based power plant could be co-located with the LNG terminal and LAES plant,providing additional power output and reducing energy waste.
基金financially supported by the UK Engineering and Physical Sciences Research Council(Nos.EP/S001905/1,EP/S032622/1,and EP/N032888/1)the Jiangsu Provincial Department of Science and Technology,China(Nos.BZ2019071 and BZ2020076)。
文摘With the increasing deployment of renewable energy-based power generation plants,the power system is becoming increasingly vulnerable due to the intermittent nature of renewable energy,and a blackout can be the worst scenario.The current auxiliary generators must be upgraded to energy sources with substantially high power and storage capacity,a short response time,good profitability,and minimal environmental concern.Difficulties in the power restoration of renewable energy generators should also be addressed.The different energy storage methods can store and release electrical/thermal/mechanical energy and provide flexibility and stability to the power system.Herein,a review of the use of energy storage methods for black start services is provided,for which little has been discussed in the literature.First,the challenges that impede a stable,environmentally friendly,and cost-effective energy storage-based black start are identified.The energy storagebased black start service may lack supply resilience.Second,the typical energy storage-based black start service,including explanations on its steps and configurations,is introduced.Black start services with different energy storage technologies,including electrochemical,thermal,and electromechanical resources,are compared.Results suggest that hybridization of energy storage technologies should be developed,which mitigates the disadvantages of individual energy storage methods,considering the deployment of energy storage-based black start services.
基金the Beijing Natural Science Foundation (JQ21010)the National Natural Science Foundation of China (52376040)+1 种基金the National Science Fund for Distinguished Young Scholars (51925604)the Beijing Nova Program (20230484479).
文摘Decarbonization of the electric power sector is essential for sustainable development.Low-carbon generation technologies,such as solar and wind energy,can replace the CO_(2)-emitting energy sources(coal and natural gas plants).As a sustainable engineering practice,long-duration energy storage technologies must be employed to manage imbalances in the variable renewable energy supply and electricity demand.Compressed air energy storage(CAES)is an effective solution for balancing this mismatch and therefore is suitable for use in future electrical systems to achieve a high penetration of renewable energy generation.This study introduces recent progress in CAES,mainly advanced CAES,which is a clean energy technology that eliminates the use of fossil fuels,compared with two commercial CAES plants at Huntorf and McIntosh which are conventional ones utilizing fossil fuels.Advanced CAES include adiabatic CAES,isothermal CAES,liquid air energy storage,supercritical CAES,underwater CAES,and CAES coupled with other technologies.The principles and configurations of these advanced CAES technologies are briefly discussed and a comprehensive review of the state-of-the-art technologies is presented,including theoretical studies,experiments,demonstrations,and applications.The comparison and discussion of these CAES technologies are summarized with a focus on technical maturity,power sizing,storage capacity,operation pressure,round-trip efficiency,efficiency of the components,operation duration,and investment cost.Potential application trends were compiled.This paper presents a comprehensive reference for developing novel CAES systems and makes recommendations for future research and development to facilitate their application in several areas,ranging from fundamentals to applications.
基金supported by a DST project named“Development and performance analysis of Semi-Transparent Solar Photovoltaic double pane Window/Facade system”funded by the Department of Science and Technology,Government of India (TMD/CERI/BEE/2016/070(G)).
文摘Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces.In the present article,mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone i.e.Jaipur.The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months(May to July).L25 Orthogonal array of design parameters(air cavity thickness,air velocity,and PV panel’s transparency)and their respective levels have been developed using Taguchi design to perform experiments.Based on experimental results,multiple linear regression has been used to forecast solar heat gain coefficient,PVs electrical power and daylighting illuminance indoors as function of design factors.The statistical significance of mathematical relationships is sorted by variance analysis,which is found to be in good accord with field measurements(R2>0.90).The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions.The Photovoltaic-DSF system with 30%transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers.
基金funded by the Institute for Research and Community Service(LPPM)Universitas Negeri Padang,Indonesia,with a Contract Number:1529/UN35.15/LT/2023.
文摘Cellulose-based film has gained popularity as an alternative to synthetic polymers due to its outstanding properties.Among all types of cellulose materials available,cellulose nanofiber(CNF)has great potential to be utilized in a diverse range of applications,including as a film material.In this study,CNF biocomposite film was prepared by using polyvinyl alcohol(PVA)as a matrix and Uncaria gambir extract as a filler.This study aims to investigate the effect of Uncaria gambir extract on the optical properties and thermal stability of the produced film.The formation of the CNF biocomposite films was confirmed using Fourier Transform Infrared Spectroscopy,their transmittance characteristics were measured using UV-Vis spectroscopy and a transmittance meter,while their reflectance was determined using a reflectance meter.The results revealed that the addition of Uncaria gambir extract to the CNF biocomposite film improved its UV-shielding properties,as indicated by the lower percentage of transmittance in the visible region,10%–70%.In addition,its reflectance increased to 10.6%compared to the CNF film without the addition of Uncaria gambir extract.Furthermore,the thermal stability of the CNF biocomposite film with the addition of Uncaria gambir extract improved to around 400℃–500℃.In conclusion,the results showed that CNF biocomposite film prepared by adding Uncaria gambir extract can be a promising candidate for optical and thermal management materials.
基金The Authors gratefully acknowledge the supportof bilateral project CNR-HAS(MTA)SAC.AD002.037.
文摘Au-based catalysts have been reported to be active in the cyclohexane oxidation to K-A oil, but they showed some limitiations in terms of productivity, selectivity and required reaction conditions. The possibility to overcome some of these limits has been explored coupling Au with Cu, which can be suitable for undergoing the electron-switch in the initial step of the cyclohexane oxidation. Hence, a bimetallic 2 wt% Au Cu/Al_(2)O_(3) catalyst was tested in the oxidation of cyclohexane, working at mild conditions of 120 ℃ and 4 bar of O_(2). The combination of the catalyst with a very small amount of benzaldehyde used as cheaper and non-toxic radical initiator allowed to obtain a very high productivity of cyclohexanol and cyclohexanone(45 mmol*m L/mgmet*h) with a selectivity of 94%. Moreover, comparing the catalysed reaction with the non-catalysed one, the role of the catalyst has been disclosed.
文摘Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/AI ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene selectivity (45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM- 5-F showed much longer lifetime (305 h) compared with ZSM-5-OH (157 h) in spite of similar crystal size and aluminum content. Characterization by NH3-TPD. Py-IR, OH-IR, SEM, TG-DTA, XRD and 1H MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-S-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests.
基金This study was supported by the National Natural Science Foundation of China(51702063 and 51672056)Natural Science Foundation of Heilongjiang(LC2018004)+1 种基金China Postdoctoral Science Foundation(2018M630340,2019T120254)the Fundamental Research Funds for the Central University.
文摘Lithium-sulfur batteries attract lots of attention due to their high specific capacity,low cost,and environmental friendliness.However,the low sulfur utilization and short cycle life extremely hinder their application.Herein,we design and fabricate a three-dimensional electrode by a simple filtration method to achieve a high-sulfur loading.Biomass porous carbon is employed as a current collector,which not only enhances the electronic transport but also effectively limits the volume expansion of the active material.Meanwhile,an optimized carboxymethyl cellulose binder is chosen.The chemical bonding restricts the shuttle effect,leading to improved electrochemical performance.Under the ultrahigh sulfur load of 28mg/cm2,the high capacity of 18mAh/cm2 is still maintained,and stable cycling performance is obtained.This study demonstrates a viable strategy to develop promising lithium-sulfur batteries with a three-dimensional electrode,which promotes sulfur loading and electrochemical performance.
基金The authors would like to thank the Methanol project Grant No.TMD/CERI/MDME/2017/001(G)for providing the necessary funding.
文摘Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions.CO2 being an inert gas becomes the most challenging to be utilized during the gasification process.The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900°C.The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs.The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied.Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction.
基金financed by the Project CRE:“Cretaceous Resin Event:Global bioevent of massive resin production at the initial diversification of modern forest ecosystems”funded by the Spanish AEI/FEDER,UE Grant CGL2017-84419Funded by the CGL2005-07445-C03-03 and CGL201123717 projects of the Ministry of Education of the Government of Spain。
文摘Many oases(wet interdunes)are sedimentary systems characterized by high-frequency water-level oscillations,marked changes in salinity and intense biological activity at their margins.They are considered to be one of the most challenging environments on Earth for ecosystem development.These dynamic,depositional settings are usually unfavourable for fossilization and subsequent preservation of vegetal remains.This paper describes bryophyte(liverwort)assemblages occurring in three successive horizons interpreted to represent(i)recurrent early successional phases of biological soil crust colonization of wet interdune margins or(ii)exceptional preservation of floating or riparian liverworts in oasis pond waters associated with a progressive fall of the interdune water level.The record of in situ colonization surfaces characterized by delicate(e.g.lignin-free)three-dimensional structures represents an exceptional type of preservation herein associated with a rapid variation in phreatic interdune water level and the subsequent establishment of anoxic and reducing conditions.The occurrence of exceptionally preserved liverwort colonies coincides with the sedimentary record of,at least,three seismite levels in the oasis.Data gathered from the site suggests that the water table of the oasis was controlled by a combination of(i)a positive creation of accommodation space due to subsidence associated with movement on syn-sedimentary extensional faults,and(ii)the rise and fall of the oasis water table controlled by the oscillations of the groundwater system due to orbital changes which appear to drive the variability of the climate system.Rising groundwater levels flooded the oasis soil crusts and lead to the exceptional recurrent preservation of liverwort colonies at the oasis margins.Alternatively,considering the hypothesis of floating or riparian liverworts in the oasis pond waters,the fall in the level of the oasis water table placed the floating liverworts in contact with the oasis bottom sediments.This fall in the level of the oasis water table could indicate a cessation of accommodation space by syn-sedimentary extensional faults and/or a regional lowering of the groundwater system level associated with drought periods.Preliminary results indicate that oasis lamination between liverwort colonies records decadal and sub-decadal cyclicity,related with 11-year Schwabe sunspot and sub-decadal NAO cyclicities,conferring for every sedimentary cycle between liverwort colonies a duration of approximately 200 years,that otherwise matches the expected recurrence period for the De Vries cycle of solar activity.
文摘Narrow spectral response,low charge separation efficiency and slow water oxidation kinetics of TiO_(2)limit its application in photoelectrochemical and photocatalytic water splitting.Herein,a promising organic/inorganic composite catalyst Ag/PANI/3DOMM‐TiO_(2–x)with a three‐dimensional ordered macro‐and meso‐porous(3DO MM)structure,oxygen vacancy and Ti^(3+)defects,heterojunction formation and noble metal Ag was designed based on the Z‐scheme mechanism and successfully prepared.The Ag/PANI/3DOMM‐TiO_(2–x)ternary catalyst exhibited enhanced hydrogen production activity in both photocatalytic and photoelectrochemical water splitting.The photocatalytic hydrogen production rate is 420.90μmol g^(–1)h^(–1),which are 19.80 times and 2.06 times higher than the commercial P25 and 3DOMM‐TiO_(2),respectively.In the photoelectrochemical tests,the Ag/PANI/3DOMM‐TiO_(2–x)photoelectrode shows enhanced separation and transfer of carriers with a high current density of 1.55 mA cm^(–2)at equilibrium potential of 1.23 V under simulated AM 1.5 G illumination,which is approximately 5 times greater than the 3DOMM‐TiO_(2).The present work has demonstrated the promising potential of organic/inorganic Z‐scheme photocatalyst in driving water splitting for hydrogen production.
文摘In this work, a radiological technique which simultaneously measures soil bulk density and water contents accurately and quickly in a non-destructive manner at different depths of the soil profile of the major soil series of Central Southwestern Nigeria is developed. Undisturbed samples from Iwo, Ondo, Egbeda, Itagunmodi, Okemessi, Mamu, Origo and Jago soil series of Southwestern Nigeria were collected on monthly intervals from June 2006 to May 2007. Using gamma-ray energy pairs of 122 and 1112 keV;and 344 and 1408 keV obtained from europium-152 (152Eu) radionuclide, the attenuation coefficients for soil and water, μs, μw and consequently ρs and θv at varying soil depths of these series were calculated. Comparative gravimetric measurements of these soil parameters were carried out. Using the XCOM computer algorithm with the soil elemental concentrations obtained using the Energy Dispersive X-Ray Fluorescence analysis (EDXRF) technique, theoretical estimates of μs for the various soil series were obtained and compared with the experimental values. The result of the developed dual energy gamma-ray transmission technique was compared with the gravimetric measurement method and Pearson correlation coefficient (0.987, p s and (0.996, p θv. The results of the measurements showed that θv minima with values 0.1931, 0.1987, 0.2377, 0.2111, 0.1738, 0.1701, 0.2334, 0.2341 and minima ρs values of 1.21 g/cm3, 1.20 g/cm3, 1.02 g/cm3, 1.38 g/cm3, 1.12 g/cm3, 1.14 g/cm3, 0.64 g/cm3, 1.33 g/cm3 were obtained respectively for the soil series stated above in January. The maxima θv with values 0.3621, 0.4212, 0.3962, 0.3794, 0.3049, 0.2811, 0.4415, 0.4416 and maxima ρs values of 1.52 g/cm3, 1.67 g/cm3, 1.74 g/cm3, 1.69 g/cm3, 1.70 g/cm3, 1.68 g/cm3, 1.08 g/cm3, 1.54 g/cm3 occurred for these soil series respectively in July except for Mamu soil series which occurred in May. These correlated very well with the occurrence of the Dry and Rainy seasons in the study area. The results of the EDXRF analysis showed that maxima Iron, Fe concentrations of 5.0890 ppm at the depth of 90 - 120 cm into the soil profile, was obtained for Iwo series, 4.4691 ppm at 50 - 70 cm for Ondo, 6.3438 ppm at 15 - 30 cm for Egbeda, 6.6845 ppm at 30 - 50 cm for Itagunmodi, 5.0252 ppm at 90 - 120 cm for Okemessi, 3.4996 ppm at 30 - 50 cm for Mamu, 5.1191 ppm at 50 - 70 cm for Jago and 4.7193 ppm at 90 - 120 cm for Origo. Maxima Potassium, K concentrations of 2.9613 ppm at the depth of 50 - 70 cm, was obtained for Iwo soil series, 2.3315 ppm at 0 - 15 cm for Egbeda, 2.2763 ppm at 70 - 90 cm for Okemessi and 3.3636 ppm at 50 - 70 cm for Mamu. Maxima Ti concentrations of 1.4822 ppm at 0 - 15 cm was obtained for Ondo soil series, 2.5159 ppm at 15 - 30 cm for Egbeda, 1.8690 ppm at 90 - 120 cm for Itagunmodi, 2.2975 ppm at 15-30 cm for Okemessi, 1.6453 ppm at 0 - 15 cm for Jago and 1.0513 ppm at 30 - 50 cm for Origo.
基金supported by the State Grid Corporation of China project titled “Study on Multisource and Multi-load Coordination and Optimization Technology Considering Desalination of Sea Water”(SGTJDK00DWJS1800011)
文摘With increasing global shortage of fresh water resources,many countries are prioritizing desalination as a means of utilizing abundantly available seawater resources.Integrated energy efficiency evaluation is a scientific method for the quantitative analysis of energy efficiency based on multiple indicators and is very useful for investment,construction,and scientific decision-making for desalination projects.In this paper,the energy efficiency evaluation of the micro energy network (MEN) of desalination for multi-source and multi-load is studied,and the basic idea of comprehensive energy efficiency evaluation is analyzed.The process includes the use of a MEN model to establish an integrated energy efficiency evaluation index system,taking into consideration energy,equipment,economic,environmental,and social factors.A combined evaluation method considering subjective and objective comprehensive weights for multi-source multi-load desalination MENs is proposed to evaluate the energy efficiency of desalination and from multiple perspectives.
文摘The epithermal neutron shape factor (α) was determined in the permanent cadmium lined irradiation channel installed in the large outer irradiation site of the Nigeria Research Reactor-1 (NIRR- 1) by the cadmium covered multimonitor method using the monitors Al-0.1% Au, Zr and Zn thin foils and Mo thin wire and was found to be -0.137 ± 0.018. The high negative value of α indicates a hardened epithermal neutron spectrum in the cadmium lined irradiation channel. The α value obtained was used in the single comparator method of ENAA (ko-ENAA) for the determination of the concentrations of elements in the standard reference material NIST 1515 Apple leaves using Al-0.1% Au thin foil as the single comparator. The concentrations of the elements Sm and Br were determined in the NIST 1515 Apple leaves because of their high Qo values and are in good agreement with the certified values.
文摘This paper assesses the evolution of generation technology-mix in Australia,with specific emphasis on understanding how such evolution has been shaped by wider political and socioeconomic influences.This assessment is predicated on the argument that the contemporary,quintessentially techno-economic,policy discourse on renewable energy is deficient,as it ignores climacteric political and socio-economic influences on generation technology-mix.The methodological framework employed in this paper is informed by the core tenets of technological change theory.The assessment suggests that generation technology-mix in Australia has historically been overwhelmingly influenced by the underlying technological paradigm of the electricity industry;and that this technological paradigm essentially draws its imprimatur from the wider political and socio-economic contexts.By implication,it suggests that a rapid uptake of renewables will have widespread ramifications,extending into political,socio-economic and cultural realms of a society.Clearly,existing policy discourse-that tends to focus on technical potentials,cost competitiveness,externalities and risks of various renewable technologies-is deficient.A much broader discourse is needed.This paper also made an attempt to develop a basis for such a discourse by reviewing broader aspects of the Australian society that would be affected by a rapid uptake of renewables.
文摘This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating system consists of an air source heat pump (ASHP) incorporated with a hot water tank as active Thermal Energy Storage (TES), where two optimization problems are integrated together to optimize both the ASHP electricity consumption and the building heating consumption utilizing a heat dynamic model of the building. The results show that the proposed EMPC can save the energy cost by load shifting compared with some reference cases.
文摘The Nigeria Research Reactor-1 (NIRR-1) is one of the Commercial Miniature Neutron Source Reactors (MNSRs) sited outside China and scheduled for conversion under the auspices of Reduced Enrichment for Research and Test Reactors (RERTR) program. Since 2006, the reduction in the fuel enrichment of MSNR facilities from greater than 90% HEU cores to less than 20% LEU cores has been embarked upon. Consequently in this work, the physics parameters of three dispersion LEU fuels, which include U3Si, U3Si2, and U9Mo enriched to 19.75% were determined by the MCNP code to investigate their suitability for the conversion of NIRR-1 to LEU. The following reactor core physics parameters were computed for the LEU fuel options: clean cold core excess reactivity (ρex), control rod (CR) worth, shut down margin (SDM), neutron flux distributions in the irradiation channels and kinetics data (i.e. effective delayed neutron fraction, βeff?and prompt neutron lifetime, lf). Results are compared with experimental and calculated data of the current HEU core and indicate that it would be feasible to use any of the LEU options for the conversion of commercial MNSR in general and NIRR-1 in particular from HEU to LEU.
文摘Prior to the installation of the Cd-liner in one of the large outer irradiation channels of NIRR-1, a Monte Carlo simulation was performed using MCNP5 version 1.4 code. This was done to investigate the effect of installation of Cd-liner in either an inner or outer irradiation channel on reactor physics parameters. Data obtained indicate that the core excess reactivity in both inner and outer irradiations channels is reduced by 3.60 ± 0.07 mk and 0.64 ± 0.06 mk, respectively. Considering the fact that NIRR-1 has a cold core excess reactivity of 3.77 mk, results obtained show that installation of the 1 mm thick Cd-sheet in one of the large outer irradiation channels would have no significant impact on the core physics data. After installation of a 1 mm Cd sheath in a large outer irradiation channel, the neutron flux distribution and the stability in the irradiation channels were monitored by foil activation method. Results indicate that the uniformity of neutron flux distribution in the irradiation channel is preserved and the neutron flux data were found to be comparable with the data obtained before the installation.