Nuclear Science and Technology Open Research最新文献

{"title":"Optimal sizing toolbox for energy generation and storage for a nuclear hybrid microgrid","authors":"Nathan Chandra, Molly Ross, Hitesh Bindra","doi":"10.12688/nuclscitechnolopenres.17453.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17453.1","url":null,"abstract":"<ns3:p>Background In recent years, renewable energy sources, such as wind, have contributed to a decrease in grid stability. This has created the need for flexible and reliable back-up energy generation. Currently this role is fulfilled by natural gas-fired power plants that are able to quickly adjust power output based on present needs. Nuclear power presents an option for a clean and reliable alternative to these natural gas-fired power plants. However, nuclear power alone is unable to provide flexible enough power generation to fill this role. Instead, nuclear power plants must be combined with strategically sized energy storage systems to effectively complement the renewable power generation. Grids such as these are generally simulated using deterministic models which are unable to account for quickly fluctuating wind power generation. This in turn creates unsafe ramp rates for the nuclear power plant. Methods The approach taken in this paper utilizes a continuous-time stochastic model to simulate a grid with wind generation, nuclear power, and an energy storage system as the only energy sources. This paper focuses on this model and a development of a GUI to form a grid sizing toolbox. This toolbox was then demonstrated with an isolated microgrid using year-long wind and load data. Wind penetration, nuclear ramp rate limitations, and storage types were all varied to observe different scenarios and determine optimal storage sizing. Results There were several outcomes from this study that can inform grid planning. Nuclear power plant size trends downwards with greater wind power generation. However, high variability of wind power limits the size reduction. Nuclear capacity factor is between 41% to 57%, dropping further as wind penetration was increased. This highlights the difficulty of maintaining high utilization in these scenarios. Conclusions All storage types had similar performance in all categories except size, in which pumped hydroelectric and compressed air storage required smaller storage sizes.</ns3:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"53 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136347621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shutdown dose rate calculations in high-temperature gas-cooled reactors using the MCNP-ORIGEN activation automation tool","authors":"Roberto Fairhurst-Agosta, Tomasz Kozlowski","doi":"10.12688/nuclscitechnolopenres.17447.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17447.1","url":null,"abstract":"<ns3:p>Background High-temperature gas-cooled reactors (HTGRs) have many distinct features from the current light water reactor (LWR) fleet, and potential decommissioning strategies should take them into consideration. The proper characterization of the shutdown dose rates can establish a suitable strategy. Methods This article introduces a new shutdown dose rate calculation capability that relies on the MCNP-ORIGEN activation automation tool and the MCNP repeated structures to explicitly model the TRistructural ISOtropic (TRISO) particles as decay radiation sources. Results Three exercises are conducted with this capability, and their results discussed. The first two exercises verify and demonstrate the workflow. The third exercise proposes a decommissioning strategy for a high-temperature gas-cooled microreactor and studies its feasibility from the shutdown dose rate standpoint. The calculations yield a dose rate map above at the reactor citadel after a three month cool-down, showing values above 40 mSv/h. Conclusions The findings imply that the decommissioning strategy based on placing the reactor in a safe shutdown state and allowing it to cool down for three months before removing various components and extracting the fuel assemblies, may not be sufficient to minimize unnecessary exposure of personnel.</ns3:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"54 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136347769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A more open future for nuclear science and technology","authors":"Robert C. Little, Guillaume Wright, Elia Merzari, Kay Burrows, James Cleaver, Kaleigh Sunday, David Strutz, John Fabian","doi":"10.12688/nuclscitechnolopenres.17478.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17478.1","url":null,"abstract":"<ns3:p>Nuclear science and technology underpins many of the world’s most important sectors, from electricity generation to applications in areas as diverse as medicine, food and agriculture, space applications, and a multitude of developing industrial uses such as for hydrogen generation, desalination, and heat generation. As society shifts focus to major challenges around future energy supply and more sustainable use of the planet’s resources, so nuclear science and its applications are changing also to continue to support improvement in people’s lives. Open science practices can accelerate the contributions of the underlying research behind this progress, via open access, open data, and reproducibility through transparency. <ns3:italic>Nuclear Science and Technology Open Research</ns3:italic> is a new open access publication venue of the American Nuclear Society, based on open science principles, and is here to help shape this brighter future.</ns3:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"2 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135391324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanocomposite physics and structure considerations in MCNP proton shielding models","authors":"Justina Freilich, Camille Palmer","doi":"10.12688/nuclscitechnolopenres.17456.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17456.1","url":null,"abstract":"<ns3:p>Background Deep space crewed missions require unique radiation shielding considerations. Due to mission duration and the heavy, high-energy nature of deep space radiation, the aluminum alloys that have historically been used for spacecrafts do not provide sufficient protection for crew members. Polymer-based nanocomposites have been proposed as potential radiation shielding materials for deep space applications; however, the high tunability of nanocomposites and the limited number of facilities able to produce representative radiation energies presents barriers to nanocomposite testing. Computational approaches may allow for preliminary investigation and discrimination of nanocomposite parameters like polymer and filler composition, loading percentage, and filler size and structure. Methods This work aims to investigate several modeling methods to perform radiation transport simulations for a nanocomposite, particularly with regards to modeling the filler nanostructure and the involved physics. Published experiments of a polydimethylsiloxane-carbon nanotube nanocomposite in 63 MeV and 105 MeV proton beams were digitally recreated in MCNP6.2 with three different nanocomposite structures. Additionally, several simulations were performed under various physics assumptions. The computationally determined water equivalent thicknesses are compared between modeling methods, as well as between the computational and the published experimental work. Results Nanostructure model complexity had no impact on the computed water equivalent thickness, with <1% difference between the three modeling methods. The inclusion of delta ray production and tracking physics produced a slight decrease in the computed water equivalent thickness and significantly increased the computational time for a single simulation by a factor of 35.7. Computationally determined water equivalent thicknesses are within 5% of published experimentally determined values. Conclusions Shielding capabilities of a polymer/carbon nanotube nanocomposite estimated using Monte Carlo radiation transport models agree well with published experimental results, even with a simplistic representation of the nanocomposite material. Radiation transport settings influenced the resulting water equivalent thickness as well as computational resource needs.</ns3:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of thermo-throttle for iodine flow rate control in multidirectional plasma thruster","authors":"Pavel Savelev, Aslan Pashaev, Andrei Shumeiko","doi":"10.12688/nuclscitechnolopenres.17411.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17411.1","url":null,"abstract":"<ns4:p><ns4:bold>Background: </ns4:bold>Recently, a new direction in the field of electric propulsion has emerged – the multidirectional plasma thrusters. These thrusters are capable of producing propulsive forces in multiple directions. The thrusters are proposed to be used for orbit maintenance and alterations, formation flights, and interplanetary flights of space artificial objects ranging in size from CubeSats to fusion-powered interplanetary spacecraft. In this paper, the results of numerical simulation of the iodine propellant supply system for the multidirectional plasma thruster are presented.</ns4:p><ns4:p> <ns4:bold>Methods:</ns4:bold> The geometry and temperature parameters of propellant supply system various elements are varied to determine the stable modes of iodine propellant ejection into the gas discharge chamber of the thruster. The temperatures of the thermo throttle and filter are found to ensure iodine mass flow rate in the range of 0.1 to 1.5 mg/s. The thermo throttle and filter temperatures are altered in the range of 65 to 200 °C and 65 to 100 °C, correspondingly.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold>The mass flow rate is critically dependent on the filter temperature and iodine saturated vapor pressure, as well as the filter and throttle geometries. The required values of iodine flow rate have been achieved by using the throttle with a diameter of 0.5 mm and a length of 60 mm and a filter with 56 holes, each hole diameter is 0.2 mm, and temperature from 90 C to 200 C.</ns4:p><ns4:p> <ns4:bold>Conclusions: </ns4:bold>According to the data obtained, the iodine storage and supply system is preferably equipped with a thermos throttle, which provides precise control of the flow rate, as well as reduces sharp jumps of the flow rate when the temperature of the filter changes. Preferred filter geometry: 56 holes, each hole 0.2 mm in diameter.</ns4:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136293228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neutronic analysis of the BYU molten salt micro reactor","authors":"Collin Bradford, Edward Mercado, Braden Clayton, LaGrande Gunnell, Andrew Larsen, Matthew Memmott","doi":"10.12688/nuclscitechnolopenres.17435.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17435.1","url":null,"abstract":"<ns3:p><ns3:bold>Background:</ns3:bold> With the rising need for reliable and clean energy, researchers at Brigham Young University created a molten salt microreactor (MSMR) concept to help meet the world’s growing energy demands. The MSMR is rated at 45 MWth and is uniquely capable of passively dissipating all decay heat using conduction only. <ns3:bold>Methods:</ns3:bold> This work presents the results of the simulated neutronic behavior of the MSMR using the Monte Carlo neutronics code OpenMC with the ENDF/B-VII.1 cross-section library at steady state conditions. The specific characteristics discussed in this work are: keff, power profile, axial and radial peak power factors, Doppler coefficient of reactivity, and the moderator temperature feedback coefficient. <ns3:bold>Results:</ns3:bold> At steady state operating conditions, keff was calculated to be 1.07091 <ns3:italic>±</ns3:italic> 0.00087 indicating that this configuration can achieve criticality. The axial peaking power factor was found to be 1.003 and the radial peaking power factor was found to be 1.45. Feedbacks were calculated by offsetting the temperature of the fuel and the moderator respectively. Doppler coefficient of reactivity to be -12.585 pcm/K and the moderator temperature coefficient of reactivity to be -0.34332 pcm/K. <ns3:bold>Conclusions:</ns3:bold> It is worth noting that the largest contributor of the negative reactivity comes from the fuel salt and not the moderator, further demonstrating the safety of the reactor. Future work will include a full neutronic optimization of the core, fuel burn up analysis, and exploration of a suitable burnable neutron poison.</ns3:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136353412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shielding factors for a fission-powered mars exploration rover","authors":"Alexander C. Bendoyro, L. Dale Thomas, Jason Cassibry, William Emrich","doi":"10.12688/nuclscitechnolopenres.17438.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17438.1","url":null,"abstract":"<ns4:p><ns4:bold>Background: </ns4:bold>With the advances in compact fission power systems and Stirling converters, the efficiency and portability of electrical energy production systems has increased substantially thanks to NASA’s Kilopower project. These 1-10 kW<ns4:sub>e</ns4:sub>-class reactors are compact enough to be transportable by pressurized rovers, allowing an extended human reach across the surface of Mars to produce scientific data at a rate that greatly surpasses the rate of robotic rover data collection. If rovers were to harness fission power while mobile, it is possible for near-limitless range. This capability could allow one crew on Mars for under a “Conjunction” class mission as outlined in NASA’s Mars Design Reference Architecture (DRA) 5.0 to visit many geological sites of interest instead of requiring additional landings to explore distant features of the Martian surface. This study explored the parameters that affected the mass of the shielding required to protect the crew against a fission reactor embedded in the chassis of a pressurized rover.</ns4:p><ns4:p> <ns4:bold>Methods: </ns4:bold> An analytical approach was devised to estimate the required mass of a hypothetical solid tungsten shield under various conditions.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold>Power levels below 3.4 kW<ns4:sub>e</ns4:sub> were found to be impractical for rover applications. Between 3.4 kW<ns4:sub>e</ns4:sub> and 10 kW<ns4:sub>e</ns4:sub> would be able to recharge the rover without returning to base camp. The increase in shielding mass from a 3.4 kW<ns4:sub>e</ns4:sub> reactor and a 10 kW<ns4:sub>e</ns4:sub> reactor was 6%. The reduction between a 10 kW<ns4:sub>e</ns4:sub> reactor at 3 m and 6 m was 7%. Varying the shield thickness in accordance with astronaut activities resulted in a 19% reduction. Powering the reactor off before exiting the vehicle resulted in an additional 65% reduction.</ns4:p><ns4:p> <ns4:bold>Conclusions: </ns4:bold>Knowledge of the crew activities and locations had the greatest impact on the required shielding mass and the mission activities should be well-understood before finalizing a shield design.</ns4:p>","PeriodicalId":475854,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136293424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}