Asad Ullah Amin Shah, Junyung Kim, Ali Mansoor, H. Kang
{"title":"Concept design, application and optimization of operational parameters for new forced safety injection tank system","authors":"Asad Ullah Amin Shah, Junyung Kim, Ali Mansoor, H. Kang","doi":"10.12688/nuclscitechnolopenres.17546.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17546.1","url":null,"abstract":"Background The engineered safety systems are designed to execute fundamental safety functions encompassing reactivity confinement, reactivity control and decay heat removal. Failure of any one of these functions can result in severe accident conditions. Passive systems have been implemented as a better option for plant safety. This research proposes a modification of existing safety injection tanks to the new forced safety injection tanks (FSITs) that utilize the backpressure from the pressurizer or steam generator to drive coolant into the reactor core under high pressure conditions. Methods FSITs aim to extend the coping-time during accidents like Station Blackout, providing an extended timing window for deployment of FLEX systems. The mathematical design is proposed and implemented into the thermal-hydraulic input of a nuclear power plant to demonstrate the system’s applicability that was demonstrated by leveraging the conventional PRA approach and risk quantification. Results The suggested system useful when used in the accident scenario of Station black out in-coincident with turbine-driven pumps fail to run. As the proposed design is a conceptual design, the optimization of associated operational parameters and set points is necessary. This optimization is performed using the risk analysis and virtual control environment-based Dynamic Probabilistic Risk Assessment framework. The method and findings of this study affirm that the coping-time for Station Blackout can be significantly extended, ensuring a substantial margin for the effective deployment of the FLEX. Conclusions A concept design of a passive forced safety injection system was suggested and demonstrated by integrating the mathematical model into a thermal-hydraulic model of a nuclear power plant. The parameters were optimized and the results demonstrated that the new system was effective in recovering the nuclear power plant from the accidents such as SBO with turbine-driven pumps fail to operate.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"4 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667974","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":"Influence of neutron decay on nuclear reactor materials","authors":"J. C. Philipps, Jeff Terry","doi":"10.12688/nuclscitechnolopenres.17547.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17547.1","url":null,"abstract":"While many of the leading factors for material degradation in irradiated reactor components have been identified through past studies, spontaneous neutron decay within components is a factor absent in the literature. The byproducts of neutron decay, largely composed of a proton, could lead to excessive hydrogen content, irradiation assisted stress corrosion cracking, epsilon martensite formation, hydrides, ion induced damage, voids, bubbles, and dislocation loops. Neutrons are the most abundant relevant fission product, and neutrons are continuously decaying at a rate proportional to their production. This paper hypothesizes that at high neutron fluence, a quantifiable contribution to material degradation can be associated with the proton byproducts of neutron decay. Literature-based degradation mechanisms are presented along with initial calculations of the neutron decay contribution. The paper will demonstrate a potential new factor for consideration in the material degradation of nuclear reactor components.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":" 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141373200","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}
Fakhrul Islam, Nathaniel Cooper, Alexander W. Abboud, Tanvir Farouk, Jamil Khan, D. Guillen, Travis Knight
{"title":"CFD model for predicting spent nuclear fuel drying conditions","authors":"Fakhrul Islam, Nathaniel Cooper, Alexander W. Abboud, Tanvir Farouk, Jamil Khan, D. Guillen, Travis Knight","doi":"10.12688/nuclscitechnolopenres.17492.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17492.1","url":null,"abstract":"Background A significant quantity of aluminum-clad spent nuclear fuel (ASNF) is currently managed by the United States (U.S.) Department of Energy (DOE) at several sites in the U.S. Much of this fuel develops a corrosion layer with adsorbed water either through pre-corrosion, in-reactor, or in wet storage depending on the source. Gamma radiation from the fuel after removal from the reactor can cause evolution of hydrogen from this corrosion layer. For long-term safety it is desirable to remove the adsorbed water from the fuel surface to limit the production of hydrogen gases when the fuel is placed in road-ready sealed canisters for eventual final disposition. Methods This study presents a series of experiments showing the effectiveness of both forced helium drying and vacuum drying methods for the removal of water from surrogate fuel assemblies. A computational fluid dynamics (CFD) model is constructed to replicate the drying processes and simulate the experiments. Results The model suggests that increasing the inlet temperature is a more efficient way of improving the efficacy of a drying process. An increase in inlet temperature leads to a reduction in drying time 28–55% greater than the same relative increase in flow rate. One of the assemblies inside the canister consistently experiences the least amount of turbulent flow and require the longest time to dry. Therefore, the assembly with the highest decay heat should be placed in this slot in the basket in order to facilitate the drying of this assembly. Conclusions The validated CFD model can be used in the future as a design and analysis tool for a full-scale drying setup with actual fuel assemblies.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"50 s250","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141377393","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}
Kyle Warns, Junyung Kim, Xinyan Wang, Xingang Zhao, Birdy Phathanapirom, Michael W. Golay, Hyun Kang
{"title":"Decision-making based on Markov decision process in integrated artificial reasoning framework—Part 2: Applications","authors":"Kyle Warns, Junyung Kim, Xinyan Wang, Xingang Zhao, Birdy Phathanapirom, Michael W. Golay, Hyun Kang","doi":"10.12688/nuclscitechnolopenres.17490.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17490.1","url":null,"abstract":"To address the challenge of interpreting the decisions made by machine learning-based control algorithms, the Integrated Artificial Reasoning Framework (IARF) introduced in Part I of this work was developed. Further implementing this framework within a Markov Decision Process (MDP) yielded a decision-making system which produces optimal decisions whose logic can be easily traced and understood. The IARF with MDP formulated in Part I of this study was applied to two case studies of relevance to the nuclear power community: 1) operational decision-making while experiencing the degradation of key components, and 2) optimal control of a nuclear power and hydrogen co-generation facility. This work details the steps of implementing and analyzing these two studies, beginning with the creation of simulation models using the Modelica programming language, covering the formulation of the MDP using the IARF, and concluding with the execution and analysis of the scenarios. Technical challenges related to implementation, such as maintaining physically understandable traceability and efficiently producing large amount of data for calculating state transition probabilities, are addressed and their resolutions are suggested. Emphasis is placed on the benefits of relying on a replaceable modeling framework for simulating system behavior. Results indicate that optimal operational trajectories were successfully found by the MDP, and through utilization of the IARF, these results are easily interpretable and understandable to any user.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"10 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141378465","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 general-purpose code for correlated sampling using batch statistics with MCNP6 for fixed-source problems","authors":"J. Favorite","doi":"10.12688/nuclscitechnolopenres.17496.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17496.1","url":null,"abstract":"Background Correlated sampling can be applied with batch statistics using MCNP6’s tally fluctuation chart (TFC) to reduce the uncertainty of a difference of tallies between a base case and a perturbed case without modifying the source code. The cases are correlated if they are run with the same random number sequence. Equations implemented Equations used to apply correlated sampling to the difference of two tallies are summarized from previous work. Equations used to apply correlated sampling to a ratio of two tallies, to the difference of two tallies divided by a third tally, and to other combinations of ratios are presented. New computer code A general-purpose, command-line-driven computer program, COSUBS (Correlated Sampling Using Batch Statistics), is presented that reads MCNP6 TFCs from output files and applies these equations. The user specifies the input relative perturbation, if desired, and any normalization tally, if desired. Example problems show how to run COSUBS and interpret the output.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"77 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140376100","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":"The Bimodal Epithermal Astronuclear Reactor (BEAR): A LONG-LIVED, Universal Space Nuclear Powerplant","authors":"Teyen Widdicombe, J. Herring, Brad Kirkwood","doi":"10.12688/nuclscitechnolopenres.17481.1","DOIUrl":"https://doi.org/10.12688/nuclscitechnolopenres.17481.1","url":null,"abstract":"A neutronic model of a Nuclear Thermal Propulsion reactor based on the NERVA Peewee design using High Assay Low Enriched Uranium (HALEU) fuel in a Zirconium Carbide matrix has been thoroughly characterised and continuously modified over the last few years at the CSNR. The initial design (Emu, for the flightless bird) created in the summer of 2020 and presented at the NETS 2021 conference, has undergone significant adjustments in this time. Two major investigations have been undertaken and evolved over time; one into the requisites for the provision of electrical power to the propelled spacecraft via the circulation of a noble gas mixture in a closed Brayton cycle, and another into the use of planetary regolith as a reflector, reducing neutron leakage at what would otherwise be the reactor’s end of life in vacuo, rekindling it for an extended period of time as well as providing a very easy ultimate disposal solution, replacing the control drums with rods. It was determined that there are no insurmountable obstacles to performance in either mode.","PeriodicalId":516082,"journal":{"name":"Nuclear Science and Technology Open Research","volume":"29 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139684122","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}